JP2003319457A - Mobile communication system and method for adaptively modulating - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a mobile communication system for adaptively changing a modulation method in response to the condition of a propagation passage without adding information for informing the modulation method to data transmitted from a base station and a mobile station, and to provide a method for adaptively modulating. <P>SOLUTION: A retransmission request managing unit 72c decides whether a demodulating method of received data of next frame is changed or not based on whether the data transmitted from the base station is correctly received or not, and informs the decision to an adaptive demodulating unit 71c. In the case of the change, the unit 71c decides the demodulating method from a plurality of the demodulating methods. A retransmission response managing unit 74d decides whether the modulation method of the data to be transmitted by next frame is changed or not, based on whether the content of the retransmission request information 22d included in the data transmitted from the mobile station is succeeded to receive or failed to receive, and informs the decision to an adaptive modulation unit 73d. In the case of the change, the unit 73d decides a demodulation method from a plurality of modulation methods. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adaptive modulation method when a base station and a plurality of mobile stations communicate with each other, and in particular, an adaptive modulation method used in the base station and the plurality of mobile stations. TECHNICAL FIELD The present invention relates to an adaptive modulation method for changing to the above and a mobile communication system capable of realizing the adaptive modulation.

[0002]

2. Description of the Related Art In mobile communication systems, modulation methods such as a phase modulation method (PSK: Phase Shift Keying) that changes the phase of a carrier and a quadrature amplitude modulation method (QAM: Quadrature Amplitude Modulation) that changes the amplitude and phase of a carrier are used. I am using. In both modulation systems, modulation processing is performed according to the amount of data that can be transmitted in one symbol. There are BPSK, QPSK, 8-phase PSK, etc. in the phase modulation system, and 16QAM, 64Q in the quadrature amplitude modulation system.
AM ... etc. With these modulation methods, basically,
BPSK, QPSK, 8-phase PSK, 16QAM, 64Q
The transmission speed increases in the order of AM ... Therefore, 64Q
Data can be transmitted in a shorter time by performing communication by AM.

However, when the amount of data that can be transmitted by one symbol increases, the positions of the phase and amplitude of different symbols become closer, and they are easily affected by multipath such as reflection, transmission, and diffraction, and a reception error occurs. Therefore, the number of retransmission requests increases, and as a result, the throughput decreases. In addition, the multipath occurs due to obstacles such as buildings and trees, terrain, and weather, so that the communication state between the base station and the mobile station constantly changes.

In such a communication environment, QPSK,
From 8PSK, 16QAM, 64QAM, for example,
If QPSK is used fixedly, the influence of interference due to multipath can be avoided, but the transmission speed becomes slower. For example, if 64QAM is fixedly used, the transmission speed becomes faster while communication is performed in a place where the state of the propagation path is poor. Will not be possible.

In order to improve such a problem, the base station or the mobile station employs an adaptive modulation method for adaptively selecting a modulation method based on the state of the propagation path estimated from the received signal.

As a conventional technique using the adaptive modulation method, there is JP-A-8-2474756. JP-A-8-24
Japanese Patent No. 74756 discloses an adaptive modulation method in which a mobile station estimates a state of a propagation path based on a signal transmitted from a base station and determines a transmission rate from the estimated result.

FIG. 21 is a block diagram showing the configuration of a mobile station in a conventional mobile communication system. There are several types of methods for switching the modulation method, but here, the mobile station loops back and transmits the channel quality information generated based on the received pilot signal from the base station to the base station. The optimum modulation method is selected by receiving the information.

The mobile station of FIG. 21 has a transmission processing unit 1a, a modulation unit 2a, a channel coding unit 3a, a reception processing unit 4a, a demodulation unit 5a, and a channel decoding unit 6
a, a control unit 7a, and a line quality estimation unit 8a. Further, in FIG. 21, 10a is transmission data, 11
a is encoded transmission data, 12a is modulated transmission data, 13
a is a transmitted signal, 14a is a received signal, 15a is received data, 16a is demodulated received data, 17a is decoded received data, 18a is a pilot signal, 19a is line quality information,
20a is a demodulation method.

FIG. 22 is a block diagram showing the configuration of a base station in a conventional mobile communication system. This base station includes a transmission processing unit 1b, a modulation unit 2b, a channel coding unit 3b, a reception processing unit 4b, a demodulation unit 5b, a channel decoding unit 6b, and a control unit 7b. Further, in FIG. 22, 10b is transmission data, 11
b is encoded transmission data, 12b is modulation transmission data, 13
Reference numeral b is a transmission signal, 14b is a reception signal, 15b is reception data, 16b is demodulation reception data, 17b is decoding reception data, 19b is line quality information, and 23b is a modulation method.

The reception processing unit 4a of the mobile station receives the received signal 14
Reception processing such as processing of a high frequency signal is performed from a and the reception data 15a is output to the demodulation unit 5a. The demodulation unit 5a performs a demodulation process on the reception data 15a in accordance with the demodulation method 20a designated by the control unit 7a, the pilot signal 18a to the channel quality estimation unit 8a, and the demodulation reception data 16a to the channel decoding unit. 6a respectively. Channel quality estimating section 8a estimates channel quality from pilot signal 18a output from demodulating section 5a, and outputs channel quality information 19a which is the estimation result to modulating section 2a. The channel decoding unit 6a uses the predetermined error correction decoding method to demodulate the reception data 16
Decoding processing is performed on a and the decoded reception data 17a is output to the control unit 7a. The control unit 7a determines the demodulation method 20a of the next received signal notified from the base station based on the channel quality of the downlink pilot signal described later, and the demodulation method 2
0a is output to the demodulation unit 5a.

For the transmission from the mobile station to the base station, the channel coding unit 3a performs an encoding process on the transmission data 10a based on a predetermined error correction encoding system, and the modulation unit 2a transmits the encoded transmission data. 11a is output. The modulation unit 2a performs modulation processing on the channel quality information 19a output from the channel quality estimation unit 8a and the coded transmission data 11a output from the channel coding unit 3a by a predetermined modulation method to obtain the modulated transmission data. 12a is output to the transmission processing unit 1a. The transmission processing unit 1a performs a transmission process on the modulated transmission data 12a and transmits the transmission signal 13a to the base station.

The reception processing unit 4b of the base station transmits the transmission signal 13a (the reception signal 1 viewed from the base station side) transmitted from the mobile station.
4b) is received, and the received data 15b is output to the demodulator 5b. The demodulator 5b receives the received data 15b
To the line quality information 19b from the demodulated data.
Is output to the control unit 7b, and demodulated received data 16b, which is the data after the line quality information 19b is extracted from the demodulated data, is output to the channel decoding unit 6b. Channel decoding unit 6b
Is, according to a predetermined error correction decoding method,
The demodulated reception data 16b is demodulated and the decoded reception data 17b is output.

On the other hand, the control unit 7b has the channel quality information 19b (the channel quality estimation unit 8 of the mobile station) output from the demodulation unit 5b.
Based on the channel quality information 19a) estimated in a, the modulation method for the next transmission to the mobile station is determined, and the modulation method 23
b is output to the modulator 2b.

In the transmission from the base station to the mobile station, the channel coding unit 3b performs an encoding process on the transmission data 10b based on a predetermined error correction encoding method, and then performs an encoding transmission to the modulation unit 2b. The data 11b is output.
The modulation unit 2b uses the modulation method 23 output from the control unit 7b.
b (demodulation method 20a determined by the control unit 7a of the mobile station)
Modulation processing is performed on the encoded transmission data 11b based on the above, and the modulation transmission data 12b is output to the transmission processing unit 1b. The transmission processing unit 1b performs a transmission process on the modulated transmission data 12b and transmits a transmission signal 13b to the mobile station.
The data transmitted from the base station to the mobile station includes data for the channel quality estimation unit 8a of the mobile station to estimate the channel quality.

As described above, in the conventional system, the base station notifies the mobile station of the modulation method of the transmission signal to be transmitted prior to the transmission data, so that the modulation method at the time of transmission adaptively changes. The correct demodulated signal is obtained. That is, when the channel quality is good, the modulation scheme with a large modulation level is notified, thereby improving the data transmission efficiency, and when the channel quality is poor, a modulation scheme with a small modulation level is notified. As a result, the error resistance in data transmission is improved.

[0016]

However, in the above-mentioned conventional technique, it is necessary to inform the communication partner station of the modulation method used at the time of transmission before the transmission data, which causes a problem that the transmission efficiency is lowered. .

Further, based on the line quality information generated by the communication partner station, the modulation method used at the time of transmission is adaptively changed, and a signal for notifying the modulation method is transmitted to the communication partner station prior to the transmission data. Because I have to
A time difference occurs between the time when the channel quality information is estimated and the time when the modulation method is adaptively changed. Therefore, there is a problem that it is necessary to estimate the line quality in consideration of the delay time.

The present invention has been made in view of the above,
An object is to obtain a mobile communication system and an adaptive modulation method that adaptively change the modulation method according to the state of the propagation path without adding information for notifying the modulation method to the data transmitted by the base station and the mobile station. I am trying.

[0019]

In order to achieve the above object, a mobile communication system according to the present invention can modulate transmission data and transmit the modulated data to a partner station, and adaptively change the modulation system. In a mobile communication system including a possible base station and mobile station, the mobile station determines whether or not the data transmitted from the base station is correctly received, and receives the next frame based on the determination result. A retransmission request management unit that determines whether or not to change the data demodulation method, and an adaptive demodulation unit that determines a demodulation method from a plurality of predetermined demodulation methods based on the determination of the retransmission request management unit The base station determines whether the content of the retransmission request information included in the data transmitted from the mobile station indicates successful reception or unsuccessful reception, and transmits in the next frame based on the determination result. A retransmission response management unit that determines whether or not to change the data modulation scheme, and an adaptive modulation unit that determines a modulation scheme from among a plurality of modulation schemes that are predetermined based on the determination of the retransmission response management unit are provided. It is characterized by

A mobile communication system according to the next invention is
In the above invention, the retransmission request management unit, when the data transmitted from the base station is correctly received a predetermined number of times in succession, performs control for switching the demodulation system in the next frame to a higher demodulation system. When the reception success signal transmitted from the mobile station is continuously received for a predetermined number of times, the retransmission response management unit performs control for switching the modulation method in the next frame to a higher modulation method. It is characterized by

A mobile communication system according to the next invention is
In the above invention, the retransmission request management unit performs control for correctly receiving data transmitted from the base station a predetermined number of times in succession and switching a demodulation method in a next frame to a higher demodulation method. After that, when the data transmitted from the base station is continuously and erroneously received a predetermined number of times, control is performed to switch the demodulation method in the next frame to a lower demodulation method.

A mobile communication system according to the next invention is
In the above invention, the retransmission request management unit is for switching the demodulation method in the next frame to a lower demodulation method when the data transmitted from the base station is erroneously received continuously for a predetermined number of times. The retransmission response management unit controls to switch the modulation method in the next frame to a lower modulation method when the reception failure signal transmitted from the mobile station is continuously received for a predetermined number of times. It is characterized by performing.

A mobile communication system according to the next invention is
In the above invention, before performing control for switching to the lower demodulation method, the retransmission response management unit determines that the reception failure signal transmitted from the mobile station is continuously received for a predetermined number of times, After performing control for switching the modulation method to a lower modulation method, the retransmission request management unit, if the data transmitted from the base station is continuously and erroneously received a predetermined number of times, the retransmission request management unit Is characterized by performing control for switching the demodulation method in the next frame to a lower demodulation method.

A mobile communication system according to the next invention is
In the above invention, the retransmission request management unit, when receiving the data transmitted from the base station over a predetermined number of times, when the number of correctly received times exceeds a predetermined number of times,
Performing control for switching the demodulation method in the next frame to a higher demodulation method, the retransmission response management unit receives the retransmission request signal transmitted from the mobile station for a predetermined number of times, When the number of receptions exceeds a predetermined number, control is performed to switch the modulation system in the next frame to a higher modulation system.

A mobile communication system according to the next invention is
In the above invention, the retransmission request management unit receives the data transmitted from the base station over a predetermined number of times, the number of correctly received times exceeds a predetermined number, and the demodulation method for the next frame is demodulated to a higher demodulation method. Performing control for switching to the system, and then when the data transmitted from the base station is continuously and erroneously received over a predetermined number of times,
It is characterized in that control is performed to switch the demodulation method in the next frame to a lower demodulation method.

A mobile communication system according to the next invention is
In the above invention, the retransmission request management unit, while receiving the data transmitted from the base station over a predetermined number of times, when the number of erroneous reception exceeds a predetermined number of times,
Control is performed to switch the demodulation method in the next frame to a lower demodulation method, and the retransmission response management unit receives a reception failure signal while receiving the retransmission request signal transmitted from the mobile station for a predetermined number of times. When the number of receptions exceeds a predetermined number, control is performed to switch the modulation system in the next frame to a lower modulation system.

A mobile communication system according to the next invention is
In the above invention, before performing control for switching to the lower demodulation method, the retransmission response management unit receives a retransmission failure signal transmitted from the mobile station for a predetermined number of times, and receives a reception failure signal. It is determined that the number of times of reception has exceeded a predetermined number of times, control is performed to switch the modulation method in the next frame to a lower modulation method, and then the retransmission request management unit changes the data transmitted from the base station. When the retransmission request management unit receives the error continuously for a predetermined number of times, the retransmission request management unit performs control for switching the demodulation method in the next frame to a lower demodulation method.

An adaptive modulation method according to the next invention is an adaptive modulation method in which transmission data is modulated and transmitted to a partner station, and the mobile station is a base station. A first step of determining whether or not the data transmitted from the mobile station is correctly received, and whether the mobile station changes the demodulation method of the received data of the next frame based on the determination result of the first step. A second step of determining whether the demodulation method is selected, a third step in which the mobile station determines a demodulation method from a plurality of predetermined demodulation methods based on the determination result of the second step, and a base station The fourth step of determining whether the content of the retransmission request information included in the data transmitted from the mobile station indicates successful reception or unsuccessful reception, and the base station based on the determination result of the fourth step. A fifth step of determining whether to change the modulation method of the transmission data in the next frame had,
The base station includes a sixth step of deciding a modulation method from a plurality of predetermined modulation methods based on the decision result of the fifth step.

In the adaptive modulation method according to the next invention, in the above invention, in the second step, it is determined that the mobile station has correctly received the data transmitted from the base station continuously for a predetermined number of times. In this case, it is decided to switch the demodulation method in the next frame to a higher-order demodulation method, and in the fifth step, the base station continuously includes the data transmitted from the mobile station for a predetermined number of times. When it is determined that the content of the retransmission request information to be received is successful, it is determined to switch the modulation method in the next frame to the higher modulation method.

In the adaptive modulation method according to the next invention, in the above invention, in the second step, it is determined that the mobile station has correctly received the data transmitted from the base station continuously for a predetermined number of times. Then, decide to switch the demodulation method in the next frame to a higher demodulation method,
After that, when it is determined that the data transmitted from the base station is erroneously received continuously for a predetermined number of times, the demodulation method in the next frame is determined to be switched to a lower demodulation method. .

In the adaptive modulation method according to the next invention, in the above invention, in the second step, the mobile station erroneously receives data transmitted from the base station continuously for a predetermined number of times. When the determination is made, it is decided to switch the demodulation method in the next frame to a lower demodulation method, and in the fifth step, the base station continuously transmits data transmitted from the mobile station for a predetermined number of times. When it is determined that the content of the retransmission request information included in the above is a reception failure, it is determined to switch the modulation scheme in the next frame to a lower modulation scheme.

In the adaptive modulation method according to the next invention, in the above invention, in the second step, before the mobile station determines to switch to a lower demodulation method,
The base station determines that the content of the retransmission request information included in the data transmitted from the mobile station is reception failure continuously for a predetermined number of times, and switches the modulation method in the next frame to a lower modulation method. When the mobile station makes a decision and then determines that the data transmitted from the base station is erroneously received continuously for a predetermined number of times, the demodulation method in the next frame is switched to a lower demodulation method. It is characterized by deciding that.

In the adaptive modulation method according to the next invention, in the above invention, in the second step, the mobile station transmits data from the base station while judging the data transmitted from the base station over a predetermined number of times. If the number of times that it is determined that the received data has been correctly received exceeds a predetermined number, it is determined to switch the demodulation method in the next frame to a higher demodulation method, and in the fifth step, the base station However, in the determination of the retransmission request information over a predetermined number of times, when the determination of successful reception exceeds a predetermined number of times, it is determined to switch the modulation system in the next frame to a higher modulation system. To do.

In the adaptive modulation method according to the next invention, in the above-mentioned invention, in the second step, the mobile station transmits data from the base station while judging data transmitted from the base station over a predetermined number of times. The number of times that it was determined that the received data has been correctly received exceeds the predetermined number of times, it is decided to switch the demodulation method in the next frame to the higher-order demodulation method, and then the base station continuously transmits for the predetermined number of times. When it is determined that the received data has been erroneously received, it is determined that the demodulation method in the next frame is switched to a lower demodulation method.

In the adaptive modulation method according to the next invention, in the above invention, in the second step, the mobile station transmits data from the base station while determining the data transmitted from the base station over a predetermined number of times. If the number of times that it is determined that the received data has been erroneously received exceeds a predetermined number, it is determined to switch the demodulation method in the next frame to a lower demodulation method, and in the fifth step, the base station When the station judges the retransmission request information for a predetermined number of times and the reception failure judgment exceeds a predetermined number of times, it decides to switch the modulation method in the next frame to a lower modulation method. And

In the adaptive modulation method according to the next invention, in the above invention, in the second step, before the mobile station determines to switch to a lower demodulation method,
The base station, while determining the retransmission request information over a predetermined number of times, determines that the reception failure determination has exceeded a predetermined number of times, determines to switch the modulation scheme in the next frame to a lower modulation scheme, After that, when the mobile station determines that the data transmitted from the base station has been erroneously received continuously for a predetermined number of times, it determines to switch the demodulation method in the next frame to a lower demodulation method. It is characterized by

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a mobile communication system and an adaptive modulation method according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a conceptual diagram showing the configuration of a mobile communication system according to the present invention. This mobile communication system is composed of a base station 40 having an arbitrary service area and a plurality of mobile stations 30 (in this case, three) that perform wireless communication with the base station 40 within the service area.

Embodiment 1. The first embodiment of the present invention will be described with reference to FIGS. In the first embodiment,
When the mobile station 30 continuously and correctly receives the transmission data from the base station 40 for a predetermined number of N times, the mobile station 30 starts the demodulation method from the next frame to the demodulation method 1 higher.
Change to 0c. The base station 40 sends the retransmission request information 22 for notifying that the mobile station 30 has correctly received the data.
When d is received N times in succession, the level of the modulation method is changed to the next higher modulation method 23d from the next frame.

FIG. 2 is a block diagram showing the structure of the transmission / reception function of the mobile station 30. The mobile station 30 includes a channel coding unit 3c, a modulation unit 2c, a transmission processing unit 1c, a reception processing unit 4c, a demodulation unit 5c, a channel decoding unit 6c, and a control unit 7c. 2, 10c is transmission data, 11c is encoded transmission data, 12c is modulated transmission data, 13c is a transmission signal, and 14 is a transmission signal.
c is a received signal, 15c is received data, 16c is demodulated received data, 17c is decoded received data, 20c is a demodulation method,
Reference numeral 21c is demodulation method selection information, and 22c is retransmission request information.

The channel coding unit 3c is, for example,
Transmission data 10 to the base station 40 based on a predetermined error correction coding method such as a turbo code or a trellis code.
Encode c.

The modulation section 2c modulates the coded transmission data 11c coded by the channel coding section 3c and the retransmission request information 22c created by the retransmission request management section 72c based on a predetermined modulation method.

The transmission processing unit 1c transmits the modulated transmission data 12c modulated by the modulation unit 2c to the base station 40.

The reception processing unit 4c receives the transmission signal 13d transmitted from the base station 40 (the reception signal 14 seen from the mobile station 30).
c) is received.

The demodulation unit 5c demodulates the reception data 15c received by the reception processing unit 4c based on the demodulation method 20c designated by the adaptive demodulation unit 71c.

The channel decoding unit 6c performs decoding processing of the demodulated reception data 16c demodulated by the demodulation unit 5c based on a predetermined error correction decoding method such as turbo code or trellis code.

The control unit 7c includes a retransmission request management unit 72c,
The adaptive demodulator 71c is provided.

The retransmission request management unit 72c determines whether or not the communication is normally performed based on the decoded reception data 17c decoded by the channel decoding unit 6c, and based on the determination, the adaptive demodulation unit 71c. Demodulation method selection information 2
1c is notified, and retransmission request information 22c including information of successful reception or unsuccessful reception is output to the modulation unit 2c.

The adaptive demodulation unit 71c has a retransmission request management unit 72.
The demodulation method 20c is changed based on the demodulation method selection information 21c notified from c, and the demodulation unit 5c is notified. Specifically, for example, as shown in FIG. 4, the modulation / demodulation system level is represented by a number, and a table representing the modulation / demodulation system is prepared in advance in association with the number of the modulation / demodulation system level.
When "2" is designated in, the demodulation unit 5c performs the demodulation processing by the 8PSK demodulation method.

FIG. 3 is a block diagram showing the configuration of the transmission / reception function of the base station 40. The base station 40 includes a transmission buffer unit 8d, a channel coding unit 3d, and a modulation unit 2d.
A transmission processing unit 1d, a reception processing unit 4d, and a demodulation unit 5d.
The channel decoding unit 6d and the control unit 7d are provided, and the control unit 7d includes an adaptive modulation unit 73d and a retransmission response management unit 74d. In FIG. 3, 10d is transmission data, 18d is transmission buffer data, 11d is encoded transmission data, 12d is modulation transmission data, 13d is transmission signal, 14d is reception signal, 15d is reception data, 16d is demodulation reception data, and 17d. Is decoded reception data, 22d is retransmission request information, 23d is a modulation scheme, 24d is modulation scheme selection information, and 25d is retransmission response information.

The transmission buffer unit 8d holds the transmission data 10d to be transmitted to the mobile station 30, and the retransmission response management unit 74d.
The transmission data 10d is updated based on the resend response information 25d notified from the.

The channel coding unit 3d is, for example,
The transmission buffer data 18d to be transmitted to the mobile station 30 is encoded based on a predetermined error correction encoding method such as a turbo code or a trellis code.

The modulation section 2d modulates the coded transmission data 11d coded by the channel coding section 3d based on the modulation method 23d designated by the adaptive modulation section 73d.

The transmission processing section 1d transmits the modulated transmission data 12d modulated by the modulation section 2d to the mobile station 30.

The reception processing unit 4d has the transmission signal 13c (the reception signal 14 seen from the base station 40) transmitted from the mobile station 30.
d) is received.

The demodulation section 5d receives the received data 15 received by the reception processing section 4d based on a predetermined demodulation method.
Demodulate d.

The channel decoding unit 6d performs a decoding process on the demodulated reception data 16d demodulated by the demodulation unit 5d based on a predetermined error correction decoding method such as a turbo code or a trellis code.

The retransmission response management unit 74d outputs the retransmission response information 25d to the transmission buffer unit 8d based on the information of the successful reception or the unsuccessful reception contained in the retransmission request information 22d from the demodulation unit 5d, and the adaptive modulation unit 73d. Then, the modulation system selection information 24d is output.

The adaptive modulation section 73d has a retransmission response management section 74.
The modulation system is selected based on the modulation system selection information 24d from d, and the modulation system 23d is output to the modulation unit 2d. As shown in FIG. 4, the mobile station 3 selects the modulation method.
A table that defines a modulation / demodulation method corresponding to a modulation / demodulation method level number similar to that of the adaptive demodulation unit 71c of 0 is prepared, and the modulation method is selected from the table.

Referring to the flow charts of FIGS. 5 to 8,
The operation of the mobile communication system of the first embodiment will be described.

First, the operation of the mobile station 30 will be described with reference to the flow charts of FIGS. Reception processing unit 4
When the reception signal 14c is received, the c performs reception processing,
The reception data 15c is output to the demodulation unit 5c (step S
100). The demodulation unit 5c performs demodulation processing on the reception data 15c based on the demodulation method 20c designated by the adaptive demodulation unit 71c, and outputs the demodulation reception data 16c to the channel decoding unit 6c (step S101). The channel decoding unit 6c performs a decoding process on the demodulated reception data 16c demodulated by the demodulation unit 5c based on a predetermined error correction decoding scheme, and retransmits the decoded reception data 17c to the control unit 7c. It is output to the request management unit 72c (step S102). The control unit 7c performs adaptive demodulation determination processing based on the decoded reception data 17c that has been decoded (step S103).

The operation of the adaptive demodulation determination processing will be described in detail with reference to the flowchart of FIG. Decoded received data 1
7c, the retransmission request management unit 72c of the control unit 7c
Determines whether the received data 15c has been correctly received by referring to the reception number and the like included in the decoded received data 17c. When the reception data 15c is not correctly received (No in step S200), the value of the reception success counter in the retransmission request management unit 72c is reset (step S201), and the adaptive demodulation determination process ends.

When the received data 15c is correctly received (step S200, Yes), the resending request information 22c including the information of successful reception is notified to the modulator 2c (step S202). Retransmission request information 22 including information on successful reception
When c is notified to the modulation unit 2c, the retransmission request management unit 72c
Counts up the internal reception success counter (step S203). The retransmission request management unit 72c compares the value of the internal reception success counter with a predetermined value N, and when the value of the reception success counter reaches the predetermined value N (step S204), that is, the mobile station. When 30 has received the reception data 15c continuously N times correctly, the adaptive demodulation unit 71c is notified to increase the level of the demodulation method by 1 using the demodulation method selection information 21c (step S20).
5) Reset the successful reception counter (step S2)
06).

When it is instructed by the demodulation system selection information 21c to increase the level of the demodulation system by one, the adaptive demodulation unit 7
The 1c selects a demodulation method one level higher than the currently used demodulation method level and notifies the demodulation section 5c of the selected demodulation method 20c (step S207). Specifically, when the demodulation method level currently used is 1, that is, QPSK, 8PSK which is the next higher level 2 is selected, the demodulation method 20c is set to 2, and the demodulation section 5c is notified. From the next frame, the demodulation unit 5c outputs the demodulation method level 2 8
The received data 15c is demodulated by PSK.

When the adaptive demodulation determination process ends, the mobile station 3
0 transmits the transmission data 10c to the base station 40.
The channel coding unit 3c performs a coding process on the transmission data 10c based on a predetermined error correction coding method, and outputs the coded transmission data 11c to the modulation unit 2c (step S104). The modulation unit 2c uses the predetermined transmission method to generate the coded transmission data 11c coded by the channel coding unit 3c and the retransmission request information 22c including the reception success information designated by the retransmission request management unit 72c. Modulation processing is performed, and modulated transmission data 1
2c is output to the transmission processing unit 1c (step S10).
5). The transmission processing unit 1c performs a transmission process on the modulated transmission data 12c that is modulated by the modulation unit 2c, and transmits the transmission signal 13c to the base station 40 (step S10).
6).

Next, the operation of the base station 40 will be described with reference to the flowcharts of FIGS. 7 and 8. The reception processing unit 4d performs reception processing of the transmission signal 13c (the reception signal 14d viewed from the base station 40) transmitted from the mobile station 30,
The reception data 15d is output to the demodulation unit 5d (step S
300). The demodulation unit 5d performs demodulation processing on the reception data 15d based on a predetermined demodulation method (step S301). The demodulation unit 5d extracts the retransmission request information 22d from the demodulated data, outputs the retransmission request information 22d to the retransmission response management unit 74d of the control unit 7d (step S302), and demodulates the demodulated data after extracting the retransmission request information 22d. The reception data 16d is output to the channel decoding unit 6d. The channel decoding unit 6d performs a decoding process on the demodulated reception data 16d that has been demodulated based on a predetermined error correction decoding method, and outputs the decoded reception data 17d (step S303). on the other hand,
The control unit 7d performs adaptive modulation determination processing based on the retransmission request information 22d extracted from the reception data 15d by the demodulation unit 5d (step S304).

The operation of the adaptive modulation determination process in the base station 40 will be described in detail with reference to the flowchart of FIG. The retransmission response management unit 74d determines whether or not the content of the retransmission request information 22d extracted from the reception data 15d by the demodulation unit 5d is a notification of successful reception (step S4).
00). If the content of the retransmission request information 22d is other than the reception success notification, the reception success counter in the retransmission response management unit 74d is reset (step S401), and the adaptive modulation determination process ends.

If the content of the resend request information 22d is a notification of successful reception, the resend response information 25d is sent to the transmission buffer section 8d.
Is used to notify the successful reception (step S402). When the retransmission response information 25d is notified to the transmission buffer unit 8d,
The retransmission response management unit 74d counts up the internal reception success counter (step S403). The retransmission response management unit 74d compares the value of the internal reception success counter with a predetermined value N, and when the value of the reception success counter reaches the predetermined value N (step S404), that is, the mobile station. When it is notified by the retransmission request information 22d that the reception data 15c has been correctly received over 30 consecutive times in 30, the adaptive modulation unit 7 uses the modulation scheme selection information 24d to raise the level of the modulation scheme by one.
3d is notified (step S405), and the reception success counter is reset (step S406).

When it is instructed by the modulation system selection information 24d to increase the level of the modulation system by one, the adaptive modulation unit 7
The 3d selects a modulation system one level higher than the currently used modulation system level, and notifies the selected modulation system 23d to the modulation unit 2d (step S407). Specifically, when the currently used modulation scheme level is 1, that is, QPSK, the next higher level 2 of 8PSK is selected, the modulation scheme 23d is set to 2, and the modulation unit 2d is notified. From the frame of, the modulation unit 2d changes the modulation method level 2 to 8P.
The encoded transmission data 11d is modulated with SK.

When the adaptive modulation determination process is completed, the base station 4
0 transmits the transmission data 10d to the mobile station 30.
When the transmission buffer unit 8d receives the retransmission response information 25d from the retransmission response management unit 74d notifying that the transmission to the immediately previous mobile station 30 has succeeded, the transmission buffer unit 8d stores the transmission data transmitted in the previous frame. The transmission data 10d that is discarded and transmitted in the next frame is fetched, held until the next retransmission response information 25d is notified, and the held transmission buffer data 18d is output to the channel coding unit 3d. (Step S305).
The channel coding unit 3d uses the transmission buffer data 1
The 8d is encoded based on a predetermined error correction encoding method, and the encoded transmission data 11d is output to the modulator 2d (step S306). Modulator 2d
Performs modulation processing on the encoded transmission data 11d encoded by the channel coding unit 3d according to the modulation scheme 23d selected by the adaptive modulation unit 73d,
The modulated transmission data 12d is output to the transmission processing unit 1d (step S307). The transmission processing unit 1d performs a transmission process on the modulated transmission data 12d that has been modulated by the modulation unit 2d, and transmits a transmission signal 13d to the mobile station 30 (step S308).

FIG. 9 is a sequence diagram showing communication between the mobile station 30 and the base station 40. In FIG. 9, PKT (x) corresponds to transmission data 10d transmitted from the base station 40 to the mobile station 30, and ACK (x) is transmitted from the mobile station 30 to the base station 40. Corresponds to the resend request information 22c notifying that the data has been correctly received,
x is a sequence number of the transmission data 10d from the base station 40.

The base station 40 transmits the transmission data PKT (N-2) to the mobile station 30, and the mobile station 30 receives the transmission data PKT (N-2). At this time, the mobile station 3
At 0, the reception processing unit 4c, the demodulation unit 5c, and the channel decoding unit 6c perform reception processing, modulation processing, and error correction decoding processing on the reception signal 14c, and the retransmission request management unit 72c performs PKT ( When it is determined that N-2) has been correctly received, the reception success counter in the retransmission request management unit 72c is counted up to N-2. The modulation unit 2c modulates the retransmission request information 22c for notifying successful reception and the coded transmission data 11c coded by the channel coding unit 3c, and the transmission processing unit 1c performs a transmission process to send an ACK (N (N) to the base station 40). -2) is transmitted.

In base station 40, when ACK (N-2) transmitted from mobile station 30 is received, reception processing section 4d performs reception processing, demodulation section 5d extracts resend request information 22d, and resend response. The management unit 74d determines whether or not the mobile station 30 correctly receives the PKT (N-2) transmitted by the base station 40 in the immediately preceding frame based on the extracted retransmission request information 22d. In this case, since the retransmission request information 22d received by the base station 40 is a notification of successful reception, the retransmission response information 25d, which is a notification of successful reception, is notified to the transmission buffer unit 8d, and the retransmission response management unit 74d stores the same. The reception success counter is counted up to N-2.

The transmission buffer section 8d has the retransmission response information 25.
Since d is a notification of successful reception, the data of PKT (N-2) currently held is erased, and the data PKT (N-1) to be transmitted next is read. The PKT (N-1) read into the transmission buffer unit 8d is encoded by the channel coding unit 3d, modulated by QPSK that is the modulation scheme level 1 currently specified by the modulation unit 2d, and transmitted by the transmission processing unit 1d. Then, the data is transmitted to the mobile station 30.

As described above, when the above operation succeeds continuously from PKT (1) to PKT (N) without the reception failure in both the mobile station 30 and the base station 40, the mobile station 30 receives The level of the demodulation method for demodulating the data received from the frame PKT (N + 1) is changed to one level, 8PSK, and ACK (N) is transmitted to the base station 40.

Also in the base station 40, if the reception of ACK (1) to ACK (N) succeeds without failure, the data is transmitted from the next transmission frame at the modulation system level which is one level higher than the modulation system level. Of the mobile station 3
Send to 0.

As described above, in the first embodiment, the mobile station 30
When the retransmission request management unit 72c determines that the data transmitted from the base station 40 has been correctly received a predetermined number of times in succession, the adaptive demodulation unit 71c instructs the adaptive demodulation unit 71c to change the level of the demodulation method. The demodulation unit 71c selects a demodulation system level one level higher than the current demodulation system level and notifies the demodulation unit 5c of the demodulation system level, thereby automatically changing the demodulation system at the next reception frame timing. The base station 40 is
Retransmission request information 22 in the data transmitted from the mobile station 30
The content of d indicates successful reception, and the retransmission response management unit 74 indicates that it has been received a predetermined number of times in succession.
When d determines, the adaptive modulation unit 73d is notified of the change in the level of the modulation system, and the adaptive modulation unit 73d that has received the notification raises the level of the currently used modulation system by 1 and notifies the modulation unit 2d. As a result, the modulator 2d automatically changes the modulation method from the next transmission frame timing. That is, the continuous reception success number N, which is a condition for changing the modulation / demodulation method, is stored in the mobile station 30 and the base station 40 in advance, and when the number is reached, the modulation / demodulation method is automatically changed. There is. As a result, the base station 40 adaptively selects the modulation method without notifying the mobile station 30 of the control data such as the modulation method used at the time of transmission, and the mobile station 30 is notified of the control data such as the demodulation method by the base station 40. It is possible to adaptively select the demodulation method without improving the transmission efficiency.

The mobile station 30 does not need to estimate the channel quality of the received pilot signal from the base station 40,
Further, since it is not necessary to notify the base station 40 of the line quality, the delay time can be suppressed and the switching of the modulation system can be realized quickly.

Embodiment 2. The second embodiment of the present invention will be described with reference to FIGS. In the first embodiment,
When the mobile station 30 continuously and correctly receives the transmission data from the base station 40 over a predetermined number of N times, the mobile station 30 changes the demodulation scheme level from the next frame to the demodulation scheme level one level higher, When the base station 40 receives the retransmission request information 22d including the reception success notifying that the mobile station 30 has correctly received the data, the base station 40 raises the level of the modulation scheme from the next frame to the next higher modulation scheme level. I changed it to. However, when the retransmission request information 22c including the information of successful reception transmitted by the mobile station 30 is not correctly received by the base station 40, the mobile station 30
And a mismatch occurs between the modulation and demodulation methods of the base station 40.

In the second embodiment, since only the mobile station 30 raises the level of the demodulation method by one,
And when there is a mismatch between the modulation and demodulation methods of the base station 40 and
The mobile station 30 automatically lowers the level of the modulation scheme by one so that the modulation and demodulation schemes of the mobile station 30 and the base station 40 match.

The configurations of the mobile station and the base station of the adaptive modulation / demodulation system of the second embodiment are the same as those shown in FIGS. 2 and 3, and therefore their explanations are omitted here.

The mobile communication system and adaptive modulation method according to the second embodiment will be described with reference to the flowchart of FIG.

The mobile station 30 performs the receiving process, the demodulating process, and the decoding process on the received signal 14c according to the receiving procedure shown in the flowchart of FIG.
c is output to the control unit 7c, and the control unit 7c performs adaptive demodulation determination processing (steps S100 to S103).

The operation of the adaptive demodulation determination processing will be described with reference to the flowchart of FIG. When the reception data 15c is correctly received, the retransmission request management unit 72c causes the modulation unit 2 to
c is notified of the retransmission request information 22c including the information of successful reception, the successful reception counter is counted up, and when the count value reaches a predetermined number N, the adaptive demodulation unit 71c is set to one demodulation level. The demodulation method selection information 21c is used to notify that the demodulation method is to be raised, the reception success counter is reset, the adaptive demodulation unit 71c selects the demodulation method based on the demodulation method selection information 21c, and the demodulation unit 5c is demodulated.
For steps S202 to S207 that output c,
Since the operation is the same as that of the first embodiment, detailed description will be omitted.

The retransmission request management unit 72c of the control unit 7c refers to the reception number and the like included in the decoded reception data 17c to determine whether or not the reception data 15c has been correctly received. When the reception data 15c is not correctly received (No in step S200), the retransmission request management unit 7
The value of the reception success counter in 2c is reset (step S201). The retransmission request management unit 72c notifies the modulation unit 2c of the retransmission request information 22c including the reception failure information (step S500). The retransmission request information 22c is sent to the modulator 2
When notified to c, the retransmission request management unit 72c counts up the internal reception failure counter (step S50).
1). The retransmission request management unit 72c compares the value of the reception failure counter with a predetermined value M, and when the value of the reception failure counter reaches the predetermined value M (step S50).
2) That is, when the reception of the continuous M times received data 15c has failed, the adaptive demodulation unit 71c is notified to lower the level of the demodulation method by one using the demodulation method selection information 21c (step S503), and the reception is performed. The failure counter is reset (step S504).

When the demodulation method selection information 21c specifies that the level of the demodulation method should be lowered by one, the adaptive demodulation section 7
1c selects a demodulation method one level below the currently used demodulation method level and notifies the selected demodulation method 20c to the demodulation unit 5c (step S505). Specifically, the demodulation method level currently used is 2, that is, 8 QPSK
In the case of 1, the next lower demodulation method level QPSK is selected, the demodulation method 20c is set to 1, and the demodulation section 5c is notified, so that the demodulation section 5c receives the QPSK of the demodulation method level 1 from the next frame. The data 15c is demodulated.

If the received data 15c has been correctly received (step S200, Yes), the resend request management unit 72
The c resets the reception failure counter (step S5).
06). The retransmission request management unit 72c notifies the modulation unit 2c of the retransmission request information 22c including the reception success information, counts up the reception success counter, and when the count value reaches a predetermined number N, performs adaptive demodulation. The demodulation system selection information 21c so that the unit 71c raises the demodulation system level by one.
Is used to reset the reception success counter, the adaptive demodulation unit 71c selects the demodulation system based on the demodulation system selection information 21c, and outputs the demodulation system 20c to the demodulation unit 5c (steps S202 to S207).

When the adaptive demodulation determination process ends, the mobile station 3
0 performs encoding processing, modulation processing, and transmission processing on the transmission data 10c according to the transmission procedure shown in the flowchart of FIG. 5, and transmits the transmission signal 13 to the base station 40.
c is transmitted (steps S104 to S106).

The operation of base station 40 is the same as the operation described with reference to the flow charts of FIGS. 7 and 8 in the first embodiment, and therefore its explanation is omitted here.

FIG. 11 is a sequence diagram showing communication between the mobile station 30 and the base station 40. In FIG. 11, PKT
(X) corresponds to the transmission data 10d transmitted from the base station 40 to the mobile station 30, and ACK (x) is the mobile station 30.
From the base station 40 to the retransmission request information 2 for notifying that the transmission data 10d from the base station 40 has been correctly received.
2c, NAK (x) is from the mobile station 30 to the base station 4
Retransmission request information 22c for notifying 0 that the transmission data 10d from the base station 40 could not be correctly received.
And x is the sequence number of the transmission data 10d from the base station 40.

The base station 40 transmits the transmission data PKT (N-2) to the mobile station 30, and the mobile station 30 receives the transmission data PKT (N-2). At this time, the mobile station 3
At 0, the reception processing unit 4c, the demodulation unit 5c, and the channel decoding unit 6c perform reception processing, modulation processing, and error correction decoding processing on the reception signal 14c, and the retransmission request management unit 72c performs PKT (N -2) is correctly received, the reception success counter in the retransmission request management unit 72c is counted up to N-2. The modulation unit 2c modulates the retransmission request information 22c for notifying successful reception and the coded transmission data 11c coded by the channel coding unit 3c, and the transmission processing unit 1c performs a transmission process to send an ACK (N (N) to the base station 40). -2) is transmitted.

In base station 40, when ACK (N-2) transmitted from mobile station 30 is received, reception processing section 4d performs reception processing, demodulation section 5d extracts resend request information 22d, and resend response. The management unit 74d determines whether or not the mobile station 30 correctly receives the PKT (N-2) transmitted by the base station 40 in the immediately preceding frame based on the extracted retransmission request information 22d. In this case, since the retransmission request information 22d received by the base station 40 is a notification of successful reception, the retransmission response information 25d, which is a notification of successful reception, is notified to the transmission buffer unit 8d, and the retransmission response management unit 74d stores the same. The reception success counter is counted up to N-2.

The transmission buffer section 8d has the retransmission response information 25.
Since d is a notification of successful reception, the data of PKT (N-2) currently held is erased, and the data PKT (N-1) to be transmitted next is read. The PKT (N-1) read into the transmission buffer unit 8d is encoded by the channel coding unit 3d and modulated by the modulation method 23d currently specified by the modulation unit 2d, that is, QPSK which is the modulation method level 1. Then, the transmission processing unit 1d performs transmission processing and transmits the mobile station 30.

In this way, if the above operation succeeds continuously from PKT (1) to PKT (N) without any reception failure in both the mobile station 30 and the base station 40, the mobile station 30 receives the appropriate reception. The level of the demodulation method for demodulating the data received from the frame PKT (N + 1) is changed to one level, 8PSK, and ACK (N) is transmitted to the base station 40.

If the base station 40 fails to receive the ACK (N), the value of the reception success counter in the retransmission response management section 74d is reset and the modulation method 23d is not changed. That is, the modulation scheme of the base station 40 remains QPSK, and the demodulation scheme 20c of the mobile station 30 is 8PSK, so that a mismatch occurs between the modulation scheme 23d of the base station 40 and the demodulation scheme 20c of the mobile station 30. Further, since the reception has failed, the retransmission response management unit 74d of the base station 40 notifies the transmission buffer unit 8d of the reception failure using the retransmission response information 25d, and the transmission response is held in the transmission buffer unit 8d. The transmission buffer data 18d stored therein is output to the channel coding unit 3d, subjected to encoding processing, modulation processing, and transmission processing, and PKT (N) is transmitted to the mobile station 30 again.

Modulation system 23d of base station 40 and mobile station 30
The mobile station 30 fails to receive the PKT (N) transmitted from the base station 40 because the demodulation schemes 20c of N.
(N + 1) is transmitted to the base station 40. The base station 40 is N
Since AK (N + 1) has been received, PKT (N + 1) is transmitted to the mobile station 30. Here, the mobile station 30 uses the PKT
It is not necessary to recognize that the (N + 1) reception failure is due to a mismatch of modulation schemes.

Modulation system 23d of base station 40 and mobile station 30
When the value of the reception failure counter in the retransmission request management unit 72c of the mobile station 30 reaches a predetermined number M times, the retransmission request management unit 72c determines that the demodulation method 20c Using the selection information 21c, the adaptive demodulation unit 71c is notified to lower the level of the demodulation system by one, and the adaptive demodulation unit 71c selects the demodulation system whose level is lowered by one from the demodulation system currently used, Demodulation method 2
0c is notified to the demodulation unit 5c. That is, since the level of the demodulation method 20c of the mobile station 30 is lowered by one, the demodulation method 20 of the mobile station 30 and the modulation method 23d of the base station 40 match,
From the next frame timing, the mobile station 30 can correctly receive the transmission data from the base station 40.

As described above, in the second embodiment, the mobile station 30
Even if a mismatch occurs between the demodulation method 20c of No. 1 and the modulation method 23d of the base station 40, if the mobile station 30 subsequently fails to receive the data transmitted from the base station 40 a predetermined number of times M, automatic Specifically, the demodulation method level of the demodulation method 20c is lowered by one. As a result, the base station 40 adaptively selects the modulation method without notifying the mobile station 30 of the control data such as the modulation method used at the time of transmission, and the mobile station 30 notifies the base station 40 of the control data such as the demodulation method. It is possible to adaptively select the demodulation method without being performed and improve the transmission efficiency.

The mobile station 30 does not need to estimate the channel quality of the received pilot signal from the base station 40,
Further, since it is not necessary to notify the base station 40 of the line quality, the delay time can be suppressed and the switching of the modulation system can be realized quickly.

Regarding the change of the demodulation method, refer to FIG.
As shown in the sequence diagram of FIG.
When +1) is received, the retransmission response management unit 74d determines that the mobile station 30 has correctly received PKT (N) in the previous frame, and ACK (1) to ACK (N) has been transmitted. It is possible to estimate and determine that the reception of the mobile station 30 has succeeded consecutively for a predetermined N times.
In this case, at the next transmission frame timing, the adaptive modulation unit 73d is notified using the modulation system selection information 24d to increase the modulation system level by 1, and the adaptive modulation unit 73d notifies the adaptive modulation unit 73d of the currently used modulation system. The modulation method 23d with a higher level is notified to the modulation unit 2d so that the modulation method 23d of the base station 40 and the demodulation method 20c of the mobile station 30 are matched.

Third embodiment. A third embodiment of the present invention will be described with reference to FIGS. In the third embodiment, when the mobile station 30 continuously fails to receive the transmission data from the base station 40 over a predetermined number of M times, the mobile station 30 lowers the level of the demodulation method by one from the next frame. When the base station 40 receives the retransmission request information 22d for notifying that the mobile station 30 has failed to receive data for M consecutive times, the base station 40 lowers the level of the modulation method by one from the next frame. To change.

The configurations of the mobile station and the base station of the mobile communication system according to the third embodiment are the same as those shown in FIGS. 2 and 3, and therefore their explanations are omitted here.

The mobile communication system and adaptive modulation method of the third embodiment will be described with reference to the flowchart of FIG.

The operation of mobile station 30 is the same as that described in Embodiment 2 with reference to the flowcharts of FIGS. 5 and 10, and therefore its description is omitted here.

The base station 40 performs the receiving process, the demodulating process, and the decoding process on the received signal 14c according to the receiving procedure shown in the flowchart of FIG.
c is output to the control unit 7c, and the control unit 7c performs adaptive tone determination processing (steps S100 to S103).

The operation of the adaptive demodulation determination processing will be described with reference to the flowchart of FIG. When the content of the resend request information 22d is a notification of successful reception, the transmission buffer unit 8d
Is notified of the reception success using the retransmission response information 25d, the reception success counter in the retransmission response management unit 74d is counted up, and when the count value reaches a predetermined value N, the modulation method selection information 24d is The adaptive modulation unit 73d is notified so as to increase the modulation system level by one, the reception success counter is reset, and based on the notification of the modulation system selection information 24d, the adaptive modulation unit 73d sets 1 from the modulation system currently used. Steps S402 to 407 for selecting the next higher modulation method and notifying the modulation method 23d to the modulation section 2d are the same operations as those in the first embodiment, and thus detailed description thereof will be omitted.

The retransmission response management section 74d has the retransmission request information 22d extracted from the received data 15d by the demodulation section 5d.
It is determined whether the content of is a notification of successful reception (step S400). When the content of the resend request information 22d is the notification of the reception failure, the reception success counter is reset (step S401). The retransmission response management unit 74d notifies the transmission buffer unit 8d of the reception failure using the retransmission response information 25d (step S600). When the mobile station 30 is notified by the retransmission response information 25d that the reception has failed, the transmission buffer unit 8d uses the held data, that is, the transmission data 10d transmitted in the previous frame as the transmission buffer data 18d. Output to the coding unit 3d.

The retransmission response management section 74d counts up the internal reception failure counter (step S601).
The retransmission response management unit 74d compares the value of the internal reception failure counter with the predetermined value M, and when the value of the reception failure counter reaches the predetermined value M (step S6).
02), that is, when the retransmission request information 22d notifies that the mobile station 30 has failed to receive the received data 15c for M consecutive times, the modulation method selection information 24d is used to lower the level of the modulation method by one. In this way, the adaptive modulation unit 73d is notified (step S603), and the reception failure counter is reset (step S604).

When the modulation system selection information 24d instructs to lower the level of the modulation system by one, the adaptive modulation unit 7
The 3d selects a modulation system one level below the currently used demodulation system level, and notifies the selected modulation system 23d to the modulation unit 2d (step S605). Specifically, when the currently used modulation scheme level is 2, that is, 8PSK, QPSK which is the next lower level 1 is selected, the modulation scheme 23d is set to 1, and the modulation unit 2d is notified. From the frame of the modulation unit 2d, the modulation method level 1 QP
The encoded transmission data 11d is modulated with SK.

When the content of the resend request information 22d is a notification of successful reception, the reception failure counter in the resend response management section 74d is reset (step S606). The retransmission response management unit 74d stores the retransmission response information 25d in the transmission buffer unit 8d.
Is used to notify the reception success, the reception success counter in the retransmission response management unit 74d is counted up, and when the count value reaches a predetermined value N, the modulation system level is calculated using the modulation system selection information 24d. To the adaptive modulation unit 73d, reset the reception success counter, and based on the notification of the modulation system selection information 24d, the adaptive modulation unit 73d detects that the modulation system is one higher than the currently used modulation system. Is selected and the modulation method 23d is notified to the modulation unit 2d (steps S402 to S407).

When the adaptive modulation judgment processing is completed, the base station 4
0 is an encoding process for the transmission buffer data 18d according to the transmission procedure shown in the flowchart of FIG.
Modulation processing and transmission processing are performed, and the transmission signal 13d is transmitted to the mobile station 30 (steps S104 to S10).
6).

FIG. 14 is a sequence diagram showing communication between the mobile station 30 and the base station 40. In FIG. 14, PKT
(X) corresponds to transmission data 10d transmitted from the base station 40 to the mobile station 30, and NAK (x) is the mobile station 30.
Corresponds to the retransmission request information 22c for notifying the base station 40 that the transmission data 10d from the base station 40 could not be correctly received, and x is the sequence number of the transmission data 10d from the base station 40.

The base station 40 and the mobile station 30 are communicating at the modulation system level 2. The base station 40 transmits the transmission data PKT (x) to the mobile station 30, and the mobile station 30
This transmission data PKT (x) is received. At this time, in the mobile station 30, the reception processing unit 4 receives the received signal 14c.
c, the demodulation unit 5c, and the channel decoding unit 6c perform reception processing, demodulation processing, and error correction decoding processing, and when the retransmission request management unit 72c determines that PKT (x) is erroneously received, The reception failure counter is incremented. The modulation unit 2c modulates the retransmission request information 22c for notifying the reception failure and the coded transmission data 11c coded by the channel coding unit 3c, and the transmission processing unit 1c.
c performs a transmission process and transmits NAK (x) to the base station 40.

In the base station 40, when the NAK (x) transmitted from the mobile station 30 is received, the reception processing unit 4d performs the reception process, the demodulation unit 5d extracts the retransmission request information 22d, and the retransmission response management unit. Retransmission request information 2 from which 74d is extracted
Based on 2d, it is determined whether or not the mobile station 30 correctly receives the PKT (x) transmitted by the base station 40 in the immediately preceding frame. In this case, since the retransmission request information 22d received by the base station 40 is the notification of the reception failure, the retransmission response information 25 which is the notification of the reception failure to the transmission buffer unit 8d.
d is notified, and the reception failure counter in the retransmission response management unit 74d is counted up.

The transmission buffer section 8d has the retransmission response information 25.
Since d indicates the reception failure, the currently held PKT (x) is output as the transmission buffer data 18d. The channel coding unit 3d performs an encoding process, the modulation unit 2d performs a modulation process at 8PSK which is the currently specified modulation scheme level 2, and the transmission processing unit 1d.
Then, transmission processing is performed to transmit PKT (x) to the mobile station 30.

In this way, when the above operation is repeated and the value of the reception failure counter in the retransmission request management unit 72c of the mobile station 30 reaches a predetermined value M, the level of the demodulation method is set to 1 from the next frame. The step-down demodulation method level is changed to 1 and NAK (x) is transmitted to the base station 40.

Also in the base station 40, since the number of times NAK (x) is received reaches M times, the modulation method is changed from the next frame timing to the modulation method one level lower than the currently used level. The PKT (x) is transmitted to the mobile station 30.

As described above, in the third embodiment, the mobile station 30
When the retransmission request management unit 72c determines that the data transmitted from the base station 40 has failed to be received continuously for a predetermined number of times, the adaptive demodulation unit 71c instructs the demodulation method level to be changed, and The demodulation unit 71c selects a demodulation system level that is one level lower than the current demodulation system level and notifies the demodulation unit 5c, and the demodulation unit 5c automatically changes the demodulation system at the next reception frame timing. In the base station 40, the content of the retransmission request information 22d in the data transmitted from the mobile station 30 indicates reception failure, and the retransmission response management unit 74d indicates that the retransmission request information 22d has been received a predetermined number of times in succession. When the determination is made, the adaptive modulation unit 73d is notified of the change of the demodulation method level, and the adaptive modulation unit 73d that has received the notification is notified.
Lowers the currently used modulation scheme level by 1,
By notifying the modulation unit 2d, the modulation unit 2d automatically changes the modulation method from the next transmission frame timing.
That is, the number of consecutive reception failures M, which is a condition for changing the modulation / demodulation method, is stored in the mobile station 30 and the base station 40 in advance, and when the number of times M is reached, the modulation / demodulation method is automatically changed. As a result, the base station 40 adaptively selects the modulation method without notifying the mobile station 30 of the control data such as the modulation method used at the time of transmission, and the mobile station 30 notifies the base station 40 of the control data such as the demodulation method. It is possible to adaptively select the demodulation method without being performed and improve the transmission efficiency.

The mobile station 30 does not need to estimate the channel quality of the received pilot signal from the base station 40,
Further, since it is not necessary to notify the base station 40 of the line quality, the delay time can be suppressed and the switching of the modulation system can be realized quickly.

Fourth Embodiment A fourth embodiment of the present invention will be described with reference to FIGS. In the third embodiment,
When the mobile station 30 consecutively fails to receive the transmission data from the base station 40 over a predetermined number of M times, the mobile station 30 changes the demodulation method level from the next frame to the demodulation method level one level lower. When the base station 40 receives the retransmission request information 22d including the reception failure notifying that the mobile station 30 has failed to receive data for M consecutive times, the base station 40 demodulates the level of the modulation scheme one level below the next frame. Changed to the system level. However, when the retransmission request information 22c including the reception success information transmitted by the mobile station 30 cannot be correctly received by the base station 40, the mobile station 30
And a mismatch occurs between the modulation and demodulation methods of the base station 40.

In the fourth embodiment, only the base station 40 lowers the level of the demodulation method by one, so that the mobile station 30
And when there is a mismatch between the modulation and demodulation methods of the base station 40 and
The mobile station 30 automatically lowers the level of the modulation scheme by one so that the modulation and demodulation schemes of the mobile station 30 and the base station 40 match.

The configurations of the mobile station and the base station of the mobile communication system of the fourth embodiment are similar to those shown in FIGS. 2 and 3, and the operations of mobile station 30 and base station 40 are the same as those of the second and the second embodiments. Since the operation is the same as that of the third embodiment, the description thereof is omitted here.

FIG. 15 is a sequence diagram showing communication between the mobile station 30 and the base station 40. In FIG. 15, PKT
(X) corresponds to the transmission data 10d transmitted from the base station 40 to the mobile station 30, and ACK (x) is the mobile station 30.
From the base station 40 to the retransmission request information 2 for notifying that the transmission data 10d from the base station 40 has been correctly received.
2c, NAK (x) is from the mobile station 30 to the base station 4
Retransmission request information 22c for notifying 0 that the transmission data 10d from the base station 40 could not be correctly received.
And x is the sequence number of the transmission data 10d from the base station 40.

The base station 40 and the mobile station 30 are communicating at the modulation system level 2. The base station 40 transmits the transmission data PKT (x) to the mobile station 30, and the mobile station 30 receives the transmission data PKT (x). At this time, in the mobile station 30, the reception processing unit 4c, the demodulation unit 5c, and the channel decoding unit 6c perform the reception process, the demodulation process, and the error correction decoding process on the reception signal 14c, and the retransmission request management unit 72c performs the reception process. If it is determined that the PKT (x) is erroneously received, the reception failure counter in the retransmission request management unit 72c is counted up. The modulation unit 2c modulates the retransmission request information 22c for notifying the reception failure and the coded transmission data 11c coded by the channel coding unit 3c, and the transmission processing unit 1c performs the transmission process to transmit the N to the base station 40.
Send AK (x).

In the base station 40, when the NAK (x) transmitted from the mobile station 30 is received, the reception processing unit 4d performs the reception process, the demodulation unit 5d extracts the retransmission request information 22d, and the retransmission response management unit. 74d determines whether or not the mobile station 30 correctly receives the PKT (x) transmitted by the base station 40 in the immediately preceding frame based on the extracted retransmission request information 22d. In this case, since the retransmission request information 22d received by the base station is a notification of reception failure, the transmission buffer unit 8
The retransmission response information 25d, which is the notification of the reception failure, is notified to d, and the reception failure counter in the retransmission response management unit 74d is counted up.

The transmission buffer section 8d has the retransmission response information 25.
Since d indicates the reception failure, PKT (x) currently held is output as the transmission buffer data 18d. The transmission buffer data 18d is encoded by the channel coding unit 3d, modulated by 8PSK which is the modulation scheme level 2 currently specified by the modulation unit 2d, and is transmitted by the transmission processing unit 1d and transmitted to the mobile station 30. To be done.

In this way, when the above operation is repeated and the value of the reception failure counter in the retransmission request management section 72c of the mobile station 30 reaches a predetermined value M, the data received from the next frame is demodulated. Decrease the level of the demodulation method by 1 and change the demodulation method level to 1 to set NAK (x) to the base station 4
However, if the mobile station 30 succeeds in reception in the Mth communication, the mobile station 30 succeeds in reception to the base station 40 without changing the demodulation method (the demodulation method level 2 remains). ACK (x) is sent to notify the fact. At this time, the base station 40 sends the ACK sent from the mobile station 30.
When the reception of (x) fails, the value of the reception failure counter in the retransmission response management unit 74d of the base station 40 reaches a predetermined value M, and the modulation method level is lowered by one from the next frame timing, and the modulation method is changed. Modulate at level 1 and PKT (x)
To send. That is, the modulation scheme level of the base station 40 and the demodulation scheme level of the mobile station 30 do not match.

Since the mobile station 30 demodulates the PKT (x) modulated by the modulation method level 1 in the base station 40 at the demodulation method level 2, the mobile station 30 fails to receive the PKT (x). PK expected by the resend request management unit 72c
If it is determined that the reception of T (x + 1) has failed, the retransmission request information 22c is used to notify the reception failure, the transmission process is performed, and NAK (x + 1) is transmitted to the base station 40.

In the base station 40, the retransmission response management section 74d determines that the mobile station 30 has the PKT (x
If it is determined that the reception of +1) has failed, the retransmission response information 2
5d is used to notify the transmission buffer unit 8d of the retransmission of PKT (x + 1). The transmission buffer unit 8d discards the data of PKT (x) currently held, and PKT (x + 1)
Is output as transmission buffer data 18d, and the output transmission buffer data 18d is subjected to encoding processing, modulation processing, and transmission processing by the channel coding unit 3d, the modulation unit 2d, and the transmission processing unit 1d, and then is transmitted to the mobile station 30. Send.

Thus, the base station 40 shown in the above operation
If the PKT (x + 1) reception failure occurs consecutively M times in the mobile station 30 due to the mismatch between the modulation scheme level of the mobile station 30 and the demodulation scheme level of the mobile station 30, one demodulation scheme level is selected from the demodulation scheme level currently used. The demodulation is performed from the next frame timing after lowering (in this case, changing to the demodulation method level 1). At this time, the mobile station 30
It is not necessary to recognize that the cause of the failure to receive the PKT (x + 1) is the modulation / demodulation scheme mismatch.

As described above, in the fourth embodiment, the mobile station 30
Even if a mismatch occurs between the demodulation method 20c of No. 1 and the modulation method 23d of the base station 40, if the mobile station 30 subsequently fails to receive the data transmitted from the base station 40 a predetermined number of times M, automatic Specifically, the demodulation method level of the demodulation method 20c is lowered by one. As a result, the base station 40 adaptively selects the modulation method without notifying the mobile station 30 of the control data such as the modulation method used at the time of transmission, and the mobile station 30 notifies the base station 40 of the control data such as the demodulation method. It is possible to adaptively select the demodulation method without being performed and improve the transmission efficiency.

The mobile station 30 does not need to estimate the channel quality of the received pilot signal from the base station 40,
Furthermore, since it is not necessary to notify the base station of the line quality,
The delay time is suppressed, and rapid switching of the modulation system can be realized.

Regarding the change of the modulation method, refer to FIG.
As shown in the sequence diagram of FIG.
When +1) is received, the retransmission response management unit 74d may determine that the mobile station 30 has correctly received PKT (x) in the previous frame. In this case, at the next transmission frame timing, the modulation method selection information 24 is set so that the modulation method level is increased by 1 with respect to the adaptive modulation unit 73d.
Then, the adaptive modulation unit 73d notifies the modulation unit 2d of the modulation system 23d that is one level higher than the modulation system currently used, and the modulation system 23d of the base station 40 and the mobile station 30d. The demodulation methods 20c of the above are matched.

Embodiment 5. Embodiment 5 of the present invention will be described with reference to FIG. In the fifth embodiment, when the mobile station 30 correctly receives the transmission data 10d from the base station 40 N times or more while the mobile station 30 receives the predetermined number of receptions L times, the mobile station 30 starts the next frame. Change the level of the demodulation method up by one. The base station 40 receives the retransmission request information 22d for notifying whether the mobile station 30 has correctly received the data over a predetermined number of times L times, and transmits the retransmission request information 22d for notifying the successful reception. When it is received N times or more, the level of the modulation system is changed to the next higher level from the next frame.

Since the configurations of the mobile station and the base station of the mobile communication system according to the fifth embodiment are the same as those shown in FIGS. 2 and 3, the description thereof will be omitted here.

The reception procedure and transmission procedure of the mobile station 30 are the same as those described with reference to the flowchart of FIG. 5 in the first embodiment, so the description thereof is omitted here and only the adaptive demodulation determination processing is performed. Will be explained. When the decoded reception data 17c is received, the number of times of reception is counted. The retransmission request management unit 72c of the control unit 7c uses the decoded reception data 17c.
It is determined whether the received data 15c is correctly received by referring to the reception number and the like included in the. If the received data 15c is not correctly received, the adaptation determination process ends.

When the received data 15c is correctly received, the resending request information 22c including the information of successful reception is notified to the modulator 2c. Retransmission request information 2 including information on successful reception
2c is notified to the modulation unit 2c, the retransmission request management unit 72c
Counts up the internal reception success counter. When the number of receptions reaches a predetermined number L, the retransmission request management unit 72c compares the value of the reception success counter in the retransmission request management unit 72c with a predetermined value N, and the value of the reception success counter is determined in advance. When the value is equal to or more than the predetermined value N, that is, when the mobile station 30 communicates with the base station 40 L times and correctly receives the reception data 15c N times or more during L times, the demodulation method selection information 21c is used. , Demodulation system level 1
The adaptive demodulation unit 71c is notified to increase.

The reception procedure and transmission procedure of the base station 40 are the same as those described in Embodiment 1 with reference to the flowchart of FIG. Only the modulation determination process will be described. Upon receiving the retransmission request information 22d, the retransmission response management unit 74d counts the number of receptions, and the retransmission request information 22d.
Determines whether the content of is a notification of successful reception. When the content of the resend request information 22d is other than the notification of successful reception,
The adaptive modulation determination process ends.

When the content of the resend request information 22d is a notification of successful reception, the resend response information 25d is sent to the sending buffer section 8d.
Is used to notify the successful reception. When the transmission buffer unit 8d is notified of the retransmission response information 25d, the retransmission response management unit 74d
Counts up the reception success counter in the retransmission response management unit 74d. When the value of the reception number counter reaches the predetermined number L, the retransmission response management unit 74d compares the value of the reception success counter in the retransmission response management unit 74d with the predetermined value N, and When the value is greater than or equal to the predetermined value N, that is, the base station 40 is the mobile station 3
Retransmission request information 22d that the mobile station 30 has correctly received the reception data 15c N times or more during L times by communicating with 0 for L times.
In case of being notified by the information of the successful reception included in, the level of the modulation system is set to 1 by using the modulation system selection information 24d.
The adaptive modulation unit 73d is notified to increase.

When the modulation system selection information 24d instructs to increase the level of the modulation system by one, the adaptive modulation unit 7
3d selects the modulation system one level higher than the currently used modulation system level, and notifies the selected modulation system 23d to the modulation unit 2d. The modulation unit 2d raises the modulation method level by 1 from the next frame timing, and the encoded transmission data 1
Modulate 1d.

FIG. 17 is a sequence diagram showing communication between the mobile station 30 and the base station 40. In FIG. 17, PKT
(X) corresponds to the transmission data 10d transmitted from the base station 40 to the mobile station 30, and ACK (x) is the mobile station 30.
Corresponds to the retransmission request information 22 for notifying that the transmission data from the base station 40 has been correctly received from the mobile station 30 to the base station 40. Corresponds to the retransmission request information 22c notifying that the transmission data 10d from the base station 40 could not be correctly received, and x is the sequence number of the transmission data 10d from the base station 40.

The base station 40 modulates the transmission data PKT (N-1) by the modulation method level 1 and transmits it to the mobile station 30, and the mobile station 30 receives this transmission data PKT (N-1). At this time, in the mobile station 30, the reception processing unit 4c, the demodulation unit 5c, and the channel decoding unit 6c perform reception processing, demodulation processing (demodulation method level 1), and error correction decoding processing on the reception signal 14c. The retransmission request management unit 72c counts up the reception number counter,
The value of the reception counter is L-2. When the retransmission request management unit 72c determines that the reception of PKT (N-1) has failed, the modulation unit 2c notifies the retransmission request information 22c for notifying the reception failure and the encoded transmission coded by the channel coding unit 3c. The data 11c is modulated, and the transmission processing unit 1c performs transmission processing to transmit NAK (N-1) to the base station 40.

In the base station 40, when NAK (N-1) transmitted from the mobile station 30 is received, the reception processing unit 4d performs reception processing, the demodulation unit 5d extracts the retransmission request information 22d, and the retransmission response. The management unit 74d determines whether or not the mobile station 30 correctly receives the PKT (N-1) transmitted by the base station 40 in the immediately preceding frame, based on the extracted retransmission request information 22d. In this case, since the retransmission request information 22d received by the base station 40 is the notification of the reception failure, the retransmission response information 25d that is the notification of the reception failure is notified to the transmission buffer unit 8d.

The transmission buffer section 8d has the retransmission response information 25.
Since d indicates the reception failure, the currently held PKT (N-1) is output as the transmission buffer data 18d. The channel coding unit 3d performs an encoding process, the modulation unit 2d performs a modulation process at QPSK which is the currently specified modulation scheme level 1, and the transmission processing unit 1d performs a transmission process so that the mobile station 30 receives PKT (N −
Send 1).

Next, since the mobile station 30 has correctly received PKT (N-1), the reception number counter in the retransmission request management section 72c becomes L-1, the value of the reception success counter is also added, and PKT (N- ACK of successful reception for 1)
(N-1) is transmitted to the base station 40. The base station 40 is P
Since ACK (N-1) of successful reception for KT (N-1) has been received, the next data, PKT (N), is transmitted.

The reception number counter of the retransmission request management unit 72c of the mobile station 30 becomes L times when PKT (N) is received. The retransmission request management unit 72c compares the number of times of the internal reception success counter with a predetermined value N. in this case,
Since the value of the reception success counter is N or more, the retransmission request management unit 72c uses the demodulation system selection information 21c to notify the adaptive demodulation unit 71c to increase the demodulation system level by one, and receives the notification to adapt. The demodulation unit 71c selects the demodulation system level 2 which is one higher than the demodulation system level currently used, and outputs the demodulation system 20c to the demodulation unit 5c so that the demodulation unit 5c starts from the next frame timing.
Performs demodulation with the demodulation method level 2. Further, the retransmission request management unit 72c uses the retransmission request information 22 including the notification of successful reception.
The modulation unit 2c is notified of c and ACK (N) is transmitted to the base station 40.

The base station 40 also receives ACK (N), and the retransmission response management section 74d reaches L times the number of receptions from the mobile station 30, and notifies of successful reception A
When CK (x) is equal to or more than the predetermined number N, the modulation method is modulated at the modulation method level 2 which is the next higher level from the next frame timing, and PKT (N + 1) is transmitted.

As described above, in the fifth embodiment, the mobile station 30
Determines that the data transmitted from the base station 40 has been correctly received N times or more while the retransmission request management unit 72c receives the data for a predetermined number L of times of reception,
It instructs the adaptive demodulator 71c to change the demodulation method level,
The adaptive demodulation unit 71c selects a demodulation system level that is one level higher than the current demodulation system level and notifies the demodulation unit 5c, and the demodulation unit 5c automatically changes the demodulation system at the next reception frame timing. While the base station 40 performs reception for a predetermined number of times L of receptions, the content of the retransmission request information 22d in the data transmitted from the mobile station 30 indicates successful reception, which is predetermined. When the retransmission response management unit 74d determines that the number of receptions is N or more times,
The adaptive modulation unit 73d is instructed to change the modulation system level,
The adaptive modulation unit 73d selects a modulation system that is one level higher than the currently used modulation system level, and notifies the modulation unit 2d,
The modulator 2d automatically changes the modulation method from the next transmission frame. That is, in order to change the modulation / demodulation method in advance, the condition that the reception is successful N times or more in the L times of reception is stored in the mobile station 30 and the base station 40, and if the condition is satisfied, the modulation / demodulation is automatically performed. Try to change the method. As a result, the base station 40 adaptively selects the modulation method without notifying the mobile station 30 of the control data such as the modulation method used at the time of transmission, and the mobile station 30 notifies the base station 40 of the control data such as the demodulation method. It is possible to adaptively select the demodulation method without being performed and improve the transmission efficiency.

The mobile station 30 need not estimate the channel quality of the received pilot signal from the base station 40,
Furthermore, since it is not necessary to notify the base station of the line quality,
The delay time is suppressed, and rapid switching of the modulation system can be realized.

Sixth Embodiment A sixth embodiment of the present invention will be described with reference to FIG. In the sixth embodiment, when the mobile station 30 correctly receives N or more times while receiving the transmission data from the base station 40 for a predetermined number of times L of receptions, the level of the demodulation method starts from the next frame. To move up by one. While the base station 40 receives the retransmission request information 22d for notifying whether the mobile station 30 has correctly received the data over a predetermined number of times L times, the retransmission request information 22d for notifying the successful reception is received. When it is received N times or more, the level of the modulation method is changed to the next higher level from the next frame. However, when the retransmission request information 22c including the information of successful reception transmitted by the mobile station 30 is not correctly received by the base station 40, the mobile station 30 and the base station 40
Inconsistency occurs in the modulation and demodulation method of.

In the sixth embodiment, when only the mobile station 30 raises the demodulation method level by one, when the modulation / demodulation methods of the mobile station 30 and the base station 40 do not match, the mobile station 30 automatically operates. By lowering the level of the modulation method by one, the modulation / demodulation methods of the mobile station 30 and the base station 40 are matched.

Since the configurations of the mobile station and the base station of the mobile communication system according to the sixth embodiment are the same as those shown in FIGS. 2 and 3, the description thereof will be omitted here.

The reception procedure and transmission procedure of the mobile station 30 are the same as those described in Embodiment 1 with reference to the flowchart of FIG. 5, and therefore description thereof will be omitted here.

The adaptive demodulation determination processing of mobile station 30 will be described. When the decoded reception data 17c is received, the number of times of reception is counted. Retransmission request management unit 72c of control unit 7c
Determines whether or not the reception data 15c is correctly received by referring to the reception number or the like included in the decoded reception data 17c, and if the reception data 15c is not correctly received, includes reception failure information. Resend request information 22
Notify c to the modulation unit 2c. The resend request management unit 72c
The internal reception failure counter is counted up, and when the value of the reception failure counter reaches a predetermined value M, that is, when the reception of the transmission data from the base station 40 fails M times, the demodulation method selection information 21c The adaptive demodulation unit 71c is notified so as to decrease the level of the demodulation method by one.

When the demodulation method selection information 21c specifies that the demodulation method level should be decreased by one, the adaptive demodulation section 71
For c, a demodulation method one level lower than the currently used demodulation method level is selected, and the selected demodulation method 20c is set to the demodulation unit 5
Then, the demodulation unit 5c lowers the demodulation method level by one and demodulates the received data 15c from the next frame.

When the received data 15c is correctly received, the resending request information 22c including the information of successful reception is notified to the modulator 2c. Retransmission request information 2 including information on successful reception
2c is notified to the modulation unit 2c, the retransmission request management unit 72c
Resets the reception failure counter while counting up the internal reception success counter. When the number of receptions reaches a predetermined number L, the retransmission request management unit 72c compares the value of the reception success counter in the retransmission request management unit 72c with a predetermined value N, and the value of the reception success counter is determined in advance. When the value becomes equal to or more than the predetermined value N, that is, when the mobile station 30 communicates with the base station 40 L times and correctly receives the reception data 15c N times during L times, the demodulation method selection information 21c is used. The adaptive demodulation unit 71c is notified to increase the level of the demodulation method by one.

The operation of base station 40 is similar to that of the fifth embodiment, and therefore its explanation is omitted here.

FIG. 18 is a sequence diagram showing communication between the mobile station 30 and the base station 40. In FIG. 18, PKT
(X) corresponds to the transmission data 10d transmitted from the base station 40 to the mobile station 30, and ACK (x) is the mobile station 30.
From the base station 40 to the retransmission request information 2 for notifying that the transmission data 10d from the base station 40 has been correctly received.
2c, NAK (x) is from the mobile station 30 to the base station 4
0 corresponds to the retransmission request information 22c notifying that the reception of the transmission data 10d from the base station 40 has failed, and x is the sequence number of the transmission data 10d from the base station 40.

Similar to the fifth embodiment, the base station 40 transmits the transmission data PKT (N-1), PKT to the mobile station 30.
(N) is transmitted and the reception counter of the mobile station 30 is set to L.
When the number of successful receptions reaches N times or more, the mobile station 30 performs demodulation with the demodulation method level 2 which is one higher than the demodulation method level from the next frame timing, and transmits ACK (N) to the base station. Send to 40. Here, the base station 40 transmits the ACK (N) transmitted from the mobile station 30 to N
If erroneously determined to be AK (N), the base station 40
Since the number of successful receptions of K (x) is less than N out of the predetermined number of times L of reception, the modulation scheme level is not changed and PKT (N) is retransmitted with the modulation scheme level 1. Since the demodulation method level of the mobile station 30 is the modulation method level 2, a mismatch occurs in the modulation / demodulation method, and the mobile station 30
Fails to receive the PKT (N) retransmitted from the base station 40. Since the mobile station 30 expects PKT (N + 1) data, NAK (N + 1) notifying reception failure.
Is transmitted to the base station 40.

When the base station 40 receives NAK (N + 1), it transmits PKT (N + 1), but since the modulation / demodulation schemes of the base station 40 and mobile station 30 do not match, the mobile station 3
When 0 is unsuccessful in reception, the reception failure counter is counted up. When the value of the reception failure counter reaches M consecutive times, the mobile station 30 lowers the demodulation method level by one.
At the next frame timing, the mobile station 30 can correctly receive PKT (N + 1) that the base station 40 has modulated with the modulation method level 1 and transmitted.

As described above, in the sixth embodiment, the mobile station 30
Determines that the data transmitted from the base station 40 has been correctly received N times or more while the retransmission request management unit 72c receives the data for a predetermined number L of times of reception,
It instructs the adaptive demodulator 71c to change the demodulation method level,
The adaptive demodulation unit 71c selects a demodulation system level that is one higher than the current demodulation system level and notifies the demodulation unit 5c, and the demodulation unit 5c automatically changes the demodulation system at the next reception frame timing. On the other hand, since the content of the retransmission request information 22d in the data transmitted from the mobile station 30 is less than N times the number of successful receptions, the base station 40 receives the predetermined number L of times of reception. The modulation method level is not changed, and the demodulation method 20c of the mobile station 30 and the base station 40
Even if the modulation scheme 23d of the above-mentioned mismatch occurs, thereafter, the mobile station 30 performs the predetermined number of times M,
When the reception of the data transmitted from the base station 40 fails,
The demodulation method level of the demodulation method 20c is automatically lowered by one. As a result, the base station 40 adaptively selects the modulation scheme without notifying the mobile station 30 of control data such as the modulation scheme used at the time of transmission, and the mobile station 30 makes the base station 4
Since the demodulation method can be adaptively selected from 0 without being notified of control data such as the demodulation method, the transmission efficiency can be improved.

The mobile station 30 does not need to estimate the channel quality of the received pilot signal from the base station 40,
Furthermore, since it is not necessary to notify the base station of the line quality,
The delay time is suppressed, and rapid switching of the modulation system can be realized.

Seventh Embodiment A seventh embodiment of the present invention will be described with reference to FIG. In the seventh embodiment, if the mobile station 30 fails to receive the transmission data 10d from the base station 40 M times or more while the mobile station 30 receives the predetermined number of receptions L times, the next The level of the demodulation method is changed by one from the frame, and the base station 40 notifies the retransmission request information 22d including the reception failure notifying that the mobile station 30 has failed to receive the data for the predetermined number of reception times L times. When the retransmission request information 22d indicating the reception failure is received M times or more, the level of the modulation method is set to 1 from the next frame.
It will be changed below.

Since the configurations of the mobile station and the base station of the mobile communication system of the seventh embodiment are the same as those shown in FIGS. 2 and 3, the description thereof will be omitted here.

The mobile station 30 is similar to that of the sixth embodiment, and therefore its explanation is omitted here.

The reception procedure and transmission procedure of base station 40 are the same as those described in Embodiment 1 with reference to the flowchart of FIG. 7, and therefore description thereof will be omitted here.

The adaptive modulation determination process of the base station 40 will be described. The resend response management unit 74d uses the resend request information 22d.
When the is received, the reception number counter is incremented. The demodulator 5d determines whether or not the content of the retransmission request information 22d extracted from the received data 15d is a notification of successful reception. When the content of the retransmission request information 22d is the notification of the reception failure, the retransmission response management unit 74d notifies the transmission buffer unit 8d of the reception failure by using the retransmission response information 25d. When the mobile station 30 is notified by the retransmission response information 25d that the reception has failed, the transmission buffer unit 8d uses the held data, that is, the transmission data 10d transmitted in the previous frame as the transmission buffer data 18d. Output to the coding unit 3d.

The retransmission response management section 74d counts up the internal reception failure counter. When the value of the reception number counter reaches the predetermined value L, the retransmission response management unit 74d compares the value of the reception failure counter in the retransmission response management unit 74d with the predetermined value M, and reception failure. When the value of the counter is equal to or larger than the predetermined value M, that is,
When the retransmission request information 22d notifies that the mobile station 30 has failed to receive the reception data 15c M times or more among the L times of receiving the retransmission request information 22d, the modulation method selection information 24d is used to change the modulation method. The adaptive modulation unit 73d is notified to decrease the level by one.

When the modulation system selection information 24d instructs to lower the level of the modulation system by one, the adaptive modulation unit 7
3d selects a modulation method one level lower than the demodulation method level currently used, notifies the selected modulation method 23d to the modulation unit 2d, and sends the encoded transmission data 11d at the modulation method level from the next frame timing. Is modulated by a modulation method that is lowered by one.

FIG. 19 is a sequence diagram showing communication between the mobile station 30 and the base station 40. In FIG. 19, PKT
(X) corresponds to the transmission data 10d transmitted from the base station 40 to the mobile station 30, and ACK (x) is the mobile station 30.
From the base station 40 to the retransmission request information 2 for notifying that the transmission data 10d from the base station 40 has been correctly received.
2c, NAK (x) is from the mobile station 30 to the base station 4
0 corresponds to the retransmission request information 22c notifying that the transmission data 10d from the base station 40 could not be correctly received, and x is the sequence number of the transmission data 10d from the base station 40.

The base station 40 and the mobile station 30 are communicating at the modulation system level 2. The base station 40 transmits the transmission data PKT (x) to the mobile station 30, the mobile station 30 receives the transmission data PKT (x), and the reception processing unit 4c and the demodulation unit 5c receive the reception signal 14c. The channel decoding unit 6c executes reception processing, demodulation processing, and error correction decoding processing. The resend request management unit 72c displays the PK
When it is determined that the reception of T (x) has failed, the reception failure counter is incremented. The modulation unit 2c modulates the retransmission request information 22c for notifying the reception failure and the coded transmission data 11c coded by the channel coding unit 3c,
The transmission processing unit 1c performs transmission processing to NAK the base station 40.
Send (x).

When the base station 40 receives the NAK (x) transmitted from the mobile station 30, the reception processing section 1d performs reception processing, the demodulation section 5d extracts the retransmission request information 22d, and the extracted retransmission The retransmission response management unit 74d determines whether or not the mobile station 30 correctly receives the PKT (x) transmitted by the retransmission response management unit 74d in the immediately preceding frame. In this case, the retransmission request information 2 received by the base station 40
Since 2d is a notification of reception failure, the transmission buffer unit 8d
To the retransmission response information 25d, which is a notification of reception failure, and the reception failure counter in the retransmission response management unit 74d is counted up.

The transmission buffer section 8d has the retransmission response information 25.
Since d indicates the reception failure, the currently held PKT (x) is output as the transmission buffer data 18d. The channel coding unit 3d performs coding processing, the modulation unit 2d modulates at 8PSK which is the currently specified modulation scheme level 2, and the transmission processing unit 1d performs transmission processing and transmits to the mobile station 30.

As described above, when the above operation is repeated and the value of the reception number counter in the retransmission request management section 72c of the mobile station 30 reaches the predetermined value L, the value of the reception failure counter is predetermined. If the value is M or more, the level of the demodulation method is decreased by 1 from the next frame and the modulation method level is decreased by 1.
And NAK (x) is transmitted to the base station 40.

Also in the base station 40, the value of the reception number counter reaches a predetermined value L and the number of times NAK (x) is received becomes M times or more. Therefore, the modulation method is currently set from the next frame timing. The PKT (x) is changed to the mobile station 30 by changing the modulation method level one level lower than the used level.
Send to.

As described above, in the seventh embodiment, the mobile station 30
Determines that the data transmitted from the base station 40 is erroneously received M times or more while the retransmission request management unit 72c receives the data for a predetermined number L of times of reception,
It instructs the adaptive demodulator 71c to change the demodulation method level,
The adaptive demodulation unit 71c selects a demodulation system level that is one level lower than the current demodulation system level and notifies the demodulation unit 5c, and the demodulation unit 5c automatically changes the demodulation system at the next reception frame timing. While the base station 40 performs reception for a predetermined number L of times of reception, the content of the retransmission request information 22d in the data transmitted from the mobile station 30 indicates reception failure, and the number of times is predetermined. Retransmission response management unit 74d receives the M or more times, which is the determined number of times.
When the determination is made, the adaptive modulation unit 73d is instructed to change the modulation system level, the adaptive modulation unit 73d selects the modulation system level one level below the current modulation system level, and the modulation unit 2d
The modulator 2d automatically changes the modulation method from the timing of the next transmission frame. That is, in order to change the modulation / demodulation method in advance, the condition that the reception fails M times or more out of L times of reception is stored in the mobile station 30 and the base station 40, and when the number of times is reached, modulation / demodulation is automatically performed. Try to change the method. This allows the base station 40 to adaptively select the modulation scheme without notifying the mobile station 30 of control data such as the modulation scheme used at the time of transmission, and the mobile station 3
It is possible to adaptively select the demodulation method 0 without being notified of the control data such as the demodulation method from the base station 40, and it is possible to improve the transmission efficiency.

Further, the mobile station 30 need not estimate the channel quality of the received pilot signal from the base station 40,
Furthermore, since it is not necessary to notify the base station of the line quality,
The delay time is suppressed, and rapid switching of the modulation system can be realized.

Eighth Embodiment Embodiment 8 of the present invention will be described with reference to FIG. In the seventh embodiment, the mobile station 3
When 0 fails to receive M times or more while receiving the transmission data from the base station 40 over the predetermined number of times of reception L times, the level of the demodulation method is changed to 1 from the next frame, The base station 40 receives the retransmission request information 22d including the reception failure notifying that the mobile station 30 has failed to receive the data, and the retransmission request information 22d of the reception failure is received M times or more among the predetermined reception times L times. Upon reception, the level of the modulation method is changed by one from the next frame. But,
When the retransmission request information 22c including the reception failure information transmitted by the mobile station 30 cannot be correctly received by the base station 40, a mismatch occurs between the modulation / demodulation schemes of the mobile station 30 and the base station 40.

In the eighth embodiment, only the base station 40 lowers the modulation method level by one, so that when the modulation / demodulation methods of the mobile station 30 and the base station 40 do not match, the mobile station 30 automatically operates. By lowering the level of the modulation method by one, the modulation / demodulation methods of the mobile station 30 and the base station 40 are matched.

Since the configurations of the mobile station and the base station of the mobile communication system according to the eighth embodiment are the same as those shown in FIGS. 2 and 3, the description thereof will be omitted here.

FIG. 20 is a sequence diagram showing communication between the mobile station 30 and the base station 40. In FIG. 20, PKT
(X) corresponds to the transmission data 10d transmitted from the base station 40 to the mobile station 30, and ACK (x) is the mobile station 30.
From the mobile station 30 to the base station 40, the NAK (x) corresponds to the retransmission request information 22c for notifying that the transmission data from the base station 40 has been correctly received. Corresponding to the resend request information 22c notifying that the transmission data from the base station 40 could not be correctly received, and x is the sequence number of the transmission data 10d from the base station 40.

The base station 40 and the mobile station 30 communicate with each other at the modulation system level 2. The base station 40 transmits the transmission data PKT (x-1) to the mobile station 30,
Correctly receives this transmission data PKT (x-1), it transmits ACK (x-1) to the base station 40. At the next frame timing, the base station 40 moves the mobile station 30
To PKT (x). Since the mobile station 30 failed to receive this PKT (x), the retransmission request management unit 72
The reception failure counter in c is incremented, and the base station 4
NAK (x) is transmitted to 0. Base station 40 is NA
Since K (x) is received, the reception failure counter in the retransmission response management unit 74d is counted up and PKT (x) is transmitted to the mobile station 30. The mobile station 30 correctly receives the PKT (x) retransmitted from the base station 40 and transmits ACK (x) to the base station 40. This ACK (x) is sent to the base station 40
If it is received by mistake, that is, if it is determined to be NAK (x), the reception failure counter in the retransmission response management unit 74d is counted up and the number of receptions reaches L times. Becomes M or more times, the modulation method level is changed by one, and PKT (x) is changed to the modulation method level 1
And is transmitted to the mobile station 30. Here, the mobile station 30
Expects data of PKT (x + 1) modulated by the modulation method level 2, and PK retransmitted from the base station 40.
Since T (x) is demodulated by the demodulation method level 2, reception fails and NAK (x + 1) is transmitted. In this way, since the modulation scheme level of the base station 40 and the demodulation scheme level of the mobile station 30 do not match, PKT (x + 1) reception failures continue. When the number of reception failures reaches M consecutive times, the mobile station 30 lowers the demodulation method level by one and demodulates the data of the next frame timing. That is, by automatically lowering the demodulation method level to the demodulation method level 1, P
Successful reception of KT (x + 1).

As described above, in the eighth embodiment, the mobile station 30
Means that while the retransmission request management unit 72c receives the data transmitted from the base station 40 for a predetermined number of times L of receptions, the number of erroneous receptions is less than M.
The current demodulation system level is selected without instructing the adaptive demodulation unit 71c to change the demodulation system level.
Demodulation is also performed after the next reception frame timing. on the other hand,
While the base station 40 performs reception for a predetermined number L of times of reception, the content of the retransmission request information 22d in the data transmitted from the mobile station 30 indicates reception failure, and the number of times M times. As described above, the adaptive modulator 73d
To the adaptive modulation section 73d.
Selects a modulation scheme level one level lower than the current modulation scheme level and notifies the modulation section 2d, and the modulation section 2d automatically changes the modulation scheme at the next transmission frame timing. Even when the modulation / demodulation method mismatch occurs between the base station 40 and the base station 40, if the mobile station 30 subsequently fails to receive the data transmitted from the base station 40 a predetermined number of times M, the demodulation method 20c is automatically set. The demodulation method level of is lowered by one. As a result, the base station 40 adaptively selects the modulation method without notifying the mobile station 30 of the control data such as the modulation method used at the time of transmission, and the mobile station 30 notifies the base station 40 of the control data such as the demodulation method. It is possible to adaptively select the demodulation method without being performed and improve the transmission efficiency.

The mobile station 30 does not need to estimate the channel quality of the received pilot signal from the base station 40,
Furthermore, since it is not necessary to notify the base station of the line quality,
The delay time is suppressed, and rapid switching of the modulation system can be realized.

[0185]

As described above, according to the mobile communication system of the present invention, the retransmission request management section of the mobile station determines whether or not the data transmitted from the base station is correctly received, and It decides whether to change the demodulation method of the received data of the next frame based on the judgment result.When changing the demodulation method, it notifies the adaptive demodulation unit that the demodulation method should be changed, and notifies the notification. Based on this, the adaptive demodulator
The demodulation method is determined from among a plurality of predetermined demodulation methods, and the retransmission response management unit of the base station determines whether the content of the retransmission request information included in the data transmitted from the mobile station indicates successful reception or unsuccessful reception. Based on the determination result, it is determined whether or not to change the modulation method of the data to be transmitted in the next frame, and when changing the modulation method, the adaptive modulation unit must change the modulation method. Based on the notification, the adaptive modulation unit determines the modulation method from a plurality of predetermined modulation methods, so that the base station moves control data such as the modulation method used at the time of transmission. It is possible to adaptively select the modulation method without notifying the station, and the mobile station can adaptively select the demodulation method without being notified of the control data such as the demodulation method from the base station, thereby improving the transmission efficiency. It is possible .

According to the mobile communication system of the next invention, when the retransmission request management section correctly receives the data transmitted from the base station a predetermined number of times in succession, the retransmission request management section sets the demodulation method for the next frame to the higher demodulation method. When the retransmission response management unit performs control for switching to the system and continuously receives the reception success signal transmitted from the mobile station for a predetermined number of times, the retransmission response management unit switches the modulation system in the next frame to the higher modulation system. Since the control is performed, the base station adaptively selects the modulation method without notifying the mobile station of the control data such as the modulation method used at the time of transmission, and the mobile station transmits the control data such as the demodulation method from the base station. It is possible to adaptively select the demodulation method without being notified, and it is possible to improve the transmission efficiency.

[0187] According to the mobile communication system of the next invention, the retransmission request management section correctly receives the data transmitted from the base station continuously for a predetermined number of times, and the demodulation method in the next frame is demodulated to a higher demodulation method. When the data transmitted from the base station is erroneously received continuously for a predetermined number of times, the control for switching the demodulation method in the next frame to the lower demodulation method is performed. Since this is performed, the base station adaptively selects the modulation method without notifying the mobile station of the control data such as the modulation method used during transmission, and the mobile station notifies the base station of the control data such as the demodulation method. It is possible to adaptively select the demodulation method without being performed and improve the transmission efficiency.

According to the mobile communication system of the next invention, when the retransmission request management section erroneously receives data transmitted from the base station a predetermined number of times in succession, the retransmission request management section sets the demodulation method for the next frame to the lower order. When the reception response signal transmitted from the mobile station is continuously received for a predetermined number of times, the retransmission response management unit performs the control for switching to the demodulation system of the lower frame. Since the control is performed to switch to, the base station adaptively selects the modulation method without notifying the mobile station of the control data such as the modulation method used at the time of transmission, and the mobile station selects the demodulation method from the base station. The demodulation method can be adaptively selected without being notified of control data, and the transmission efficiency can be improved.

According to the mobile communication system of the next invention, the retransmission request management section erroneously continuously receives the data transmitted from the base station a predetermined number of times, and the demodulation method for the next frame is set to the lower order. Before the control for switching to the demodulation method is performed, the retransmission response management unit determines that the reception failure signal transmitted from the mobile station has been continuously received for a predetermined number of times, and switches the modulation method to a lower modulation method. If the retransmission request management unit determines that the data transmitted from the base station has been erroneously received continuously for a predetermined number of times after performing the control of step 1, the demodulation method in the next frame is switched to a lower demodulation method. Therefore, the base station adaptively selects the modulation method without notifying the mobile station of control data such as the modulation method used at the time of transmission, and The demodulation method without being notified of the control data, such as demodulation scheme than the station adaptively can select, it is possible to improve the transmission efficiency.

According to the mobile communication system of the next invention, the retransmission request management section receives the data transmitted from the base station for a predetermined number of times, and when the number of correctly received times exceeds the predetermined number of times, Control is performed to switch the demodulation method in the next frame to a higher demodulation method, and the retransmission response management unit receives the retransmission request signal transmitted from the mobile station for a predetermined number of times, and When the predetermined number of times is exceeded, control is performed to switch the modulation method in the next frame to the higher-order modulation method, so the base station notifies the mobile station of control data such as the modulation method used during transmission. The mobile station can adaptively select the demodulation method without being informed of the control data such as the demodulation method from the base station. It is possible to improve.

According to the mobile communication system of the next invention, the retransmission request management section receives the data transmitted from the base station for a predetermined number of times, the number of correctly received times exceeds the predetermined number of times, and the next frame is transmitted. When the control is performed to switch the demodulation method in the above to the higher demodulation method, and then the data transmitted from the base station is continuously and mistakenly received for a predetermined number of times, the demodulation method in the next frame is changed to the lower demodulation method. Since the control is performed to switch to, the base station adaptively selects the modulation method without notifying the mobile station of the control data such as the modulation method used at the time of transmission, and the mobile station demodulates from the base station. It is possible to adaptively select a demodulation method without being notified of control data such as, and improve transmission efficiency.

According to the mobile communication system of the next invention, the retransmission request management section receives the data transmitted from the base station a predetermined number of times, and when the number of erroneous receptions exceeds the predetermined number of times. , Controls to switch the demodulation method in the next frame to a lower demodulation method, and the retransmission response management unit receives the reception failure signal while receiving the retransmission request signal transmitted from the mobile station for a predetermined number of times. When the number of times the number of times of operations exceeds the predetermined number of times, control is performed to switch the modulation method in the next frame to a lower-order modulation method, so the base station moves control data such as the modulation method used during transmission. It is possible to adaptively select the modulation scheme without notifying the station, and the mobile station can adaptively select the demodulation scheme without being notified of the control data such as the demodulation scheme from the base station, Thereby improving the transmission efficiency.

According to the mobile communication system of the next invention, while the retransmission request management section receives data transmitted from the base station for a predetermined number of times, the number of erroneous receptions exceeds the predetermined number of times, and Before performing the control to switch the demodulation method in the frame to the lower demodulation method, the retransmission response management unit received the reception failure signal while receiving the retransmission request signal transmitted from the mobile station for the predetermined number of times. It judges that the number of times has exceeded the predetermined number of times, performs control to switch the modulation method in the next frame to a lower modulation method, and then the retransmission request management unit continuously transmits the data transmitted from the base station for a predetermined number of times. If it is determined that the error has been received by the retransmission request management unit, the retransmission request management unit performs control to switch the demodulation method in the next frame to a lower demodulation method. The base station adaptively selects the modulation method without notifying the mobile station of the control data such as the modulation method used during transmission, and the mobile station selects the demodulation method without notifying the base station of the control data such as the demodulation method. It can be adaptively selected, and the transmission efficiency can be improved.

According to the adaptive modulation method of the next invention, the mobile station judges whether or not the data transmitted from the base station is correctly received, and based on the judgment result, the received data of the next frame is detected. Determines whether to change the demodulation method, determines the demodulation method from a plurality of predetermined demodulation method based on the determination result, the base station, the retransmission request included in the data transmitted from the mobile station It is determined whether the content of the information is reception success or reception failure, and based on the result of the determination, it is determined whether or not to change the modulation method of the transmission data in the next frame, and it is predetermined based on the result of the determination. Since the modulation method is determined from a plurality of modulation methods, the base station adaptively selects the modulation method without notifying the mobile station of control data such as the modulation method used at the time of transmission, and the mobile station base The demodulation method without being further notified of the control data, such as demodulation schemes adaptively can select, it is possible to improve the transmission efficiency.

According to the adaptive modulation method of the next invention, when the mobile station determines that it has correctly received the data transmitted from the base station continuously for a predetermined number of times,
After deciding to switch the demodulation method in the next frame to the higher-order demodulation method, the base station continuously receives the contents of the retransmission request information contained in the data transmitted from the mobile station for a predetermined number of times indicating that the reception was successful. If it is determined that it is determined that the modulation method in the next frame is switched to the higher-order modulation method, the base station does not need to notify the mobile station of control data such as the modulation method used at the time of transmission. It is possible to adaptively select the modulation method and to adaptively select the demodulation method without the mobile station being notified of the control data such as the demodulation method from the base station, thereby improving the transmission efficiency.

According to the adaptive modulation method of the next invention, the mobile station determines that the data transmitted from the base station has been correctly received continuously for a predetermined number of times, and the demodulation method for the next frame is set to the higher order. If it is determined that the data transmitted from the base station has been erroneously received continuously for a predetermined number of times, the demodulation method for the next frame is switched to the lower demodulation method. Therefore, the base station adaptively selects the modulation method without notifying the mobile station of the control data such as the modulation method used during transmission, and the mobile station controls the demodulation method from the base station. The demodulation scheme can be adaptively selected without being notified of data, and the transmission efficiency can be improved.

According to the adaptive modulation method of the next invention, when the mobile station determines that the data transmitted from the base station has been erroneously received continuously for a predetermined number of times, the demodulation in the next frame is performed. When it is determined that the scheme is switched to a lower demodulation scheme, the base station continuously determines that the content of the retransmission request information included in the data transmitted from the mobile station is a reception failure for a predetermined number of times, Since it is decided to switch the modulation method in the next frame to a lower modulation method, the base station adaptively changes the modulation method without notifying the mobile station of control data such as the modulation method used at the time of transmission. The mobile station can adaptively select the demodulation method without being notified of the control data such as the demodulation method from the base station, and the transmission efficiency can be improved.

According to the adaptive modulation method of the next invention, the mobile station determines that the data transmitted from the base station has been erroneously received continuously for a predetermined number of times, and the demodulation method for the next frame is set. Before deciding to switch to the lower demodulation method, the base station determines that the content of the retransmission request information included in the data transmitted from the mobile station has failed in reception for a predetermined number of times in succession, and If the mobile station decides to switch the modulation method in the frame to a lower modulation method and then determines that the mobile station has erroneously received the data transmitted from the base station for a predetermined number of times in succession, the next frame Since it is decided to switch the demodulation method in step 1 to a lower demodulation method, the modulation method can be used without notifying the mobile station of control data such as the modulation method used by the base station during transmission. Adaptively selected demodulation scheme without the mobile station is notified of the control data, such as demodulation scheme from the base station can adaptively select, it is possible to improve the transmission efficiency.

According to the adaptive modulation method of the next invention, the number of times that the mobile station judges that the data transmitted from the base station has been correctly received, while judging the data transmitted from the base station a predetermined number of times. When the number of times exceeds a predetermined number, it is determined that the demodulation method in the next frame is switched to a higher-order demodulation method, and the base station determines retransmission request information for a predetermined number of times. When the predetermined number of times is exceeded, it is decided to switch the modulation method in the next frame to the higher-order modulation method, so the base station notifies the mobile station of control data such as the modulation method used at the time of transmission. It is possible to adaptively select the modulation method without the mobile station being notified of the control data such as the demodulation method from the base station, thereby improving the transmission efficiency. It is possible.

According to the adaptive modulation method of the next invention, the number of times the mobile station determines that the data transmitted from the base station has been correctly received, while determining the data transmitted from the base station for a predetermined number of times. Exceeds a certain number of times,
If it is decided to switch the demodulation method in the next frame to a higher demodulation method, and then it is determined that the data transmitted from the base station has been erroneously received continuously for a predetermined number of times, the next frame Since it is decided to switch the demodulation method of to the lower demodulation method,
The base station adaptively selects the modulation method without notifying the mobile station of the control data such as the modulation method used during transmission, and the mobile station selects the demodulation method without notifying the base station of the control data such as the demodulation method. It can be adaptively selected, and the transmission efficiency can be improved.

According to the adaptive modulation method of the next invention, the mobile station judges that the data transmitted from the base station has been erroneously received while judging the data transmitted from the base station for a predetermined number of times. When the number of times exceeds a predetermined number, it is determined that the demodulation method in the next frame is switched to a lower demodulation method, and the base station determines retransmission request information for a predetermined number of times When the number of times exceeds a predetermined number, it is decided to switch the modulation method in the next frame to a lower modulation method, so the base station notifies the mobile station of control data such as the modulation method used at the time of transmission. The mobile station can adaptively select the demodulation method without being notified of the control data such as the demodulation method by the base station, thereby improving the transmission efficiency. It is possible.

According to the adaptive modulation method of the next invention, the mobile station determines that the data transmitted from the base station has been erroneously received while determining the data transmitted from the base station for a predetermined number of times. The number of times exceeds a predetermined number,
Before deciding to switch the demodulation method in the next frame to a lower demodulation method, the base station determines that the retransmission request information has exceeded a predetermined number of times while determining retransmission request information for a predetermined number of times, If it decides to switch the modulation scheme in the next frame to a lower modulation scheme, and then determines that the mobile station has erroneously received the data transmitted from the base station continuously for a predetermined number of times, Since it is decided to switch the demodulation method in the next frame to a lower demodulation method, the base station adaptively changes the modulation method without notifying the mobile station of control data such as the modulation method used at the time of transmission. The mobile station can adaptively select the demodulation method without being notified of the control data such as the demodulation method from the base station, and the transmission efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a mobile communication system to which the present invention is applied.

2 is a block diagram showing a configuration of a mobile station 30 shown in FIG.

FIG. 3 is a block diagram showing a configuration of a base station shown in FIG.

FIG. 4 is a diagram showing a table of modulation / demodulation system levels and modulation systems.

FIG. 5 is a flowchart for explaining the operation of the mobile station according to the first embodiment.

FIG. 6 is a flowchart for explaining details of the adaptive modulation determination process shown in FIG.

FIG. 7 is a flowchart for explaining the operation of the base station according to the first embodiment.

FIG. 8 is a flowchart for explaining details of the adaptive demodulation determination process shown in FIG.

FIG. 9 is a sequence diagram showing communication between the base station and the mobile station according to the first embodiment.

FIG. 10 is a flowchart illustrating details of adaptive demodulation determination processing according to the second embodiment.

FIG. 11 is a sequence diagram showing communication between the base station and the mobile station according to the second embodiment.

FIG. 12 is a sequence diagram showing communication between a base station and a mobile station according to the second embodiment.

FIG. 13 is a flowchart for explaining details of adaptive modulation determination processing according to the third embodiment.

FIG. 14 is a sequence diagram showing communication between a base station and a mobile station according to the third embodiment.

FIG. 15 is a sequence diagram showing communication between a base station and a mobile station according to the fourth embodiment.

FIG. 16 is a sequence diagram showing communication between the base station and the mobile station according to the fourth embodiment.

FIG. 17 is a sequence diagram showing communication between a base station and a mobile station according to the fifth embodiment.

FIG. 18 is a sequence diagram showing communication between a base station and a mobile station according to the sixth embodiment.

FIG. 19 is a sequence diagram showing communication between the base station and the mobile station according to the seventh embodiment.

FIG. 20 is a sequence diagram showing communication between a base station and a mobile station according to the eighth embodiment.

FIG. 21 is a block diagram showing a configuration of a conventional mobile station.

FIG. 22 is a block diagram showing a configuration of a conventional mobile station.

[Explanation of symbols]

1a, 1b, 1c, 1d reception processing units, 2a, 2b, 2
c, 2d modulation section, 3a, 3b, 3c, 3d channel coding section, 4a, 4b, 4c, 4d reception processing section, 5a, 5b, 5c, 5d demodulation section, 6a, 6b, 6
c, 6d channel decoding unit, 7a, 7b, 7
c, 7d control unit, 8a channel quality estimation unit, 10a, 1
0b, 10c, 10d transmission data, 11a, 11b,
11c, 11d encoded transmission data, 12a, 12b,
12c, 12d modulated transmission data, 13a, 13b, 1
3c, 13d transmission signal, 14a, 14b, 14c, 1
4d reception signal, 15a, 15b, 15c, 15d reception data, 16a, 16b, 16c, 16d demodulation reception data, 17a, 17b, 17c, 17d decoding reception data, 18a pilot signal, 18d transmission buffer data, 19a, 19b Channel quality Information, 20a, 20c
Demodulation method 21c Demodulation method selection information, 22c, 22
d retransmission request information, 23d modulation method, 24d modulation method selection information, 25d retransmission response information, 30 mobile station, 4
0 base station, 71c adaptive demodulation unit, 72c retransmission request management unit, 73d adaptive modulation unit, 74d retransmission response management unit.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5K004 AA05 AA08 FE00 FG00 JE00                       JG00                 5K034 AA02 DD02 EE03 EE10 FF11                       HH01 HH02 MM08 NN04 NN12                 5K067 AA21 BB04 BB21 DD11 DD41                       EE02 EE10 FF02 GG01 HH22                       JJ21

Claims (18)

[Claims] 1. A mobile communication system comprising a base station and a mobile station capable of modulating transmission data to be transmitted to a partner station and adaptively changing a modulation method, wherein the mobile station comprises: A retransmission request management unit that determines whether or not the data transmitted from the base station is correctly received, and determines whether or not to change the demodulation method of the received data of the next frame based on the determination result; An adaptive demodulation unit that determines a demodulation method from among a plurality of predetermined demodulation methods based on the determination of the request management unit, the base station, of the retransmission request information included in the data transmitted from the mobile station Determine whether the content was received successfully or failed,
A retransmission response management unit that determines whether to change the modulation system of data to be transmitted in the next frame based on the determination result, and a plurality of modulation systems that are predetermined based on the determination of the retransmission response management unit. A mobile communication system, comprising: 2. The retransmission request management section, when the data transmitted from the base station is correctly received a predetermined number of times in succession, performs control for switching a demodulation method in a next frame to a higher demodulation method. When the reception success signal transmitted from the mobile station is continuously received for a predetermined number of times, the retransmission response management unit performs control for switching the modulation scheme in the next frame to a higher modulation scheme. The mobile communication system according to claim 1, wherein: 3. The retransmission request management section performs control for correctly receiving data transmitted from the base station a predetermined number of times in succession and switching a demodulation method in a next frame to a higher demodulation method. ,afterwards,
The control for switching the demodulation method in the next frame to a lower demodulation method when the data transmitted from the base station is erroneously received continuously for a predetermined number of times. Two
The mobile communication system according to. 4. The retransmission request management unit switches the demodulation method in the next frame to a lower demodulation method when data transmitted from the base station is continuously and erroneously received a predetermined number of times. Control, the retransmission response management unit, for receiving a reception failure signal transmitted from the mobile station for a predetermined number of times consecutively, a control for switching the modulation method in the next frame to a lower modulation method The mobile communication system according to claim 1, wherein 5. Before performing control for switching to the lower demodulation method, the retransmission response management unit determines that the reception failure signal transmitted from the mobile station has been continuously received for a predetermined number of times, After performing control for switching the modulation method to a lower modulation method, the retransmission request management unit,
When the data transmitted from the base station is erroneously received continuously for a predetermined number of times, the retransmission request management unit performs control for switching the demodulation method in the next frame to a lower demodulation method. The mobile communication system according to claim 4. 6. The retransmission request management unit receives the data transmitted from the base station over a predetermined number of times, and when the number of times of correct reception exceeds a predetermined number, sets the demodulation method for the next frame. When performing control for switching to a higher demodulation method, the retransmission response management unit receives a retransmission request signal transmitted from the mobile station for a predetermined number of times, and when the reception of a reception success signal exceeds a predetermined number of times. The mobile communication system according to claim 1, wherein control is performed to switch the modulation method in the next frame to a higher-order modulation method. 7. The retransmission request management unit receives the data transmitted from the base station a predetermined number of times, and the number of correctly received times exceeds a predetermined number,
Control is performed to switch the demodulation method in the next frame to a higher demodulation method, and then, if the data transmitted from the base station is continuously and erroneously received for a predetermined number of times, the demodulation in the next frame is performed. 7. The control for switching the system to a lower demodulation system is performed.
The mobile communication system according to. 8. The retransmission request management unit receives the data transmitted from the base station for a predetermined number of times, and if the number of erroneous receptions exceeds a predetermined number, a demodulation method for the next frame Is controlled to switch to a lower demodulation method, the retransmission response management unit receives a retransmission request signal transmitted from the mobile station over a predetermined number of times, the number of times the reception failure signal is received is a predetermined number of times. The mobile communication system according to claim 1, wherein when the number exceeds the limit, control is performed to switch the modulation method in the next frame to a lower modulation method. 9. Before the control for switching to the lower demodulation system is performed, the retransmission response management unit receives a retransmission request signal transmitted from the mobile station for a predetermined number of times, and receives a reception failure signal. It is determined that the number of times of reception has exceeded a predetermined number of times, control is performed to switch the modulation method in the next frame to a lower modulation method, and then the retransmission request management unit changes the data transmitted from the base station. The mobile station according to claim 8, wherein, when the retransmission request management unit is erroneously received continuously for a predetermined number of times, the retransmission request management unit performs control for switching a demodulation method in a next frame to a lower demodulation method. Communications system. 10. An adaptive modulation method capable of modulating transmission data to be transmitted to a partner station and adaptively changing a modulation method, wherein a mobile station correctly receives data transmitted from a base station. A first step of determining whether or not the second step, and a second step of determining whether or not the mobile station changes the demodulation method of the reception data of the next frame based on the determination result of the first step. A step of: the mobile station determining a demodulation method from a plurality of predetermined demodulation methods based on the determination result of the second step; and a base station transmitted from the mobile station. A fourth step of determining whether the content of the retransmission request information included in the data indicates successful reception or unsuccessful reception, and the base station transmits the transmission data in the next frame based on the determination result of the fourth step. A fifth step of deciding whether to change the modulation method of No., and the base station deciding a modulation method from among a plurality of predetermined modulation methods based on the decision result of the fifth step. 6. An adaptive modulation method comprising the steps of: 11. In the second step, when it is determined that the mobile station correctly receives data transmitted from a base station continuously for a predetermined number of times,
It is decided to switch the demodulation method in the next frame to a higher demodulation method, and in the fifth step, the base station continuously transmits a retransmission request included in the data transmitted from the mobile station for a predetermined number of times. 11. The adaptive modulation method according to claim 10, wherein, when it is determined that the information content has been successfully received, it is determined to switch the modulation method in the next frame to a higher-order modulation method. 12. In the second step, the mobile station determines that the data transmitted from the base station has been correctly received continuously for a predetermined number of times, and the demodulation method in the next frame is set to a higher demodulation method. After deciding to switch to the other system, if it is determined that the data transmitted from the base station has been erroneously received continuously for a predetermined number of times, then the demodulation system in the next frame is switched to the lower demodulation system. 10. The method according to claim 10 or 1, wherein
1. The adaptive modulation method according to 1. 13. In the second step, when the mobile station determines that the data transmitted from the base station has been erroneously received continuously for a predetermined number of times, the demodulation method for the next frame is set. It is determined to switch to a lower demodulation method, and in the fifth step, the base station continuously receives a predetermined number of times and the content of the retransmission request information included in the data transmitted from the mobile station indicates that the reception failure has occurred. 11. The adaptive modulation method according to claim 10, wherein when it is determined that the modulation scheme in the next frame is to be switched to a lower modulation scheme. 14. In the second step, before the mobile station decides to switch to a lower demodulation scheme, the base station continuously transmits data transmitted from the mobile station for a predetermined number of times. It is determined that the content of the resend request information included is a reception failure, and a decision is made to switch the modulation method in the next frame to a lower modulation method, after which the mobile station continuously outputs a predetermined number of times to the base station. 14. The adaptive modulation method according to claim 13, wherein when it is determined that the data transmitted from is received by mistake, the demodulation method in the next frame is switched to a lower demodulation method. 15. In the second step, a predetermined number of times the mobile station judges that the data transmitted from the base station has been correctly received, while the mobile station judges data transmitted from the base station a predetermined number of times. When it exceeds the number of times, it is decided to switch the demodulation method in the next frame to a higher demodulation method, and in the fifth step, the base station determines the retransmission request information for a predetermined number of times. 11. The adaptive modulation method according to claim 10, wherein when the number of successful reception determinations exceeds a predetermined number, it is determined to switch the modulation method in the next frame to a higher-order modulation method. 16. In the second step, a predetermined number of times the mobile station judges that the data transmitted from the base station has been correctly received, while the mobile station judges data transmitted from the base station a predetermined number of times. Over the number of times
If it is decided to switch the demodulation method in the next frame to a higher demodulation method, and then it is determined that the data transmitted from the base station has been erroneously received continuously for a predetermined number of times, the next frame 10. It is determined to switch the demodulation method of 1 to a lower demodulation method.
5. The adaptive modulation method according to item 5. 17. In the second step, the number of times the mobile station determines that the data transmitted from the base station has been erroneously received in the determination of the data transmitted from the base station over a predetermined number of times. When the predetermined number of times is exceeded, it is determined to switch the demodulation method in the next frame to a lower demodulation method, and in the fifth step, the base station determines the retransmission request information for a predetermined number of times. 11. The adaptive modulation method according to claim 10, wherein, when the reception failure determination exceeds a predetermined number of times, it is determined to switch the modulation method in the next frame to a lower modulation method. 18. In the second step, the base station determines the retransmission request information for a predetermined number of times before the mobile station decides to switch to a lower demodulation scheme, and reception failure occurs. It is determined that the number of times exceeds a predetermined number of times, and it is determined to switch the modulation method in the next frame to a lower modulation method, and then the mobile station is continuously transmitted from the base station for a predetermined number of times. 18. The adaptive modulation method according to claim 17, wherein when it is determined that the data is erroneously received, the demodulation method in the next frame is switched to a lower demodulation method.