JP2001292466A - Wireless phone system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wireless phone system that can search a new base station with full slots without interrupting a voice for searching the base station. SOLUTION: A mobile station has a reception section 2 that demodulates a received signal resulting from receiving a transmission signal from a base station and outputs demodulated data and a control section 8 that controls the entire sections of the mobile station. The control section 8 processes demodulation data of the received signal in one slot of two slots of the same frame sent from a base station with which the mobile station makes communication as received data and controls the reception section 2 to stop the reception signal of the other slot in the two slots of the same frame sent from the base station that makes a communication with the opposite party so as to receive a control channel of other base station than the base station that makes the communication with the opposite party by using the other slot than the one slot.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio telephone system for performing radio communication between a base station and a mobile station using a time division multiplex system.

[0002]

2. Description of the Related Art Conventionally, a radio telephone system for performing communication between a mobile station and a base station using a time division multiplex system has been put to practical use. For example, P
In the HS, time division multiplexing is performed by dividing a time of 5 msec into eight equal parts, and using four as reception slots and the remaining four as transmission slots. In such a radio telephone system, the area in which communication with one base station is possible is limited, so if the mobile station moves away from the base station and the radio condition with the base station in communication deteriorates, the mobile station will In this case, the communication with the old base station (base station in communication) that was initially performing communication was interrupted, a new base station with good radio wave conditions was searched, and handover was performed.
In recent PHS wireless telephone systems, while maintaining communication with the old base station, a new base station with good radio wave conditions is searched for in an empty slot that is not performing transmission and reception with the old base station, and handover is performed. I was going.

[0003]

However, in the above-mentioned conventional radio telephone system, in the case of a system in which communication with the old base station is interrupted to search for a base station having a good radio wave condition and handover is performed, the new base station is used. In order to search for, the communication with the old base station is interrupted, so that there is a problem that the interruption of voice is long. In the method of searching for a new base station with a good radio wave condition and performing handover in an empty slot not transmitting and receiving to and from the old base station while maintaining communication with the old base station, communication with the old base station is performed. Since the base station transmitting the control channel cannot be received in the same slot as the middle slot, there is a problem that an optimum base station may not be found in some cases.

In this radio telephone system, two radio signals generated from the same transmission data are transmitted from the base station side after being multiplexed by the time division multiplexing system, and the mobile station side generates the two radio signals from the same transmission data. When two radio signals are received and a new base station is searched for handover, two radio signals in one frame sent from the old base station are used.
While receiving one of the two transmission signals, a search for a new base station is performed in the vacant slot. By performing a search for a new base station in an empty slot while receiving, there is a demand that a search for a new base station can be performed in all slots without interruption of voice for the base station search. .

SUMMARY OF THE INVENTION An object of the present invention is to provide a radio telephone system capable of searching for a new base station in all slots without interrupting voice for base station search in order to satisfy this demand. I do.

[0006]

SUMMARY OF THE INVENTION In order to solve this problem, a radio telephone system according to the present invention divides a frame of a predetermined fixed time into equal parts, and transmits a transmission signal in each of the equally divided time slots. When performing communication between a base station and a mobile station by multiplexing a received signal, a radio signal generated from the same transmission signal is transmitted from the base station in two slots of the same frame, and the mobile station transmits the radio signal from the base station. A time-division multiplexing radio telephone system for receiving a radio signal of two slots in the same frame, wherein the mobile station demodulates a received signal generated by receiving a transmission signal from a base station to demodulate data. And a control unit for controlling the whole. The control unit is configured to control the reception signal of one of the two slots of the same frame transmitted from the base station currently communicating. By processing the demodulated data as received data and controlling the receiving unit to stop the received signal of the other of the two slots of the same frame sent from the base station currently communicating, It has a configuration for receiving a control channel from a base station other than the base station currently communicating in slots other than.

[0007] Thus, a radio telephone system that can search for a new base station in all slots without interrupting the voice due to the base station search can be obtained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A radio telephone system according to a first aspect of the present invention divides a frame of a predetermined fixed time into equal parts, and divides a transmission signal and a reception signal in each equally divided time slot. When multiplexing and performing communication between the base station and the mobile station, a radio signal generated from the same transmission signal is transmitted from the base station in two slots of the same frame, and the mobile station transmits the same signal transmitted from the base station. A time-division multiplexing radio telephone system for receiving radio signals of two slots in a frame, wherein a mobile station demodulates a reception signal generated by receiving a transmission signal from a base station and outputs demodulated data. And a control unit for controlling the whole, and the control unit transmits demodulated data of a received signal of one of two slots of the same frame transmitted from the base station currently communicating. By controlling the receiving unit to process the received data and stop the reception signal of the other slot of the two slots of the same frame sent from the base station currently communicating, the slot other than the one slot is used. This is to receive a control channel from a base station other than the base station currently communicating.

With this configuration, two radio signals generated from the same transmission data are transmitted from the base station after being multiplexed by the time division multiplexing method, and the two radio signals generated from the same transmission data are transmitted from the mobile station to the mobile station. When a radio signal is received and a new base station is searched for handover, one of the two transmission signals in one frame sent from the old base station is received while an empty slot is being received. Searching for a new base station, and subsequently searching for a new base station in an empty slot while receiving the other of the two transmission signals in one frame sent from the old base station. Therefore, the reception of the radio signal from the old base station is not interrupted, so that the sound is not interrupted for the base station search, and the new base station is supported in all the slots. It has the effect that it is possible to detect the optimal base station by Ji.

An embodiment of the present invention will be described below with reference to FIGS.

(Embodiment 1) FIG. 1 is a block diagram showing a mobile station constituting a wireless telephone system according to Embodiment 1 of the present invention. FIGS. 2 (a) to 2 (e) show an embodiment of the present invention. FIG. 2F is a timing chart showing transmission and reception timings of the base station in Embodiment 1, and FIG. 2F is a timing chart showing transmission and reception timings of the mobile station in Embodiment 1 of the present invention.

In FIG. 1, 1 is an antenna for transmitting and receiving radio signals, 2 is a receiving section for demodulating and outputting received data from an input radio signal, and 3 is a converter for converting input transmission data (transmission signal). A transmitting unit 4 for generating and outputting a radio signal for transmission by extracting audio data from the demodulated data demodulated by the receiving unit 2, converting the audio data into an analog signal, and outputting the analog signal;
An audio processing unit for converting an input analog audio signal into audio data, adding synchronization data and the like, generating and outputting transmission data, and a reception quality detection unit for detecting a level (reception level) of a reception signal. And 6, a speaker that outputs a voice signal reproduced from the demodulated received data as a voice, 7 a microphone that outputs an input voice as a voice signal for transmission, and 8 a control unit that controls the entire mobile station. The function of the reception quality detection unit 5 will be described in detail. The reception quality detection unit 5 detects the reception level of the radio signal received by the reception unit 2 and determines the reception level in advance in the slot during communication on the communication channel. When the value falls below the set value, a signal for notifying that the reception level has decreased is output, and a signal corresponding to the received reception level of the control channel is output in the reception slot of the control channel.

FIG. 2 shows transmission / reception timings of the base station and the mobile station, FIG. 2 (a) shows transmission / reception timings of the first base station, and FIG. 2 (b) shows transmission / reception timings of the second base station. 2 (c) is the transmission / reception timing of the third base station, FIG.
2D shows the transmission and reception timing of the fourth base station, FIG. 2E shows the transmission and reception timing of the fifth base station, and FIG. 2F shows the transmission and reception timing of the mobile station. In the example of FIG. 2, one frame is divided into eight slots, and the first four slots in the frame, that is, the first to fourth slots are set as transmission slots from the base station (mobile stations are set as reception slots), An example is shown in which the latter four slots, that is, the fifth to eighth slots are set as reception slots from the base station (the mobile station is set as a transmission slot) and time-division multiplex communication of a voice signal is performed. The first base station transmits a control channel in the first slot. In FIG. 2, the control channel is described as “CCH”. Similarly, the second base station is in the second slot, the third base station is in the third slot, and the fourth base station is in the fourth slot.
The control channel is being transmitted in the slot. The fifth base station is a base station that is in communication with the mobile station, and a communication channel from the base station through the first slot and the second slot (FIG. 2).
In this example, the communication channel is referred to as “TCH”), and the mobile station transmits the communication channel in the fifth slot and the sixth slot corresponding to the transmission slot from the base station. The five base stations and the mobile station receive two communication channels in accordance with the transmission slot of the other party.

Hereinafter, the operation of the base station and the mobile station will be described with reference to FIGS.

First, the operation during normal communication, that is, FIG.
The operation in the case where the fifth base station and the mobile station are communicating on two communication channels as in the first frame T1 shown in FIG.

The radio signal from the fifth base station is transmitted to the antenna 1
And demodulated by the receiving unit 2.
The demodulated data demodulated by the receiving unit 2 is output to the audio processing unit 4 and the control unit 8. In addition, the reception quality detection unit 5 detects the reception level of the radio signal received from the base station by the reception unit 2 and determines that the reception level has decreased when the reception level falls below a predetermined value. The control unit 8 is notified. The control unit 8 determines whether the demodulated data demodulated by the receiving unit 2 is audio data or control data. If the demodulated data is audio data, the audio processing unit 4 reproduces an analog audio signal from the demodulated data. Then, control is performed so as to output from the speaker 6. At this time, since the same signal is transmitted in two slots in one frame from the fifth base station, the control unit 8 transmits the two slots in the same frame from the base station of the communication partner. After the reception of the signal is completed, the reception state of the two slots is determined, and the audio processing unit 4 is controlled so that the demodulated data having no reception error is converted into an analog signal and output. At this time, the reception state is determined by adding a CRC code to transmission data used in digital wireless communication such as PHS, transmitting the data, and checking the demodulated data demodulated from the received signal and the CRC code on the receiving side. A method of determining whether there is no reception error in the demodulated data or the like is used.

At the time of transmission, the audio signal input from the microphone 7 is converted into a digital signal by the audio processing unit 4 and transmission data (transmission signal) is generated by adding a synchronization signal and a signal for error determination. , And is converted to a radio signal by the transmission unit 3 and output from the antenna 1. At this time, since the control unit 8 needs to transmit a radio signal generated from the same transmission data in two slots in the same frame also from the mobile station to the base station, The audio processing unit 4 and the transmission unit 3 are controlled so that the generated transmission data is output in two transmission slots corresponding to the reception slots.

Next, the operation at the time of handover will be described. The handover is a method in which when the radio condition between the mobile station and the base station is deteriorated, the communication is switched to a base station having a good radio condition to continue the communication.
When the control unit 8 is notified that the level of the received signal has been lowered from the base station, or when the base station notifies the control unit 8 of control data that notifies the handover, the control data that notifies the handover is received by the receiving unit 2, Activated when detected by the unit 8. At the time of handover, the control unit 8 first searches for a new base station having a good reception state. In order to search for the base station, the control unit 8 stops one of the communication channels during communication with the old base station, and uses the stopped slot and the stopped slot not used for communication with the old base station to set up the new base station. Receiving unit 2 so as to receive the control channel of the station.
Control. Also, to prevent interruptions in the audio during the search,
The audio processing unit 4 is controlled so as to reproduce an audio signal from demodulated data of a communication channel which has not been stopped in communication with the old base station. One of the communication channels during communication with the old base station (fifth base station) (second slot) is stopped, and the reception slots other than the remaining communication channels during communication (second slot to second slot) are stopped.
A control channel search in the fourth slot) is performed for a predetermined time, and the control channel of the base station (second base station to fourth base station) is received in the slot receiving the control channel at this time. Then, the reception level is detected by the reception quality detection unit 5 and notified to the control unit 8 (the second frame T2 and the third frame T3 in FIG. 2).

Thereafter, the control unit 8 resumes the reception of the communication channel (second slot) with the old base station which was stopped earlier, and resumes the audio signal reproduced by the audio processing unit 4 in the slot. Is performed so as to generate the data from the received data of the old base station, the communication channel (the first slot) with the old base station that was communicating is stopped, and the stopped slot (the first
The control channel of the new base station (first, third, and fourth base stations) is determined in advance by the inactive slots (third slot, fourth slot) not used for communication with the old base station. Time reception (the fourth frame T4 and the fifth frame T5 in FIG. 2). When the search for the base station is completed, the communication with the old base station in the two slots is restarted (sixth frame T6 in FIG. 2). Then, in the mobile station,
An optimum base station is determined based on the received level of the received control channel, a control sequence with the new base station for handover is performed with the optimum base station, and communication is switched to the new base station.

FIG. 2 shows an example in which a plurality of base stations receivable by the mobile station transmit control channels in different slots. However, the mobile station operates as described above. The control channels of the second, third, and fourth base stations are received in the second and third frames, and the control channels of the first, third, and fourth base stations are received in the fourth and fifth frames. Therefore, all base stations other than the old base station can be searched regardless of the communication slot used for communication with the old base station.

In this embodiment, an example has been described in which the control channel search is performed in the first four reception slots in the frame. However, in the second four transmission slots in the frame, the old base station is searched. It is also possible to search for a control channel in a slot other than the slot currently used for transmission. At this time, the two slots used for transmission with the old base station are alternately stopped similarly to the case of reception, so that all base stations can be searched in the transmission slot.

As described above, according to the present embodiment, a frame of a predetermined fixed time is equally divided, and the transmission signal and the reception signal are multiplexed in the equally divided time slots, and the base station and the base station are multiplexed. When communicating with mobile stations,
A radio signal generated from the same transmission signal is transmitted from the base station in two slots of the same frame, and the mobile station receives a radio signal of two slots in the same frame transmitted from the base station. In a wireless telephone system, a mobile station includes a receiving unit 2 that demodulates a received signal generated by receiving a transmission signal from a base station and outputs demodulated data, and a control unit 8 that controls the entire system. Part 8
Processes demodulated data of a received signal in one of two slots of the same frame sent from the base station currently communicating, as received data, and performs processing on the same frame sent from the base station currently communicating. By controlling the receiving unit 2 so as to stop the reception signal of the other slot of the two slots, a control channel from a base station other than the base station with which communication is currently being performed is received in a slot other than the one slot. With this, two radio signals generated from the same transmission data are transmitted from the base station after being multiplexed by the time division multiplexing method, and the two radio signals generated from the same transmission data are transmitted from the mobile station to the mobile station. When receiving and searching for a new base station for handover, one of the two transmission signals in one frame sent from the old base station is received. While searching for a new base station in the vacant slot, and while receiving the other of the two transmission signals in one frame sent from the old base station, Since the base station can be searched, the reception of the radio signal from the old base station is not interrupted, so that the sound is not interrupted for the base station search, and the new base station is searched in all slots. By doing so, an optimal base station can be detected.

[0023]

As described above, according to the radio telephone system of the present invention, a predetermined fixed time frame is equally divided, and a transmission signal and a reception signal are multiplexed in each equally divided time slot. When communication is performed between the base station and the mobile station, a radio signal generated from the same transmission signal is transmitted from the base station in two slots of the same frame, and the mobile station transmits the same frame transmitted from the base station. A time division multiplexing radio telephone system for receiving radio signals of two of the slots, wherein the mobile station demodulates a reception signal generated by receiving a transmission signal from a base station and outputs demodulated data. And a control unit for controlling the whole, and the control unit is configured to control the demodulated data of the reception signal of one of the two slots of the same frame transmitted from the base station currently communicating. By processing the received data and controlling the receiving unit to stop the reception signal of the other of the two slots of the same frame sent from the base station currently communicating, the slot other than one of the two slots can be used. By receiving a control channel from a base station other than the base station currently communicating, two radio signals generated from the same transmission data are transmitted from the base station side in different slots. When a signal is received and a new base station is searched, two slots used for communication with the old base station can be stopped alternately to search the control channel of the entire section. There is no interruption of the reception of the radio signal from, so there is no interruption in the sound for the base station search,
By searching for a new base station in all slots, an advantageous effect that an optimum base station can be detected can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a mobile station constituting a wireless telephone system according to a first embodiment of the present invention.

FIG. 2A is a timing chart showing transmission / reception timing of a base station according to Embodiment 1 of the present invention. FIG. 2B is a timing chart showing transmission / reception timing of a base station according to Embodiment 1 of the present invention. (D) Timing diagram showing transmission / reception timing of base station according to Embodiment 1 of the present invention (d) Timing diagram showing transmission / reception timing of base station according to Embodiment 1 of the present invention (e) Base station according to Embodiment 1 of the present invention Timing chart showing transmission / reception timing of a station (f) Timing chart showing transmission / reception timing of a mobile station according to Embodiment 1 of the present invention

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 antenna 2 reception unit 3 transmission unit 4 audio processing unit 5 reception quality detection unit 6 speaker 7 microphone 8 control unit

Claims (1)

[Claims] When a communication between a base station and a mobile station is performed by dividing a frame of a predetermined fixed time into equal parts and multiplexing a transmission signal and a reception signal in each equally divided time slot. Transmitting a radio signal generated from the same transmission signal from the base station in two slots of the same frame, and the mobile station receiving radio signals of two slots in the same frame transmitted from the base station. A wireless telephone system of a division multiplex system, wherein the mobile station demodulates a reception signal generated by receiving a transmission signal from the base station and outputs demodulated data, and a control unit that controls the whole. The control unit processes demodulated data of a received signal of one of two slots of the same frame transmitted from a base station with which communication is currently being performed, as received data. By controlling the receiving unit so as to stop the reception signal of the other slot of the two slots of the same frame sent from the base station with which the current communication is being performed, the slot in slots other than the one slot A wireless telephone system for receiving a control channel from a base station other than the base station currently communicating.