JP4490932B2 - Radio base station apparatus and transmission rate notification method - Google Patents

Description

  The present invention relates to a radio base station apparatus and a transmission rate notification method.

  Conventionally, various devices have been made for a method that enables high-speed packet transmission on a downlink from a radio base station to a communication terminal, for example, HSDPA (High Speed Downlink Packet Access). Along with this, it is necessary to expand the capacity of the uplink from the communication terminal to the radio base station so that data transmission with a large capacity or low delay is possible. ing.

  In the high-speed packet transmission on the uplink, the introduction of scheduling technology is being studied as in the downlink. Uplink packet scheduling is performed at the base station, and the base station transmits the created scheduling information to each communication terminal. Each communication terminal transmits an uplink packet to the base station based on the scheduling information received from the base station. In scheduling in the base station, a communication terminal that permits transmission of an uplink packet is selected, and communication parameters such as a permitted transmission rate and transmission power are transmitted to the selected communication terminal using a downlink control signal. .

  One of scheduling methods in high-speed packet transmission on the uplink is a method called Time and Rate Scheduling (see Non-Patent Document 1). This Time and Rate Scheduling consists of the following three steps. That is, in the first step, the communication terminal notifies the base station of the required transmission rate, data amount, transmission power margin, and the like. Next, in the second step, the base station performs scheduling based on the notified requested transmission rate, data amount, transmission power margin, etc., selects a communication terminal that permits transmission of an uplink packet, and the selected communication terminal On the other hand, communication parameters such as a permitted transmission rate and transmission power are indicated by a downlink control signal. In the third step, the communication terminal that has received the control signal addressed to itself transmits an uplink packet at a transmission rate equal to or lower than the transmission rate instructed by the base station or a transmission power equal to or lower than the transmission power instructed from the base station. To do.

Here, as a transmission rate that can be used for high-speed packet transmission on the uplink, 32 types of MCS (Modulation and Coding Scheme) in “3GPP, R1-030667, HARQ Efficiency in E-DPDCH” (non-patent document 2). ) Has been proposed. In addition, the transmission of control signals in the downlink when using these MCSs in Time and Rate Scheduling has been proposed in “3GPP, R1-031232, Text Proposal on DL Signaling Overhead” (Non-patent Document 3). Yes. Non-Patent Document 3 proposes “5-bit reconfiguration pointer” as “E-DCH TFCS reconfiguration (ie scheduling Grant for Time-and-Rate scheduling)”. Since 5 bits can be expressed in 32 ways, Non-Patent Document 3 proposes to prepare 32 control signals capable of instructing all 32 MCSs to the communication terminal.
3GPP, R1-030592, Node B Controlled Time and Rate Scheduling 3GPP, R1-030667, HARQ Efficiency in E-DPDCH 3GPP, R1-031232, Text Proposal on DL Signaling Overhead

  However, as described above, if a control signal capable of expressing all the transmission rates that can be used for high-speed packet transmission on the uplink is prepared, the number of bits of the control signal increases. For example, as described above, when 32 control signals capable of instructing all 32 MCSs to the communication terminal are prepared, the number of bits of the control signal is 5 bits. When the number of bits of the control signal increases, as shown in FIG. 32, it is necessary to increase the transmission power of the control signal in order to satisfy the required reception quality (error rate) at the communication terminal of the control signal.

  For example, in a wireless communication system that simultaneously performs high-speed packet transmission on the uplink and high-speed packet transmission on the downlink, the number of bits of the control signal transmitted on the downlink affects the transmission power of the downlink packet. . That is, as shown in FIG. 33, since there is an upper limit in downlink transmission power resources, when the number of bits of the downlink control signal increases from N bits to M bits (N <M), the downlink is increased by that amount. The transmission power of the control signal increases, and conversely, the transmission power resources that can be used for downlink packets decrease accordingly, and as a result, sufficient transmission power resources can be allocated to downlink packets. There is a problem that the quality of the downlink packet is lowered and the transmission speed is lowered.

  Also, as shown in FIG. 34, sufficient downlink transmission power resources are allocated, and sufficient transmission power resources are allocated to downlink packets even if the number of bits of the downlink control signal increases from N bits to M bits. Even in such a case, the total transmission power in the base station increases due to an increase in transmission power due to an increase in the number of bits of the downlink control signal, which causes a problem that interference to other cells increases.

  Such a problem is not limited to the case where the control signal is transmitted on the downlink, but also occurs when the control signal is transmitted on the uplink.

  For example, when communication parameters such as the data length of a packet transmitted on the uplink are notified from the communication terminal to the base station, for example, 32 control signals capable of notifying the base station of all 32 data lengths are prepared. In this case, the control signal transmitted on the uplink requires 5 bits. When the number of bits of the control signal increases, it is necessary to increase the transmission power of the control signal in order to satisfy the required reception quality (error rate) of the control signal at the base station, as described above. Therefore, similarly to the above, there are problems that the quality of the packet, the transmission rate, and the interference with other cells are increased in the uplink.

  As described above, an increase in the number of bits of the control signal for notifying the communication parameter similarly becomes a problem in both the downlink and the uplink.

  The present invention has been made in view of the above points, and an object thereof is to provide a radio base station apparatus and a transmission rate notification method capable of suppressing the consumption of transmission power resources.

A radio base station apparatus according to one aspect of the present invention selects any one of a plurality of transmission rates and notifies a communication terminal apparatus that permits transmission of an uplink packet. And limiting means for limiting transmission rate candidates that can be selected to a part of the plurality of transmission rates, and selection for selecting a transmission rate of the uplink packet from the limited transmission rate candidates And a transmission means for wirelessly transmitting and notifying transmission rate information indicating the selected transmission rate to the communication terminal apparatus.

  ADVANTAGE OF THE INVENTION According to this invention, consumption of the transmission power resource by the transmission power increase of a control signal can be suppressed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
1 is a block diagram showing a configuration of a radio base station apparatus according to Embodiment 1 of the present invention.

  The radio base station apparatus shown in FIG. 1 has individual channel signal forming units 101-1 to 101-N for communication terminals that perform communication, and also has control signal forming units 110 and 120.

  Individual channel signal forming units 101-1 to 101-N form individual channel signals addressed to the respective communication terminals by spreading the transmission data addressed to the respective communication terminals by using spreading codes assigned to the respective communication terminals. To do.

  On the other hand, control signal forming units 110 and 120 spread control information addressed to each communication terminal when each communication terminal transmits an uplink packet using a common spreading code in each communication terminal in the cell. Thus, a control signal is formed.

  Since the processing of each individual channel signal forming unit 101-1 to 101-N is the same, only the configuration of one individual channel signal forming unit 101-1 will be described here. The dedicated channel signal forming unit 101-1 multiplexes the pilot signal (PILOT), transmission data, and uplink transmission power control command (UL-TPC) by the channel encoding unit 102. Note that transmission data is subjected to error correction coding processing before multiplexing. The multiplexed signal is subjected to modulation processing by the modulation unit 103 and then transmitted to the spreading unit 104.

  Spreading section 104 spreads the modulated signal using a spreading code specific to each communication terminal. That is, each individual channel signal forming unit 101-1 to 101 -N performs spreading processing using different spreading codes. The signal after spreading processing is sent to the amplification unit 105. Amplifying section 105 amplifies the power of the spread signal in accordance with the transmission power control signal from transmission power control section 106, and sends the amplified signal to transmission radio section 107.

  As a result, individual channel signals for individual communication terminals formed using different spreading codes are output from the individual channel signal forming units 101-1 to 101 -N. The individual channel signal is subjected to predetermined radio processing such as analog-digital conversion and up-conversion by the transmission radio unit 107 and then transmitted via the antenna 108.

  On the other hand, the control signal forming unit 110 inputs the ACK / NACK addressed to each communication terminal obtained by the error detection unit 28 to the channel encoding unit 111. Channel encoding section 111 time-division-multiplexes ACK / NACK addressed to each communication terminal at a position determined in advance with each communication terminal. The output from the channel encoding unit 111 is subjected to modulation processing by the modulation unit 112 and then sent to the spreading unit 113.

  The spreading unit 113 spreads the modulated signal using a spreading code common to all communication terminals in communication. The signal after the diffusion processing is sent to the amplification unit 114. Amplifying section 114 amplifies the power of the spread signal in accordance with the transmission power control signal from transmission power setting section 115, and sends the amplified signal to transmission radio section 107.

  Further, the control signal forming unit 120 inputs the scheduling result information addressed to each communication terminal obtained by the scheduling unit 31 to the channel encoding unit 121. The channel encoding unit 121 time-division multiplexes scheduling result information addressed to each communication terminal at a position determined in advance with each communication terminal. The output from the channel encoding unit 121 is subjected to modulation processing by the modulation unit 122 and then sent to the spreading unit 123.

  The spreading unit 123 spreads the modulated signal using a spreading code common to all communication terminals in communication. The signal after the spreading process is sent to the amplifying unit 124. Amplifying section 124 amplifies the power of the spread signal in accordance with the transmission power control signal from transmission power setting section 125, and sends the amplified signal to transmission radio section 107.

  As a result, control information (in this embodiment, ACK / NACK and scheduling result information) when each communication terminal transmits an uplink packet using a dedicated channel is transmitted from control signal forming units 110 and 120. A control signal that is time-division multiplexed at a timing determined between the communication terminals and spread using a common spreading code in each communication terminal is output. This control signal is transmitted via the antenna 108 after being subjected to predetermined radio processing such as analog-digital conversion and up-conversion by the transmission radio unit 107. In this example, control information for transmitting uplink packets (in this embodiment, ACK / NACK and scheduling result information) is time-division multiplexed at a timing determined with a communication terminal. As described above, code multiplexing may be performed by assigning more orthogonal signatures on one spreading code. Further, although an example in which one spreading code is shared by a plurality of communication terminals has been described here, a plurality of spreading codes may be used by a plurality of communication terminals.

  In the radio base station apparatus shown in FIG. 1, a signal received by the antenna 108 is input to the reception radio unit 20. The reception radio unit 20 obtains a reception baseband signal by performing predetermined radio processing such as down-conversion and analog-digital conversion on the reception signal, and obtains the reception baseband signal by the number N of communication terminals. To 21-N. Since the processing of each of the reception processing units 21-1 to 21-N is the same, only the configuration of one reception processing unit 21-1 will be described here.

  The despreading unit 22 performs a despreading process on the received baseband signal using a spreading code corresponding to the communication terminal, thereby extracting an individual channel signal transmitted from the communication terminal apparatus and outputting it to the demodulation unit 23 . The despreading unit 22 despreads the pilot symbols and sends them to the SIR measurement unit 29.

  The demodulator 23 demodulates the output signal from the despreader 22 and sends the demodulated signal to the channel decoder 24. The channel decoding unit 24 performs decoding processing such as error correction decoding on the output signal of the demodulation unit 23, and extracts received data, a downlink transmission power control command (DL-TPC), and the like. Incidentally, the received data is sent to the control station which is a higher station of the base station, and the DL-TPC is sent to the transmission power control unit 106.

  The SIR measurement unit 29 calculates the interference wave power from the dispersion value of the pilot symbols after despreading, calculates the ratio (SIR) between the desired wave power and the interference wave power, and displays information indicating the SIR as the TPC generation unit 30 and It is sent to the scheduling unit 31. The TPC generation unit 30 generates an uplink transmission power control command (UL-TPC) that instructs increase / decrease in uplink transmission power based on the magnitude relationship between the uplink reception SIR and the target SIR. UL-TPC is sent to the channel encoding unit 102.

  The scheduling unit 31 determines communication terminal devices that are permitted to transmit uplink packets based on transmission rate request information, SIR, transmission rate combination information, and uplink packet received power resources from each communication terminal device, Scheduling is performed to determine the MCS (that is, transmission rate) at the time of transmission of the uplink packet. Then, the scheduling unit 31 sends scheduling result information including information indicating the determined communication terminal device (terminal information) and information indicating the determined transmission rate (transmission rate information) to the channel encoding unit 121. In the present embodiment, the scheduling unit 31 performs Time and Rate Scheduling.

  The despreading unit 25 despreads the received baseband signal with the same spreading factor as when the communication terminal spreads the uplink packet. Note that information such as the spreading factor, modulation multi-level number, and coding rate of the uplink packet is embedded in the signal by the communication terminal and transmitted, and the radio base station apparatus shown in FIG. 1 is embedded in the received data, for example. These pieces of information are extracted and notified to the despreading unit 25, the demodulation unit 26, and the channel decoding unit 27. That is, the despreading unit 25, the demodulating unit 26, and the channel decoding unit 27 are configured to be able to change the spreading factor, the modulation multi-level number, and the coding rate according to the transmission parameter information from the communication terminal.

  The demodulator 26 demodulates the uplink packet output from the despreader 25 and sends the demodulated signal to the channel decoder 27. The channel decoding unit 27 performs decoding processing such as error correction decoding on the demodulated signal, extracts the received packet, and outputs it to the error detection unit 28. Further, the channel decoding unit 27 extracts transmission rate request information and sends it to the scheduling unit 31.

  The error detection unit 28 performs error detection on the received packet. If no error is detected, the error detection unit 28 outputs the received packet to the control station, which is a higher station of the base station, and sends an ACK signal indicating that it has been correctly demodulated to the channel encoding unit 111. . On the other hand, when an error is detected, the error detection unit 28 sends a NACK signal indicating that the demodulation has not been correctly performed to the channel encoding unit 111.

  Next, a communication terminal apparatus that communicates with the radio base station apparatus shown in FIG. 1 will be described. FIG. 2 is a block diagram showing a configuration of the communication terminal apparatus according to Embodiment 1 of the present invention.

  First, the receiving system will be described. The communication terminal apparatus shown in FIG. 2 inputs a signal received via the antenna 41 to the reception radio unit 42. The reception radio unit 42 obtains a reception baseband signal by performing down-conversion and analog-digital conversion processing on the reception signal, and sends this to the despreading units 43, 48 and 51.

  The despreading unit 43 obtains a signal addressed to itself by performing a despreading process using the spread code for each communication terminal. The despread signal is sequentially demodulated and decoded by the demodulating unit 44 and the channel decoding unit 45, whereby reception data and an uplink transmission power control command (UL-TPC) are obtained. The despread signal is sequentially input to the SIR measurement unit 46 and the TPC generation unit 47, whereby a downlink transmission power control command (DL-TPC) is obtained from the TPC generation unit 47.

  The despreading unit 48 extracts a control signal by despreading the reception baseband signal output from the reception radio unit 42 using a spread code common to each communication terminal in the cell. The despread signal output from the despreader 48 is demodulated by the demodulator 49 and then input to the channel decoder 50. The channel decoding unit 50 extracts ACK / NACK addressed to its own terminal from ACK / NACK addressed to each communication terminal time-division multiplexed on the control signal. Based on this ACK / NACK, the communication terminal controls retransmission of the uplink packet.

  Further, the despreading unit 51 extracts a control signal by despreading the reception baseband signal output from the reception radio unit 42 using a spread code common to each communication terminal in the cell. The despread signal output from the despreader 51 is demodulated by the demodulator 52 and then input to the channel decoder 53. The channel decoding unit 53 extracts scheduling result information addressed to its own terminal from scheduling result information addressed to each communication terminal that is time-division multiplexed on the control signal. Based on the scheduling result information, the communication terminal controls the transmission rate of the uplink packet.

  Next, the transmission system will be described. The communication terminal apparatus shown in FIG. 2 changes the coding rate, the modulation multi-level number, and the spreading factor for transmission packets, but does not change these parameters for other data. Specifically, a pilot signal (PILOT), a downlink signal transmission power control command (DL-TPC), and transmission data include a channel encoding unit 250 in which the coding rate, the modulation multi-level number, and the spreading factor are fixed, and the modulation, respectively. After being sequentially processed by the unit 251 and the spreading unit 252, the spread signal is sent to the amplifying unit 253.

  On the other hand, the transmission packet is first stored in the buffer 254. Based on ACK / NACK, the buffer 254 deletes the previously transmitted transmission packet if it is ACK and outputs the first transmission packet to the channel encoding unit 259. If NACK, the buffer 254 again transmits the previously transmitted transmission packet to the channel encoding unit 259. Output to.

  In addition, the data amount of the transmission packet stored in the buffer 254 is measured by the data amount measurement unit 255, and the data amount measurement unit 255 sends the measurement result to the transmission rate selection unit 257 and the rate request selection unit 256.

  The transmission rate selection unit 257 transmits transmission rate information included in the scheduling result information sent from the radio base station apparatus shown in FIG. 1 and extracted by the channel decoding unit 53, the amount of data stored in the buffer 254, the transmission power margin, Based on the transmission rate combination information, the transmission rate of the uplink packet to be actually transmitted is selected within a range equal to or lower than the transmission rate indicated by the transmission rate information, and the selected transmission rate is notified to the rate request selection unit 256. The transmission parameter setting unit 258 is notified. Here, when the transmission power resource of the communication terminal is insufficient, or when the transmission data of the communication terminal is small, the transmission rate selection unit 257 selects a transmission rate lower than the transmission rate indicated by the transmission rate information. There are things to do.

  The rate request selection unit 256 generates transmission rate request information based on the transmission rate notified from the transmission rate selection unit 257, the amount of data stored in the buffer 254, and the transmission power margin, and transmits this to the channel encoding unit. 259. This transmission rate request information is information indicating the transmission rate of the transmission packet desired by the communication terminal apparatus, and is represented by, for example, 1 to n (n is a natural number of 2 or more).

  The transmission parameter setting unit 258 controls the read rate of the transmission packets stored in the buffer 254 based on the transmission rate notified from the transmission rate selection unit 257, and at the same time, the coding rate and modulation unit in the channel encoding unit 259 The modulation multi-level number in 260 and the spreading factor in spreading section 261 are set, and these transmission parameters are sent to channel encoding section 259, modulating section 260, and spreading section 261, respectively. The transmission parameter setting unit 258 sets an offset amount of transmission power when transmitting a packet based on the transmission rate, and sends this to the transmission power control unit 263.

  Incidentally, the transmission power margin input to the transmission rate selection unit 257 and the rate request selection unit 256 is set by the transmission power measurement unit 265. Specifically, the transmission power measurement unit 265 is based on the transmission power controlled by the transmission power control unit 264 according to the uplink transmission power control command (UL-TPC) and the maximum transmission power that can be transmitted by the terminal itself. Set the transmission power margin. The transmission power control unit 263 that generates a transmission power control signal for a transmission packet is a transmission power control unit 264 that generates a transmission power control signal for other pilot signals, downlink transmission power control commands (DL-TPC) and transmission data. A transmission power control signal in which the offset set by the transmission parameter setting unit 258 is added to the control signal from is generated.

  Each spread signal output from the spreading unit 252 and the spreading unit 261 is independently amplified by the corresponding amplifying units 253 and 262, and then subjected to predetermined radio processing such as digital-analog conversion and up-conversion by the transmission radio unit 266. After being applied, it is transmitted via the antenna 41.

  Next, the scheduling unit 31 of the radio base station apparatus illustrated in FIG. 1 will be described. FIG. 3 is a block diagram showing a configuration of the scheduling section of the radio base station apparatus according to Embodiment 1 of the present invention.

  In FIG. 3, terminal selection unit 311 receives transmission rate request information (requested transmission rate, transmission power margin, data amount, etc.) transmitted from the communication terminal. The terminal selection unit 311 selects a communication terminal that permits transmission of an uplink packet from terminals that have transmitted transmission rate request information according to a predetermined scheduling algorithm (for example, a round robin method or a proportional fairness method). Then, terminal information (for example, terminal number) indicating the selected terminal is input to the transmission rate selection unit 312 and the scheduling result information output unit 314.

  The mapping control unit 313 receives transmission rate combination information indicating a combination of a plurality of transmission rates that can be taken as the transmission rate of the uplink packet. Note that the transmission rate combination information may be unique to the mobile communication system and stored in any one of the base station apparatuses, or notified from a control station that is a higher station. It may be a thing. Then, the mapping control unit 313 limits the transmission rate candidates that can be selected by the transmission rate selection unit 312 to a part of the plurality of transmission rates indicated by the transmission rate combination information. Then, the mapping control unit 313 converts the limited transmission rate candidates into bits and maps them, and inputs the mapped bits to the transmission rate selection unit 312. A more specific operation of the mapping control unit 313 will be described later.

  Transmission rate selection section 312 receives transmission rate request information and uplink packet received power resources. Terminal information is input from the terminal selection unit 311, mapped bits (that is, limited transmission rate candidates) are input from the mapping control unit 313, and SIR is input from the SIR measurement unit 29. The transmission rate selection unit 312 uses a mapping control unit as a transmission rate permitted for the uplink packet transmitted by the communication terminal selected by the terminal selection unit 311 (that is, the communication terminal permitted to transmit the uplink packet). One of the transmission rate candidates limited in 313 is selected within the range of the uplink packet received power resource. The transmission rate selection unit 312 is necessary reception power for each of the transmission rate candidates limited by the mapping control unit 313 (offset information indicating how much power is transmitted from the communication terminal with respect to the dedicated channel). And the SIR, the reception power is predicted for each transmission rate, and the transmission rate that is the highest rate within the range of the uplink packet reception power resource is selected. Then, the transmission rate selection unit 312 inputs transmission rate information indicating the selected transmission rate to the scheduling result information output unit 314.

  The scheduling result information output unit 314 generates scheduling result information by combining the terminal information input from the terminal selection unit 311 and the transmission rate information input from the transmission rate selection unit 312, and the scheduling result information is channel encoding unit Input to 121. The scheduling result information is wirelessly transmitted as a control signal from the antenna 108 with the communication terminal indicated by the terminal information as a destination, and is notified to the communication terminal.

  Next, a more specific operation of the mapping control unit 313 will be described.

First, the transmission rate combination information shown in FIG. In the transmission rate combination information shown in FIG. 4, for example, eight types of transmission rates from 32 kbps to 4 Mbps are shown as combinations of transmission rates that can be taken as the transmission rate of the uplink packet. That is, in this mobile communication system, eight types of transmission rates from 32 kbps to 4 Mbps can be used as the transmission rate of the uplink packet. Therefore, in the transmission rate combination information, all eight types of transmission rates are defined as selection candidates (transmission rates that are selection candidates are indicated as “YES”). Further, since there are 8 types of transmission rates indicated by the transmission rate combination information, 3 bits (2 ³ ) are required as shown in FIG. Then, eight types of transmission rates from 32 kbps to 4 Mbps are mapped to 3 bits of “111” to “000”, respectively.

Then, as shown in FIG. 5, the mapping control unit 313 sets transmission rate candidates to four types of transmission rates from 512 kbps to 4 Mbps among the eight types of transmission rates from 32 kbps to 4 Mbps indicated by the transmission rate combination information. (A transmission rate that is a selection candidate is indicated as 'YES', and a transmission rate that is not a selection candidate is indicated as 'NO'). Since there are four types of transmission rate candidates limited by the mapping control unit 313 in the example of FIG. 5, 2 bits (2 ² ) are required to indicate a bit string. As described above, the limited number of bits of the transmission rate candidate is set to be smaller than the number of bits of the transmission rate indicated by the transmission rate combination information. Then, the mapping control unit 313 maps the four types of transmission rates from 512 kbps to 4 Mbps to 2 bits “11” to “00”, respectively. Then, the four types of mapped transmission rate candidates are input to the transmission rate selection unit 312.

The transmission rate selection unit 312 selects from four limited transmission rate candidates, that is, 512 kbps ('11'), 1 Mbps ('10'), 2 Mbps ('01'), and 4 Mbps ('00'). Then, the transmission rate of the uplink packet transmitted by the communication terminal apparatus selected by the terminal selection unit 311 is selected.

  Here, Time and Rate Scheduling is a scheduling method suitable for causing a small number of communication terminals to transmit uplink packets at a high transmission rate. For this reason, the possibility that the transmission rate selection unit 312 selects a lower transmission rate is very small. Therefore, even if the lower transmission rate is excluded from the selection candidates, there is almost no influence. Therefore, in the present embodiment, as shown in FIG. 5, mapping control section 313 assigns transmission rate candidates to four transmission rates in order from the highest of the eight transmission rates indicated by the transmission rate combination information. Limited to.

  Note that the four types of transmission rates excluded from the selection candidates may be notified using a conventional scheduling method for dedicated channels or other medium / low speed rates. For example, as described in Non-Patent Document 2, rate scheduling in which transmission rate addition or deletion (E-DCH TFCS addition / deletion) is performed with an Up / down pointer may be used.

  As described above, according to the present embodiment, the number of transmission rates that can be notified to the communication terminal is reduced from eight to four, and the number of bits of transmission rate information is reduced from 3 bits to 2 bits. The transmission power of the line control signal can be reduced. Therefore, it is possible to suppress the consumption of downlink transmission power resources. Further, by reducing the number of bits of the transmission rate information, the number of combinations of transmission rates is reduced from eight to four, and the inter-code distance between the transmission rate information is increased accordingly. As a result, it is possible to improve the transmission rate information determination accuracy in the communication terminal.

  In the present embodiment, an example is described in which the types of transmission rates that can be notified to the communication terminal are limited from 8 types to 4 types, but may be limited to, for example, 8 types to 7 types or less. For example, when “000” and “111” are excluded from “000” to “111” and the types of transmission rates that can be notified to the communication terminal are limited to six, the number of bits of the transmission rate information is 3 bits. However, the number of combinations of transmission rates is reduced from eight to six, and the inter-code distance between the transmission rate information increases accordingly. That is, when ‘000’ is excluded, the communication terminal is less likely to mistake the notified ‘100’, ‘010’, and ‘001’ as ‘000’ and the error rate is reduced. Similarly, when “111” is excluded, the communication terminal is less likely to mistake the notified “110”, “101”, and “011” as “111”, and the error rate is reduced. Thus, even if the number of bits is not reduced in the limited transmission rate information, the error rate is reduced by limiting the number of transmission rate candidates that can be selected. Therefore, when trying to maintain the error rate after limitation at the same level as the error rate before limitation, the transmission power of the downlink control signal for transmitting the transmission rate information is reduced by the amount that the error rate characteristic is improved. be able to.

(Embodiment 2)
In the present embodiment, a case will be described in which transmission rate candidates are limited while substantially maintaining a selectable transmission rate range.

  As in the first embodiment, the transmission rate combination information shown in FIG. Then, as shown in FIG. 6, the mapping control unit 313 transmits to four transmission rates of 64 kbps, 256 kbps, 1 Mbps, and 4 Mbps among the eight transmission rates from 32 kbps to 4 Mbps indicated by the transmission rate combination information. Limit rate candidates. In the transmission rate combination information shown in FIG. 4, the relationship between adjacent transmission rates is doubled among the eight types of transmission rates from 32 kbps to 4 Mbps. On the other hand, in FIG. 6, the transmission rates that are selection candidates are limited to four types of 64 kbps, 256 kbps, 1 Mbps, and 4 Mbps, and the relationship between adjacent transmission rates is 4 among the four types of transmission rates. It has become a double relationship. In other words, in this embodiment, when limiting transmission rate candidates, the change width between each of the limited transmission rate candidates is larger than the change width between each of the plurality of transmission rates indicated by the transmission rate combination information. Make it bigger. In this embodiment, the maximum transmission rate and the minimum transmission rate are substantially maintained in limiting the transmission rate candidates. Specifically, the selectable range in FIG. 4 is 32 kbps to 4 Mbps, whereas in FIG. 6, it is 64 kbps to 4 Mbps. After limiting the selection candidates in this way, the mapping control unit 313 sets the four transmission rates of 64 kbps, 256 kbps, 1 Mbps, and 4 Mbps to 2 of “11”, “10”, “01”, and “00”, respectively. Map to bits. Then, the four types of mapped transmission rate candidates are input to the transmission rate selection unit 312.

  As described above, according to the present embodiment, the transmission rate selection candidates are intermittently thinned to limit the transmission rate selection candidates, so that the transmission rate information is maintained while the range of selectable transmission rates is substantially maintained. Therefore, the transmission power of the downlink control signal can be reduced.

(Embodiment 3)
In the present embodiment, a case will be described in which a plurality of communication terminals existing in a cell are divided into a plurality of groups and the same transmission rate is notified to the communication terminals belonging to each group.

  When a plurality of communication terminals existing in a cell are divided into a plurality of groups, scheduling is performed by the following three steps as shown in FIG. In FIG. 7, four communication terminals, communication terminal (MS) #A to communication terminal #D, are grouped into group 1 (communication terminals #A and #C) and group 2 (communication terminals #B and #D). Here are some examples. First, in the first step, the communication terminals #A to #D request a transmission rate from the base station (FIG. 7 (a)). Next, in the second step, the base station (BS) performs scheduling based on the requested transmission rate notified from the communication terminals #A to #D, and selects communication terminals that permit transmission of uplink packets in units of groups. The common scheduling result information is transmitted to all the communication terminals belonging to the selected group (FIG. 7B). Here, it is assumed that group 1 is selected. In the third step, the communication terminals (that is, communication terminals #A and #C) that have received the control signal addressed to the terminal transmit uplink packets at a transmission rate equal to or lower than the transmission rate instructed by the base station ( FIG. 7 (c)).

  As described above, when one scheduling result information is transmitted to a plurality of grouped communication terminals, the transmission of uplink packets is permitted to the plurality of communication terminals at the same time. That is, a plurality of communication terminals simultaneously use uplink received power resources in the base station. Further, the uplink received power resource in the base station has an upper limit as in the downlink. Therefore, when one scheduling result information is transmitted to a plurality of grouped communication terminals, a relatively low transmission rate is selected for each communication terminal. That is, when communication terminals are grouped, there is little possibility that a high transmission rate is selected in the transmission rate selection unit 312. Therefore, even if the higher transmission rate is excluded from the selection candidates, there is almost no influence. .

  Therefore, in the present embodiment, as shown in FIG. 8, mapping control section 313 assigns four types of transmission rate candidates in order from the lowest of the eight types of transmission rates indicated by the transmission rate combination information. Limited to rate. That is, the mapping control unit 313 limits transmission rate candidates to four types of transmission rates from 32 kbps to 256 kbps among the eight types of transmission rates from 32 kbps to 4 Mbps indicated by the transmission rate combination information. Then, the mapping control unit 313 maps the four types of transmission rates from 32 kbps to 256 kbps to 2 bits “11” to “00”. Then, the four types of mapped transmission rate candidates are input to the transmission rate selection unit 312.

  Thus, according to the present embodiment, the number of transmission rates that can be notified to the communication terminal is reduced from eight to four, and the number of bits of transmission rate information is changed from 3 bits to 2 bits, as in the first embodiment. Therefore, the transmission power of the downlink control signal can be reduced. Therefore, it is possible to suppress the consumption of downlink transmission power resources.

(Embodiment 4)
In the present embodiment, a case will be described in which transmission rate candidates are limited according to the capabilities of the communication terminal. Note that the capability of a communication terminal is, for example, the maximum transmission rate with which the communication terminal can communicate, the maximum data length, the maximum number of codes, the minimum spreading factor, and the supported TTI (Transmission Time Interval) length. Defined by type.

  FIG. 9 is a block diagram showing a configuration of a scheduling section of the radio base station apparatus according to Embodiment 4 of the present invention. In FIG. 9, the same components as those in FIG. 3 (Embodiment 1) are denoted by the same reference numerals, and description thereof is omitted.

  The mapping control unit 315 receives transmission rate combination information. Further, terminal capability information indicating the capability of the communication terminal that has transmitted the transmission rate request information is input to the mapping control unit 315. The terminal capability information here indicates to what transmission rate the communication terminal can transmit. For example, when the communication terminal #A is a communication terminal (4 Mbps terminal) capable of transmitting up to 4 Mbps, the terminal capability information of the communication terminal #A is “4 Mbps”, and the communication terminal #B is capable of transmitting up to 1 Mbps. In the case of (1 Mbps terminal), the terminal capability information of the communication terminal #B is “1 Mbps”. Based on the terminal capability information, mapping control section 315 limits transmission rate candidates that can be selected by transmission rate selection section 312 to a part of the plurality of transmission rates indicated by the transmission rate combination information. Specifically, it is limited as follows.

  For example, when the communication terminal #A is a 4 Mbps terminal and the communication terminal #B is a 1 Mbps terminal, the mapping control unit 315 maximizes the transmission rate indicated by the terminal capability information of each communication terminal as shown in FIG. The transmission rate selection candidates are limited as the rate. In the example illustrated in FIG. 10, for communication terminal #A (4 Mbps terminal), the maximum rate of 4 Mbps is set, and transmission rate selection candidates are limited to four transmission rates (4 Mbps, 2 Mbps, 1 Mbps, 512 kbps). In addition, for communication terminal #B (1 Mbps terminal), the maximum rate of 1 Mbps is limited and transmission rate selection candidates are limited to four transmission rates (1 Mbps, 512 kbps, 256 kbps, 128 kbps). As described above, in the present embodiment, the limited transmission rate candidates are made different according to the capabilities of the communication terminal.

  Further, the limited transmission rate mapping is also changed according to the capability of the communication terminal. That is, in FIG. 10, transmission rates of 1 Mbps and 512 kbps can be selected for both communication terminal #A (4 Mbps terminal) and communication terminal #B (1 Mbps terminal). However, for communication terminal #A (4 Mbps terminal), 1 Mbps is mapped to “10” and 512 kbps is mapped to “11”, whereas for communication terminal #B (1 Mbps terminal), 1 Mbps is “00”. “512” and 512 kbps are mapped to “01”.

  In the mapping control unit 315, as shown in FIG. 11, for the communication terminal #A (4 Mbps terminal), the maximum transmission rate is 4 Mbps and the transmission rate is changed to four transmission rates (4 Mbps, 2 Mbps, 1 Mbps, 512 kbps). Whereas the selection candidates are limited, for communication terminal #B (1 Mbps terminal), the maximum rate of 1 Mbps is limited and the transmission rate selection candidates are limited to two transmission rates (1 Mbps, 512 kbps). The number may vary depending on the capabilities of the communication terminal. In this case, it is preferable to reduce the number of transmission rates to be limited as the terminal capability is lower.

  As described above, according to the present embodiment, the transmission rate selection candidates are limited according to the capability of the communication terminal and the transmission rate selection candidates are limited. Therefore, the number of bits of the transmission rate information is reduced, and the downlink The transmission power of the control signal can be reduced, and an appropriate transmission rate according to the capability of the communication terminal can be notified to each communication terminal.

(Embodiment 5)
In the present embodiment, a case will be described in which the transmission rate candidates to be limited can be switched during communication.

  FIG. 12 is a block diagram showing a configuration of a scheduling section of the radio base station apparatus according to Embodiment 5 of the present invention. In FIG. 12, the same components as those in FIG. 3 (Embodiment 1) are denoted by the same reference numerals and description thereof is omitted.

  The transmission rate combination information is input to the mapping control unit 316. Further, transmission rate restriction information is input to the mapping control unit 316. The transmission rate restriction information is notified from the control station that is the upper station during the communication of the base station. The control station is in a communication state such as the number of communication terminals currently accommodated in the wireless communication system, the amount of interference, the user throughput of the uplink or downlink, the system throughput, the traffic volume (for example, the amount of data in the buffer), etc. Accordingly, the contents of the transmission rate restriction information are switched appropriately and notified. Then, each time the transmission rate restriction information notified from the control station is input during the communication of the base station, the mapping control unit 316 selects the transmission rate candidates that can be selected by the transmission rate selection unit 312 as transmission rate combination information. Are limited to the transmission rate indicated by the transmission rate restriction information. That is, the mapping control unit 316 limits the transmission rate candidates that can be selected by the transmission rate selection unit 312 to a part of the plurality of transmission rates indicated by the transmission rate combination information based on the transmission rate restriction information. Then, the mapping control unit 316 converts the limited transmission rate candidates into bits and maps them, and inputs the mapped bits to the transmission rate selection unit 312. Specifically, it is as follows.

The mapping control unit 316 receives the transmission rate restriction information shown in FIGS. 13A to 13C that is switched and notified by the control station as appropriate. This transmission rate restriction information is information for limiting the transmission rate candidates that can be selected by the transmission rate selection unit 312 to a part of the plurality of transmission rates indicated by the transmission rate combination information (transmission rate as a selection candidate). Is indicated as “YES”, and a transmission rate that is not a selection candidate is indicated as “NO”). Further, there are four or three types of transmission rate candidates indicated by the transmission rate restriction information in the examples of FIGS. 13A to 13C, so that 2 bits (2 ² ) are required to indicate a bit string. . Thus, the number of bits of the transmission rate candidate indicated by the transmission rate restriction information is set to be smaller than the number of bits of the transmission rate indicated by the transmission rate combination information.

  When the transmission rate restriction information shown in FIG. 13A is input, the mapping control unit 316 has 256 kbps to 2 Mbps among the eight transmission rates from 32 kbps to 4 Mbps indicated by the transmission rate combination information. The transmission rate candidates are limited to the four types of transmission rates. Then, the mapping control unit 316 maps the four types of transmission rates from 256 kbps to 2 Mbps to 2 bits “11” to “00”, respectively. Then, the four types of mapped transmission rate candidates are input to the transmission rate selection unit 312.

  When the transmission rate restriction information shown in FIG. 13B is input, the mapping control unit 316 has 128 kbps to 1 Mbps among the eight transmission rates from 32 kbps to 4 Mbps indicated by the transmission rate combination information. The transmission rate candidates are limited to the four types of transmission rates. Then, the mapping control unit 316 maps the four types of transmission rates from 128 kbps to 1 Mbps to 2 bits “11” to “00”. Then, the four types of mapped transmission rate candidates are input to the transmission rate selection unit 312.

  Also, when the transmission rate restriction information shown in FIG. 13C is input, the mapping control unit 316 has 256 kbps to 1 Mbps among the eight transmission rates from 32 kbps to 4 Mbps indicated by the transmission rate combination information. The transmission rate candidates are limited to the three types of transmission rates. Then, the mapping control unit 316 maps the three types of transmission rates from 256 kbps to 1 Mbps into 2 bits of “11”, “10”, and “01”, respectively. Then, the three types of mapped transmission rate candidates are input to the transmission rate selection unit 312.

  Thus, according to the present embodiment, in order to notify the base station from the control station by appropriately switching the content of the transmission rate limit information according to the communication state such as the number of communication terminals and the amount of interference that change during communication, The base station can appropriately switch the limited transmission rate candidates during communication. As a result, the number of bits of the transmission rate information can be reduced to reduce the transmission power of the downlink control signal and the communication. An appropriate transmission rate according to the state can be notified to each communication terminal.

(Embodiment 6)
In the present embodiment, a case will be described in which transmission rate candidates to be limited are different depending on the destination of the transmission rate information.

  FIG. 14 is a block diagram showing a configuration of a scheduling section of the radio base station apparatus according to Embodiment 6 of the present invention. In FIG. 14, the same components as those in FIG. 3 (Embodiment 1) are denoted by the same reference numerals and description thereof is omitted.

  The transmission rate combination information is input to the mapping control unit 317. Further, terminal information is input from the terminal selection unit 311 to the mapping control unit 317. The terminal information is information indicating a communication terminal permitted to transmit an uplink packet and information indicating a destination of transmission rate information. Furthermore, when a plurality of communication terminals existing in a cell are grouped as in Embodiment 3 and communication terminals that permit transmission of uplink packets are selected in units of groups, the terminal information is the terminal selection This is information (for example, group number) that identifies the group selected by the unit 311. On the other hand, when a plurality of communication terminals are not grouped, or when a communication terminal that allows transmission of uplink packets is selected for each communication terminal even when a plurality of communication terminals are grouped The terminal information is information (for example, a terminal number) that identifies the communication terminal selected by the terminal selection unit 311. That is, there are cases where the destination of the transmission rate information is information specifying each communication terminal and information specifying a group to which each communication terminal belongs.

  Therefore, the mapping control unit 317 changes the transmission rate candidates to be limited as shown in FIG. 15 according to the terminal information input from the terminal selection unit 311 (that is, information indicating the destination of the transmission rate information). Make it. That is, when the terminal number is input as the destination from the terminal selection unit 311, the mapping control unit 317 determines the transmission rate candidates from the eight types indicated by the transmission rate combination information as shown in FIG. The transmission rates are limited to four transmission rates in descending order. On the other hand, when the group number is input as the destination from the terminal selection unit 311, as shown in FIG. 15 (b), the transmission rate candidate is the lower of the eight transmission rates indicated by the transmission rate combination information. Are limited to four types of transmission rates in order.

  As described above, in the present embodiment, the transmission rate candidates to be limited are different depending on whether the destination of the transmission rate information is a terminal number or a group number. Rate candidates can be limited. In addition, since the scheduling result information format can be shared between the case where the destination of the transmission rate information is a terminal number and the case of the group number, the communication terminal can use the case where the destination of the transmission rate information is a terminal number and the group number. Therefore, the scheduling result information can be demodulated by the same demodulation method as in the case of the above, so that a plurality of communication terminals can be grouped without complicating the demodulation process in the communication terminals.

  In addition, although the case where the transmission rate which can be selected was limited was demonstrated in the said embodiment, it can implement similarly when limiting the transmission power which can be selected regarding the transmission power of an uplink packet. For example, among eight types of transmission power of 22 dBm, 20 dBm, 18 dBm, 16 dBm, 14 dBm, 12 dBm, 10 dBm, and 8 dBm, the transmission power selection candidates are limited to two types of 22 dBm and 20 dBm, and two types of transmission of 22 dBm and 20 dBm are transmitted. You may make it select the transmission rate corresponding to any one of electric power.

  Further, although cases have been described with the above embodiment where transmission rates that can be selected are limited, transmission power offsets of uplink packet channels with respect to other channels such as dedicated channels (for example, transmission power offset of E-DPDCH with respect to DPCCH) The transmission power offset that can be selected with respect to the transmission power offset of DPDCH + E-DPDCH with respect to DPCCH, or the transmission power offset of a channel other than DPCCH with respect to DPCH) can be similarly implemented. For example, among eight types of transmission power offsets of 30 dB, 25 dB, 20 dB, 15 dB, 10 dB, 5 dB, 0 dB, and −5 dB, transmission power offset selection candidates are limited to four types as shown in FIG. 16 or FIG. . That is, when there is no limit, it is limited to 4 types of 30 dB, 25 dB, 20 dB, and 15 dB, and when there is a limit of 25 dB, it is limited to 4 types of 25 dB, 20 dB, 15 dB, and 10 dB, and there is a limit to 20 dB Is limited to four types of 20 dB, 15 dB, 10 dB, and 5 dB, and a transmission rate corresponding to any one of these four types of transmission power offset candidates may be selected. In this example, the step width of the transmission power offset is 5 dB, but the step width is not limited to this. Further, although the transmission power offset is expressed in dB, it may be expressed as a true value. Furthermore, it may be expressed not by the power ratio but by the amplitude ratio.

(Embodiment 7)
In the present embodiment, a case will be described in which the data length of a transmission packet is used as transmission rate information, and data length selection candidates notified from the communication terminal to the base station are limited according to the capability of the communication terminal. The communication terminal notifies the base station of the data length of the transmission packet as the transmission rate information because the base station device that receives this packet has the data length over the transmission rate when decoding the packet. Because it is convenient. The data length may include an error detection code such as a CRC bit.

  FIG. 18 is a block diagram showing a configuration of a communication terminal apparatus according to Embodiment 7 of the present invention. In FIG. 18, the same components as those in FIG. 2 (Embodiment 1) are denoted by the same reference numerals, and description thereof is omitted.

  The transmission rate selection unit 257 selects the data length of the uplink packet to be actually transmitted, notifies the selected data length to the rate request selection unit 256 and notifies the transmission parameter setting unit 258. Also, the transmission rate selection unit 257 generates transmission rate information indicating this data length and outputs it to the channel encoding unit 267. This transmission rate information is encoded by the channel encoding unit 267, modulated by the modulation unit 268, spread by the spreading unit 269, amplified by the amplification unit 270, and transmitted by the transmission radio unit 266 by a predetermined unit such as digital-analog conversion or up-conversion. After being subjected to radio processing, it is transmitted to the base station via the antenna 41.

  Next, the transmission rate selection unit 257 of the communication terminal apparatus shown in FIG. 18 will be described. FIG. 19 is a block diagram showing a configuration of a transmission rate selection unit of the communication terminal apparatus according to Embodiment 7 of the present invention.

  The mapping control unit 411 receives transmission rate combination information indicating a combination of a plurality of data lengths that can be taken as the data length of the uplink packet. Note that the transmission rate combination information may be unique to the mobile communication system and stored in any one of the communication terminal devices, or the base station may be assigned from a control station that is a higher station. It is also possible to be notified. Further, terminal capability information indicating the capability of the communication terminal shown in FIG. 18 is input to the mapping control unit 411. Based on the terminal capability information, mapping control section 411 limits data length candidates that can be selected by selection section 412 to a part of the plurality of data lengths indicated by the transmission rate combination information. Then, the mapping control unit 411 converts and maps the limited data length candidates into bits, and inputs the mapped bits to the selection unit 412. A more specific operation of the mapping control unit 411 will be described later.

  Scheduling result information, transmission packet data amount, and transmission power margin are input to the selection unit 412. Also, the mapped bits (that is, limited data length candidates) are input from the mapping control unit 411. The selection unit 412 selects one of the data length candidates limited by the mapping control unit 411 as the data length of the uplink packet to be transmitted. At this time, the selection unit 412 selects any one data length based on the scheduling result information, the data amount, and the transmission power margin. Then, the selection unit 412 outputs transmission rate information indicating the selected data length to the transmission parameter setting unit 258, the rate request selection unit 256, and the channel encoding unit 267. Then, the transmission rate information output to channel encoding section 267 is notified to the base station apparatus as a control signal indicating the data length of the uplink packet transmitted from the communication terminal apparatus.

  In the above description, only the transmission rate information is input to the channel encoding unit 267. However, other information may be input and encoded together with the transmission rate information. For example, when HARQ (Hybrid Automatic Repeat reQuest) is applied, control information (number of transmissions, new data index, IR redundancy version, etc.) related to HARQ is encoded together with transmission rate information and transmitted to the base station apparatus. May be.

  Next, a more specific operation of the mapping control unit 411 will be described.

First, the transmission rate combination information shown in FIG. 20 is input to the mapping control unit 411. In the transmission rate combination information shown in FIG. 20, for example, 12 types of data lengths from Nbits to 128 Nbits are shown as combinations of data lengths that can be taken as the data length of the uplink packet. That is, in this mobile communication system, 12 types of data lengths from Nbits to 128 Nbits can be used as the data length of the uplink packet. Therefore, in the transmission rate combination information, all 12 types of data lengths are defined as selection candidates (data lengths that are selection candidates are indicated as “YES”). Further, since there are 12 types of data lengths indicated by the transmission rate combination information, 4 bits (2 ⁴ ) are required to indicate the bit string as shown in FIG. Then, 12 types of data lengths from Nbits to 128 Nbits are mapped to 4 bits “0000” to “1011”, respectively. In the data length, N indicates a predetermined number of bits serving as a reference. For example, the data length 2N indicates that the data length is twice the number of reference bits.

  Here, the terminal capability information in the present embodiment indicates to what data length the communication terminal can transmit. For example, when the communication terminal #A is a communication terminal (high-capacity terminal) capable of transmitting up to 128 Nbits, the terminal capability information of the communication terminal #A is “128 Nbits” and the communication terminal #B can transmit up to 32 Nbits. In the case of a terminal (low-capacity terminal), the terminal capability information of the communication terminal #B is “32 Nbits”. Based on the terminal capability information, mapping control section 411 limits data length candidates that can be selected by selection section 412 to a part of the plurality of data lengths indicated by the transmission rate combination information. Specifically, it is limited as follows.

  For example, when the communication terminal #A is a high-capacity terminal and the communication terminal #B is a low-capacity terminal, the mapping control unit 411 displays the data length indicated by the terminal capability information of each communication terminal as shown in FIG. Is selected as the maximum data length, and data length selection candidates are limited. In the example shown in FIG. 21, for communication terminal #A (high-capacity terminal), the maximum data length is 128 Nbits, and the data length is 8 data lengths (128 Nbits, 64 Nbits, 32 Nbits, 24 Nbits, 16 Nbits, 12 Nbits, 8 Nbits, 6 Nbits). The selection candidates are limited. For communication terminal #B (low capability terminal), the data length selection candidates are limited to 8 data lengths (32 Nbits, 24 Nbits, 16 Nbits, 12 Nbits, 8 Nbits, 6 Nbits, 4 Nbits, 3 Nbits) with 32 Nbits as the maximum data length. To do. As described above, in the present embodiment, the maximum data length that is a selection candidate and the data length candidates to be limited are made different according to the capability of the communication terminal.

  Further, the mapping of the limited data length is also made different according to the capability of the communication terminal. That is, in FIG. 21, a data length of 6 Nbits to 32 Nbits can be selected for both communication terminal #A (high-capacity terminal) and communication terminal #B (low-capacity terminal). However, in the case of communication terminal #A (high-capacity terminal), for example, 32 Nbits is mapped to “101” and 24 Nbits is mapped to “100”, whereas in the case of communication terminal #B (low-capacity terminal), 32 Nbits Is mapped to '111' and 24 Nbits is mapped to '110'.

  Then, the mapping control unit 411 inputs the mapped eight types of data length candidates to the selection unit 412, and the selection unit 412 selects any one of these eight types of data length candidates. Transmission rate information.

  In addition, in the mapping control unit 411, as shown in FIG. 22, the data length indicated by the terminal capability information of each communication terminal may be the maximum data length, and the data length selection candidates may be limited intermittently.

  Further, the communication terminal apparatus may appropriately switch the capability of the communication terminal according to the communication status.

  Thus, according to the present embodiment, the data length of the transmission packet is used as the transmission rate information, the number of data lengths that can be notified to the base station apparatus is reduced from 12 types to 8 types, and the bit of the transmission rate information Since the number is reduced from 4 bits to 3 bits, the transmission power of the uplink control signal can be reduced. Therefore, consumption of uplink transmission power resources can be suppressed. Further, since the data length selection candidates are limited by changing the selectable data length according to the capability of the communication terminal, it is possible to notify the base station apparatus of an appropriate data length according to the capability of the communication terminal.

(Embodiment 8)
The shorter the TTI of the uplink packet, the shorter the data length that can be transmitted in one packet. Conversely, the longer the TTI of the uplink packet, the longer the data length that can be transmitted in one packet. Therefore, in the case of a relatively short TTI, even if a long data length that cannot be transmitted by the TTI is prepared as a selection candidate, such a long data length is not likely to be selected in the first place. As described above, the appropriate data length as a selection candidate varies depending on the TTI. Therefore, in the present embodiment, data length candidates notified from the communication terminal to the base station are limited according to the TTI.

  FIG. 23 is a block diagram showing a configuration of a transmission rate selection unit of the communication terminal apparatus according to Embodiment 8 of the present invention. In FIG. 23, the same components as those in FIG. 19 (Embodiment 7) are denoted by the same reference numerals and description thereof is omitted.

  As described above, the transmission rate combination information shown in FIG. 20 is input to the mapping control unit 413. The mapping control unit 413 receives TTI information indicating the TTI to be used. Then, as illustrated in FIG. 24, the mapping control unit 413 determines a data length candidate that can be selected by the selection unit 412 based on the TTI information as a part of the plurality of data lengths indicated by the transmission rate combination information. Limited to.

  That is, when the TTI indicated by the TTI information is longer than a predetermined value (in the case of a long TTI), as shown in FIG. 24, for example, the data length of 128 Nbits is set to the maximum data length, and eight data lengths (128 Nbits, 64 Nbits, 32 Nbits). , 24 Nbits, 16 Nbits, 12 Nbits, 8 Nbits, 6 Nbits). When the TTI indicated by the TTI information is shorter than a predetermined value (in the case of a short TTI), as shown in FIG. 24, for example, the data length of 24 Nbits is set to the maximum data length and eight data lengths (24 Nbits, 16 Nbits, 12 Nbits). , 8 Nbits, 6 Nbits, 4 Nbits, 3 Nbits, 2 Nbits). As described above, in the present embodiment, the maximum data length that is a selection candidate and the data length candidates to be limited are made different according to the TTI.

  Also, the mapping of the limited data length is made different depending on the TTI. That is, in FIG. 24, a data length of 6 Nbits to 24 Nbits can be selected for both a long TTI and a short TTI. However, in the case of a long TTI, for example, 24 Nbits is mapped to '100' and 16 Nbits is mapped to '011', whereas in the case of a short TTI, 24 Nbits is mapped to '111' and 16Nbits is mapped to '110'. To be mapped.

  Then, the mapping control unit 413 inputs the mapped eight types of data length candidates to the selection unit 412, and the selection unit 412 selects any one of the eight types of data length candidates. Transmission rate information.

  In addition, in the mapping control unit 413, as shown in FIG. 25, the maximum data length may be set according to each TTI, and the data length selection candidates may be limited intermittently.

  Further, this embodiment may be implemented in combination with the seventh embodiment.

  Thus, according to the present embodiment, as in the seventh embodiment, the data length of the transmission packet is used as the transmission rate information, and the number of data lengths that can be notified to the base station apparatus is reduced from 12 to eight. Since the number of bits of the transmission rate information is reduced from 4 bits to 3 bits, the transmission power of the uplink control signal can be reduced. Therefore, consumption of uplink transmission power resources can be suppressed. Moreover, since the data length selection candidates are limited by changing the selectable data length according to the TTI, it is possible to notify the base station apparatus of an appropriate data length according to the TTI used.

(Embodiment 9)
In the present embodiment, a case will be described in which data length candidates notified from the communication terminal to the base station can be switched during communication of the communication terminal.

  FIG. 26 is a block diagram showing the configuration of the transmission rate selection unit of the communication terminal apparatus according to Embodiment 9 of the present invention. In FIG. 26, the same components as those in FIG. 19 (Embodiment 7) are denoted by the same reference numerals and description thereof is omitted.

  The transmission rate combination information is input to the mapping control unit 414. Also, the transmission rate restriction information is input to the mapping control unit 414. The transmission rate restriction information is notified from the control station, which is a higher station, to the communication terminal via the base station during communication of the communication terminal. The control station is in a communication state such as the number of communication terminals currently accommodated in the wireless communication system, the amount of interference, the user throughput of the uplink or downlink, the system throughput, the traffic volume (for example, the amount of data in the buffer), etc. Accordingly, the contents of the transmission rate restriction information are switched appropriately and notified. In addition, the control station may appropriately switch and notify the content of the transmission rate restriction information according to the hardware usage status of the base station. In addition, when the code tree is partially used by another channel (for example, DPDCH, DPCCH, HS-DPCCH, etc.) in the communication terminal, the control station removes the code tree being used from the entire code tree. The upper limit of the transmission rate determined from the code tree (that is, the usable code tree) may be notified as the transmission rate restriction information. Also, an index (for example, MCS index) of a combination of a spreading factor and the number of codes indicating the E-DPDCH code resource may be notified as transmission rate restriction information. Further, the transmission rate restriction information may be generated in the communication terminal device. Further, the content of the transmission rate restriction information may be different for each communication terminal, or may be different for each cell, frequency, and operator.

  The mapping control unit 414 selects a data length candidate that can be selected by the selection unit 412 every time transmission rate restriction information notified from the control station via the base station is input during communication of the communication terminal. Of the plurality of data lengths indicated by the information, the data length is limited to the data length indicated by the transmission rate restriction information. That is, the mapping control unit 414 limits the data length candidates that can be selected by the selection unit 412 to a part of the plurality of data lengths indicated by the transmission rate combination information, based on the transmission rate restriction information. Then, the mapping control unit 414 converts the limited data length candidates into bits and maps them, and inputs the mapped bits to the selection unit 412. Specifically, it is as follows.

27 is input to the mapping control unit 414 as shown in FIG. This transmission rate restriction information is information for limiting the data length candidates that can be selected by the selection unit 412 to a part of a plurality of data lengths indicated by the transmission rate combination information (the data length as a selection candidate is' “YES” is shown, and the data length that is not considered as a selection candidate is shown as “NO”). In addition, in the example of FIG. 27, there are 6 to 8 types of transmission rate candidates indicated by the transmission rate restriction information. Therefore, 3 bits (2 ³ ) are required to indicate a bit string. Thus, the number of bits of the data length candidate indicated by the transmission rate restriction information is set to be smaller than the number of bits of the data length indicated by the transmission rate combination information.

  Then, according to the transmission rate restriction information, the mapping control unit 414 performs Nbits to 4Nbits, 8Nbits, 16Nbits, 32Nbits among 12 types of data lengths from Nbits to 128Nbits indicated by the transmission rate combination information when there is no restriction. The data length candidates are limited to 8 types of data lengths of 128 Nbits. Then, the mapping control unit 414 maps these eight types of data lengths to 3 bits “000” to “111”, respectively. Then, the eight types of mapped data length candidates are input to the selection unit 412.

  In the mapping control unit 412, as shown in FIG. 28, the mapping of the data length limited according to the transmission rate restriction information may be changed according to the upper limit of the usable data length. That is, in FIG. 28, a data length of 16 Nbits can be selected for any of no limitation, limitation to 32 Nbits, and limitation to 16 Nbits. However, 16 Nbits is mapped to “101” when there is no limit, “110” when there is a limit of 32 Nbits, and “111” when there is a limit up to 16 Nbits, and the upper limit of usable data length. Depending on the mapping.

  27 and 28 include the data length excluded from the selection candidates, but a table excluding the data length excluded from the selection candidates may be provided. That is, as shown in FIG. 29, when there is no upper limit of the data length (when there is no limit), the eight types of data lengths that are selection candidates and their mapping are grasped in advance in the communication terminal, and the limit to 32 Nbits If there is a limit or up to 16 Nbits, data length candidates may be further limited from the eight types of data length according to the transmission rate limit information. Also, as shown in FIG. 28, when the number of limited data lengths that are candidates for selection is the same regardless of the upper limit of the data length (all eight types in FIG. 28), the communication terminal is as shown in FIG. Alternatively, mapping of different data lengths may be grasped in advance according to the upper limit of the usable data length, and the mapping may be varied according to the upper limit of the data length. For example, when a plurality of tables (for example, three tables of maximum values: 128 Nbits, 32 Nbits, and 16 Nbits) corresponding to the maximum data length that can be used are defined in the communication terminal, the tables are switched according to the transmission rate restriction information. By using, the mapping of each data length can be made different according to the upper limit of the usable data length.

  In addition to the upper limit of the usable data length, as shown in FIG. 31, the upper limit of the number of codes that can be used for the channel for uplink packets (for example, usable when converted to a specific spreading factor in E-DPDCH) The number of data length candidates may be limited according to the number of codes, and the data length mapping may be different. Similarly, a table may be defined according to the number of codes used in other channels (for example, DPDCH, DPCCH, HS-DPCCH, etc.), peak transmission rate, terminal capability, terminal category, TTI, and MCS index. .

  Further, this embodiment mode may be implemented in combination with Embodiment Mode 7 or Embodiment Mode 8.

  As described above, according to the present embodiment, the content of the transmission rate restriction information is appropriately switched according to the communication state such as the number of communication terminals and the amount of interference that change during communication, and the communication terminal communicates via the base station from the control station. Therefore, the communication terminal can appropriately switch the data length candidates to be limited during communication. As a result, the number of bits of the transmission rate information can be reduced to reduce the transmission power of the uplink control signal. And an appropriate data length according to the communication state can be notified to the base station apparatus.

  Note that although cases have been described with the above embodiments where the transmission rate or data length is a communication parameter to be notified to a base station or a communication terminal, the types of communication parameters to be notified are not limited to these. The present invention can be similarly applied to communication parameters that take a plurality of values and are notified by mapping the plurality of values to a plurality of bit strings.

  The present invention is particularly useful in a wireless communication system such as a high-speed packet transmission system or a wireless LAN system.

The block diagram which shows the structure of the radio base station apparatus which concerns on Embodiment 1 of this invention. The block diagram which shows the structure of the communication terminal device which concerns on Embodiment 1 of this invention. The block diagram which shows the structure of the scheduling part which concerns on Embodiment 1 of this invention. Transmission rate combination information according to Embodiment 1 of the present invention Operation explanatory diagram of the scheduling unit according to Embodiment 1 of the present invention Operation explanatory diagram of the scheduling unit according to Embodiment 2 of the present invention Explanatory drawing of the scheduling method which concerns on Embodiment 3 of this invention. Operation explanatory diagram of scheduling section according to Embodiment 3 of the present invention FIG. 9 is a block diagram showing a configuration of a scheduling unit according to Embodiment 4 of the present invention. Operation explanatory diagram of scheduling section according to Embodiment 4 of the present invention Operation explanatory diagram of scheduling section according to Embodiment 4 of the present invention FIG. 7 is a block diagram showing a configuration of a scheduling unit according to Embodiment 5 of the present invention. Operation explanatory diagram of scheduling section according to Embodiment 5 of the present invention FIG. 9 is a block diagram showing a configuration of a scheduling unit according to Embodiment 6 of the present invention. Operation explanatory diagram of scheduling section according to Embodiment 6 of the present invention Operation explanatory diagram of scheduling section according to Embodiment 6 of the present invention Operation explanatory diagram of scheduling section according to Embodiment 6 of the present invention The block diagram which shows the structure of the communication terminal device which concerns on Embodiment 7 of this invention. The block diagram which shows the structure of the transmission rate selection part which concerns on Embodiment 7 of this invention. Transmission rate combination information according to Embodiment 7 of the present invention Operation explanatory diagram of the transmission rate selection unit according to the seventh embodiment of the present invention. Operation explanatory diagram of the transmission rate selection unit according to the seventh embodiment of the present invention. The block diagram which shows the structure of the transmission rate selection part which concerns on Embodiment 8 of this invention. Operation explanatory diagram of the transmission rate selection unit according to the eighth embodiment of the present invention. Operation explanatory diagram of the transmission rate selection unit according to the eighth embodiment of the present invention. The block diagram which shows the structure of the transmission rate selection part which concerns on Embodiment 9 of this invention. Operation explanatory diagram of the transmission rate selection unit according to the ninth embodiment of the present invention. Operation explanatory diagram of the transmission rate selection unit according to the ninth embodiment of the present invention. Operation explanatory diagram of the transmission rate selection unit according to the ninth embodiment of the present invention. Operation explanatory diagram of the transmission rate selection unit according to the ninth embodiment of the present invention. Operation explanatory diagram of the transmission rate selection unit according to the ninth embodiment of the present invention. Diagram showing the relationship between the number of bits and transmission power Diagram showing downlink transmission power resources Diagram showing downlink transmission power resources

Explanation of symbols

31 Scheduling unit 107 Transmission radio unit 121 Channel encoding unit 122 Modulating unit 123 Spreading unit 124 Amplifying unit 125 Transmission power setting unit 257 Transmission rate selection unit 311 Terminal selection unit 312 Transmission rate selection units 313, 315, 316, 317, 411, 413 414 Mapping control unit 314 Scheduling result information output unit 412 selection unit

Claims (4)

Sending should do an uplink packet based and transmission rate combination information indicating the mapping of bit sequences allocated to each of the plurality of transmission rates, on the transmission rate information indicating either one of the transmission rates of the plurality of transmission rates A wireless base station device that notifies the transmission rate information to a communication terminal device that selects a transmission rate ,
Limiting means for limiting candidate transmission rates that can be selected to a portion of the plurality of transmission rates;
A selection means for selecting a transmission rate of the uplink packet from the limited transmission rate candidates;
A transmission means for wirelessly transmitting the bit string mapped to the selected transmission rate in the transmission rate combination information as the transmission rate information to the communication terminal device ; and
The limiting means can switch the transmission rate candidates to be limited during communication.
Wireless base station device. Sending should do an uplink packet based and transmission rate combination information indicating the mapping of bit sequences allocated to each of the plurality of transmission rates, on the transmission rate information indicating either one of the transmission rates of the plurality of transmission rates A radio base station apparatus that notifies the transmission rate information to a communication terminal apparatus that selects a transmission rate ,
Limiting means for limiting candidate transmission rates that can be selected to a portion of the plurality of transmission rates;
Selecting means for selecting a transmission rate of the uplink packet from the limited transmission rate candidates;
A transmission means for transmitting the bit string mapped to the selected transmission rate in the transmission rate combination information by wireless transmission to the communication terminal device as the transmission rate information ; and
The limiting means is configured to limit the transmission rate when the destination of the transmission rate information is information specifying each communication terminal device and when specifying the group to which each communication terminal device belongs. Different candidates,
Wireless base station device. An uplink packet should be transmitted based on transmission rate combination information indicating mapping of bit strings assigned to each of a plurality of transmission rates and transmission rate information indicating any one of the plurality of transmission rates A transmission rate notification method of notifying the transmission rate information to a communication terminal device that selects a transmission rate,
A limiting step of limiting possible transmission rate candidates to a portion of the plurality of transmission rates;
A selection step of selecting a transmission rate of the uplink packet from the limited transmission rate candidates;
A transmission step of transmitting a bit string mapped to the selected transmission rate in the transmission rate combination information by wireless transmission to the communication terminal device as the transmission rate information; and
In the limiting step, the transmission rate candidates to be limited can be switched during communication.
Transmission rate notification method. An uplink packet should be transmitted based on transmission rate combination information indicating mapping of bit strings assigned to each of a plurality of transmission rates and transmission rate information indicating any one of the plurality of transmission rates A transmission rate notification method of notifying the transmission rate information to a communication terminal device that selects a transmission rate,
A limiting step of limiting possible transmission rate candidates to a portion of the plurality of transmission rates;
A selection step of selecting a transmission rate of the uplink packet from the limited transmission rate candidates;
A transmission step of transmitting a bit string mapped to the selected transmission rate in the transmission rate combination information by wireless transmission to the communication terminal device as the transmission rate information; and
In the limiting step, the transmission rate is limited when the destination of the transmission rate information is information specifying each communication terminal device and when the destination is information specifying a group to which each communication terminal device belongs. Different candidates for
Transmission rate notification method.

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