JP2003224888A - Communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system, wherein a communication resource can be allocated to each communication terminal on the basis of the quality of a downlink, that can prevent a throughput of the downlink from being deteriorated. <P>SOLUTION: A communication mode determination section 201 determines a communication mode on the basis of the CIR (Carrier to Interference Ratio) measured by a CIR measurement section 219, a DRC (Date Rate Control) signal generating section 202 generates a DRC signal with a number corresponding to the communication mode, a DRC power control section 205 refers to a transmission power table 206 denoting the correspondence between the DRC numbers and the transmission power and, on the basis of the transmission power of the pilot signal outputted from a pilot power control section 209, increases the transmission power is proportion as the DRC signal indicates that downlink channel quality is good. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a communication terminal device used in a cellular communication system.

[0002]

2. Description of the Related Art In a cellular communication system, one base station performs wireless communication with a plurality of communication terminals at the same time, and it has been required to improve transmission efficiency with the increase in demand in recent years.

HDR (High Data Rate) has been proposed as a technique for improving the transmission efficiency of a downlink from a base station to a communication terminal. In HDR, a base station performs scheduling in which communication resources are time-divided and allocated to each communication terminal,
Further, it is a method of transmitting data by setting a transmission rate for each communication terminal according to the downlink channel quality.

The operation of the base station and the communication terminal performing wireless communication in HDR will be described below. First, the base station transmits a pilot signal to each communication terminal. Each communication terminal estimates the channel quality of the downlink by CIR (desired wave to interference wave ratio) based on the pilot signal, and obtains a communicable transmission rate. Then, each communication terminal selects a communication mode that is a combination of a packet length, an encoding method, and a modulation method based on a communicable transmission rate,
Data rate control indicating communication mode (hereinafter "D
"RC". ) Send a signal to the base station.

The types of modulation schemes that can be used in each system are BPSK, QPSK, 16QAM, and 64.
It is predetermined such as QAM. The types of coding that can be used in each system are 1/2 turbo code, 1
/ 3 turbo code, 3/4 turbo code, etc. are predetermined. A plurality of usable transmission rates in each system are defined by the combination of the packet length, the modulation method, and the coding method. Each communication terminal selects a combination that allows the most efficient communication in the current downlink line quality from among those combinations,
A DRC signal indicating the selected communication mode is transmitted to the base station. Generally, the DRC signal is represented by numbers 1 to N, and the larger the number, the better the downlink channel quality.

The base station uses the DR transmitted from each communication terminal.
Scheduling is performed based on the C signal, a transmission rate is set for each communication terminal, and a signal indicating allocation of communication resources to each communication terminal is notified to each communication terminal through the control channel. In general, the base station preferentially allocates communication resources to the communication terminal having the best downlink channel quality, that is, the communication terminal that has transmitted the DRC signal with the highest number, in consideration of the improvement of the transmission efficiency of the system. Allocate.

Then, the base station transmits data only to the corresponding communication terminal at the allotted time. For example, when the time t1 is allocated to the communication terminal A, the base station transmits the data only to the communication terminal A and does not transmit the data to the communication terminals other than the communication terminal A at the time t1.

As described above, conventionally, the transmission rate is set for each communication terminal according to the line quality by the HDR, and the communication resource is preferentially allocated to the communication terminal having a high communicable transmission rate. Improves transmission efficiency.

[0009]

However, when the communication mode determined by the communication terminal is erroneously received by the base station due to deterioration of the uplink channel condition from the communication terminal to the base station, the base station will Data is sent in the wrong communication mode. In the communication terminal, the determined communication mode and the communication mode of the transmitted data are different,
Data cannot be demodulated and decoded.

Further, as described above, the base station operates at time t1.
Is assigned to the communication terminal A, the data is transmitted only to the communication terminal A at the time t1, and the data is not transmitted to the communication terminals other than the communication terminal A.

From the above, when the communication mode determined by the communication terminal is erroneously received by the base station, there arises a section in which the time-divided communication resource is not used and the throughput of the downlink decreases. is there.

The present invention has been made in view of the above points, and can prevent a decrease in downlink throughput in a communication system in which communication resources are allocated to each communication terminal based on the downlink channel quality. An object is to provide a communication terminal device.

[0013]

A communication terminal apparatus of the present invention measures downlink quality and is information generated based on the downlink quality, and is a plurality of digits including an upper digit and a lower digit. Measuring means for outputting configured information, and a second code word having a lower digit of the information having a minimum inter-code distance smaller than that of the first code word, while encoding the upper digit of the information into a first code word Encoding means for encoding into
Multiplexing means for arranging the second codeword after the codeword to time-multiplex the first codeword and the second codeword, and the time-multiplexed first codeword and second codeword And a transmitting means for transmitting to the base station device.

Further, the communication terminal apparatus of the present invention measures downlink quality and is information generated based on the downlink quality, the information being composed of a plurality of digits including an upper digit and a lower digit. And a coding means for coding the upper digit of the information into a first code word and the lower digit of the information into a second code word having a smaller number of bits than the first code word. Means, a multiplexing means for arranging the second code word after the first code word to time-multiplex the first code word and the second code word, and the time-multiplexed first code word and the And a transmitting means for transmitting the second code word to the base station apparatus.

With these configurations, it is possible to prevent a decrease in downlink throughput in a communication system in which communication resources are allocated to each communication terminal based on the downlink channel quality.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The essence of the present invention is that, out of information indicating downlink channel quality, a communication terminal is likely to reduce downlink throughput if the base station erroneously receives the information. This is to prevent a decrease in downlink throughput by transmitting with less error in the propagation path.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. (Embodiment 1) As described above, the base station preferentially allocates the communication resource to the communication terminal having the best downlink channel quality. In other words, the base station has the highest D
The RC signal is selected, and communication resources are preferentially allocated to the communication terminal that has transmitted the selected DRC signal. Therefore,
The DRC signal selection frequency in the base station is as shown in FIG. FIG. 1 is a graph showing the frequency of DRC signal selection in the base station. In this figure, DRC numbers 1 to 5 are used, and the higher the number, the better the line quality.

As shown in FIG. 1, a DRC signal with a larger number has a higher frequency of being selected by the base station. That is, the communication terminals having better downlink channel quality are more frequently assigned communication resources. Such a relationship is caused by a large number of communication terminals and an increase in the probability that there are communication terminals with good downlink channel quality.

Thus, the selection frequency of each DRC signal is
It differs depending on the line quality. That is, since the DRC signal indicating that the downlink channel quality is good tends to be selected more frequently, if the DRC signal indicating that the downlink channel quality is good is received by mistake, Throughput is likely to decrease. Also, since the DRC signal indicating that the downlink channel quality is poor tends to be selected less frequently, even if the DRC signal indicating that the downlink channel quality is poor is received by mistake, The impact on the decrease in throughput is small.

Therefore, the communication terminal according to the first embodiment of the present invention increases the transmission power of the DRC signal indicating that the downlink channel quality is good and transmits the DRC signal. Also,
The base station according to Embodiment 1 of the present invention excludes DRC signals whose reception power is lower than a predetermined threshold value and allocates communication resources.

FIG. 2 is a block diagram showing the configuration of the base station according to Embodiment 1 of the present invention. In FIG. 2, the allocation unit 101 uses the D extracted by the demodulation unit 114 described later.
Allocation of communication resources to each communication terminal is determined based on the DRC signal excluding the DRC signal detected by the unused DRC detection unit 116 described later from the RC signal. Then, allocation section 101 instructs buffer 102 to output downlink transmission data, instructs adaptive coding section 103 to code the downlink transmission data based on the determined allocation of communication resources, and adaptive modulation section 104. Instruct the downlink transmission data modulation method.

The buffer 102 holds the downlink transmission data and outputs the downlink transmission data for a predetermined communication terminal to the adaptive coding unit 103 according to the instruction from the allocating unit 101. The adaptive encoding unit 103 encodes the output signal from the buffer 102 according to the instruction of the allocation unit 101 and outputs the encoded signal to the adaptive modulation unit 104. The adaptive modulator 104
According to the instruction from the allocation unit 102, the adaptive encoding unit 103
The output signal from the signal is modulated and output to the spreading section 105. Spreading section 105 spreads the output signal from adaptive modulation section 104 and outputs the spread signal to multiplexing section 108.

Modulation section 106 modulates the pilot signal and outputs it to spreading section 107. The diffusion unit 107 includes the modulation unit 1
The output signal from 06 is spread and output to multiplexing section 108.

The multiplexing unit 108 time-multiplexes the spread pilot signal with the spread downlink transmission data at predetermined intervals,
Output to the transmission RF unit 109. The transmission RF unit 109 converts the frequency of the output signal from the multiplexing unit 108 into a radio frequency and outputs the radio frequency to the duplexer 110.

The duplexer 110 wirelessly transmits the output signal from the transmission RF unit 109 from the antenna 111 to the communication terminal. Further, the duplexer 110 outputs a signal wirelessly transmitted from each communication terminal and wirelessly received by the antenna 111 to the reception RF unit 112.

RF receiving section 112 converts the frequency of the radio frequency signal output from duplexer 110 into a base band and outputs it to despreading section 113. The despreading unit 113 despreads the baseband signal with a spreading code that is spreading the DRC signal to demodulate the demodulation unit 114 and the reception power calculation unit 11.
Output to 5.

Demodulation section 114 demodulates the output signal from despreading section 113 to extract the DRC signal, and assigning section 10
Output to 1.

The reception power calculation unit 115 determines the DR after despreading.
The reception power of the C signal is measured, and the unused DRC detection unit 116
Output to. The unused DRC detection unit 116 is set with a predetermined threshold value, which will be described later, detects a DRC signal having a reception power lower than this threshold value, and outputs the detection result to the allocation unit 101.

The despreading unit 113, the demodulation unit 114, the reception power calculation unit 115, and the unused DRC detection unit 116.
Is provided for each communication terminal, the DRC signal for each communication terminal is output from each demodulation unit 114, and the detection result for each communication terminal is output from each unused DRC detection unit 116.

FIG. 3 is a block diagram showing the configuration of the communication terminal according to the first embodiment of the present invention. In FIG.
The communication mode determining unit 201 includes a CIR measuring unit 21 described later.
Based on the CIR measured in step 9, the communication mode indicating the combination of the modulation method and the coding method is determined, and the DRC
The signal is output to the signal generator 202. In addition, the communication mode determination unit 201 instructs the adaptive demodulation unit 216 to demodulate the downlink received data and the adaptive decoding unit 217 to decode the downlink received data based on the determined communication mode.

The DRC signal creating section 202 creates a DRC signal having a number corresponding to the communication mode output from the communication mode determining section 201, and outputs it to the modulating section 203 and the DRC power control section 205.

Modulation section 203 modulates the DRC signal and outputs it to spreading section 204. The diffusion unit 204 is the modulation unit 203.
The output signal from is spread and output to the DRC power control unit 205. The DRC power control unit 205 uses the transmission power table 20 indicating the correspondence between the DRC number and the transmission power.
6, DR based on the transmission power of the pilot signal output from the pilot power control unit 209 described later.
It controls the transmission power of the C signal and outputs the DRC signal after the transmission power control to the multiplexing unit 210. A specific control method of the DRC signal transmission power will be described later.

Modulation section 207 modulates the pilot signal and outputs it to spreading section 208. The diffusion unit 208 includes the modulation unit 2
The output signal from 07 is spread and the pilot power control unit 2
It outputs to 09. Pilot power control section 209 controls the transmission power of the pilot signal and outputs the pilot signal after the transmission power control to multiplexing section 210. Further, pilot power control section 209 outputs the transmission power of the pilot signal to DRC power control section 209.

The multiplexing section 210 is a DRC after transmission power control.
The signal and the pilot signal after transmission power control are time-multiplexed at a predetermined interval and output to the transmission RF section 211. RF transmission
The unit 211 converts the frequency of the output signal from the multiplexing unit 210 into a radio frequency and outputs the radio frequency to the duplexer 212.

The duplexer 212 wirelessly transmits the output signal from the RF transmitter 211 from the antenna 213 to the base station.
Further, the duplexer 212 outputs a signal wirelessly transmitted from the base station and wirelessly received by the antenna 213 to the reception RF unit 214.

RF receiving section 214 converts the frequency of the radio frequency signal output from duplexer 212 into a baseband, and outputs it to despreading section 215 and despreading section 218.

Despreading section 215 despreads the data component of the baseband signal and outputs it to adaptive demodulation section 216. Adaptive demodulation section 216 demodulates the output signal from despreading section 215 according to the instruction from communication mode determination section 201, and outputs the demodulated signal to adaptive decoding section 217. The adaptive decoding unit 217, according to the instruction from the communication mode determining unit 201, the adaptive demodulating unit 216.
The output signal from is decoded to obtain the received data.

Despreading section 218 despreads the pilot signal component of the baseband signal and outputs it to CIR measuring section 219. CIR measuring section 219 measures the CIR of the pilot signal output from despreading section 218 and outputs it to communication mode determining section 201.

Next, the base station shown in FIG. 2 and the base station shown in FIG.
A procedure for transmitting / receiving a signal to / from the communication terminal shown in will be described.

First, at the start of communication, the modulator 10 of the base station
6, the pilot signal is modulated, spread by spreading section 107, and output to multiplexing section 108. Only the spread pilot signal is output from the multiplexing unit 108 to the transmission RF unit 109. The spread pilot signal is used as the transmission RF unit 10.
The frequency is converted into a radio frequency at 9 and is wirelessly transmitted from the antenna 111 to each communication terminal via the duplexer 110.

The radio signal of only the pilot signal component wirelessly transmitted from the base station is received by the antenna 213 of the communication terminal, and is frequency-converted to the baseband by the reception RF section 214 via the duplexer 212. The pilot signal component of the baseband signal is despread by the despreading unit 218,
It is output to the CIR measuring unit 219.

Next, CIR measuring section 219 measures the CIR of the pilot signal output from despreading section 218, and communication mode determining section 201 determines the communication mode based on the CIR. Then, the DRC signal creation unit 202 creates a DRC signal having a number corresponding to the communication mode.

The DRC signal is modulated by the modulation section 203 and spread by the spreading section 204, and the DRC power control section 20.
5 is output. In the DRC power control unit 205,
The transmission power of the DRC signal is controlled based on the transmission power of the pilot signal output from the pilot power control unit 209 and the ratio of the transmission power of the pilot signal and the transmission power of the DRC signal preset in the transmission power table 206. To be done.

The contents set in the transmission power table 206 will be described below. FIG. 4 is a diagram showing the contents of the transmission power table included in the communication terminal according to the first embodiment of the present invention.

The transmission power table 206 shows the correspondence between the DRC number and the transmission power of the DRC signal.
The transmission power is set to increase as the DRC number increases. Here, the DRC number is 1 to
5 is used, and the higher the number, the better the downlink channel quality. That is, the transmission power table 206 is set so that the transmission power becomes higher as the DRC signal indicating that the downlink channel quality is better.

As described above, since the DRC signal indicating that the downlink channel quality is good tends to be selected more frequently in the base station, the present embodiment indicates that the downlink channel quality is better. The DRC signal shown has a higher transmission power to make it less likely to cause an error. As a result, the probability that the DRC signal indicating that the downlink channel quality is good is erroneously received can be made lower than the probability that the DRC signal indicating that the downlink channel quality is bad is erroneously received. . In other words, the probability that the DRC signal that is frequently selected by the base station is erroneously received can be lower than the probability that the DRC signal that is less frequently selected by the base station is erroneously received.

The DRC signal transmission power set in the transmission power table 206 is represented by the ratio to the pilot signal transmission power. Here, as shown in FIG. 4, DRC number 3 corresponding to the center of DRC numbers 1 to 5
DR that indicates a number smaller than DRC number 3 on the basis of
The C signal is set to be transmitted at a transmission power lower than that of the pilot signal, and the DRC signal indicating a number larger than the DRC number 3 is set to be transmitted at a transmission power higher than that of the pilot signal. That is, here, the DRC signal showing the line quality that is worse than the predetermined line quality (here, the line quality corresponding to the DRC signal of DRC number 3) is transmitted with a transmission power lower than the transmission power of the pilot signal, The DRC signal showing the line quality better than the line quality is set to be transmitted with a transmission power higher than that of the pilot signal.

As described above, in this embodiment, the conventional D
Compared with the transmission power of the RC signal (that is, the transmission power of the pilot signal here), a DRC signal that increases the transmission power and a DRC signal that decreases the transmission power are set, and the DRC is set.
By setting the total increase / decrease value of the signal transmission power to ± 0 dB, DR indicating that the downlink channel quality is good while keeping the average transmission power of the DRC signal constant compared to the conventional one.
It is possible to make the error less likely to occur for the C signal. In other words, without reducing the capacity of the uplink compared to the conventional,
It is possible to make the error less likely to occur as the DRC signal indicates that the downlink quality is good.

Further, as described above, the DRC signal (DRC signals of DRC numbers 1 and 2 in FIG. 4) indicating that the downlink channel quality is poor is transmitted with a lower transmission power than the conventional one, and Power consumption can be reduced in a communication terminal that is located far from the station and is likely to transmit a DRC signal indicating that the downlink channel quality is poor. That is, while a communication terminal that transmits a DRC signal indicating that the downlink channel quality is poor has conventionally transmitted a DRC signal with a high transmission power, according to the present embodiment, Since the transmission power can be made lower than the high transmission power, the power consumption of the communication terminal can be greatly reduced.

Since the DRC signal indicating that the downlink channel quality is poor is selected at the base station in the first place, the DRC signal indicating that the downlink channel quality is poor is lower than the conventional one. Even if the data is transmitted with the transmission power, there is almost no effect on the decrease in throughput.

Further, in the present embodiment, the DRC signal (in FIG. 4, D
The DRC signals of RC numbers 4 and 5) are transmitted with higher transmission power than before. However, there is a high possibility that a DRC signal indicating that the uplink channel quality is good will be transmitted from a communication terminal that is relatively close to the base station. In addition, by the transmission power control for the pilot signal normally performed in the uplink, the transmission power of the pilot signal transmitted from the communication terminal that is relatively close to the base station (that is,
The conventional DRC signal transmission power is low in the first place. Therefore, in a communication terminal that transmits a DRC signal indicating that the uplink line quality is good, the DRC signal transmission power is still low and the power consumption is still low even if the DRC signal transmission power, which was conventionally low, increases. , Has almost no effect on power consumption.

In the DRC power control unit 205, the transmission power of the pilot signal output from the pilot power control unit 209 is adjusted by the ratio set in the transmission power table 206 to obtain the transmission power of the DRC signal. . Then, in DRC power control section 205, the transmission power of the DRC signal output from spreading section 204 is controlled to the obtained transmission power, and the DRC signal after the transmission power control is output to multiplexing section 210. Specifically, for example, when the number of the DRC signal output from the DRC signal creation unit 202 to the DRC power control unit 205 is 5, the transmission power of the DRC signal output from the spreading unit 204 is the pilot power. The transmission power is controlled to be 2 dB lower than the transmission power of the pilot signal output from the control unit 209.

The DRC signal after the transmission power control is the multiplexing unit 2
At 10, the signal is multiplexed with the pilot signal, and the transmission RF unit 2
The frequency is converted into a radio frequency at 11 and is wirelessly transmitted from the antenna 213 to the base station via the duplexer 212.

The signal wirelessly transmitted from the communication terminal is received by the antenna 111 of the base station and input to the reception RF section 112 via the duplexer 110. The signal input to the reception RF unit 112 is frequency-converted to a baseband, and is despread by the despreading unit 113 with a spreading code that is spreading the DRC signal, and the demodulation unit 114 and the reception power calculation unit 115 are provided.
Is output to.

Demodulation section 114 demodulates the output signal from despreading section 113 to extract the DRC signal and outputs it to allocation section 101.

Here, in the communication terminal, the DRC signal indicating that the downlink channel quality is poor is transmitted with lower transmission power than the conventional one, so that the base station DRC signal indicating that the downlink channel quality is poor. Is more likely to be received in error. Further, if communication resources are allocated based on the DRC signal received by mistake, the downlink throughput decreases as described above.

Therefore, the reception power calculation unit 115 measures the reception power of the despread DRC signal, and determines the unused DRC.
It is output to the detection unit 116. Unused DRC detector 116
Indicates that the DRC indicates that the downlink channel quality is the worst.
The lowest reception power at which an error does not occur in the signal (DRC signal of DRC number 1 in FIG. 4) is preset as the threshold value. Then, the unused DRC detection section 116 detects a DRC signal of reception power smaller than this threshold value, and outputs the detection result to the allocation section 101. The DRC signal detected by the unused DRC detection unit 116 is a DRC signal that the allocation unit 101 does not use when determining allocation of communication resources.

The allocation unit 101 allocates communication resources to each communication terminal based on the remaining DRC signals obtained by excluding the DRC signals detected by the unused DRC detection unit 116 from the DRC signals extracted by the demodulation unit 114. Is determined.

As described above, the base station according to the present embodiment excludes DRC signals having a reception power lower than the lowest reception power at which the DRC signal indicating the worst downlink channel quality is not erroneously received. . That is, the base station according to the present embodiment determines the allocation of downlink communication resources by excluding notification signals that are prone to error. Therefore, according to the base station according to the present embodiment, even if the DRC signal indicating that the downlink channel quality is poor is transmitted with a lower transmission power than the conventional one, the communication resources are allocated based on the incorrect DRC signal. Can be prevented from being determined.

As described above, according to the present embodiment, since the DRC signal indicating that the downlink channel quality is good is transmitted with higher transmission power, the DRC signal indicating that the downlink channel quality is good. The less error-prone,
It is possible to reduce the error occurrence rate of the DRC signal that is frequently selected by the base station. This makes the wrong D
Since it is possible to reduce the possibility that communication resource allocation will be determined based on the RC signal, it is possible to prevent a decrease in downlink throughput.

The base station according to this embodiment may have a configuration as shown in FIG. FIG. 5 is a block diagram showing another configuration of the base station according to Embodiment 1 of the present invention. That is, instead of the reception power calculation unit 115 and the unused DRC detection unit 116 shown in FIG.
The base station may be configured to include the 1 and the unused DRC detection unit 302. In the following description, FIG.
The same components as those in FIG. 2 are assigned the same reference numerals as those in FIG. 2 and detailed description thereof will be omitted.

In FIG. 5, the likelihood calculating section 301 uses the DR
The likelihood indicating the degree of certainty of the C signal is calculated and output to the unused DRC detection unit 302. In the unused DRC detection section 302, the lowest likelihood that an error does not occur in the DRC signal indicating that the downlink channel quality is the worst is preset as a threshold value. Then, the unused DRC detection section 302 detects a DRC signal having a likelihood smaller than this threshold value, and outputs the detection result to the allocation section 101.

Even when the base station according to the present embodiment is configured as shown in FIG. 5 in this way, the same effect as described above is exhibited.

(Embodiment 2) In the communication terminal according to Embodiment 2 of the present invention, a DRC signal indicating that the downlink channel quality is good has a larger minimum inter-code distance with respect to a code word of another DRC signal. It is converted into a code word and transmitted.

FIG. 6 is a block diagram showing the configuration of the communication terminal according to the second embodiment of the present invention. As shown in this figure, the communication terminal according to the present embodiment has a modulation unit 2 shown in FIG.
03, spreading section 204, DRC power control section 205 and transmission power table 206, instead of a codeword selecting section 401,
Codeword table 402, modulator 403, and spreader 40
4 is provided. In the following description, the same components as those in FIG. 3 will be assigned the same reference numerals as those in FIG. 3 and detailed description thereof will be omitted.

The code word selection unit 401 uses the code word table 4
02, the DRC signal created by the DRC signal creation unit 202 is converted into a predetermined code word, and the modulation unit 403.
Output to. Modulation section 403 modulates the codeword and outputs it to spreading section 404. Spreading section 404 spreads the output signal from modulating section 403 and outputs the spread signal to multiplexing section 210.

Next, the operation of the communication terminal according to this embodiment will be described. First, the setting contents of the code word table 402 will be described. FIG. 7 shows the second embodiment of the present invention.
It is a figure which shows the content of the code word table with which the communication terminal which concerns on is equipped.

The code word table 402 shows the correspondence between the DRC number and the code word after the DRC signal conversion. As the DRC number increases, the code word is converted into a code word having a larger minimum inter-code distance. It is set. In addition,
Here, 1 to 5 are used for the DRC number, and it is assumed that the higher the number, the better the channel quality of the downlink. That is, the codeword table 402 is set so that a DRC signal indicating that the downlink channel quality is good is converted into a codeword having a larger minimum inter-code distance.

Here, the inter-code distance is the number of bits that differ between each code word, and the minimum inter-code distance is the minimum number of bits that a code word differs from all other code words. Is. Specifically, the code word corresponding to the DRC signal of DRC number 5 is "111111111", and this code word '
111111111 ′ differs by at least 6 bits when compared with any of the code words corresponding to the DRC signals of DRC numbers 1 to 4. Therefore, the minimum inter-code distance of the code word corresponding to the DRC signal of DRC number 5 is 6. Similarly, DR
The minimum intersymbol distance of the codeword corresponding to the DRC signal of C number 4 is 3.

Therefore, the code word corresponding to the DRC signal of DRC number 5 is less likely to cause an error in other code words than the code word corresponding to the DRC signal of DRC number 4. That is, a code word having a larger minimum inter-code distance is less likely to cause an error in another code word.

In the code word selecting unit 401, the DRC signal output from the DRC signal creating unit 202 is converted into the code word set in the code word table 402, and the modulating unit 4
It is output to 03. Specifically, for example, the DRC signal output from the DRC signal creation unit 202 is the DRC of number 5.
If it is a signal, it is converted into codeword '111111111'.

The code word after conversion is modulated by modulating section 403 and spread by spreading section 404. The spread codeword is multiplexed with the pilot signal in the multiplexing unit 210, frequency-converted into a radio frequency in the transmission RF unit 211, and wirelessly transmitted from the antenna 213 to the base station via the duplexer 212.

As described above, according to the present embodiment, a DRC signal indicating that the downlink channel quality is good is converted into a code word having a larger minimum inter-code distance with respect to the code words of other DRC signals and transmitted. Therefore, it is possible to make an error less likely to occur in a DRC signal indicating that the downlink channel quality is good, and it is possible to reduce an error occurrence rate of a DRC signal that is frequently selected by the base station. By this means, it is possible to reduce the possibility that communication resource allocation will be determined based on an erroneous DRC signal, and thus it is possible to prevent a decrease in downlink throughput.

Further, according to the present embodiment, it is possible to reduce the error occurrence rate of the DRC signal that is frequently selected in the base station without increasing the transmission power of the DRC signal, and therefore the communication terminal consumption Without increasing the power, it is possible to reduce the possibility that the communication resource allocation is determined based on the wrong DRC signal.

Further, according to the present embodiment, it is possible to change the error resistance of the code word corresponding to each DRC signal while keeping the code length of the code word constant. Since it is not necessary to have multiple demodulation systems accordingly,
The device configuration of the base station can be simplified.

(Embodiment 3) A base station according to Embodiment 3 of the present invention uses a control signal for rewriting a table based on a DRC signal generation rate excluded when allocation of communication resources is determined. To the communication terminal, and the communication terminal according to the third embodiment of the present invention rewrites the contents of the transmission power table or the code word table based on the control signal transmitted from the base station.

FIG. 8 is a block diagram showing the configuration of the base station according to Embodiment 3 of the present invention. As shown in this figure, the base station according to the present embodiment is configured to further include detection rate calculation section 501, control signal creation section 502, modulation section 503, and spreading section 504 in addition to the configuration shown in FIG. In addition,
In the following description, the same components as those in FIG. 2 will be assigned the same reference numerals as those in FIG. 2 and detailed description thereof will be omitted.

In FIG. 8, the detection rate calculation section 501 calculates the detection rate in the unused DRC detection section 116 and outputs it to the control signal generation section 502. That is, the detection rate calculation unit 50
1 calculates the occurrence rate of DRC signals that are excluded when the allocation of communication resources is determined. Control signal generator 5
02 generates a control signal for rewriting the table (hereinafter referred to as “table rewriting signal”) based on the detection rate, and outputs it to the modulating unit 503. The modulator 503 modulates the table rewrite signal and outputs the table rewrite signal to the spreader 504. Spreading section 504 spreads the output signal from modulating section 503 and outputs the spread signal to multiplexing section 108.

FIG. 9 is a block diagram showing the configuration of the communication terminal according to the third embodiment of the present invention. As shown in this figure, the communication terminal according to the present embodiment has the configuration shown in FIG.
Further, it comprises a despreading unit 601, a demodulation unit 602 and a table rewriting unit 603. In the following description, the same components as those in FIG. 3 will be assigned the same reference numerals as those in FIG. 3 and detailed description thereof will be omitted.

In FIG. 9, despreading section 601 despreads the baseband signal with a spreading code spreading the table rewriting signal and outputs it to demodulation section 602. The demodulation unit 602 demodulates the output signal from the despreading unit 601 to extract the table rewriting signal, and the table rewriting unit 6
Output to 03. The table rewriting unit 603 rewrites the contents of the transmission power table according to the table rewriting signal.

Next, the base station shown in FIG.
A procedure for transmitting / receiving a signal to / from the communication terminal shown in will be described.

First, the detection rate calculation section 501 of the base station calculates the detection rate of the unused DRC detection section 116 and outputs it to the control signal generation section 502. The detection rate can be calculated, for example, from the number of times of detection in a predetermined time.

A predetermined threshold value of the detection rate is set in the control signal generation section 502, and this threshold value is compared with the detection rate calculated by the detection rate calculation section 501. And
When the detection rate calculated by the detection rate calculation section 501 is equal to or higher than the threshold value, a table rewrite signal for instructing to increase all the transmission powers set in the transmission power table 206 is created, and the modulation section is generated. It is output to 503. That is, in the control signal generation unit 502, when the occurrence rate of DRC signals excluded when the allocation of communication resources is determined is equal to or higher than a predetermined threshold value, the transmission power of each DRC signal is set to be higher than that at present. A table rewrite signal instructing to uniformly increase is created.

The table rewrite signal is modulated by the modulator 503, spread by the spreader 504, and multiplexed by the multiplexer 108.
Is output to. The spread table rewriting signal is multiplexed with the transmission data and the pilot signal by the multiplexing unit 108, frequency-converted into a radio frequency by the transmission RF unit 109, and wirelessly transmitted from the antenna 111 to each communication terminal via the duplexer 110. To be done.

The radio signal wirelessly transmitted from the base station is received by the antenna 213 of the communication terminal, and is frequency-converted to the baseband by the reception RF section 214 via the duplexer 212. The baseband signal is despread by the despreading unit 601 and demodulated by the demodulation unit 602 to extract the table rewriting signal. The extracted table rewrite signal is
It is output to the table rewriting unit 603.

Then, the table rewriting unit 603 transmits the transmission power table 2 in accordance with the table rewriting signal.
The contents of 06 are rewritten. That is, the table rewriting unit 603 increases all the transmission powers set in the transmission power table 206.

In the above description, the table rewriting unit 603 rewrites the contents of the transmission power table 206. However, this embodiment is applied to the communication terminal according to the second embodiment, and the table rewriting unit 603 performs the drawing. The content of the codeword table 402 shown in FIG. 6 may be rewritten.

In this case, control signal generating section 502 of the base station according to the present embodiment sets codeword table 402 when the detection rate calculated by detection rate calculating section 501 is equal to or greater than the threshold value. A table rewrite signal is generated to instruct to increase all the minimum intersymbol distances of the codewords. In other words, the control signal generation unit 502, when the occurrence rate of DRC signals excluded when the allocation of communication resources is determined is equal to or higher than a predetermined threshold value, the DR
A table rewrite signal for instructing to uniformly increase the minimum inter-code distance of the code word corresponding to the C signal from the present is created. Then, the table rewriting unit 6 of the communication terminal
03 rewrites the contents of the codeword table 402 according to the table rewrite signal. That is, the table rewriting unit 603 rewrites the codeword set in the codeword table 402 to a codeword in which the minimum inter-code distance is larger than that at the present.

As described above, in the present embodiment, the contents of the transmission power table or the code word table are rewritten based on the occurrence rate of the DRC signal that is excluded when the allocation of communication resources is determined. In other words, in the present embodiment, the contents of the transmission power table or codeword table are adaptively rewritten in response to changes in the communication environment. That is, according to the present embodiment, DRCs that are excluded when the communication environment is deteriorated and communication resource allocation is determined.
To increase the transmission power of each DRC signal or to increase the minimum inter-code distance of the code word corresponding to each DRC signal when the signal generation rate becomes equal to or higher than a predetermined threshold value,
Even when the communication environment deteriorates, the error occurrence rate of the DRC signal can be suppressed.

In the present embodiment, the predetermined threshold value of the detection rate is appropriately determined in consideration of the environment to which the communication system is applied.

Further, in the present embodiment, the second predetermined threshold value is further set in the control signal generation unit 502, and the detection rate calculated by the detection rate calculation unit 501 is the second threshold value. If it is smaller than the value, the transmission power table 20
A table rewrite signal instructing to reduce all the transmission power set to 6 may be created. By this means, when the reception quality of the DRC signal becomes excessive, the transmission power of the DRC signal can be reduced, so that the power consumption of the communication terminal can be reduced.

Further, in the present embodiment, the table is rewritten based on the detection rate of the unused DRC detection section 116, but it is used to determine the allocation of communication resources in the DRC signal transmitted from the mobile station. The table may be rewritten based on the distribution of the obtained DRC signal so that the distribution becomes an optimal distribution. In this case, the base station shown in FIG. 8 is configured to include a used DRC distribution determination unit instead of the detection rate calculation unit, and the used DRC distribution determination unit,
DRC signal output from demodulation unit 114 and unused DRC
The distribution of the DRC signals used for determining the allocation of the communication resource is determined from the detection result output from the detection unit 116, and a signal indicating the distribution is output to the control signal creation unit 502. Further, the control signal creation unit 502 creates a table rewrite signal based on the signal indicating the distribution output from the used DRC distribution determination unit.

(Embodiment 4) The communication terminal according to Embodiment 4 of the present invention transmits CIR information indicating that the downlink channel quality is good with higher transmission power. Further, the base station according to Embodiment 4 of the present invention excludes CIR information whose reception power is lower than a predetermined threshold,
It allocates communication resources.

In the first embodiment, the communication terminal is the CI
The communication mode is determined based on R, the DRC signal corresponding to the determined communication mode is transmitted to the base station with a predetermined transmission power, and the base station transmits the communication resource to each communication terminal based on the DRC signal. The allocation has been decided. Since the DRC signal can be represented by a very small number of bits as compared with other information indicating the downlink channel quality (for example, downlink CIR), the use of the DRC signal can improve the uplink channel usage efficiency. It has the advantage that it can be increased. On the other hand, the communication terminal needs to determine the communication mode and create the DRC signal, and needs to have a table for determining the communication mode, a table for creating the DRC signal, etc. However, there is a disadvantage that the number of devices increases and the scale of the device increases.

Therefore, in this embodiment, the communication terminal is
The CIR information is transmitted to the base station with a predetermined transmission power, the base station determines the communication mode based on the CIR information, and then determines the allocation of communication resources to each communication terminal. By doing so, there is a disadvantage in that the uplink line usage efficiency is somewhat reduced, but the communication terminal does not need to determine the communication mode and create the DRC signal, and Since there is no need to provide a table for (1), a table for creating a DRC signal, etc., there is a great advantage that the power consumption of the communication terminal can be reduced and the device scale can be reduced. Further, in the present embodiment, the base station can compare the CIR information of a plurality of terminals to surely determine an accurate communication mode,
The present embodiment is particularly effective when each communication terminal cannot simply determine the communication mode from the CIR.

The base station according to this embodiment and the communication terminal according to this embodiment will be explained below. Figure 10
FIG. 9 is a block diagram showing a configuration of a base station according to Embodiment 4 of the present invention. In the following description, the same components as those in FIG. 2 will be assigned the same reference numerals as those in FIG. 2 and detailed description thereof will be omitted.

In FIG. 10, demodulation section 701 demodulates the output signal from despreading section 113 to extract a signal containing CIR information (hereinafter referred to as “CIR signal”) and outputs it to allocation section 704.

Reception power calculation section 702 receives CI after despreading.
The reception power of the R signal is measured, and the unused CIR detection unit 703
Output to. A predetermined threshold value is set in the unused CIR detection unit 703 as in the first embodiment. A CIR signal of the reception power lower than this threshold value is detected, and the detection result is assigned to the allocation unit 704. Output.

Despreading section 113, demodulation section 701, reception power calculation section 702 and unused CIR detection section 703.
Is provided for each communication terminal, the CIR signal for each communication terminal is output from each demodulation unit 701, and the detection result for each communication terminal is output from each unused CIR detection unit 703.

The allocating unit 704 excludes the CIR signal detected by the unused CIR detecting unit 703 from the CIR signal extracted by the demodulating unit 701, based on the CIR information indicated by the CIR signal, and allocates the communication resource to each communication terminal. Determine allocation. Then, allocation section 704 instructs buffer 102 to output downlink transmission data based on the determined allocation of communication resources, and outputs CIR information to communication mode determination section 705.

The communication mode determining section 705 is assigned to the assigning section 7
Based on the CIR information output from 04, the communication mode indicating the combination of the modulation method and the coding method is determined,
A signal indicating the communication mode is output to the modulation unit 706.
In addition, the communication mode determination unit 705 instructs the adaptive coding unit 103 on the downlink transmission data coding system and the adaptive modulation unit 104 on the downlink transmission data modulation system based on the determined communication mode. The modulation unit 706 modulates the signal indicating the communication mode and outputs the signal to the spreading unit 707. Diffuser 7
07 spreads the output signal from the modulator 706 and outputs it to the multiplexer 108.

FIG. 11 is a block diagram showing the configuration of the communication terminal according to the fourth embodiment of the present invention. In the following description, the same components as those in FIG. 3 will be assigned the same reference numerals as those in FIG. 3 and detailed description thereof will be omitted.

In FIG. 11, a CIR information creating section 801
Is a CI indicating the CIR measured by the CIR measuring unit 219.
An R signal is created and output to the modulator 802 and the CIR information power controller 804. Modulation section 802 modulates the CIR signal and outputs it to spreading section 803. The diffusion unit 803 is
The output signal from the modulator 802 is spread and output to the CIR information power controller 804. CIR information power control unit 804
Refers to the transmission power table 805 which shows the correspondence between the CIR magnitude and the transmission power, and determines the transmission power of the CIR signal based on the transmission power of the pilot signal output from the pilot power control unit 209. The CIR signal after control and transmission power control is output to multiplexing section 210.

The despreading section 807 converts the baseband signal into
The signal indicating the communication mode is despread with the spreading code and the despread signal is output to communication mode detecting section 808. The communication mode detection unit 808 demodulates the output signal from the despreading unit 807 and detects the communication mode. Then, the communication mode detection unit 808 instructs the adaptive demodulation unit 216 to demodulate the downlink received data and the adaptive decoding unit 217 to decode the downlink received data based on the detected communication mode.

Next, a procedure for transmitting / receiving a signal between the base station shown in FIG. 10 and the communication terminal shown in FIG. 11 will be described.

First, in the communication terminal shown in FIG.
The IR measuring section 219 measures the CIR of the pilot signal output from the despreading section 218, and the CIR information creating section 801 creates the CIR signal.

The CIR signal is modulated by modulator 802, spread by spreader 803, and output to CIR information power controller 804. Similar to the first embodiment, the transmission power table 805 shows the correspondence between the CIR magnitude and the CIR signal transmission power, and is set so that the CIR signal transmission power increases as the CIR increases. ing. That is, the transmission power table 805 is set so that the transmission power becomes higher as the CIR signal indicating that the downlink channel quality is better, as in the first embodiment. Also, the CIR set in the transmission power table 805
The signal transmission power is represented by the ratio to the pilot signal transmission power, as in the first embodiment.

In the CIR information power control unit 804,
The transmission power of the pilot signal output from the pilot power control unit 209 is adjusted according to the ratio set in the transmission power table 805, so that the transmission power of the CIR signal is obtained. Then, the CIR information power control unit 804
In the above, the transmission power of the CIR signal output from spreading section 803 is controlled to the calculated transmission power, and the CIR signal after the transmission power control is output to multiplexing section 210.

The CIR signal after the transmission power control is the multiplexing unit 2
At 10, the signal is multiplexed with the pilot signal, and the transmission RF unit 2
The frequency is converted into a radio frequency at 11 and is wirelessly transmitted from the antenna 213 to the base station via the duplexer 212.

In the base station shown in FIG. 10, demodulation section 701 demodulates the output signal from despreading section 113 to obtain CIR.
The signal is extracted and output to the allocation unit 704. The reception power calculator 702 measures the reception power of the despread CIR signal and outputs it to the unused CIR detector 703. The unused CIR detector 703 has a CIR indicating that the downlink has the worst line quality, as in the first embodiment.
The lowest reception power that does not cause an error in the signal is preset as the threshold value. Then, the unused CIR detector 7
03, the CIR of the receiving power smaller than this threshold
The signal is detected and the detection result is output to the allocation unit 704. CIR detected by unused CIR detector 703
The signal is a CIR signal that the allocating unit 704 does not use when determining allocation of communication resources.

The allocating unit 704 excludes the CIR signal detected by the unused CIR detecting unit 703 from the CIR signal extracted by the demodulating unit 701, and communicates to each communication terminal based on the CIR indicated by the remaining CIR signal. The resource allocation is determined, and the CIR information is the communication mode determination unit 705.
Is output to.

Communication mode determining section 705 determines the communication mode based on the CIR information output from allocating section 704, and a signal indicating the communication mode is output to modulating section 70.
6 is output. The signal indicating the communication mode is transmitted to the modulator 70.
6 and modulated by the spreading unit 707 and then multiplexed by the multiplexing unit 1
08, multiplexed with transmission data and pilot signal,
The transmission RF unit 109 performs frequency conversion into a radio frequency, and the data is wirelessly transmitted from the antenna 111 to the communication terminal via the duplexer 110.

In the communication terminal shown in FIG. 11, despreading section 80 is used.
At 7, the baseband signal is despread, and the despread signal is output to communication mode detecting section 808. In the communication mode detection unit 808, the output signal from the despreading unit 807 is demodulated to detect the communication mode, and based on the detected communication mode, the adaptive demodulation unit 216 is instructed to demodulate the downlink received data, The decoding unit 217 is instructed about the decoding method of the downlink received data.

As described above, according to the present embodiment, as in the first embodiment, a CIR signal indicating that the downlink channel quality is good is transmitted with a higher transmission power, so that it is used in the base station. It is possible to reduce the error occurrence rate of CIR information that is frequently used. This causes the wrong CI
Since it is possible to reduce the possibility that communication resource allocation will be determined based on the R information, it is possible to prevent a decrease in downlink throughput.

Further, according to the present embodiment, as in the first embodiment, the CIR of the reception power lower than the lowest reception power at which the CIR signal indicating the worst downlink channel quality is not erroneously received. Since the signal is excluded, even if the CIR signal indicating that the downlink channel quality is poor is transmitted with a transmission power lower than the conventional one, the allocation of communication resources is prevented from being determined based on erroneous CIR information. be able to.

The base station according to the present embodiment is shown in FIG.
The configuration may be as shown in. FIG. 12 is a block diagram showing another configuration of the base station according to Embodiment 4 of the present invention. That is, the reception power calculation unit 702 shown in FIG.
Also, instead of the unused CIR detection unit 703, a likelihood calculation unit 901 and an unused CIR detection unit 902 may be provided to configure a base station. In the following explanation,
The same components as those in FIG. 10 are designated by the same reference numerals as those in FIG. 10, and detailed description thereof will be omitted.

In FIG. 12, the likelihood calculating section 901 uses C
The likelihood indicating the degree of certainty of the IR signal is calculated and output to the unused CIR detection unit 902. In the unused CIR detector 902, the lowest likelihood that an error does not occur in the CIR signal indicating that the downlink channel quality is the worst is preset as a threshold value. Then, in the unused CIR detection unit 902, the CIR having the likelihood smaller than this threshold value is used.
The signal is detected and the detection result is output to the allocation unit 704.

Even when the base station according to the present embodiment has a configuration as shown in FIG. 12 as described above, the same effect as described above is exhibited.

(Embodiment 5) In the communication terminal according to Embodiment 5 of the present invention, the CIR signal indicating that the downlink channel quality is good, the greater the minimum inter-code distance with respect to the code word of another CIR signal. It is converted into a code word and transmitted.

FIG. 13 is a block diagram showing the configuration of the communication terminal according to the fifth embodiment of the present invention. As shown in this figure, the communication terminal according to the present embodiment has a modulation section 802, a spreading section 803, and a CIR information power control section 804 shown in FIG.
Also, instead of the transmission power table 805, a codeword selection unit 1001, a codeword table 1002, a modulation unit 1003, and a spreading unit 1004 are provided. In the following description, the same components as those in FIG. 11 will be assigned the same reference numerals as those in FIG. 11 and detailed description thereof will be omitted.

The codeword selection unit 1001 refers to the codeword table 1002, converts the CIR signal created by the CIR information creation unit 801 into a predetermined codeword, and the modulation unit 1
Output to 003. Modulation section 1003 modulates the codeword and outputs it to spreading section 1004. Spreading section 1004 spreads the output signal from modulating section 1003 and outputs the result to multiplexing section 210.

Next, the operation of the communication terminal according to this embodiment will be described. Similar to the second embodiment, the codeword table 1002 shows the correspondence between the CIR magnitude and the codeword after CIR signal conversion. The larger the CIR magnitude, the smaller the minimum inter-code distance. Is set so that the CIR signal is converted into a codeword having a large value. That is, the codeword table 1002 is set so that a CIR signal indicating that the downlink channel quality is good is converted into a codeword having a larger minimum inter-code distance.

In the code word selection unit 1001, the CIR
The CIR signal output from the information creating unit 801 is converted into a codeword set in the codeword table 1002 and output to the modulating unit 1003. The code word after conversion is the modulation unit 1
It is modulated in 003 and spread in the spreading section 1004. The codeword after spreading is multiplexed with the pilot signal in the multiplexing unit 210, frequency-converted into a radio frequency in the transmission RF unit 211, and the antenna 2 is transmitted via the duplexer 212.
It is wirelessly transmitted from 13 to the base station.

Thus, according to the present embodiment, as in the case of Embodiment 2, the CIR signal indicating that the downlink channel quality is good has the minimum inter-code distance with respect to the codewords of other CIR signals. Since it is converted into a large codeword and transmitted,
It is possible to reduce the error occurrence rate of CIR information frequently used in the base station. This causes the wrong C
Since it is possible to reduce the possibility that communication resource allocation will be determined based on IR information, it is possible to prevent a decrease in downlink throughput.

Further, according to the present embodiment, like the second embodiment, it is possible to reduce the error occurrence rate of CIR information frequently used in the base station without increasing the transmission power of the CIR signal. Therefore, it is possible to reduce the possibility that communication resource allocation will be determined based on erroneous CIR information without increasing the power consumption of the communication terminal.

Further, according to the present embodiment, similarly to the second embodiment, each CIR is maintained with the code length of the code word being constant.
Since it is possible to change the error resistance of the code word corresponding to the signal, it is not necessary for the base station to have a plurality of demodulation systems according to each code length, so the device configuration of the base station can be simplified.

(Embodiment 6) Embodiment 6 of the present invention
The communication terminal according to No. 8 transmits the information with a greater change amount in the CIR information with less error in the propagation path. In other words, the communication terminals according to Embodiments 6 to 8 of the present invention transmit information in which the rougher the value of the CIR information, the less likely it is to make an error in the propagation path.

Here, the "information having a large amount of change" and the "information indicating a rough value" are, for example, C
When the IR value is indicated by a decimal value (for example, 8.7 dB), it means the integer part (that is, “8” here). In this case, the amount of change per unit of the integer part is 1 dB
Since the amount of change per unit of the minority part is 0.1 dB, the integer part is “information with a large amount of change”.
Therefore, in the base station, if the integer part is received by mistake, the degree of error becomes larger than that in the case where the decimal part is received by mistake, and there is a high possibility that the wrong communication mode is determined. That is, there is a high possibility that downlink throughput will decrease.

Further, the CIR information is usually converted into a code word having a limited number of bits and transmitted to the base station. Also,
There are also restrictions on the transmission power that can be used for transmitting CIR information and the spreading rate of the spreading code. Therefore, it is difficult to make the entire CIR information hard to be erroneous.

Therefore, in the sixth to eighth embodiments of the present invention,
Within the above limits for the transmission of CIR information, only the “information with a large amount of change” (that is, “information indicating a rough value”) of the CIR information is correctly received within the above limits. The larger the amount of information, ”the less likely it is to make an error in the propagation path before transmission.

The communication terminal according to the sixth embodiment of the present invention will be described below. The communication terminal according to Embodiment 6 of the present invention converts a CIR value into a codeword having a code length with a higher digit value and transmits the codeword.

FIG. 14 is a block diagram showing the configuration of the communication terminal according to the sixth embodiment of the present invention. In the following description, the same components as those in FIG. 11 will be assigned the same reference numerals as those in FIG. 11, and detailed description thereof will be omitted.

In FIG. 14, the CIR signal generator 110
1 converts the CIR value measured by CIR measuring section 219 into a code word to create a CIR signal, and outputs the created CIR signal to multiplexing section 210. At this time, the CIR signal creation unit 1101 creates a CIR signal by converting the CIR value into a code word having a longer code length as the value of the higher digit.

Next, the configuration of CIR signal generating section 1101 will be described. FIG. 15 is a block diagram showing the configuration of the CIR signal creation section of the communication terminal according to Embodiment 6 of the present invention.

In FIG. 15, the upper digit information generating section 120
1 outputs the value of the upper digit of the CIR value output from the CIR measuring unit 219 to the 6-bit encoding unit 1203. The lower digit information generation unit 1202 has a CIR measurement unit 219.
The value of the lower digit of the CIR value output from is output to the 4-bit encoding unit 1204. Specifically, for example, CI
When the CIR value output from the R measurement unit 219 is 8.7 dB, the higher digit information generation unit 1201 outputs the value of the integer part “8” to the 6-bit encoding unit 1203,
The lower digit information generation unit 1202 outputs the value of the decimal part of “7” to the 4-bit encoding unit 1204.

The 6-bit encoding unit 1203 converts the value (here, “8”) output from the higher-order digit information generating unit 1201 into a 6-bit code word, and the 6-bit code word is time-multiplexed. Output to 1205. 4-bit encoding unit 1204
Converts the value (here, “7”) output from the lower digit information generation unit 1202 into a 4-bit codeword, and outputs the 4-bit codeword to the time multiplexing unit 1205. Here, the number of bits that can be used to indicate the CIR value is 10 bits.

The time multiplexing unit 1205 stores a 6-bit codeword in the first half of one slot and a 4-bit codeword in the second half of the 1st slot. , The code word corresponding to the value of the upper digit) and the code word of the minority part of the CIR value (that is, the code word corresponding to the value of the lower digit) are time-multiplexed. Then, time multiplexing section 1205 outputs the time-multiplexed 10-bit codeword as a CIR signal to modulation section 1206.
In addition, here, one slot consists of 10 bits,
The first half 6 bits represent the integer part of the CIR value, and the second half 4 bits represent the decimal part of the CIR value.

Modulation section 1206 modulates the CIR signal and outputs it to spreading section 1207. Spreading section 1207 spreads the output signal from modulating section 1206 and outputs it to multiplexing section 210.

Next, the operation of the communication terminal having the above configuration will be described. In the 6-bit encoding unit 1203, C
The upper digit value (here, “8”) of the IR value is converted into a 6-bit codeword. On the other hand, the 4-bit encoding unit 12
In 04, the value of the lower digit of the CIR value (here, '
7 ') is converted into a 4-bit codeword.

Since there are 2 ⁶ types of codewords represented by 6 bits and 2 ⁴ types of codewords represented by 4 bits, the codewords represented by 6 bits are different from each other. The minimum inter-code distance between code words can be increased. Therefore, the code word represented by 6 bits is less likely to cause an error in other code words than the code word represented by 4 bits. That is, in the present embodiment, the value of the upper digit of the CIR value is less likely to cause an error.

As described above, the communication terminal according to the present embodiment converts into a code word having a longer code length as the value of the higher digit in the CIR value is within the limit of 10 bits that can be used to indicate the CIR value. By doing so, it is possible to transmit with higher error in the higher digit value with a larger variation amount. As a result, even if an error occurs in the CIR signal in the propagation path, the base station has a higher probability of being able to receive the CIR value with higher accuracy, and the degree of error in the CIR value can be reduced. You can Therefore, the base station can reduce the possibility that the wrong communication mode is determined.

The present embodiment has been described on the assumption that the upper digit value is converted to a 6-bit code word and the lower digit value is converted to a 4-bit code word. However, if the number of bits of the code word corresponding to the value of the upper digit is larger than the number of bits of the code word corresponding to the value of the lower digit, the number of bits is not particularly limited.

(Embodiment 7) A communication terminal according to Embodiment 7 of the present invention is designed to increase the transmission power as the value of the higher digit in the CIR value is transmitted.

Since the communication terminal according to the present embodiment differs from the communication terminal according to Embodiment 6 only in the internal configuration of CIR signal generating section 1101, only the CIR signal generating section 1101 will be described below. To do.

FIG. 16 is a block diagram showing the structure of the CIR signal generating section of the communication terminal according to the seventh embodiment of the present invention. In the following description, the same configuration as that of FIG.
The same reference numeral as 5 is assigned and the detailed description thereof is omitted.

A CIR signal generator 1101 shown in FIG.
Converts the CIR value measured by the CIR measurement unit 219 into a code word, and increases the transmission power as the value of the higher digit increases C
Create an IR signal.

In FIG. 16, the 5-bit encoding unit 130
1 is the value output from the upper digit information generation unit 1201 is 5
It is converted into a bit code word and the 5-bit code word is output to the modulation unit 1303. Also, the 5-bit encoding unit 1302
Converts the value output from the lower digit information generation unit 1202 into a 5-bit codeword, and converts the 5-bit codeword into the modulation unit 1
Output to 304. As described above, in the present embodiment, both the value of the upper digit and the value of the lower digit are converted into a 5-bit code word. Therefore, in terms of the code word, there is no difference in error resistance between the two. Absent.

The modulation section 1303 is a 5-bit encoding section 13
The code word output from 01 is modulated, and the upper digit spreading unit 1
Output to 305. Further, modulator 1304 modulates the codeword output from 5-bit encoder 1302, and outputs it to lower digit spreader 1306.

The upper digit spreading section 1305 is a modulation section 1303.
The output signal from the high-order digit power control unit 1307
Output to. Also, the lower digit spreading section 1306 is the modulation section 1
The output signal from the 304 is spread and the lower digit power control unit 1
Output to 308. At this time, the upper digit spreading unit 1305 and the lower digit spreading unit 1306 respectively perform spreading processing using spreading codes of the same type but different types. That is,
The value of the upper digit and the value of the lower digit of the CIR value are spread by different spreading codes having the same spreading factor.

The upper digit power control unit 1307 controls the transmission power of the signal indicating the upper digit value of the CIR value on the basis of the transmission power of the pilot signal output from the pilot power control unit 209 to control the transmission power. The latter signal is output to the code multiplexing unit 1309. In addition, the lower digit power control unit 130
Reference numeral 8 controls the transmission power of the signal indicating the lower digit of the CIR value based on the transmission power of the pilot signal output from the pilot power control unit 209, and the signal after the transmission power control is performed by the code multiplexing unit 1309. Output to. A specific control method of the transmission power will be described later.

The code multiplexing unit 1309 multiplexes the signal indicating the value of the upper digit of the CIR value and the signal indicating the value of the lower digit of the CIR value in the same time zone. That is, the code multiplexing unit 1309
A signal indicating the value of the upper digit and a signal indicating the value of the lower digit are code-multiplexed.

Next, the operation of the communication terminal having the above configuration will be described. In the upper digit power control unit 1307, C
The signal indicating the upper digit value of the IR value is controlled to have a transmission power higher than the transmission power of the pilot signal by a predetermined value. The lower digit power control unit 1308 controls the signal indicating the lower digit of the CIR value to a transmission power that is lower than the transmission power of the pilot signal by a predetermined value. That is, the higher the digit of the CIR value, the higher the transmission power.

As described above, the communication terminal according to the present embodiment transmits the data with higher transmission power for the higher digit of the CIR value, so that the higher the digit of the CIR value, the less likely the error is. Then you can send it. This allows
Even if an error occurs in the CIR signal in the propagation path, the base station has a higher probability of being able to receive the CIR value with higher accuracy, and the degree of error in the CIR value can be suppressed to a low level. Therefore, at the base station,
The possibility that the wrong communication mode is determined can be reduced.

Further, in the present embodiment, as compared with the conventional transmission power of the CIR signal (that is, the transmission power of the pilot signal here), the transmission power of the upper digit is increased and the transmission power of the lower digit is increased. Regarding the value, by lowering the transmission power by an amount corresponding to the higher digit value and making the total increase / decrease value of the transmission power ± 0 dB, the transmission power of the entire CIR signal becomes the same as that of the conventional CIR signal. I tried to keep it the same. Therefore, according to the present embodiment, it is possible to maintain the transmission power of the CIR signal at the same level as the conventional one, and to transmit the CIR signal with higher error in the higher digit. In other words, it is possible to perform transmission with the higher digit value being less likely to cause an error without reducing the uplink capacity as compared with the conventional case.

(Embodiment 8) A communication terminal according to Embodiment 8 of the present invention spreads a CIR value with a spreading code having a higher spreading factor for transmission, and transmits it.

The communication terminal according to the present embodiment is the same as the communication terminals according to the sixth and seventh embodiments, and CIR signal creating section 11
Since only the internal configuration of 01 is different, in the following description,
Only the CIR signal generator 1101 will be described.

FIG. 17 is a block diagram showing the structure of the CIR signal generating section of the communication terminal according to Embodiment 8 of the present invention. In the following description, the same components as those in FIG. 15 or FIG. 16 will be assigned the same reference numerals as those in FIG. 15 or 16, and detailed description thereof will be omitted.

The CIR signal generator 1101 shown in FIG.
Converts a CIR value measured by the CIR measuring unit 219 into a code word, and spreads it with a spreading code having a higher spreading factor for higher digit values to create a CIR signal.

In FIG. 17, upper digit spreading section 1401
Outputs the output signal from the modulator 1303 to the time multiplexer 1205. Also, the lower digit spreading section 1402
Outputs the output signal from the modulator 1304 to the time multiplexer 1205. At this time, the upper digit diffusion unit 140
1 is the same type as that used in the lower digit spreading section 1402, and performs spreading processing with a spreading code having a spreading rate higher than that of the lower digit spreading section 1402. That is, the value of the upper digit of the CIR value is spread with a higher spreading factor than the value of the lower digit. As a result, the higher the digit value, the less likely it is that an error will occur in the propagation path.

As described above, the communication terminal according to the present embodiment transmits the data with a higher spreading factor for the higher digit of the CIR value, so that the higher the digit of the CIR value, the more likely the error is to occur. Then you can send it. As a result, even if an error occurs in the CIR signal in the propagation path, the base station has a higher probability of being able to receive the CIR value with higher accuracy, and the degree of error in the CIR value can be reduced. You can Therefore, the base station can reduce the possibility that the wrong communication mode is determined.

Further, in the present embodiment, the spreading factor is set higher for the upper digit value and higher for the lower digit value than the conventional CIR signal spreading factor. Only lower the diffusion rate. In this way, the amount of data that can be sent in one slot is kept equal to that of the conventional CIR signal. Therefore, according to the present embodiment, it is possible to reduce the amount of data that can be transmitted in one slot, and to transmit with higher error in the higher digits.

It is also possible to combine the communication terminal according to the first embodiment with the communication terminal according to the second embodiment. It is also possible to combine and implement the communication terminal according to the fourth embodiment and the communication terminal according to the fifth embodiment. It is also possible to combine and implement the communication terminals according to the sixth to eighth embodiments. Further, the transmission power table included in the communication terminal according to the fourth embodiment and the code word table included in the communication terminal according to the fifth embodiment are converted into control signals from the base station in the same manner as in the third embodiment. It is also possible to appropriately rewrite based on this.

Further, although cases have been described with the above-described first to eighth embodiments where pilot signals are time-multiplexed, the first to eighth embodiments are not limited to this, and pilot signals are code-multiplexed. It is also applicable in some cases.

Further, in the above-described first to eighth embodiments, CIR is used as a value indicating the reception quality of the pilot signal,
The value is not limited to this, and any value can be used as long as it can indicate the reception quality.

Further, although the predetermined threshold values set in the unused DRC detection section and the unused CIR detection section are fixed values in the first to fifth embodiments, the error rate of the DRC signal and the CIR signal The threshold may be adaptively changed according to the error rate.

Further, in the above sixth to eighth embodiments, when each code word is multiplexed, either time multiplexing or code multiplexing may be used.

Further, in the above-mentioned sixth to eighth embodiments, the CIR value represented by one digit of the integer part and one digit of the decimal part has been described as an example. However, the present invention is not limited to this, and Embodiments 6 to 8 above are all practicable for CIR values represented by a plurality of digits.

In the sixth to eighth embodiments, the CIR
The value of the upper digit of the value is described as "information having a large amount of change". However, "information with a large amount of change" does not necessarily correspond to the digit size. For example, a method of indicating a rough value such as 0 dB, 2 dB, 4 dB, 6 dB with a value that changes by 2 dB first, and adding information indicating whether or not there is an increase of 1 dB to the rough value and expressing the CIR value as an integer is a method. When it is taken, a value that changes by 2 dB is “information with a large amount of change”. In this method, for example, when a CIR value of 7 dB is represented, a CIR signal including two pieces of information indicating 6 dB and information indicating that there is an increase of 1 dB is transmitted to the base station. At this time, the communication terminal apparatus transmits information indicating 6 dB with less error than information indicating that there is an increase of 1 dB, as in Embodiments 6 to 8 above.

[0169]

As described above, according to the present invention,
In a communication system in which communication resources are allocated to each communication terminal based on downlink channel quality, it is possible to prevent downlink throughput from decreasing.

[Brief description of drawings]

FIG. 1 is a graph showing the frequency of DRC signal selection in a base station.

FIG. 2 is a block diagram showing a configuration of a base station according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a communication terminal according to the first embodiment of the present invention.

FIG. 4 is a diagram showing contents of a transmission power table provided in the communication terminal according to the first embodiment of the present invention.

FIG. 5 is a block diagram showing another configuration of the base station according to the first embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a communication terminal according to a second embodiment of the present invention.

FIG. 7 is a diagram showing the contents of a codeword table provided in the communication terminal according to the second embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of a base station according to Embodiment 3 of the present invention.

FIG. 9 is a block diagram showing a configuration of a communication terminal according to a third embodiment of the present invention.

FIG. 10 is a block diagram showing a configuration of a base station according to Embodiment 4 of the present invention.

FIG. 11 is a block diagram showing a configuration of a communication terminal according to Embodiment 4 of the present invention.

FIG. 12 is a block diagram showing another configuration of the base station according to Embodiment 4 of the present invention.

FIG. 13 is a block diagram showing a configuration of a communication terminal according to a fifth embodiment of the present invention.

FIG. 14 is a block diagram showing a configuration of a communication terminal according to a sixth embodiment of the present invention.

FIG. 15 is a CI of the communication terminal according to the sixth embodiment of the present invention.
Block diagram showing the configuration of the R signal creation unit

FIG. 16 is a CI of the communication terminal according to the seventh embodiment of the present invention.
Block diagram showing the configuration of the R signal creation unit

FIG. 17 is a CI of the communication terminal according to the eighth embodiment of the present invention.
Block diagram showing the configuration of the R signal creation unit

[Explanation of symbols]

101, 704 Allocation unit 102 Buffer 103 Adaptive coding unit 104 Adaptive modulation unit 105, 107, 204, 208, 704, 504, 7
07,803,1004 Diffusion part 106,203,207,403,503,706,8
02,1003 Modulator 108,210 Multiplexer 113,215,218,601 Despreader 114,602,701 Demodulator 115,702 Reception power calculator 116,302 Unused DRC detector 201,705 Communication mode determiner 202 DRC signal creation unit 205 DRC power control unit 206, 805 Transmission power table 209 Pilot power control unit 216 Adaptive demodulation unit 217 Adaptive decoding unit 219 CIR measurement unit 301, 901 Likelihood calculation unit 401, 1001 Code word selection unit 402, 1002 Codeword table 501 Detection rate calculation unit 502 Control signal creation unit 603 Table rewriting unit 703, 902 Unused CIR detection unit 801 CIR information creation unit 804 CIR information power control unit 1101 CIR signal creation unit 1201 Upper digit information generation unit 1202 Lower digit Information generator 12 3 6-bit coding section 1204 4-bit coding section 1305,1401 upper digit spreading section 1306,1402 lower digit spreading section 1307 upper digit power controller 1308 lower digit power controller

Continued front page    (72) Inventor Junichi Aizawa             3-1, Tsunashima-Higashi 4-chome, Kohoku-ku, Yokohama-shi, Kanagawa             Matsushita Communication Industry Co., Ltd. F term (reference) 5K014 AA01 FA11 GA02 HA10                 5K022 EE02 EE14 EE21 EE31                 5K067 AA23 BB21 DD11 DD43 EE02                       EE10

Claims (2)

[Claims] 1. Measuring means for measuring downlink quality and outputting information generated based on the downlink quality, the information being composed of a plurality of digits including an upper digit and a lower digit, While encoding the upper digit of the information into the first code word,
Encoding means for encoding a lower digit of the information into a second code word having a minimum inter-code distance smaller than that of the first code word; and the second code word arranged after the first code word. Multiplexing means for time-multiplexing one codeword and the second codeword, and transmitting means for transmitting the time-multiplexed first codeword and second codeword to a base station apparatus. A characteristic communication terminal device. 2. Measuring means for measuring downlink quality and outputting information generated based on the downlink quality, the information being composed of a plurality of digits including an upper digit and a lower digit, While encoding the upper digit of the information into the first code word,
Encoding means for encoding a lower digit of the information into a second code word having a smaller number of bits than the first code word; and the first code by arranging the second code word after the first code word. A multiplexing unit that time-multiplexes the word and the second code word, and a transmitting unit that transmits the time-multiplexed first code word and the second code word to a base station apparatus. Communication terminal device.