JP3948367B2 - Wireless communication method for wireless communication device, wireless communication method for wireless communication system, wireless communication system, and wireless communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system for attaining desired reception quality while preventing an average transmission power from being increased even on the occurrence of propagation path gain variations for a comparatively short period. <P>SOLUTION: The wireless communication system controls the transmission power so as to decrease the transmission power when the propagation path gain is decreased and increase the transmission power when the propagation path gain is increased so as to relieve data missing due to reduction in the transmission power through error correction. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for controlling radio transmission power of a radio communication system, and is particularly suitable for application to a mobile communication system.
[0002]
[Prior art]
In a wireless communication system, a technique for controlling transmission power of a wireless communication device in order to obtain desired reception quality is known. For example, in USP 5,267,262, in a CDMA mobile communication system, a signal reception power from a terminal is measured at a base station, and an instruction to increase transmission power is given when it is smaller than a desired value, and an instruction to decrease transmission power when it is larger. A technique is disclosed in which the mobile station controls the transmission power according to the transmission power control instruction to keep the reception power at the base station substantially constant.
[0003]
Also, in USP 5,559,790, the mobile station measures the reception quality of the pilot signal transmitted by the base station with a known power, and when the reception quality is poor based on the measurement result, it is larger than when the reception quality is good. A transmission power control signal requesting transmission power is transmitted to the base station, and the base station controls the transmission power of the signal directed to the mobile station based on the transmission power control signal, so that the signal from the base station in the mobile station A technique for keeping reception quality substantially constant is disclosed.
[0004]
Each of these techniques aims to control the reception power and quality at the reception side to be constant. That is, with the above-described conventional transmission power control method, reception quality is made constant, and degradation of reception quality due to propagation path gain fluctuations and unnecessary interference in the system due to excessive transmission power are prevented. .
[0005]
[Problems to be solved by the invention]
However, if there is fading, which is a relatively short-cycle propagation path gain fluctuation that occurs as the mobile station moves, using the conventional technology, a very large transmission occurs when the propagation path gain decreases instantaneously. As a result, the average transmission power increases. The increase in average transmission power increases the mutual interference given to the entire system, resulting in a decrease in communication throughput of the entire system. Further, in the terminal, an increase in average transmission power increases power consumption and shortens the available call time.
[0006]
Further, when the average transmission power is not increased, the average reception power is decreased, and the capacity of the communication path is reduced due to the deterioration of the reception quality (SN ratio, SNR). That is, the maximum data rate that can be communicated is reduced.
[0007]
[Means for Solving the Problems]
In one aspect of the present invention, control is performed such that the transmission power is increased when the propagation path gain is increased and the transmission power is decreased when the propagation path gain is decreased.
Variations in the quality of received data and loss of received data caused by lowering the transmission power when the channel gain is small are remedied with a powerful error correction code such as a turbo code.
[0008]
Other aspects of the present invention will be clarified in the embodiments of the present invention.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
First, the power control algorithm of the present invention will be described.
[0010]
Consider the case where the channel gain fluctuates as shown in FIG. That is, consider a propagation path in which the average gain becomes 1 at times t1, t2, t3, and t4 and gains of 2, 1, 1/3, and 2/3, respectively. Assuming that constant noise is added at power 1 on the receiving side as shown in FIG. 2, this is equivalent to power 1/2, 1, 2, and t4 at times t1, t2, t3, and t4 as shown in FIG. Equivalent to the addition of 3, 3/2 noise. That is, the fluctuation of the propagation path gain can be equivalently regarded as the fluctuation of the noise power.
[0011]
On the other hand, it is known that the capacity C of the communication path is theoretically C = W log2 (1 + S / N). Here, C is the number of bits that can be transmitted per second, W is the frequency bandwidth, S is the signal power, N is the noise power, and log2 (x) is the logarithm of x with 2 as the base. Therefore, the channel capacity in the time-varying propagation path as described above is C = Ave (W log2 (1 + S (t)), where signal power S (t) at time t and noise power N (t) / N (t))). Here, Ave (x) represents the time average of x. Therefore, when S (t) is changed with time by power control, the channel capacity changes. In the present invention, transmission power is controlled so as to increase the channel capacity as much as possible. Specifically, it is as follows.
[0012]
Consider S (t) that maximizes the channel capacity C when the average transmission power, that is, the time average Ave (S (t)) of S (t) is constant. Since Ave (S (t)) is constant, if the transmission power at a certain time is increased, the transmission power at another time must be decreased. Here, since the rate of increase of C with respect to the slight increase of S is dC / dS = W / log (2) / (N + S) from the definition equation of the channel capacity, constant power is distributed in the time direction. Sometimes distributing transmission power where N + S is the smallest will increase the channel capacity. In this way, when the transmission power is sequentially distributed to the place where N + S is the smallest, when all the power is finally distributed, N + S is constant and N is higher than S + N achieved. S is not distributed at all in the time zone when is large, and this state has the largest channel capacity.
[0013]
Here, if the noise power received by the receiver is the time function Nr (t) and the propagation path gain is the time function g (t), the equivalent noise power N (t) seen on the transmission side is N (t ) = Nr (t) / g (t). Therefore, the transmission power S (t) that maximizes the channel capacity is a condition that N (t) + S (t) = Nr (t) / g (t) + S (t) = P_const. Meet. That is, the control may be performed so that S (t) = P_const−Nr (t) / g (t) . However, when S (t) <0, the actual transmission power is 0 (that is, transmission is stopped). If P_const is increased, average transmission power and channel capacity increase. Conversely, if P_const is reduced, the average transmission power and the channel capacity are reduced. Therefore, it is only necessary to determine P_const to a value that provides a desired communication path capacity.
[0014]
For example, when the average transmission power is 1 under the propagation path gain fluctuation shown in FIG. 1, the transmission power control result is as shown in FIG. In the figure, a portion surrounded by a thick line is signal power, and a portion surrounded by a thin line is noise power. That is, the transmission powers at times t1, t2, t3, and t4 are 11/6, 4/3, 0, and 5/6, respectively. Average transmission power is
(11/6 + 4/3 + 0 + 5/6) / 4 = 1
Also, the received power when the result of the transmission power control in FIG. 4 is viewed on the receiving side is 11/3, 4/3, and t3 at time t1, t2, t3, t4, respectively, as shown in FIG. 0, 5/9.
[0015]
On the other hand, in the power control according to the conventional technique, in order to keep the reception power or the reception quality constant, the transmission power is controlled to be proportional to the noise power as shown in FIG. That is, the transmission powers at times t1, t2, t3, and t4 are 1/3, 2/3, 2, and 1, respectively. Average transmission power is
(1/3 + 2/3 + 2 + 1) / 4 = 1
In addition, the received power when the result of power distribution (transmission power control) in FIG. 6 is viewed on the receiving side is 2/3 at time t1, t2, t3, t4, respectively, as shown in FIG. 2/3, 2/3, 2/3.
[0016]
FIG. 8 compares transmission power control with respect to fluctuations in propagation path gain. The horizontal axis represents propagation path gain, and the vertical axis represents transmission power as a transmission power control result. In the figure, circles indicate the present invention, and diamonds indicate the prior art. In other words, in the conventional transmission power control, the channel gain and the transmission power are in an inversely proportional relationship, and when the channel gain decreases, the transmission power increases, whereas when the channel gain increases, the transmission power decreases. In the present invention, conversely, when the channel gain decreases, the transmission power is reduced, and when the channel gain increases, the transmission power is increased.
[0017]
The channel capacity achieved by the transmission power control according to the present invention is
C = W (log2 (1 + 11/3) + log2 (1 + 4/3) + log2 (1 + 0) + log2 (1 + 5/9)) / 4
= 1.02 W
It becomes. On the other hand, the channel capacity achieved by the conventional transmission power control is
C = W log2 (1 + 2/3) = 0. 737 W
It becomes.
[0018]
Thus, in the example shown here, according to the power control of the present invention, the channel capacity is increased 1.38 (= 1.02 / 0.737 ) times as compared with the conventional power control method. On the other hand, using the conventional transmission power control method, in order to achieve the same channel capacity as that when the present invention is applied, 1.02 = log2 (1 + 1.028 ). N = 1.028 is required, and an average transmission power of 1.54 (= 1.028 / (2/3)) times S / N = 2/3 achieved by the conventional transmission power control is required. Therefore, according to the present invention, the transmission power for achieving the same channel capacity is reduced to 0.649 times that in the case of using the conventional technique.
[0019]
The transmission power control algorithm that theoretically maximizes the channel capacity has been described above, but substantially the same effect can be obtained without strictly following the above algorithm. That is, it is possible to perform transmission power using a function that approximates the relationship between the propagation path gain and transmission power shown in FIG. It is desirable for this function to have a positive slope as a whole. For example, even a simple function that makes the transmission power proportional to the channel gain can obtain substantially the same effect.
[0020]
Note that according to the algorithm S (t) = P_const−Nr (t) / g (t) for determining the transmission power, the transmission gain is increased when the channel gain increases stepwise as shown in FIG. 9 at time t0. The power also changes stepwise as shown in FIG. 10 (a). Further, when a control delay occurs, it changes with a certain rise time as shown in FIG. 10 (b).
[0021]
In the control of FIGS. 10 (a) and 10 (b), the channel capacity is large when the mobile station is located near the base station where the channel gain is large, and conversely the mobile station is located far from the base station. Sometimes the channel capacity becomes smaller. If this difference is undesirable in system design, for example
P_const = C0 Ave (Nr (t)) / Ave (g (t))
Thus, it is practical to control P_const relatively slowly using the average gain and noise power of the current channel condition. Here, C0 is a constant. As a result, the power control is applied to short-term fluctuations in the communication path while obtaining a substantially constant communication path capacity regardless of the distance from the base station.
[0022]
In this case, for the propagation path gain fluctuation shown in FIG.
As shown in FIGS. 10 (c) and 10 (d), the transmission power becomes the same as that shown in FIGS. 10 (a) and 10 (b) in a short time, and then the channel gain fluctuation is changed as in the conventional power control. A response that gradually approaches the canceling transmission power is shown.
[0023]
According to the power control described above, the channel capacity varies with time. In conventional power control, the channel capacity is made constant by keeping the reception quality constant, so the channel has characteristics close to AWGN (Additive White Gaussian Noise), so it is suitable for AWGN channels. An error correction code was suitable. On the other hand, in the power control described above, the reception quality varies greatly, and a part of the reception data is almost lost. Therefore, for relatively short time period fluctuations, interleaving eliminates the temporal correlation of reception quality variations, and further applies a powerful error correction code such as a turbo code, and uses that redundancy to receive data. It is preferable to relieve reception data with poor quality with reception data with good reception quality. It is also preferable to apply an LDPC (Low Density Parity Check) code or a product code in place of the turbo code. More generally, it is known that a large number of bits constituting a codeword have a complex chain of dependencies, and high error correction capability can be obtained by applying iterative decoding that performs decoding again using intermediate results of decoding. It is preferable to apply the error correction code.
In addition, if the state of poor reception quality continues for a certain period of time (for example, a time corresponding to an encoding unit or an interleaving unit of an error correction code), it cannot be remedied by error correction. Therefore, when the reception quality is good for a certain amount of time and the channel capacity is above the average, the bit rate is controlled and communication is performed at a high bit rate. Conversely, when the reception quality is poor and the channel capacity is below the average, It is preferable to perform communication at a low bit rate.
[0024]
In addition, it is not necessary to explicitly control the bit rate by making the average time of Ave (Nr (t)) and Ave (g (t)) used for calculating P_const coincide with the unit for performing substantially channel coding. It is possible to improve the average bit rate, which is suitable for a system that requires a constant bit rate.
[0025]
Hereinafter, a system and apparatus configuration for executing the above algorithm will be described.
[0026]
FIG. 30 shows the system configuration of the present invention. A plurality of mobile stations 3, 4, 5 communicate with the base stations 1, 2 via radio, and the base stations 1, 2 are controlled by the base station control station 6 between the mobile stations or in a fixed network Establish communication with the communication device to which it belongs.
[0027]
Configuration of receiving-side radio communication apparatus of the present invention in FIG. 11 shows the transmission of a signal radio communication apparatus configuration of the present invention in FIG. 13. Here, the wireless communication device whose transmission power is controlled by the transmission power control of the present invention is a transmission-side wireless communication device, and the other is a reception-side wireless communication device. In the system configuration shown in FIG. 30, either the mobile station or the base station may be either radio communication device, and if the base station is a transmission side radio communication device, the transmission power control of the downlink signal is performed. On the contrary, if the mobile station is a transmitting side wireless communication device, the transmission power control of the uplink signal is performed.
[0028]
The signal received from the antenna in FIG. 11 is converted into a baseband signal by the radio frequency circuit 101. The baseband signal is subjected to demodulation processing such as detection by the demodulator 102 and error-corrected by the channel decoder 121. On the other hand, the baseband signal is input to the power signal generation unit 105 to generate a transmission power control signal according to the power control algorithm. This transmission power control signal is sent to the third pilot signal generated by the third pilot signal generation unit 130, the data signal subjected to channel coding by the error correction encoder 106 and the interleaver 107, and the multiplexer 109. Are multiplexed. This multiplexed signal has a format as shown in FIG. 14, for example. 303 is a data signal, 304 is a power control signal, and 305 is a third pilot signal. In the figure, the horizontal direction represents time and the vertical direction represents a code used for code division. Multiplexed in the way. The multiplexed signal is modulated by the modulator 110 and sent to the radio propagation path via the radio frequency circuit 101.
[0029]
A signal transmitted from the reception-side wireless communication device is received by the transmission-side wireless communication device shown in FIG. Operations of 101, 102, 103, and 104 are the same as those of the reception-side wireless communication device. The transmission power control unit 111 extracts the power control signal 304, and calculates transmission power according to the extracted transmission power control signal 304. On the other hand, the transmission data encoded by the channel encoder 122 is multiplexed by the multiplexer 112 with the second pilot signal generated by the second pilot signal generator 108 and input to the transmission power variable means 113. . The transmission power varying means 113 varies the signal amplitude so that the transmission power specified by the transmission power control unit 111 is obtained. The output of the transmission power varying means 113 is multiplexed with the first pilot signal set to a predetermined power by the first pilot signal generating means 114 and the multiplexer 115, and a signal having a format as shown in FIG. It becomes. In FIG. 12, 301 is a first pilot signal, 302 is a second pilot signal, and 303 is a data signal.
[0030]
As shown in FIG. 12, various multiplexing formats are possible. The first pilot signal 301 (P0) is transmitted with a predetermined power without being subjected to power control by the transmission power control unit 111. On the other hand, the second pilot signal 302 is transmitted together with the data signal 303 under the power control. The signal multiplexed in the format of FIG. 12 is modulated by the modulator 110 and sent to the radio propagation path via the radio frequency circuit 101.
[0031]
The transmission power signal generation unit 105 in the reception-side wireless communication device and the transmission power generation unit 111 in the transmission-side wireless communication device are configured as shown in FIGS. 15 and 16, for example. The transmission power signal generator in FIG. 15 separates the first pilot signal and the second pilot signal by the first pilot signal separation unit 201 and the second pilot signal separation unit 205, respectively, and the S (t) = P_const-In Nr (t) / g (t) , whether the current transmission power is larger or smaller than the transmission power of P_const = C0 Ave (Nr (t)) / Ave (g (t)) A determination is made by the comparator 211, and a transmission power control signal 304 is generated to instruct a decrease in transmission power when it is large and an increase in transmission power when it is small. Accordingly, the transmission power control unit in FIG. 16 extracts the previous transmission power control signal 304, and increases or decreases the current transmission power according to this transmission power control signal. In FIG. 15, the noise power is obtained from the second pilot signal, but can also be obtained from the first pilot signal (dotted line). A configuration example of the error correction encoder 106 is shown in FIG. FIG. 31 performs encoding of a turbo code. The input transmission data is encoded in accordance with data rate information, and an encoding result is output. The input transmission data is convolutionally encoded by a recursive convolutional encoder E1 (231) to become a signal Y1. Further, the transmission data is subjected to convolutional coding by another recursive convolutional encoder E2 (232) after changing the data order by the interleaver 230, and becomes a signal Y2. Thereafter, the original transmission data X (or U), Y1, and Y2 are combined into one signal by the parallel-serial (P / S) converter 233, and the encoding result is output. A configuration example of the error correction decoder 104 is shown in FIG. FIG. 32 is an error correction decoder corresponding to the signal encoded by the turbo encoder of FIG. 31, and performs error correction decoding by iterative decoding according to the received signal and data rate information, and outputs a decoding result U ″ . The input received signal is separated into U ′, Y1 ′, and Y2 ′ by the serial-parallel (S / P) converter 234 by the reverse operation of the parallel-serial (P / S) converter 233. . The soft decision decoder D1 (235) performs soft decision decoding processing corresponding to the recursive convolutional encoder E1 (231) using the separated U ′ and Y1 ′. The result of decoding by the soft decision decoder D1 (235) is input to the soft decision decoder D2 (238) via the interleaver 237. On the other hand, the output U ′ of the serial-parallel (S / P) converter 234 is exchanged by the interleaver 236 and input to the soft decision decoder D2 (238). Here, the interleavers 236 and 237 follow the same order changing rules as the interleaver 230 in FIG. The soft decision decoder D2 (238) performs soft decision decoding using the output Y2 ′ of the serial-parallel (S / P) converter 234, the output of the interleaver 236, and the output of the interleaver 237, and outputs the decoding result. Output. The decoding result of soft decision decoder D2 (238) is input to deinterleaver 239, and the order of data is changed. The deinterleaver 239 works to restore the data order by the reverse operation of the interleaver 230, 236, 237. The output of the deinterleaver 239 is input to the soft decision decoder D1 (235), and the decoding process is performed again. In this way, the soft decision decoders D1 (235) and D2 (238) are repeatedly and alternately passed to improve decoding accuracy. After decoding a sufficient number of times, one of the soft decision decoders D1 (235) and D2 (238) is output as a final decoding result. FIG. 31 and FIG. 32 are examples using a turbo code. As described above, an error correction encoder corresponding to an error correction code such as an LDPC code or a product code that can exhibit high error correction capability by iterative decoding processing, An error correction decoder may be used. In the above embodiment, when the channel capacity is above the average over a certain period of time as described above, the bit rate is controlled to perform communication at a high bit rate, and conversely, when the channel capacity is below the average, It is preferable to perform communication at a low bit rate. For this purpose, in place of the channel encoder 122 in FIG. 13 and the channel decoder 121 in FIG. 11, a channel encoder and channel decoder as shown in FIGS. 17 and 18, respectively, are used. That's fine. The channel encoder shown in FIG. 17 includes an error correction encoder 106 that performs encoding at the data rate specified by the data rate instruction, and data rate information that is information about the data rate specified by the data rate instruction. A rate information generating unit 123 that generates and outputs the information, an interleaving unit 107 that interleaves the output of the error correction encoder 106, an output of the interleaving unit 107, and an output of the rate information generating unit 123. And a multiplexing unit 124. 18 includes a rate information separation unit 125 that separates data rate information from the received signal, a deinterleaving unit 103 that deinterleaves the remaining data from which the data rate information has been separated, And an error correction decoder 104 for decoding the output of the deinterleave unit based on the separated data rate information.
[0032]
The transmission power control unit 105 can be configured as shown in FIG. In the figure, a function calculation unit 214 calculates a function f (x) whose output increases as the input signal increases. Thereby, when the propagation path gain increases from the average value, a transmission power control signal instructing an increase in transmission power is generated. Further, when it can be assumed that the noise power is constant regardless of time, simplification is possible as shown in FIG.
[0033]
Furthermore, as shown in FIG. 21, even when the second pilot signal 302 is not included in the signal transmitted by the transmission-side wireless communication device, for example, the normalized transmission power S (t) / It is possible to obtain P0, use this as a transmission power control signal, and obtain S (t) by the transmission power control unit shown in FIG. More simply, the configuration of FIG. 24 can be used instead of FIG. 22, and the configuration of FIG. 25 can be used instead of FIG.
[0034]
Also, as shown in FIG. 26, even when the first pilot signal 301 is not included in the signal transmitted by the transmission-side wireless communication device, for example, the transmission power control signal generation unit shown in FIG. The transmission power control unit can determine S (t). More simply, the configuration of FIG. 28 can be used instead of FIG. 27, and the configuration of FIG. 29 can be used instead of FIG.
[0035]
As described above, according to the above-described embodiment of the present invention, there is provided a transmission power control method that achieves desired reception quality while preventing an increase in average transmission power even when a channel gain fluctuation with a relatively short period occurs. Can be provided,
Further, even when a propagation gain variation with a relatively short period occurs, the communication channel capacity can be kept large.
【The invention's effect】
According to the present invention, required transmission power is reduced and mutual interference is reduced. Further, according to the present invention, the channel capacity is increased, and the bit rate capable of communication can be improved.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a first example of time variation of propagation path gain;
FIG. 2 is a diagram for explaining an example of a temporal change in noise power.
FIG. 3 is a diagram for explaining an example of a temporal change in equivalent noise power at a transmission end.
FIG. 4 is a diagram for explaining a first example of transmission power control according to the present invention.
FIG. 5 is a diagram showing a temporal change in received power when the transmission power control shown in FIG. 4 is applied.
FIG. 6 is a diagram for explaining an example of transmission power control according to a conventional technique.
7 is a diagram showing a temporal change in received power when the transmission power control shown in FIG. 6 is applied.
FIG. 8 is a comparison of transmission power between transmission power control according to the present invention and transmission power control according to the prior art. FIG. 9 is a diagram for explaining a second example of propagation path gain fluctuation.
FIG. 10 is a diagram for explaining a second example of transmission power control according to the present invention.
FIG. 11 is a diagram illustrating a configuration example of a receiving-side wireless communication device according to the present invention.
FIG. 12 is a diagram for explaining a first example of a transmission signal multiplexing format of a transmitting side wireless communication device according to the present invention;
FIG. 13 is a diagram for explaining a configuration example of a transmitting side wireless communication device according to the present invention;
FIG. 14 is a diagram showing an example of a transmission signal multiplexing format of the receiving side wireless communication device according to the present invention.
FIG. 15 is a diagram illustrating a first configuration example of a transmission power control signal generation unit according to the present invention.
FIG. 16 is a diagram illustrating a first configuration example of a transmission power control unit according to the present invention.
FIG. 17 is a diagram illustrating a configuration example of an encoder with a data rate control function according to the present invention.
FIG. 18 is a diagram illustrating a configuration example of a decoder with a data rate control function according to the present invention.
FIG. 19 is a diagram illustrating a second configuration example of a transmission power control signal generation unit according to the present invention.
FIG. 20 is a diagram illustrating a third configuration example of the transmission power control signal generation unit according to the present invention.
FIG. 21 is a diagram showing a second example of the transmission signal multiplexing format of the transmission-side wireless communication device according to the present invention.
FIG. 22 is a diagram illustrating a fourth configuration example of the transmission power control signal generation unit according to the present invention.
FIG. 23 is a diagram illustrating a second configuration example of a transmission power control unit according to the present invention.
FIG. 24 is a diagram illustrating a fifth configuration example of a transmission power control signal generation unit according to the present invention.
FIG. 25 is a diagram illustrating a third configuration example of the transmission power control unit according to the present invention.
FIG. 26 is a diagram showing a third example of the transmission signal multiplexing format of the transmission-side wireless communication device according to the present invention.
FIG. 27 is a diagram illustrating a sixth exemplary configuration of the transmission power control signal generation unit according to the present invention.
FIG. 28 is a diagram illustrating a seventh exemplary configuration of the transmission power control signal generation unit according to the present invention.
FIG. 29 is a diagram illustrating a fourth configuration example of the transmission power control unit according to the present invention.
FIG. 30 is a diagram for explaining a configuration example of a communication system according to the present invention.
FIG. 31 is a diagram illustrating a configuration example of an error correction encoder of a transmitting-side radio according to the present invention.
FIG. 32 is a diagram illustrating a configuration example of an error correction decoder of a reception-side radio according to the present invention.
[Explanation of symbols]
1,2 Base station
3,4,5 mobile station
6 Base station control station
7 Fixed net
101 radio frequency circuit
102 Demodulator
103 Deinterleaver
104 Error correction decoder
121 Channel decoder
105 Transmission power control signal generator
106 Error correction encoder
107 Interleaver
109, 112, 115, 124 Signal multiplexer
110 modulator
111 Transmit power controller
122 channel encoder
108 Second pilot signal generator
113 Transmission power variable means
114 First pilot signal generator
130 Third pilot signal generator
301 1st pilot signal
302 2nd pilot signal
303 Data signal
304 Power control signal
305 3rd pilot signal
201 First pilot signal separation means
202, 210 Signal power measurement means
203, 207, 223 Signal averaging means
204, 212, 216, 217, 228 Divider
205 Second pilot signal separation means
206 Noise power measurement means
208, 213, 215, 218, 222, 224, 226 multiplier
209, 219, 225 Adder
211 Comparison means
220 Power control signal separation means
221 Transmission power calculation means
123 Data rate information generation means
125 Data rate information separation means
214 Function calculation means
227 Signal delay means
230, 236 Interleaver
231, 232 Recursive convolutional encoder
233 Parallel-serial (P / S) converter
234 Serial-Parallel (S / P) Converter
235, 238 soft decision decoder
239 Deinterleaver.

Claims (11)

A transmission control method in a wireless communication system, comprising:
A first step of determining a propagation path condition between the transmitter and the receiver;
A second step of encoding the transmission signal with a turbo code, an LDPC code, or a product code;
A third step of controlling transmission power of a signal transmitted from the transmitter to the receiver based on the determined propagation path state;
In the third step, when the propagation path state is improved, the transmission power is increased,
A transmission control method comprising performing the control so as to reduce transmission power when the propagation path state deteriorates .   The transmission control method according to claim 1, further comprising a fourth step of performing iterative decoding on the received signal in the receiver that has received the signal from the transmitter.   The transmission control method according to claim 1, wherein when higher transmission power is set, signal transmission is performed at a higher data rate. A wireless communication system having a transmitter and a receiver,
The transmitter encodes a transmission signal to be transmitted to the receiver with a turbo code, an LDPC code, or a product code, and controls transmission power of the transmission signal according to a propagation path state with the receiver. ,
The control is a control for increasing the transmission power when the propagation path state is improved and decreasing the transmission power when the propagation path state is deteriorated ,
The wireless communication system, wherein the receiver decodes a received signal in accordance with encoding in the transmitter.   5. The wireless communication system according to claim 4, wherein the receiver performs iterative decoding on a received signal.   5. The radio communication system according to claim 4, wherein when higher transmission power is set, signal transmission is performed at a higher data rate. A transmission device in a wireless communication system,
An encoding unit for encoding a transmission signal;
A transmission power control unit for controlling the transmission power of the transmission signal;
A radio unit that performs transmission of the transmission signal in which the transmission power is controlled and reception of a signal from a receiving device that is a transmission destination of the transmission signal
The encoding unit encodes with a turbo code, an LDPC code, or a product code,
The transmission power control unit increases the transmission power when a propagation path state with the receiving apparatus is improved, and decreases the transmission power when the propagation path state is deteriorated, from the transmitter to the receiver. A transmission apparatus that controls transmission power of a signal to be transmitted.   8. The transmission apparatus according to claim 7, wherein when higher transmission power is set, signal transmission is performed at a higher data rate. A receiving device in a wireless communication system,
A radio unit for receiving a signal from the transmission device and transmitting a control signal to the transmission signal;
A decoding unit for decoding the received signal;
A control signal generator that generates the control signal based on the received signal;
The decoding unit performs decoding using a turbo code, an LDPC code, or a product code,
The control signal generation unit determines a propagation path state with the transmission device based on the received signal,
Generates a control signal instructing to transmit a signal from the transmission device with increased transmission power when the propagation path state is improved and with reduced transmission power when the propagation path state is deteriorated. A receiving apparatus.   The receiving apparatus according to claim 9, wherein the decoding unit performs iterative decoding on the received signal.   10. The receiving device according to claim 9, further comprising a data rate control unit, wherein the data rate control unit sets a higher data rate and notifies the transmitting device when a propagation path condition is better. A receiver characterized by.

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