WO2011118168A1

WO2011118168A1 - Wireless receiver and wireless receiving method

Info

Publication number: WO2011118168A1
Application number: PCT/JP2011/001592
Authority: WO
Inventors: 中尾正悟; 今村大地; 榎貴志; Kenichi MIYOSHI (三好憲一)
Original assignee: パナソニック株式会社; 市川窓花; 市川笑愛
Priority date: 2010-03-25
Filing date: 2011-03-17
Publication date: 2011-09-29

Abstract

Disclosed is a wireless receiver which enables a destination node to receive a constellation signal with outstanding error rate characteristics, even if a relay node relays only the phase bit (phase information) of a transmission signal sent from a source node to the destination node. In the wireless receiver, a demodulation unit (306) demodulates a signal composed of a transmission signal that has been modulated by a source node using a first constellation, and a relay signal in which only the phase information of the aforementioned transmission signal has been modulated by a relay node using a second constellation. The first constellation has a signal point with a first amplitude and a signal point with a second amplitude which is larger than the first amplitude, and the second constellation has only a signal point with a third amplitude. In addition, a determination unit (310) determines the first amplitude and the second amplitude using the third amplitude detected from a pilot signal from the relay node, in such a manner that the total value of the first amplitude and the third amplitude is the same as half of the total value of the second amplitude and the third amplitude.

Description

Radio receiving apparatus and radio receiving method

The present invention relates to a wireless reception device and a wireless reception method.

Recently, a communication system having a relay function (repeater function) in which a radio communication mobile station apparatus (hereinafter simply referred to as a mobile station) relays a signal addressed to another mobile station has been studied.

In this communication system, for example, another mobile station in which a mobile station having a relay function (wireless communication relay station apparatus; hereinafter simply referred to as a relay station) is transmitted from a wireless communication base station apparatus (hereinafter simply referred to as a base station). Relay the addressed signal. As a result, even a mobile station that is difficult to directly communicate with the base station can communicate with the base station via the relay station, and the system capacity increases.

Further, in the communication system, the relay station transmits in accordance with the channel information of the signal transmitted directly from the transmission side to the reception side and the channel information of the signal transmitted from the transmission side to the reception side via the relay station. A conventional technique for correcting the phase and amplitude (amplification factor) of the signal from the side and relaying the corrected signal (relay signal) has been proposed (for example, see Patent Document 1). As a result, the reception side can receive a signal obtained by combining the signal directly transmitted from the transmission side and the relay signal relayed from the relay station on the propagation path without causing deterioration in communication quality.

JP 2005-229524 A

In the above-described prior art, the relay station is connected from the transmission side according to the channel information of the signal transmitted directly from the transmission side to the reception side and the channel information of the signal transmitted from the transmission side to the reception side via the relay station. Correct the phase and amplitude of the transmitted signal. However, when the relay station relays only the phase information of the transmission signal from the transmission side to the reception side, a symbol determination error tends to occur in the signal received on the reception side, and the error rate (BER: Bit Error) Rate) characteristics may be deteriorated.

The details will be described below. In the following description, as shown in FIG. 1, a generation node (source node) that is a transmission side device, a relay node (relay node) that is a relay station, and a destination node (destination node) that is a reception side device. Will be described.

The generation node shown in FIG. 1 modulates a transmission signal (data) using a constellation on the IQ plane shown in FIG. 2A (here, 8PASK (8 Amplitude Shift Keying), sometimes called 8QAM). In FIG. 2A, the amplitude (that is, the origin and signal on the IQ plane) of the signal point (hereinafter referred to as the inner signal point) located on the inner circle (ring) among the signal points (constellation point) constituting the constellation. The distance of the point) is 'a', and the amplitude of the signal point (hereinafter referred to as the outer signal point) located on the outer circle (ring) is '2a'. Also, as shown in FIG. 2A, among the 3 bits constituting the symbols arranged at each signal point, the upper 2 bits are phase information (that is, bits whose values fluctuate due to changes in phase; hereinafter referred to as phase bits). The lower 1 bit represents amplitude information (that is, a bit whose value fluctuates due to a change in amplitude, hereinafter referred to as amplitude bit).

Further, the relay node shown in FIG. 1 modulates the transmission signal transmitted from the originating node, and relays the modulated signal (relay signal) to the destination node. Here, as shown in FIG. 2B, the relay node relays only the phase bits of the transmission signal transmitted from the originating node using the constellation on the IQ plane shown in FIG. 2B. For example, in the first quadrant of the IQ plane shown in FIG. 2B, the phase bit (upper 2 bits) is “00” regardless of whether the transmission signal from the occurrence node is “000” or “001” shown in FIG. 2A. Relay only. The same applies to the second to fourth quadrants shown in FIG. 2C. Further, the amplitude of the signal point constituting the constellation shown in FIG. 2B is ‘b’. For example, the amplitude “b” of the signal point is the channel information of the signal directly transmitted from the transmission side to the reception side, and the signal transmitted from the transmission side to the reception side via the relay station, as in the above-described prior art. It is set according to the channel information.

Therefore, the amplitude of each signal point (signal point amplitude) in the constellation of the signal received at the destination node shown in FIG. 1 is the signal point amplitude ('a') in the constellation shown in FIG. 2A, as shown in FIG. 2C. And '2a') are added to the signal point amplitude ('b') in the constellation shown in FIG. 2B. Specifically, among the signal points constituting the constellation shown in FIG. 2C, the amplitude of the inner signal point is ‘a + b’, and the amplitude of the outer signal point is ‘2a + b’.

The destination node uses the pilot signals shown in FIG. 2C (PL _in and PL _out (pilot signals from the originating node) shown _in FIG. 2A, PL _in (pilot signal from the relay node) shown _in FIG. 2B) Specify the judgment axis. In FIG. 2C, among the plurality of bits constituting each symbol, the amplitude bit determination axis is between two signal points in each quadrant (that is, on the circle between the inner circle and the outer circle shown in FIG. 2C). (Not shown)) and the phase bit determination axis is on the IQ axis. Then, the destination node performs symbol determination of the received signal using the specified symbol determination axis.

Here, FIG. 2A (constellation used by the occurrence node) is compared with FIG. 2C (constellation used by the destination node). The amplitude of the inner signal point (inner circle radius 'a') in each quadrant of the constellation shown in FIG. 2A and the distance between the outer and inner two signal points (the amplitude difference between the two signal points. The difference 'a') between the radius of the outer circle and the radius of the inner circle is the same. As shown in FIG. 2A, when the amplitude of the inner signal point in each quadrant of the constellation is the same as the distance (amplitude difference) between the outer and inner signal points, the symbol determination accuracy for the amplitude bit is , Uniform between the inner and outer signal points. In other words, in this case, the error rate characteristics of the amplitude bits are averaged at all signal points, and a signal with good error rate characteristics is obtained. That is, it can be said that the constellation shown in FIG. 2A is a constellation with excellent error rate characteristics.

In contrast, the amplitude of the inner signal point in each quadrant of the constellation shown in FIG. 2C (that is, the radius “a + b” of the inner circle) and the distance between the outer and inner signal points (two signals) Amplitude difference between points, ie, the difference 'a' between the radius of the outer circle and the radius of the inner circle. Specifically, the distance between two outer and inner signal points (amplitude difference 'a') is smaller than the amplitude ('a + b') of the inner signal point. That is, in the constellation shown in FIG. 2C, the distance (amplitude difference 'a' between the outer and inner signal points with respect to the amplitude ('a + b') of the inner signal point (ie, the symbol determination axis for the amplitude bit). 2 is relatively narrow compared to the constellation shown in FIG. 2A.

Therefore, as compared with FIG. 2A, in the constellation shown in FIG. 2C, the accuracy of symbol determination with respect to amplitude bits deteriorates, so that a symbol determination error with respect to amplitude bits tends to occur. That is, in the constellation shown in FIG. 2C, the error rate characteristic of the phase bit is comparable to the constellation shown in FIG. 2A, but the error rate characteristic of the amplitude bit is deteriorated compared to the constellation shown in FIG. 2A. End up.

Thus, when the relay node relays only the phase bit (phase information) of the transmission signal from the originating node to the destination node, the symbol determination accuracy for the amplitude bit in the constellation of the signal received at the destination node is high. to degrade. For this reason, the destination node has a problem that the error rate characteristic of the received signal deteriorates.

An object of the present invention is to receive a signal with a constellation having excellent error rate characteristics at the destination node even when the relay node relays only the phase bits (phase information) of the transmission signal from the originating node to the destination node. Provided are a wireless reception device and a wireless reception method.

In a communication system including a wireless transmission device, a wireless reception device, and a wireless relay device that relays communication between the wireless transmission device and the wireless reception device, the wireless reception device according to the first aspect of the present invention, Determining means for determining an amplitude of a signal point in the first constellation used by the wireless transmission device based on a pilot signal transmitted from the wireless relay device, the amplitude and phase being used; A transmission signal modulated by the wireless transmission device using the first constellation, and a relay signal in which only phase information of the transmission signal is modulated by the wireless relay device using a second constellation; And a demodulating means for demodulating the synthesized signal, wherein the first constellation has a first amplitude signal point and the first constellation. A constellation having a second amplitude signal point larger than a width, wherein the second constellation is a constellation having only a third amplitude signal point, and the determining means Using the detected third amplitude, the total value of the first amplitude and the third amplitude is the same as half of the total value of the second amplitude and the third amplitude. Thus, the structure which determines the said 1st amplitude and the said 2nd amplitude is taken.

A radio reception method according to a second aspect of the present invention includes a radio transmission device, a radio reception device, and a radio relay device that relays communication between the radio transmission device and the radio reception device. A determination step for determining an amplitude of a signal point in the first constellation used by the wireless transmission device based on a pilot signal transmitted from the wireless relay device, using the amplitude and the phase; A transmission signal modulated by the wireless transmission device using the first constellation, and a relay signal in which only phase information of the transmission signal is modulated by the wireless relay device using a second constellation; And a demodulating step of demodulating the synthesized signal, wherein the first constellation comprises a first amplitude constellation point and a previous amplitude signal point. A constellation having signal points with a second amplitude greater than the first amplitude, and the second constellation is a constellation having only signal points with a third amplitude, and the determining step comprises the steps of: Using the third amplitude detected from the pilot signal, the total value of the first amplitude and the third amplitude is half the total value of the second amplitude and the third amplitude. The first amplitude and the second amplitude are determined so as to be the same.

According to the present invention, even when the relay node relays only the phase bit (phase information) of the transmission signal from the originating node to the destination node, the destination node receives the signal with a constellation having excellent error rate characteristics. be able to.

The figure which shows the communication system provided with the origin node, the relay node, and the destination node Diagram showing the constellation used by the originating node Diagram showing constellation used by relay node Diagram showing the constellation of the signal received at the destination node The figure which shows the communication system which concerns on embodiment of this invention The block diagram which shows the structure of the occurrence node which concerns on embodiment of this invention The block diagram which shows the structure of the relay node which concerns on embodiment of this invention The block diagram which shows the structure of the destination node which concerns on embodiment of this invention The figure which shows the constellation which the occurrence node which concerns on embodiment of this invention uses The figure which shows the constellation which the relay node which concerns on embodiment of this invention uses The figure which shows the constellation of the signal received at the destination node which concerns on embodiment of this invention The figure which shows the amplitude of each signal transmitted from the occurrence node which concerns on embodiment of this invention The figure which shows the amplitude of each signal transmitted from the relay node which concerns on embodiment of this invention The figure which shows the amplitude of each signal received by the destination node which concerns on embodiment of this invention

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

In the following description, as shown in FIG. 3, the occurrence node 100 (radio transmission apparatus. For example, the above-described base station), the relay node 200 (radio relay apparatus. For example, the above-described mobile station having the relay function), A communication system having a destination node 300 (wireless receiving apparatus, for example, the other mobile station described above) will be described.

The occurrence node 100 shown in FIG. 3 transmits data addressed to the destination node 300. At this time, the occurrence node 100 modulates the data addressed to the destination node 300 by a modulation method using amplitude and phase (for example, 8PASK described above). That is, the modulation system constellation used by the occurrence node 100 includes a first amplitude signal point (for example, an inner signal point shown in FIG. 2A) and a second amplitude signal point (a signal point having a second amplitude larger than the first amplitude). For example, a constellation having outer signal points shown in FIG. 2A. Therefore, the transmission signal modulated by the occurrence node 100 using the constellation has an amplitude bit (amplitude information, that is, a bit whose value fluctuates due to a change in the amplitude of each symbol) and a phase bit (phase information. , A bit whose value varies according to a change in the phase of each symbol). Further, as illustrated in FIG. 3, the occurrence node 100 is based on the amplitudes of the signal points in the constellation (the first amplitude and the second amplitude) indicated in the mapping instruction information transmitted from the destination node 300. Thus, the constellation used for modulating the data addressed to the destination node 300 is determined.

Relay node 200 shown in FIG. 3 modulates only the phase bits (phase information) of the data addressed to destination node 300 transmitted from source node 100, and transmits the modulated transmission data (relay signal) to destination node 300. Relay. That is, the modulation system constellation used by the relay node 200 is a constellation having only a certain amplitude signal point.

The destination node 300 shown in FIG. 3 receives a signal obtained by combining the transmission signal transmitted from the occurrence node 100 and the relay signal relayed from the relay node 200 on the propagation path. Then, the destination node 300 obtains data addressed to the destination node 300 by demodulating the received signal. Further, the destination node 300 determines the amplitude of the signal point (the first amplitude and the second amplitude) in the modulation scheme (constellation) used by the originating node 100 based on the pilot signal transmitted from the relay node 200. To do. Then, the destination node 300 transmits mapping instruction information indicating the determined amplitude to the occurrence node 100.

Next, FIG. 4 shows the configuration of the occurrence node 100 according to the present embodiment.

4, the reception RF unit 102 receives a signal from the destination node 300 via the antenna 101. The reception RF unit 102 performs reception processing such as down-conversion and A / D conversion on the received signal, and outputs the signal after reception processing to the CQI extraction unit 103 and the mapping instruction information extraction unit 105. Note that this signal includes channel quality information (here, CQI (Channel QualitydicIndicator)) generated at the destination node 300 and mapping instruction information.

The CQI extraction unit 103 extracts the CQI generated by the destination node 300 from the signal input from the reception RF unit 102. Then, CQI extraction section 103 outputs the extracted CQI to MCS (Modulation & channel? Coding & Scheme) determination section 104.

The MCS determination unit 104 determines the coding rate and modulation scheme of data addressed to the destination node 300 based on the CQI input from the CQI extraction unit 103. Then, MCS determination section 104 outputs MCS information including the determined coding rate and modulation scheme to encoding section 109 and modulation section 110. The originating node 100 notifies the destination node 300 of the MCS information determined by the MCS determining unit 104 (not shown).

The mapping instruction information extraction unit 105 extracts mapping instruction information from the signal input from the reception RF unit 102. Then, the mapping instruction information extraction unit 105 outputs the extracted mapping instruction information to the mapping determination unit 106.

The mapping determination unit 106 determines a signal point (mapping position) where data is arranged for the destination node 300 on the IQ plane based on the mapping instruction information input from the mapping instruction information extraction unit 105. Specifically, the mapping instruction information indicates the amplitude of the signal point (the first amplitude and the second amplitude) in the constellation used when modulating the data addressed to the destination node 300. For example, when the first amplitude and the second amplitude are indicated in the mapping instruction information, the mapping determination unit 106 determines the amplitude of the signal point in the constellation used when modulating the data addressed to the destination node 300 as the first amplitude and the second amplitude. Set to the amplitude of. Then, the mapping determination unit 106 outputs mapping position information indicating the mapping position of the signal point in the determined constellation to the inner PL generation unit 107, the outer PL generation unit 108, and the modulation unit 110.

The inner PL generation unit 107 has a pilot signal (hereinafter referred to as an inner signal) having the same amplitude (power) as the amplitude of the inner signal point (the first amplitude) indicated in the mapping position information input from the mapping determination unit 106. This is referred to as a pilot signal (for example, PL _in ) shown _in FIG. Then, inner PL generation section 107 outputs the generated inner pilot signal to modulation section 110.

The outer PL generation unit 108 has a pilot signal (hereinafter referred to as an outer side) having the same amplitude (power) as the amplitude of the outer signal point (the second amplitude) indicated in the mapping position information input from the mapping determination unit 106. This is referred to as a pilot signal, for example, PL _out shown in FIG. Then, outer PL generation section 108 outputs the generated outer pilot signal to modulation section 110.

The encoding unit 109 performs error correction encoding processing on the data addressed to the destination node 300 based on the encoding rate indicated in the MCS information input from the MCS determination unit 104, and modulates the encoded signal to the modulation unit To 110.

Modulation section 110 receives an inner pilot signal input from inner PL generation section 107 based on the modulation scheme indicated in the MCS information input from MCS determination section 104 and the mapping position information input from mapping determination section 106. The outer pilot signal input from the outer PL generation unit 108 and the data addressed to the destination node 300 input from the encoding unit 109 are modulated. That is, the modulation unit 110 modulates the data addressed to the destination node 300 with a constellation that uses the amplitude and phase indicated in the mapping position information. Modulation section 110 then outputs the modulated signal to transmission RF section 111.

The transmission RF unit 111 performs transmission processing such as D / A conversion, amplification, and up-conversion on the signal input from the modulation unit 110, and transmits the signal after transmission processing from the antenna 101.

Next, FIG. 5 shows the configuration of relay node 200 according to the present embodiment.

In the relay node 200 shown in FIG. 5, the reception RF unit 202 receives the signal transmitted from the occurrence node 100 (FIG. 4) via the antenna 201. The reception RF unit 202 performs reception processing such as down-conversion and A / D conversion on the received signal, and outputs the signal after reception processing to the demodulation unit 203. The signal transmitted from the source node 100 includes data addressed to the destination node 300, pilot signals (inner pilot signal and outer pilot signal) addressed to the destination node 300, and a signal for measuring reception quality (not shown). included.

Demodulation section 203 demodulates the signal input from reception RF section 202 and outputs the demodulated signal (bit string) to reception quality measurement section 204, data signal extraction section 206 and pilot signal extraction section 208.

The reception quality measurement unit 204 extracts a reception quality measurement signal from the signal input from the demodulation unit 203, and measures the reception quality of the signal transmitted from the occurrence node 100 based on the extracted signal. Reception quality measuring section 204 then outputs reception quality information indicating the measurement result to relay method determining section 205.

The relay method determination unit 205 determines the relay method of the data addressed to the destination node 300 and the pilot signal addressed to the destination node 300 based on the reception quality information input from the reception quality measurement unit 204. Here, relay scheme determining section 205 determines a modulation scheme that uses a constellation having signal points with a certain amplitude as the relay scheme. That is, the relay method determining unit 205 determines to relay only the phase information of the data addressed to the destination node 300 transmitted from the originating node 100 and the pilot signal addressed to the destination node 300. Relay scheme determining section 205 then outputs the determined relay scheme to relay data signal generating section 207 and pilot signal generating section 209.

The data signal extraction unit 206 extracts data addressed to the destination node 300 from the signal input from the demodulation unit 203. Then, the data signal extraction unit 206 outputs the data addressed to the destination node 300 to the relay data signal generation unit 207.

The relay data signal generation unit 207 converts the data addressed to the destination node 300 input from the data signal extraction unit 206 into a signal format for the relay destination destination node 300 based on the relay method input from the relay method determination unit 205. Processing to form is performed. For example, the relay method determining unit 205 determines a relay method for relaying only the phase information in the data addressed to the destination node 300 transmitted from the originating node 100. In this case, the relay data signal generation unit 207 generates a relay data signal including only phase bits (phase information) among data addressed to the destination node 300. Relay data signal generation section 207 then outputs the generated relay data signal (phase bit) to modulation section 210.

The pilot signal extraction unit 208 extracts a pilot signal addressed to the destination node 300 from the signal input from the demodulation unit 203. Pilot signal extraction section 208 then outputs the extracted pilot signal addressed to destination node 300 to pilot signal generation section 209.

Based on the relay method input from relay method determination unit 205, pilot signal generation unit 209 converts the pilot signal addressed to destination node 300 input from pilot signal extraction unit 208 to the signal format for destination node 300 as the relay destination. The process which forms is performed. For example, a relay system that relays only phase information among data addressed to the destination node 300 transmitted from the source node 100 in the relay system determination unit 205 (that is, a modulation system based on a constellation having only a signal point of a certain amplitude). It is determined. In this case, pilot signal generation section 209 adjusts the amplitude of the pilot signal (both the inner pilot signal and the outer pilot signal) addressed to destination node 300 to the certain amplitude. Relay data signal generation section 207 then outputs the generated pilot signal to modulation section 210.

Based on the relay method input from the relay method determination unit 205, the modulation unit 210 receives data addressed to the destination node 300 including only the relay data signal (that is, phase bits (phase information)) input from the relay data signal generation unit 207. ) And the pilot signal input from the pilot signal generation unit 209 is modulated. Modulation section 210 then outputs the modulated signal to transmission RF section 211.

The transmission RF unit 211 performs transmission processing such as D / A conversion, amplification, and up-conversion on the signal input from the modulation unit 210, and transmits the signal after transmission processing from the antenna 201 to the destination node.

Next, the configuration of the destination node 300 according to the present embodiment is shown in FIG.

In the destination node 300 illustrated in FIG. 6, the reception RF unit 302 transmits a signal obtained by combining the signal transmitted from the occurrence node 100 and the signal transmitted from the relay node 200 (relay signal) on the propagation path to the antenna 301. Receive via. Then, the reception RF unit 302 performs reception processing such as down-conversion and A / D conversion on the received signal, and sends the signal after reception processing to the outer PL extraction unit 303, the inner PL extraction unit 304, and the demodulation unit 306. Output.

Outer PL extraction section 303 extracts an outer pilot signal (for example, PL _out shown in FIG. 2A) transmitted from occurrence node 100 from the signal input from reception RF section 302, and estimates the extracted outer pilot signal. Output to 305.

The inner PL extraction unit 304, from the signal input from the reception RF unit 302, the inner pilot signal transmitted from the occurrence node 100 (for example, PL _in shown _in FIG. 2A) or the pilot signal transmitted from the relay node 200. (For example, PL _in shown _in FIG. 2B) is extracted. Then, the inner PL extraction unit 304 outputs the inner pilot signal from the occurrence node 100 to the estimation unit 305, and outputs the pilot signal from the relay node 200 to the estimation unit 305 and the detection unit 309.

The estimation unit 305 receives the outer pilot signal from the occurrence node 100 input from the outer PL extraction unit 303, and the inner pilot signal from the occurrence node 100 and the relay node 200 input from the inner PL extraction unit 304. Using the pilot signal, the state of the propagation path (channel) between the originating node 100 and the destination node 300 and the state of the propagation path (channel) between the relay node 200 and the destination node 300 are estimated. Then, estimation section 305 outputs a channel estimation value that is an estimation result to demodulation section 306 and CQI generation section 308.

The MCS information notified from the occurrence node 100 is input to the demodulation unit 306 from a receiving unit (not shown). Demodulation section 306 demodulates the signal input from reception RF section 302 based on the channel estimation value and MCS information input from estimation section 305. Specifically, the demodulation unit 306 identifies a symbol determination axis of a signal input from the reception RF unit 302 based on the channel estimation value, and is input from the reception RF unit 302 using the specified determination axis. Signal symbol determination. Demodulation section 306 outputs the demodulated signal (bit string) to decoding section 307.

The decoding unit 307 performs error correction decoding processing on the signal input from the demodulation unit 306 and outputs the decoding result as received data.

On the other hand, the CQI generating unit 308 generates a CQI indicating the state of the propagation path (channel) between the originating node 100 and the destination node 300 based on the channel estimation value input from the estimating unit 305. Then, CQI generation section 308 outputs the generated CQI to modulation section 311.

The detection unit 309 detects the amplitude of the pilot signal from the relay node 200 input from the inner PL extraction unit 304, that is, the amplitude of each signal point constituting the constellation used by the relay node 200. Then, the detection unit 309 outputs the detected amplitude to the determination unit 310.

The determination unit 310 receives a signal in the constellation (constellation using amplitude and phase) used by the occurrence node 100 based on the amplitude of each signal point included in the constellation used by the relay node 200, which is input from the detection unit 309. Determine the amplitude of the points. As described above, the constellation used by the occurrence node 100 is a constellation having a first amplitude signal point and a second amplitude signal point larger than the first amplitude. The constellation used by the relay node 200 is It is a constellation having only signal points of a certain amplitude (here, the third amplitude). Therefore, the determination unit 310 uses the third amplitude detected from the pilot signal from the relay node 200, for example, the total value of the first amplitude and the third amplitude becomes the second amplitude and the third amplitude. The first amplitude and the second amplitude are determined so as to be equal to half of the total value of the amplitudes. Then, the determination unit 310 outputs mapping instruction information indicating the determined first amplitude and second amplitude to the modulation unit 311.

Modulation section 311 modulates the CQI input from CQI generation section 308 and the mapping instruction information input from determination section 310, and outputs the modulated signal to transmission RF section 312.

The transmission RF unit 312 performs transmission processing such as D / A conversion, amplification, and up-conversion on the signal input from the modulation unit 311, and transmits the signal after transmission processing from the antenna 301 to the occurrence node 100.

Next, the operation of the communication system according to the present embodiment will be described in detail.

In the following description, the occurrence node 100 (FIG. 4) shown in FIG. 3 uses an 8PASK constellation shown in FIG. 7A as an example of a constellation using amplitude and phase. Further, in the constellation shown in FIG. 7A, among the 3 bits constituting one symbol, the upper 2 bits are phase bits (phase information, bits whose values fluctuate due to changes in phase), and the lower 1 bits are amplitude bits ( Amplitude information (bits whose values vary with changes in amplitude).

That is, as shown in FIG. 7A, when the lower 1 bit (amplitude bit) of the 3 bits constituting one symbol is “1”, the signal is arranged on the outer circle (ring) and the lower 1 bit ( When the (amplitude bit) is '0', the signal is arranged on the inner circle (ring). Further, as shown in FIG. 7A, when the upper 2 bits (phase bits) of 3 bits constituting one symbol are “00”, “10”, “11”, “01”, Signals are arranged in the first quadrant to the fourth quadrant.

Here, in the constellation shown in FIG. 7A, the amplitude (the first amplitude) of the inner signal point (the signal point where the amplitude bit “0” is arranged) is set to “d”, and the outer signal point ( Let the amplitude (the second amplitude) of the signal point at which the amplitude bit “1” is arranged be “c + d”. However, the amplitudes “d” and “c + d” of signal points in the constellation shown in FIG. 7A are determined based on mapping instruction information transmitted from the destination node 300 (described later).

Meanwhile, the relay node 200 (FIG. 5) shown in FIG. 3 uses the constellation shown in FIG. 7B. Here, the amplitude of the signal point in the constellation shown in FIG. 7B (the third amplitude) is ‘b’.

Further, relay node 200 generates pilot signal PL _in having the same amplitude as the amplitude 'b' of the constellation signal point shown in FIG. 7B.

Therefore, first, the detection unit 309 of the destination node 300 (FIG. 6) detects the amplitude “b” of the pilot signal PL _in transmitted from the relay node 200, which is input from the inner PL extraction unit 304.

Then, the determination unit 310 uses the third amplitude 'b' detected from the pilot signal PL _in transmitted from the relay node 200, which is detected by the detection unit 309, and is illustrated in FIG. The amplitude of the signal point in the constellation (first amplitude 'd' and second amplitude 'c + d') is determined. For example, the determination unit 310 determines that the total value of the first amplitude 'd' and the third amplitude 'b' (= b + d) is the total value of the second amplitude 'c + d' and the third amplitude 'b' ( The amplitudes ('d' and 'c + d') are determined so as to be equal to half the value of = b + c + d). In other words, the determination unit 310 determines the difference between the total value (= b + d) of the third amplitude 'b' and the first amplitude 'd' and the second amplitude 'c + d' and the first amplitude 'd'. The amplitudes ('d' and 'c + d') are determined so that (= (c + d) -d = c) is the same (ie, b + d = c).

Then, the determination unit 310 generates mapping instruction information indicating the determined amplitudes “d” and “c + d”.

Next, as shown in FIG. 7A, the mapping determination unit 106 of the originating node 100, based on the mapping instruction information transmitted from the destination node 300, has a signal point with an amplitude “d” (inner signal point) and an amplitude “c + d”. Determine the constellation consisting of 'signal points (outer signal points).

Then, modulation section 110 (FIG. 4) of generation node 100 modulates the transmission signal (data addressed to destination node 300 and pilot signal) using the constellation shown in FIG. 7A. Further, the inner PL generation unit 107 of the occurrence node 100 generates an inner pilot signal PL _in having the same amplitude as the amplitude 'd' of the signal point inside the constellation shown in FIG. 7A. Similarly, the outer PL generation unit 108 generates an outer pilot signal PL _out having the same amplitude as the amplitude 'c + d' of the signal point outside the constellation shown in FIG. 7A.

Therefore, as shown in FIG. 8A, among the signals transmitted from the occurrence node 100, a symbol (symbol “110” having an amplitude bit of “0”) arranged at a signal point inside the constellation shown in FIG. 7A. , '010', '100', '000') and the amplitude of the pilot signal PL _in become 'd'. On the other hand, the amplitude and pilot signal of symbols (symbols “101”, “101”, “011”, and “111” whose amplitude bits are “1”) arranged at signal points outside the constellation shown in FIG. 7A The amplitude of PL _out is 'c + d'.

On the other hand, the relay data signal generation unit 207 (FIG. 5) of the relay node 200 performs phase bits (upper 2 bits of 3 bits constituting each symbol in FIG. 7A) of the data addressed to the destination node 300 transmitted from the originating node 100. ) Is extracted to generate a relay data signal. Further, the pilot signal generation unit 209 makes the pilot signal PL _in , the amplitude of the pilot signal PL _in , PL _out transmitted from the generation node 100 the same as the amplitude “b” of the signal point in the constellation shown in FIG. 7B. _in is generated.

Then, modulation section 210 modulates data (only phase bits) and pilot signals addressed to destination node 300 using the constellation shown in FIG. 7B. That is, as shown in FIG. 8B, the amplitude of each symbol transmitted from the relay node 200 and the amplitude of the pilot signal PL _in are all “b”.

Therefore, the amplitude of the signal point (signal point amplitude) in the constellation of the signal received by the destination node 300 (the signal obtained by combining the signal directly transmitted from the transmission side and the relay signal relayed from the relay station) is As shown in 7C, the signal point amplitude ('b') in the constellation shown in FIG. 7B is added to the signal point amplitudes ('d' and 'c + d') in the constellation shown in FIG. 7A. That is, among the signal points constituting the constellation shown in FIG. 8C, the amplitude of the inner signal point is ‘b + d’ and the amplitude of the outer signal point is ‘b + c + d’.

Here, in the determination unit 310 of the destination node 300, the total value (= b + d) of the amplitude 'b' and the amplitude 'd' is the same as half the total value of the amplitude 'c + d' and the amplitude 'b'. As described above, the amplitude ('d' and 'c + d') of the constellation used by the occurrence node 100 is determined. Therefore, in the constellation shown in FIG. 7C, the sum (b + d) of the amplitude ‘b’ and the amplitude ‘d’ and the amplitude ‘c’ are the same (that is, b + d = c). That is, as shown in FIG. 7C, the amplitude of the inner signal point in each quadrant of the constellation of the signal received at the destination node 300 (that is, the radius of the inner circle 'b + d') and the outer and inner two The distance between the signal points (the amplitude difference between the two signal points, that is, the difference 'c' between the radius of the outer circle and the radius of the inner circle) is the same.

As described above, when the amplitude of the inner signal point in each quadrant of the constellation is the same as the distance (amplitude difference) between the two outer and inner signal points, the symbol determination accuracy for the amplitude bit is the inner signal. Uniform between the point and the outer signal point. That is, in the constellation of the signal received at the destination node 300 (FIG. 7C), the error rate characteristics of the amplitude bits are averaged at all signal points, and the destination node 300 can obtain a signal with good error rate characteristics. . In other words, the destination node 300 can receive data addressed to the destination node 300 using a constellation (FIG. 7C) with excellent error rate characteristics, as in the constellation shown in FIG. 2A.

In this way, the destination node 300 has an inner signal in each quadrant of the constellation of the signal received by the destination node 300 (the signal directly transmitted from the transmission side and the relay signal relayed from the relay station). The constellation used by the occurrence node 100 so that the amplitude of the signal point ('b + d' shown in FIG. 7C) and the distance between the outer and inner two signal points ('c' shown in FIG. 7C) are the same. Determine the amplitude of the signal points at ('d' and 'c + d').

That is, the destination node 300 predicts in advance that the transmission signal directly transmitted from the occurrence node 100 and the relay signal transmitted from the relay node 200 are combined on the propagation path, and is transmitted from the occurrence node 100. Determine the constellation of the transmitted signal. As a result, the occurrence node 100 can modulate data destined for the destination node 300 using a constellation that takes into account that signals relayed by the relay node 200 are combined on the propagation path.

Thereby, in the constellation of the signal received by the destination node 300 (the signal after synthesis), the error rate characteristics of the amplitude bits are averaged, and a signal with good error rate characteristics is obtained. That is, as shown in FIG. 7C, the destination node 300 can receive data addressed to the destination node 300 with a constellation having excellent error rate characteristics.

Therefore, according to the present embodiment, even when the relay node relays only the phase bit (phase information) of the transmission signal from the originating node to the destination node, the destination node has a constellation with excellent error rate characteristics. A signal can be received.

Further, according to the present embodiment, in a relay node (for example, a mobile station having a relay function), only a phase bit (phase information) in a signal transmitted from a source node (wireless transmission device) is transmitted to a destination node (wireless). Relay to the receiving device. Therefore, the relay node can reduce the power consumption required for the relay process as compared with the case where all signals transmitted from the occurrence node are relayed. Therefore, when performing the relay process for signals addressed to other mobile stations. The decrease in the charging capacity of the battery can be minimized. Thus, the system capacity of the entire communication system can be increased by performing relay transmission of signals of other mobile stations while transmitting / receiving signals of the mobile station (relay node) itself having a relay function. That is, according to the present embodiment, it is possible to increase the system capacity by reducing the power consumption required for the relay process in the mobile station having the relay function.

In the above embodiment, as an example, the case where the originating node uses 8 PASK as the modulation method has been described. However, the modulation method used by the occurrence node is not limited to 8 PASK, and may be any modulation method corresponding to a constellation composed of a plurality of signal points having different amplitudes. For example, 4QAM in which the number of bits constituting one symbol is 2 bits, the upper 1 bit is an amplitude bit, and the lower 1 bit is a phase bit may be used as a modulation method used by the generation node. Alternatively, 4PASK in which the number of bits constituting one symbol is 2 bits, the lower 1 bit is an amplitude bit, and the upper 1 bit is a phase bit may be used as a modulation method used by the generation node.

In the above embodiment, a case has been described where the relay node relays only the phase bit (phase information) in the signal (data destined for the destination node) transmitted from the originating node. However, the relay node, depending on the reception quality of the signal transmitted from the originating node, all the signals (data destined for the destination node) transmitted from the originating node (amplitude bits (amplitude information) and phase bits (phase information)). Relay of only one of the amplitude bit and the phase bit, or cancellation of relay of data addressed to the destination node may be selected. In this way, the relay node can reduce the power consumption required for the relay process by adaptively controlling the relay process based on the reception quality of the signal transmitted from the occurrence node. In this case, when the relay node relays only the phase bit of the signal (data destined for the destination node) transmitted from the originating node, it is possible to prevent the reception error rate characteristic from being deteriorated in the destination node as in the above embodiment. it can.

In the above embodiment, the destination node transmits mapping instruction information indicating the amplitude of signal points (for example, “d” and “c + d” shown in FIG. 7A) to the occurrence node in the constellation used by the occurrence node. Explained. However, the mapping instruction information is not limited to the amplitude of the signal point in the constellation used by the occurrence node. That is, the destination node transmits information on distortion of the constellation of the transmission signal transmitted from the generation node, which is generated when the transmission signal from the generation node and the relay signal from the relay node are combined on the propagation path. Please feed back. For example, the mapping instruction information may be the difference (cd) between the distance (amplitude difference) ‘c’ between the outer and inner signal points in FIG. 7A and the amplitude ‘d’ of the inner signal point. That is, the amplitude ‘b (= cd)’ of the pilot signal transmitted from the relay node may be used as the mapping instruction information. Here, it is assumed that the amplitude of the signal point in the constellation used by the occurrence node is the first amplitude e and the second amplitude f (where e <f). In this case, the occurrence node is based on the mapping instruction information ('cd' or 'b'), and the first node that satisfies the relationship of fe = 'cd' (or e + 'b' = f) is satisfied. By determining the amplitude e and the second amplitude f, a constellation to be used at the time of modulating data addressed to the destination node 300 may be determined.

Further, although cases have been described with the above embodiment as examples where the present invention is configured by hardware, the present invention can also be realized by software in cooperation with hardware.

Further, each functional block used in the description of the above embodiment is typically realized as an LSI which is an integrated circuit. These may be individually made into one chip, or may be made into one chip so as to include a part or all of them. Although referred to as LSI here, it may be referred to as IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.

Further, the method of circuit integration is not limited to LSI, and implementation with a dedicated circuit or a general-purpose processor is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

Furthermore, if integrated circuit technology that replaces LSI emerges as a result of advances in semiconductor technology or other derived technology, it is naturally also possible to integrate functional blocks using this technology. Biotechnology can be applied.

The disclosure of the description, drawings and abstract contained in the Japanese application of Japanese Patent Application No. 2010-070455 filed on Mar. 25, 2010 is incorporated herein by reference.

The present invention can be applied to a mobile communication system or the like.

DESCRIPTION OF SYMBOLS 100 Originating node 200 Relay node 300 Destination node 101,201,301 Antenna 102,202,302 Reception RF part 103 CQI extraction part 104 MCS determination part 105 Mapping instruction information extraction part 106 Mapping determination part 107 Inner PL generation part 108 Outer PL generation part 108 Unit 109

encoding unit

110, 210, 311

modulation unit

1111, 211, 312

transmission RF unit

203, 306 demodulation unit 204 reception quality measurement unit 205 relay scheme determination unit 206 data signal extraction unit 207 relay data signal generation unit 208 pilot signal extraction Unit 209 pilot signal generation unit 303 outer PL extraction unit 304 inner PL extraction unit 305 estimation unit 307 decoding unit 308 CQI generation unit 309 detection unit 310 determination unit

Claims

In a communication system including a wireless transmission device, a wireless reception device, and a wireless relay device that relays communication between the wireless transmission device and the wireless reception device,
Determination means for determining an amplitude of a signal point in the first constellation using the amplitude and phase based on a pilot signal transmitted from the wireless relay device. When,
A transmission signal modulated by the wireless transmission device using the first constellation, and a relay signal in which only phase information of the transmission signal is modulated by the wireless relay device using a second constellation; Demodulating means for demodulating the combined signal,
The first constellation is a constellation having a first amplitude signal point and a second amplitude signal point larger than the first amplitude, and the second constellation is a third amplitude signal. A constellation having only points,
The determination means uses the third amplitude detected from the pilot signal, and the total value of the first amplitude and the third amplitude is the sum of the second amplitude and the third amplitude. Determining the first amplitude and the second amplitude to be equal to half of the value;
Wireless receiver.
The determination means uses the third amplitude to make the total value of the third amplitude and the first amplitude and the difference between the second amplitude and the first amplitude the same. Determining the first amplitude and the second amplitude as follows:
The wireless receiver according to claim 1.
In a communication system including a wireless transmission device, a wireless reception device, and a wireless relay device that relays communication between the wireless transmission device and the wireless reception device,
A determination step of determining an amplitude of a signal point in the first constellation using the amplitude and the phase, which is a first constellation used by the wireless transmission device, based on a pilot signal transmitted from the wireless relay device When,
A transmission signal modulated by the wireless transmission device using the first constellation, and a relay signal in which only phase information of the transmission signal is modulated by the wireless relay device using a second constellation; And a demodulation step for demodulating the combined signal,
The first constellation is a constellation having a first amplitude signal point and a second amplitude signal point larger than the first amplitude, and the second constellation is a third amplitude signal. A constellation having only points,
The determining step uses the third amplitude detected from the pilot signal, and the total value of the first amplitude and the third amplitude is the sum of the second amplitude and the third amplitude. Determining the first amplitude and the second amplitude to be equal to half of the value;
Wireless reception method.