JP5576313B2 - Instantaneous power scaling circuit and method - Google Patents

Description

  The present invention relates to an instantaneous power scaling circuit and method in a cooperative transmission system that performs radio transmission between a source station and a destination station via a relay station.

  In recent years, cooperative communication schemes that improve communication characteristics by making cooperative relay transmissions to radio stations other than a source station and a destination station have attracted attention, and many studies have been made. The system model of the cooperative communication system is determined mainly by three elements of the relay station transfer protocol, the cooperative system configuration, and the cooperative protocol.

  The relay station transfer protocol indicates what kind of signal processing is performed on the signal received by the relay station and forwards it to the destination station. The most basic relay station transfer protocol is the DF (Decode-and-Forward) method and the AF (Amplify-and-Forward) method. The DF method is a technique in which decoding and reproduction are performed once at a relay station and then transferred to a destination station. The AF method is a method in which the relay station does not perform decoding and reproduction, but simply performs amplification, and then forwards it to the destination station.

  The cooperative system configuration indicates the number of radio stations constituting the cooperative system and the number of cooperative relay hops performed in the system. The simplest is a 1-Relay2-Hop (1R2H) configuration in which one relay station R (Relay) exists between the source station S (Source) and the destination station D (Destination). In the 1R2H configuration, since one slot of radio resources (time or frequency) is generally allocated to transmission / reception from the source station to the relay station and from the relay station to the destination station, it is assumed that one cycle of the entire cooperative system is two slots. Consideration is often made.

  The cooperative protocol indicates a combination of transmission / reception relationships between radio stations (source station, destination station, relay station) within one cycle of the entire cooperative system.

  Here, FIGS. 5A to 5D are conceptual diagrams for explaining the cooperation protocol. For example, in the 1R2H configuration cooperative system, as shown in FIG. 5A, the source station S performs broadcast transmission to both the relay station R and the destination station D in slot # 1, and relays in slot # 2. A cooperative protocol in which the station R and the transmitting station S transmit simultaneously to the destination station D is conceivable. This cooperative protocol is called a MIMO type or a protocol I (see Non-Patent Document 1, for example).

  Also, as shown in FIG. 5B, in slot # 1, the source station S performs broadcast transmission to both the relay station R and the destination station D, and in slot # 2, the relay station R is the destination station D. The cooperative protocol to send to is called SIMO type, or Protocol II. Further, as shown in FIG. 5C, the transmitting station S transmits to the relay station R in the slot # 1, and the relay station R and the transmitting station S transmit simultaneously to the destination station D in the slot # 2. The cooperative protocol is called MISO type or Protocol III. Similarly, as shown in FIG. 5D, a cooperative protocol is also conceivable in which the transmitting station S transmits to the relay station R in slot # 1, and the relay station R transmits to the destination station D in slot # 2. . Here, this cooperative protocol is called SISO type or protocol IV.

(1) Transmission / Reception System FIG. 6 is a block diagram showing a configuration of a cooperative transmission system having a general 1R2H configuration. The transmitting station (S) 1 includes a channel encoding process 1-1, an interleaver process 1-2, a modulation process 1-3, and a passband conversion process 1-4. The destination station (D) 3 includes a baseband conversion process 3-1, a demodulation process 3-2, a deinterleaver process 3-3, and a channel decoding process 3-4.

  Here, an AF method and an OFDM (Orthogonal Frequency Division Multiplexing) transmission method are considered. First, the information bit stream to be transmitted is input to the channel encoding process 1-1 of the transmitting station. The input information bits are converted into encoded bits, and an encoded bit stream is output from the channel encoding process 1-1. This channel encoding process 1-1 can have a scramble function in addition to the encoding function. The encoded bit stream is input to the interleaver process 1-2, and interleaving is performed to prevent characteristic deterioration due to continuous errors. The interleaved encoded bit stream is input to the modulation process 1-3.

  The encoded bitstream input to the modulation process 1-3 is subjected to constellation mapping, inverse discrete Fourier transform (IDFT), and guard interval (GI) addition processing. The obtained time domain data complex sample stream is finally converted from the baseband to the passband by the passband conversion processing 1-4 and transmitted only in the slots # 1 and # 2 or the slot # 1. The transmitted signal passes through the propagation path and is received only by the relay station (R) 2 and the destination station (D) 3 or the relay station (R) 2.

In the following, the transmission / reception relationship of the three radio stations in the slots # 1 and # 2 will be seen in the frequency domain with the protocol I as an example. In slot # 1, the source station (S) 1 performs broadcast transmission to the relay station (R) 2 and the destination station (D) 3. The reception signal Y _d1 of the frequency domain representation (corresponding to the kth subcarrier) at the destination station (D) 3 in the slot # 1 is expressed by the following equation (1).

Here, H _sd is the channel frequency response (CFR) corresponding to the k-th subcarrier between the source station (S) 1 and the destination station (D) 3, and P _s1 is the source station (S) 1 W _d1 is a white additive Gaussian noise with an average of 0 and variance σ ² _w corresponding to the k-th subcarrier at the destination station (D) 3 of the slot # 1 Represents the frequency domain representation of AWGN). The value of the variance σ ² _w is assumed to be known and constant by the three radio stations. Further, in the cooperative protocols III and IV, the destination station (D) 3 does not receive a signal in the slot # 1, so the mathematical formula (1) does not exist in these two protocols.

Also, the received signal Y _r1 at the relay station (R) 2 in the slot # 1 is expressed by the following equation (2).

Here, H _sr is the CFR between the transmission station (S) 1 and the relay station (R) 2, and W _r1 is the frequency of the AWGN with an average of 0 and variance σ ² _w at the relay station (R) 2 in slot # 1. Represents an area representation. H _sr is 0 on average and variance G ₂ . H _sr generally indicates an equivalent channel from before the modulation process 1-3 to after the DFT process 2-3 (see FIG. 1).

Signal relay station (R) 2 is received in the slot # 1 is amplified by the amplification factor alpha _r. This amplification method will be described in detail in (2) Amplification method described later.

Considering the simultaneous transmission of signals from the source station (S) 1 and the relay station (R) 2 and the presence of additional noise at the time of reception, the transmission signal at the destination station (D) 3 in slot # 2 Y _d2 is expressed by the following equation (3).

Here, H _srd is the CFR between the transmitting station (S) 1 _-the relay station (R) 2 -the destination station (D) 3, and √ (P _s 1P _r2 ) is the transmitting station (S) 1 in the slot # 2. P _s2 represents the transmission power of the transmitting station (S) 1 in slot # 2. Further, in the cooperative protocols II and IV, the transmitting station (S) 1 does not perform signal transmission in the slot # 2, so the second term on the right side of the equation (3) does not exist in these two protocols.

  Channel estimation and channel equalization are performed in the demodulation process 3-2, and the detection value corresponding to the frequency domain complex QAM symbol is demapped and converted to the detection value corresponding to the coded bit. The detection value corresponding to the encoded bit is input to the deinterleaver process 3-3. The input detection values are output after the interleaving order is restored (deinterleaving). The output detection value is channel-decoded by the channel decoding process 3-4, and a detection value corresponding to the information bit is obtained.

(2) Amplification method Here, the amplification coefficient α _r is used for transmission with the transmission power of the relay station (R) 2 made constant by multiplying Y _r1 that changes every moment. Thereby, the received power in the destination station (D) 3 can be smoothed. _Y r1 ^| _| received power in formulas (2) than the slot # 1 of the relay station (R) 2 If was calculated based on the ^second average alpha _r and alpha _r0, the following equation (4).

Since P _s1 and σ ² _w do not change with time, CFRH _sr becomes a dominant parameter of α _r , and fixed power scaling (FPS) and instantaneous power scaling (Instantaneous Power scaling) are handled depending on the handling. There is a method of obtaining an amplification coefficient by Scaling (IPS).

(2-1) Conventional method: Fixed Power Scaling (FPS)
FPS is a technique that uses the average of channel power for calculation of amplification coefficients.
When the average of the instantaneous channel power | H _sr | ² between the source station (S) 1 and the relay station (R) 2 is taken with respect to α _{r0 in the} formula (4), the following formula (5) is obtained.

G ₂ is the average of the channel power | H _sr | ² , which is known by the relay station (R) 2.
At this time, the values of α _{r and FPS} are constant in the frequency domain and the time domain with respect to the subcarrier.

(2-2) Conventional method: Instantaneous Power Scaling (IPS)
IPS is a technique that uses instantaneous channel power as an amplification coefficient. The amplification coefficient α _{r and IPS in IPS} is α _r0 in Equation (4). At this time, the values of the amplification coefficients α _{r and IPS} are not constant in the frequency domain and the time domain with respect to the subcarrier.

RU Nabar, H. Bolcskei, and FW Kneubuhler, “Fading relay channels: Performance limits and space-time signal design,” IEEE J. Sel. Areas Commun., Vol. 22, no. 6, pp. 1099-1109, Jun . 2004. H. A. Suraweera and J. Armstrong, “Performance of OFDM based dual-hop amplify-and-forward relaying,” IEEE Communications Letters, vol. 11, no. 9, pp. 726-728, 2007.

Comparing the features of FPS and IPS described above, as seen in Non-Patent Document 2, generally IPS provides better characteristics than FPS. However, unlike _{the FPS} amplification coefficients α _{r and FPS ,} the values of _{the IPS} amplification coefficients α _{r and IPS} are not constant in the frequency domain and the time domain with respect to the subcarriers. For this reason, unlike FPS, in IPS, there is a computational load of calculating the amplification coefficient for each subcarrier and for each reception. Further, multiplication of the IPS reception signal by the amplification coefficient needs to be performed in the frequency domain. Therefore, in the IPS, the received signal must be frequency domain converted in the relay station 2 as shown in the figure, so that DFT processing and IDFT processing are required, and a huge amount of calculation load is generated here.

In the IPS according to the background art described above, there is a problem that the amount of calculation is enormous because it is necessary to derive the amplification coefficient α _{r and IPS} for each subcarrier.

  The present invention has been made in view of such circumstances, and an object of the present invention is to instantaneously reduce the amount of calculation of the IPS amplification coefficient calculation by approximating the instantaneous channel power between the transmission station and the relay station. It is to provide a power scaling circuit and method.

  In order to solve the above-described problems, the present invention provides a transmitting station that transmits a wireless signal, a destination station that receives the wireless signal, and a wireless signal that is transmitted from the transmitting station and transmits the wireless signal to the destination station. An instantaneous power scaling circuit of the relay station in a wireless relay system configured with a relay station that performs channel frequency response calculation means for calculating a channel frequency response between the source station and the relay station, and the channel Amplification coefficient for calculating the amplification coefficient by calculating the sum of the absolute value of the in-phase component and the absolute value of the quadrature component of the channel frequency response calculated by the frequency response calculation means and multiplying by a predetermined first coefficient The transmission signal to the destination station is calculated by multiplying the amplification coefficient calculated by the calculation means and the amplification coefficient calculation means by the radio signal received from the source station. The instantaneous power scaling circuit characterized in that it comprises a transmission signal generating means for generating a.

  According to the present invention, in the above invention, the comparison means for comparing each of the absolute value of the in-phase component and the absolute value of the quadrature component of the channel frequency response with a predetermined threshold value, and 2 of the absolute value of the channel frequency response. Calculation means for calculating a power, wherein the comparison means determines that the absolute value of the in-phase component and the absolute value of the quadrature component of the channel frequency response are greater than a predetermined threshold value. In such a case, the amplification coefficient is calculated based on the square of the absolute value of the channel frequency response.

  The present invention, in the above-mentioned invention, further comprises a comparison means for comparing each of the absolute value of the in-phase component and the absolute value of the quadrature component of the channel frequency response with a predetermined threshold value, the amplification coefficient calculation means, When the comparison means determines that the absolute value of the in-phase component of the channel frequency response and the absolute value of the quadrature component are larger than a predetermined threshold, the absolute value of the in-phase component of the channel frequency response is orthogonal The amplification coefficient is calculated by multiplying the sum of the absolute values of the phase components by a second coefficient different from the first coefficient.

  In order to solve the above-described problem, the present invention provides a source station that transmits a radio signal, a destination station that receives the radio signal, and a radio signal transmitted from the source station to receive the destination station. An instantaneous power scaling method of the relay station in a wireless relay system configured with a relay station that transmits to the channel frequency response calculating step of calculating a channel frequency response between the transmitting station and the relay station; The sum of the absolute value of the in-phase component and the absolute value of the quadrature component of the channel frequency response calculated in the channel frequency response calculation process is calculated, and the amplification coefficient is calculated by multiplying by a predetermined first coefficient. An amplification factor calculation process, and a transmission signal to the destination station by multiplying the amplification coefficient calculated in the amplification coefficient calculation step and the radio signal received from the source station The instantaneous power scaling method which comprises a transmission signal generation process to be generated.

  According to the present invention, in the above-described invention, a comparison process of comparing each of the absolute value of the in-phase component and the absolute value of the quadrature component of the channel frequency response with a predetermined threshold value, and 2 of the absolute value of the channel frequency response. A calculation step of calculating a power, wherein the amplification factor calculation step determines in the comparison step that the absolute value of the in-phase component and the absolute value of the quadrature component of the channel frequency response are greater than a predetermined threshold value. In such a case, the amplification coefficient is calculated based on the square of the absolute value of the channel frequency response.

  The present invention, in the above invention, further includes a comparison process of comparing each of the absolute value of the in-phase component and the absolute value of the quadrature component of the channel frequency response with a predetermined threshold value, and the amplification coefficient calculation process includes: If it is determined in the comparison process that the absolute value of the in-phase component of the channel frequency response and the absolute value of the quadrature component are larger than a predetermined threshold, the absolute value of the in-phase component of the channel frequency response is orthogonal The amplification coefficient is calculated by multiplying the sum of the absolute values of the phase components by a second coefficient different from the first coefficient.

  According to the present invention, it is possible to reduce the amount of calculation when calculating the amplification coefficient of the relay station.

It is a block diagram which shows the structural example of the relay station 2 of this invention. It is a block diagram which shows the example of a procedure of the channel power calculation process 2-4 by the linear approximation method by 1st Embodiment of this invention. It is a block diagram which shows the example of a procedure of the channel power calculation process 2-4 by the threshold linear approximation method # 1 by 2nd Embodiment of this invention. It is a block diagram which shows the example of a procedure of the channel power calculation process 2-4 by the threshold linear approximation method # 2 by 3rd Embodiment of this invention. It is a figure explaining a cooperation protocol. It is a block diagram which shows the cooperative transmission of 1R2H structure.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  The non-regenerative relay in wireless communication is a system in which a data signal is not restored from a radio signal received by a relay station and relayed by performing amplification processing as it is. As described above, in the conventional non-regenerative relay (wireless relay by the AF method), a method of calculating a simple amplification factor based on a fixed value called the FPS method, a subcarrier called the IPS method, and There has been a method for calculating the amplification factor using the square of the absolute value of the channel response for each received signal. The former has almost no arithmetic processing, but has a problem that the followability to channel fluctuation is low and the quality is poor, and the latter has a problem that there are many arithmetic processes although the followability to channel fluctuation is high.

  The present invention reduces the amount of computation by using an approximate expression obtained by multiplying the absolute values of the in-phase component and the quadrature component of the channel response by a predetermined coefficient instead of the square of the absolute value of the channel response, while reducing the amount of calculation. Provides follow-up to channel variations. In addition, when the received power is large, there is a problem that the transmission power of the relay station becomes excessive. However, according to the approximate expression, when the received power is large, by switching to the calculation using the IPS method, This problem can be solved. Furthermore, this problem can be solved by using different coefficients when the received power is large. The present invention is a technique that can be applied to all protocols I to IV shown in FIG.

First, the configuration of the relay station 2 of the present invention will be described.
FIG. 1 is a block diagram showing a functional configuration of a relay station 2 according to the present invention. The relay station 2 includes a baseband conversion process 2-1, a GI removal process 2-2, a DFT process 2-3, a channel power calculation process 2-4, an amplification coefficient calculation process 2-5, a baseband amplification process 2-6, It consists of an IDFT process 2-7, a GI addition process 2-8, and a passband conversion process 2-9.

In addition, although the amplification coefficient in IPS was α _r0 in Expression (4), it is expressed by the following Expression (6) using Ξ here.

(First embodiment)
A linear approximation method according to the first embodiment of the present invention will be described.
FIG. 2 is a block diagram showing the configuration of the channel power calculation process 2-4 of the linear approximation method according to the first embodiment of the present invention. The in-phase component A and the quadrature component B of the CFR estimation value H _sr between the transmitting station 1 and the relay station 2 are input to the absolute value calculation process 2-4-1 for each subcarrier. Subsequently, in the absolute value calculation process 2-4-1, | A | and | B | are output and input to the sum-integration process 2-4-2. In the summation integration process 2-4-2, | A | + | B | is calculated, and then the value of (| A | + | B |) is multiplied by γ. As described above, the output value の of the channel power calculation process 2-4 in this case is expressed by the following equation (7).

  Here, the value of γ is appropriately given according to the state of the system. By substituting Ξ obtained by Equation (7) into Equation (6), the amplification coefficient at relay station (R) 2 is obtained.

According to the first embodiment described above, the reception power of the destination station (D) 3 is smoothed while following the channel variation in the same manner as IPS by calculating the amplification coefficient for each subcarrier and for each reception. Can be Further, instead of calculating the square of the absolute value of the CFR estimated value H _sr itself, a coefficient is added to the sum of the absolute values of the in-phase component A and the quadrature component B of the CFR estimated value H _sr according to the equation (7) The amount of calculation can be reduced by using an approximate expression obtained by multiplying.

(Second embodiment)
Next, the threshold linear approximation method # 1 according to the second embodiment of the present invention will be described.
In the second embodiment, when the reception power of the relay station (R) 2 is large, the mathematical expression (4) by IPS is used instead of the approximate expression of the mathematical expression (7). That is, regardless of the magnitude of the received power of the relay station (R) 2, using the formula (7), it is considered that when the received power is large, the limit of the transmission power of the relay station (R) 2 is exceeded. In such a case, if the nonlinear region of the amplifier is used, there is a problem that the signal is distorted. Therefore, it is necessary to avoid this.

FIG. 3 is a block diagram showing a configuration of the channel power calculation process 2-4 of the threshold linear approximation method # 1 according to the second embodiment of the present invention. The in-phase component A and the quadrature component B of the CFR estimation value H _sr between the transmission station (S) 1 and the relay station (R) 2 are respectively input to the absolute value threshold value evaluation process 2-4-3.

In the absolute value threshold value evaluation process 2-4-3, the absolute values | A | and | B | of A and B are calculated, and for the threshold value A _th > 0, in the conditional expression (8), (1) YES (2) NO is determined.

(1) In the case of YES | A | and | B | are output from the absolute value threshold evaluation process 2-4-3 and input to the real-imaginary part square calculation process 2-4-4. | A | and | B | are respectively squared, and | A | ² and | B | ² are output and input to the summation integration process 2-4-5. Here, the instantaneous channel power | H _sr | ² = | A | ² + | B | ² is output by the sum of | A | ² and | B | ² , and the obtained | H _sr | ² = | A | ² + | B | ² is multiplied by the transmission power P _s1 of the transmitting station (S) 1 in slot # 1 in the integration process. As described above, the output value の of the channel power calculation process 2-4 in this case is expressed by the following equation (9).

  The value of Equation (9) is the same as the output value of the IPS according to Equation (4) and Equation (6).

(2) In the case of NO | A | and | B | are output from the absolute value threshold value evaluation process 2-4-3, and input to the sum integration process 2-4-5. In the summation integration process 2-4-5, | A | + | B | is calculated, and then the value of (| A | + | B |) is multiplied by γ. As described above, the output value の of the channel power calculation process 2-4 in this case is expressed by Equation (10).

  According to the second embodiment described above, in addition to the first embodiment described above, when the reception power of the relay station (R) 2 is large, the amplification coefficient becomes small, so that the transmission power becomes excessive. The effect that there is no is obtained.

(Third embodiment)
The feature of the third embodiment is that, in the configuration of the second embodiment, (1) in the case of YES, the mathematical expression (9) is not used, and (2) a parameter γ ₂ different from that in the case of NO is used. There is.

FIG. 4 is a block diagram showing a configuration of channel power calculation processing 2-4 of the threshold linear approximation method # 2 according to the third embodiment of the present invention. The in-phase component A and the quadrature component B of the CFR estimation value H _sr between the transmission station (S) 1 and the relay station (R) 2 are respectively input to the absolute value threshold evaluation processing 2-4-6.

In the absolute value threshold value evaluation process 2-4-6, the absolute values | A | and | B | of A and B are calculated, and the threshold value A _th > 0 of the inputs | A | and | B | It is determined whether (1) YES or (2) NO in the conditional expression.

(1) When YES: γ ₂ is used as the integration coefficient in the addition integration process 2-4-7.

(2) When NO: γ ₁ is used as the integration coefficient of the addition integration process 2-4-7.

| A | and | B | are output from the absolute value threshold value evaluation process 2-4-6 and input to the summation process 2-4-7. In summing within accumulation process 2-4-7, | A | + | B | is calculated, followed by (| A | + | B | ) to the value of the integrated coefficient gamma ₁ or gamma ₂ is multiplied. The values of the integration coefficients γ ₁ and γ ₂ are appropriately given depending on the state of the system. As described above, the output value の of the channel power calculation process 2-4 in this case is expressed by Equation (11).

  According to the third embodiment described above, even when the reception power of the relay station (R) 2 is large, the transmission power does not become excessive, and the calculation amount can be reduced as compared with the second embodiment described above. it can.

(Modification of this embodiment)
Below, the modification of this embodiment is demonstrated.

(1) Application to various multicarrier systems There are various types of multicarrier systems, such as OFDM systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, and multicarrier code division multiple access. (Multi Carrier-Code Division Multiple Access: MC-CDMA) system and the like are known. The present invention is applicable to these arbitrary multicarrier schemes.

(2) Application to MIMO System In the first to third embodiments described above, the SISO system has one antenna each for the transmission station (S) 1, the relay station (R) 2, and the destination station (D) 3. However, the present invention is also applicable to a MIMO (Multiple Input Multiple Output) system in which the transmitting station (S) 1 and the relay station (R) 2 each have a plurality of antennas.

(3) Application to a multi-relay system In the first to third embodiments described above, the present invention is applied to a single relay system in which the number of relay stations (R) 2 is 1, but the number of relay stations (R) 2 The present invention can also be applied to a multi-relay system having a plurality of.

(4) Application to a multi-hop system In the first to third embodiments described above, the present invention is applied to a two-hop system of a source station (S) 1, a relay station (R) 2, and a destination station (D) 3. The present invention can also be applied to a multi-hop system in which a plurality of relay stations (R) 2 exist and perform multi-hop transmission.

DESCRIPTION OF SYMBOLS 1 Source station 1-1 Channel encoding process 1-2 Interleaver process 1-3 Modulation process 1-4 Passband conversion process 2 Relay station 2-1 Baseband conversion process 2-2 GI removal process 2-3 DFT process 2- 4-channel power calculation process 2-4-1, 2-4-2, 2-4-6 absolute value threshold value evaluation process 2-4-2, 2-4-5, 2-4-7 addition and integration process 2- 4-4 Real-imaginary part square calculation process 3 Destination station 3-1 Baseband conversion process 3-2 Demodulation process 3-3 Deinterleaver process 3-4 Channel decoding process

Claims (6)

The wireless relay system comprising: a transmitting station that transmits a wireless signal; a destination station that receives the wireless signal; and a relay station that receives the wireless signal transmitted from the transmitting station and transmits the wireless signal to the destination station. A relay station instantaneous power scaling circuit,
Channel frequency response calculating means for calculating a channel frequency response between the transmitting station and the relay station;
Obtained by calculating the sum of the absolute value of the in-phase component and the quadrature component of the channel frequency response calculated by the channel frequency response calculating means and multiplying by the first coefficient given by the system state Amplification coefficient calculating means for calculating the amplification coefficient α _r by substituting the value に into the following equation;
Transmission signal generation means for generating a transmission signal to the destination station by multiplying the amplification coefficient α _r calculated by the amplification coefficient calculation means and the radio signal received from the transmission station. Instantaneous power scaling circuit.
α _r = √ {1 / (Ξ + σ _w ² )}
Where σ _w ² is the variance of white additive Gaussian noise at the relay station. Comparing means for comparing each of the absolute value of the in-phase component and the absolute value of the quadrature component of the channel frequency response with a predetermined threshold value;
Calculating means for calculating the square of the absolute value of the channel frequency response;
The amplification coefficient calculation means includes
When the comparison means determines that the absolute value of the in-phase component and the absolute value of the quadrature component of the channel frequency response are larger than a predetermined threshold, it is based on the square of the absolute value of the channel frequency response. The instantaneous power scaling circuit according to claim 1 , wherein the amplification coefficient is calculated. Comparing means for comparing each of the absolute value of the in-phase component and the absolute value of the quadrature component of the channel frequency response with a predetermined threshold,
The amplification coefficient calculation means includes
When the comparison means determines that the absolute value of the in-phase component of the channel frequency response and the absolute value of the quadrature component are larger than a predetermined threshold, the absolute value of the in-phase component of the channel frequency response is orthogonal 2. The instantaneous power scaling circuit according to claim 1 , wherein the amplification coefficient is calculated by multiplying a sum of absolute values of phase components by a second coefficient different from the first coefficient. The wireless relay system comprising: a transmitting station that transmits a wireless signal; a destination station that receives the wireless signal; and a relay station that receives the wireless signal transmitted from the transmitting station and transmits the wireless signal to the destination station. A method for instantaneous power scaling of a relay station,
A channel frequency response calculation process for calculating a channel frequency response between the source station and the relay station;
Obtained by calculating the sum of the absolute value of the in-phase component and the quadrature component of the channel frequency response calculated in the channel frequency response calculation process, and multiplying by the first coefficient given by the system state An amplification coefficient calculation process for calculating the amplification coefficient α _r by substituting the value に into the following equation;
A transmission signal generation step of generating a transmission signal to the destination station by multiplying the amplification factor α _r calculated in the amplification factor calculation step and the radio signal received from the transmission station. Instantaneous power scaling method.
α _r = √ {1 / (Ξ + σ _w ² )}
Where σ _w ² is the variance of white additive Gaussian noise at the relay station. A comparison process comparing each of the absolute value of the in-phase component and the absolute value of the quadrature component of the channel frequency response with a predetermined threshold value;
And calculating a square of an absolute value of the channel frequency response,
The amplification coefficient calculation process includes:
If it is determined in the comparison process that the absolute value of the in-phase component and the quadrature component of the channel frequency response are larger than a predetermined threshold value, it is based on the square of the absolute value of the channel frequency response. The method according to claim 4 , wherein the amplification coefficient is calculated. A comparison step of comparing each of the absolute value of the in-phase component and the absolute value of the quadrature component of the channel frequency response with a predetermined threshold value;
The amplification coefficient calculation process includes:
If it is determined in the comparison process that the absolute value of the in-phase component of the channel frequency response and the absolute value of the quadrature component are larger than a predetermined threshold, the absolute value of the in-phase component of the channel frequency response is orthogonal 5. The instantaneous power scaling method according to claim 4 , wherein the amplification coefficient is calculated by multiplying a sum of the absolute value of the phase component by a second coefficient different from the first coefficient.

Images