JP6466284B2 - Wireless relay device and wraparound cancellation method - Google Patents

Description

  The present invention relates to a technique for reducing residual self-interference power after wraparound cancellation in a full-duplex relay wireless relay device (relay station).

  Generally, when direct communication is not possible between a base station and a destination station, a relay station is arranged between the base station and the destination station. The relay station uses a full-duplex relay system that retransmits to the destination station using the same radio resources (time and frequency) as the signal received from the base station, improving frequency utilization efficiency and throughput (for example, patents) Reference 1). A full-duplex relay relay station needs to suppress self-interference in which a signal transmitted from a transmission antenna wraps around the reception antenna, and thus wraparound cancellation is performed.

M. Jain, et al., “Practical, Real-time, Full Duplex Wireless,” Proc., MobiCom 11, 2011.

  However, even when the roundabout cancellation is performed appropriately, there is a problem that a residual self-interference component occurs in the signal after the roundabout cancellation due to the estimation error of the roundabout path. In particular, when the residual self-interference power is large, the demodulation error characteristics of the relay station deteriorate.

  In view of the above problems, an object of the wireless relay device and the wraparound canceling method according to the present invention is to reduce residual self-interference power and improve demodulation error characteristics in the wireless relay device.

The first invention is a wireless relay device for transmitting a radio signal from the transmitting antenna at the same frequency received from the receiving antenna, an adjustment unit for adjusting at least one of propagation environment transmit or receive antennas are adjusted by the adjustment section and a plurality of propagation environment, and transmit a training signal from the transmitting antenna, an estimation unit for their respective estimating the response of a wraparound path to the receiving antenna, response and the self-device of the plurality of sneak paths estimated by the estimation unit Calculate the residual self-interference power in multiple propagation environments based on the response of the internal cancellation signal path , select the propagation environment with the smallest residual self-interference power from the multiple propagation environments, and select the selected propagation sets the adjustment unit so that the environment, the transmitting antenna based on the response of the echo path in the propagation environment And having a calculation unit for calculating a cancellation response for canceling the echo signal to et the receiving antenna.

In the second aspect of the invention, the calculation unit , based on the response of the wraparound path and the response of the cancellation signal path, responds between the transmission antenna and the reception antenna of the wraparound path and the response of the transmission circuit that transmits a radio signal from the transmission antenna. calculated as G _T1, and response G _T0 of the transmission circuit of the Cancel signal path, the attenuation √L cancellation signal path, the response G _R of a receiver circuit for receiving a radio signal from the receiving antenna, and a noise power sigma ² The residual self-interference power E is calculated by the following equation.

  In the third invention, the adjustment unit adjusts the propagation environment by at least one of control of the radiation direction of the radio signal by the array antenna, selection or switching control of a plurality of antennas, and control of the radiation direction by the antenna rotation mechanism. It is characterized by that.

A fourth invention is a wraparound cancellation method in a radio relay apparatus that transmits a radio signal received from a reception antenna from a transmission antenna at the same frequency, and an adjustment process for adjusting a propagation environment of at least one of the transmission antenna and the reception antenna; in a plurality of propagation environment adjusted by the adjustment process, and sends a training signal from the transmitting antenna, and estimating process for their respective estimating the response of a wraparound path to the receiving antennas, a plurality of estimated by the estimation process wraparound Calculate the residual self-interference power in multiple propagation environments based on the response of the path and the cancellation signal path inside the device, and select the propagation environment that minimizes the residual self-interference power among the multiple propagation environments and, performs adjustment processing such that the selected propagation environment, times in the propagation environment And performing the transmitting antennas based on the response of the write path and a calculation process for calculating a cancellation response for canceling the echo signal to the receiving antenna.

In the fifth invention, in the calculation process, based on the response of the wraparound path and the response of the cancellation signal path, the response H between the transmission antenna and the reception antenna of the wraparound path and the response of the transmission circuit that transmits a radio signal from the transmission antenna calculated as G _T1, and response G _T0 of the transmission circuit of the Cancel signal path, the attenuation √L cancellation signal path, the response G _R of a receiver circuit for receiving a radio signal from the receiving antenna, and a noise power sigma ² The residual self-interference power E is calculated by the following equation.

In the sixth invention, in the adjustment process, the control of the radial radio signal by the array antenna, a plurality of antennas of selection or switching control by at least one control of the control in the radial direction by the antenna rotating mechanism, adjust the propagation environment It is characterized by doing.

  The radio relay apparatus and the wraparound cancellation method according to the present invention can reduce residual self-interference power and improve demodulation error characteristics in the radio relay apparatus.

It is a figure which shows an example of the radio | wireless communications system in this embodiment. It is a figure which shows the example which adjusts a roundabout propagation environment. It is a figure which shows an example of a relay station. It is a figure which shows an example of a demodulation-modulation part. It is a figure which shows each parameter for calculating residual self-interference electric power. It is a figure which shows the comparative example of the measurement of the residual self-interference power by a training signal, and the calculation of the residual self-interference power by an analytical expression. It is a figure which shows the process sequence in this embodiment. It is a figure which shows an example of the transmission signal of a base station, and the transmission signal of a relay station. It is a figure which shows the parameter example of computer simulation. It is a figure which shows the result of the computer simulation in K = 0. It is a figure which shows the result of the computer simulation in K = 4. It is a figure which shows the result of the computer simulation in K = 10.

  Hereinafter, embodiments of a wireless relay device and a wraparound canceling method according to the present invention will be described with reference to the drawings. In the present embodiment, the wireless relay device is referred to as a relay station.

  FIG. 1 shows an example of a wireless communication system 100 using a relay station 101 described in the present embodiment. In FIG. 1, a wireless communication system 100 includes a relay station 101, a base station 102, and a destination station 103.

  In FIG. 1, a relay station 101 receives a radio signal transmitted from a base station 102, demodulates it once, and transmits a remodulated radio signal to a destination station 103 in real time. Here, the frequency of the radio signal received from the base station 102 and the frequency of the radio signal transmitted to the destination station 103 are the same frequency. As described above, the relay station 101 according to the present embodiment retransmits a radio signal having the same frequency as the radio signal received from the base station 102 to the destination station 103 at the same time.

  Here, in FIG. 1, the relay station 101 includes an antenna 201, an antenna 202, a demodulation-modulation unit 203, a wraparound cancellation unit 204, and an adder 205.

  The antenna 201 is an antenna that receives a radio signal transmitted from the base station 102.

  The antenna 202 is an antenna that transmits a radio signal to the destination station 103.

  Demodulation-modulation section 203 once demodulates the signal received from base station 102 and remodulates it.

  The sneak cancel unit 204 generates a signal having a characteristic that cancels the sneak path characteristic in which the radio wave radiated from the antenna 202 is received by the antenna 201.

  The adder 205 is a circuit that adds the reception signal of the antenna 201 and the output signal of the wraparound cancellation unit 204. The adder 205 outputs a signal obtained by canceling the sneak signal included in the reception signal of the antenna 201 to the demodulation / modulation unit 203.

  In this way, the relay station 101 can retransmit the signal from which the signal sneaking from the antenna 202 to the antenna 201 through the sneak path is removed to the destination station 103.

  However, even when wraparound cancellation is performed properly, there is a problem that residual self-interference components occur in the signal after wraparound cancellation due to estimation error of the wraparound path. Error characteristics are degraded.

  Therefore, the relay station 101 according to the present embodiment analyzes the residual self-interference power while adjusting the wraparound propagation environment by using an array antenna or the like, and selects a propagation environment having a small residual self-interference power among a plurality of propagation environments. Then, the demodulation error characteristic in the demodulation-modulation section 203 of the relay station 101 is improved. In the present embodiment, a case where the two propagation antennas are adjusted by controlling two array antennas will be described. However, the present invention can be similarly applied if a plurality of array antennas are used. As a method for adjusting the propagation environment, a technique such as switching of a plurality of antennas, rotation of the antenna direction by a rotator or the like can be used.

  FIG. 2 shows an example of adjusting the wraparound propagation environment by controlling two array antennas. 2, blocks having the same reference numerals as those in FIG. 1 have the same or similar functions as those in FIG.

  In FIG. 2, relay station 101 has two array antennas, antenna 202 (1) and antenna 202 (2), as antenna 202 for transmission to destination station 103 shown in FIG. Thereby, the relay station 101 can adjust the wraparound propagation environment by switching the antenna 202 (1) or the antenna 202 (2), for example. Alternatively, the wraparound propagation environment can be adjusted by rotating the antenna direction that radiates the radio wave of the antenna 202 (1) or the antenna 202 (2) with a rotator or the like. Note that a plurality of antennas may be arranged for the antenna 201. Here, it is assumed that the antenna 201 is a single antenna and is rotated by a rotator or the like to adjust the propagation environment on the reception side.

Here, as shown in FIG. 2, the relay station 101 controls the antenna 202 to adjust the wraparound propagation environment, whereby the wraparound path changes. In the example of FIG. 2, N _R different propagation environments such as a sneak path 1, a sneak path 2,..., A sneak path N _R (N _R : a positive integer) are obtained. The relay station 101 according to the present embodiment adjusts the wraparound propagation environment so that the residual self-interference power is reduced.

  FIG. 3 shows an example of the relay station 101. 3 shows a detailed configuration example of the relay station 101 shown in FIG. 1, and blocks having the same reference numerals as those in FIG. 1 have the same or similar functions as those in FIG.

  In FIG. 3, the relay station 101 includes a reception-side propagation environment adjustment unit 301, a signal synthesis unit 302, a reception signal conversion unit 303, an analog-digital (AD) conversion unit 304, a demodulation-modulation unit 305, and a digital-analog (DA) conversion unit. 306, a transmission signal conversion unit 307, a transmission side propagation environment adjustment unit 308, a cancellation response multiplication unit 309, a digital analog (DA) conversion unit 310, a transmission signal conversion unit 311, a control unit 312, and a memory 313.

  Here, in FIG. 3, an AD conversion unit 304, a demodulation-modulation unit 305, a DA conversion unit 306, a cancellation response multiplication unit 309, and a DA conversion unit 310 are included in a digital circuit unit 300 that performs digital processing.

  The reception-side propagation environment adjustment unit 301 adjusts the wraparound propagation environment for the antenna 201 by controlling an array antenna, multiple antenna switching, a rotator, and the like.

  The signal synthesis unit 302 synthesizes the reception signal and the cancel signal, and cancels the signal component of the wraparound path from the reception signal.

  The reception signal conversion unit 303 performs RF (Radio Frequency) signal processing (filtering, amplification, down-conversion, etc.) on the analog reception signal, and converts the reception signal into a baseband signal.

  The AD conversion unit 304 samples an analog baseband signal at a predetermined sampling period and converts the analog baseband signal into a digital baseband signal.

  The demodulation-modulation unit 305 once demodulates and remodulates the signal received from the base station 102 for regenerative relay.

  The DA converter 306 converts the digital baseband signal for transmission output from the demodulator-modulator 305 into an analog baseband signal.

  The transmission signal conversion unit 307 performs RF signal processing (up-conversion, filter, amplification, etc.) on the analog baseband signal and converts it to a transmission RF signal.

  The transmission-side propagation environment adjustment unit 308 adjusts the wraparound propagation environment with respect to the antenna 202 by a mechanism such as an array antenna, multiple antenna switching, and a rotator. For example, when the relay station 101 has the configuration shown in FIG. 2, the transmission side propagation environment adjustment unit 308 controls the two array antennas of the antenna 202 (1) and the antenna 202 (2), and the wraparound propagation environment. Adjust.

  The cancel response multiplication unit 309 generates a cancel baseband signal by multiplying the transmission signal by a response for canceling the wraparound signal.

  The DA conversion unit 310 converts the digital wraparound cancel baseband signal generated by the cancellation response multiplication unit 309 into an analog baseband signal.

  The transmission signal converter 311 performs RF signal processing (up-conversion, filter, amplification, etc.) on the analog baseband signal, and converts it into an RF signal for cancellation. The cancellation RF signal is output to the signal synthesis unit 302. Then, the signal synthesis unit 302 synthesizes the cancellation RF signal with the received signal, and cancels the wraparound signal.

  The control unit 312 controls the operation of each unit of the relay station 101 based on a program stored in advance inside. The control unit 312 controls the operation sequence of each unit at the start of full-duplex relay, for example, transmission of training signals (signals having predetermined information), reception-side propagation environment adjustment unit 301 and transmission-side propagation Control and setting of the environment adjustment unit 308, setting and delivery of parameters of each unit, and the like are performed. In addition, the control unit 312 stores the residual self-interference power and the cancellation response calculated for each propagation environment in the memory 313 in association with the setting contents of the propagation environment. In the example of FIG. 4, the control unit 312 and the memory 313 are provided for easy understanding, but the functions of the control unit 312 and the memory 313 may be included in each block.

  In this way, the relay station 101 according to the present embodiment adjusts the propagation environment of at least one of the antenna 201 and the antenna 202, and the wraparound path included in the received signal by the cancellation signal generated by the cancellation response multiplier 309. Cancel the signal component of.

  FIG. 4 shows an example of the demodulation / modulation unit 305. 4 shows a detailed configuration example of the demodulation-modulation unit 305 shown in FIG. 3, and blocks having the same reference numerals as those in FIG. 3 have the same or similar functions as those in FIG.

  In FIG. 4, a demodulation / modulation unit 305 includes a channel equalization unit 401, a decoding unit 402, a transmission signal generation unit 403, a training signal control unit 404, a channel estimation unit 405, a cancellation response calculation unit 406, and residual self-interference. A power calculation unit 407 is included.

  The communication channel equalization unit 401 equalizes distortion in the communication channel. For example, the communication path equalization unit 401 equalizes distortion such as intersymbol interference in the communication path from the base station 102 to the relay station 101.

  The decoding unit 402 decodes the baseband signal equalized by the communication path equalization unit 401 into received data using a predetermined communication method. For example, in the case of a quadrature-modulated baseband signal, the decoding unit 402 performs determination processing according to the signal point and decodes the received data.

  The transmission signal generation unit 403 generates a transmission signal using the decoded reception data as transmission data using a predetermined communication method. For example, in the case of the multi-level modulation method, the transmission signal generation unit 403 determines transmission data for each modulation unit and maps it to signal points.

  The training signal control unit 404 generates a training signal having predetermined information for acquiring the characteristics of the wraparound path, and outputs the training signal as a transmission signal via the transmission signal generation unit 403.

  The communication path estimation unit 405 estimates the characteristics of the communication path with the base station 102, the characteristics of the sneak path, and the characteristics of the cancellation signal path inside the relay station 101. For example, the communication path estimation unit 405 estimates the characteristics of the communication path with the base station 102 and outputs the estimated characteristics to the communication path equalization unit 401. Further, the communication path estimation unit 405 estimates the characteristics of the sneak path and the cancellation signal path and outputs the estimated characteristics to the cancellation response calculation unit 406.

  The cancellation response calculation unit 406 calculates a cancellation response based on each characteristic estimated by the communication path estimation unit 405. Here, the cancellation response calculation unit 406 includes a residual self-interference power calculation unit 407. In the present embodiment, the residual self-interference power calculation unit 407 is provided to make the explanation easy to understand. Here, the residual self-interference power calculation unit 407 calculates the residual self-interference power after cancellation for each propagation environment. A method for calculating the residual self-interference power will be described later. Then, the cancellation response calculation unit 406 compares the residual self-interference power for each propagation environment, selects the propagation environment with the minimum residual self-interference power, and cancels the response from the response of the sneak path corresponding to the selected propagation environment. Calculate the response. Here, the process of comparing the residual self-interference power for each propagation environment and selecting the propagation environment with the minimum residual self-interference power may be performed by the control unit 312 described with reference to FIG.

As described above, the relay station 101 according to the present embodiment can reduce the residual self-interference power by adjusting the wraparound propagation environment and improve the demodulation error characteristic of the relay station 101. Specifically, the relay station 101 measures the residual self-interference component while adjusting the propagation environment, and adopts the optimum propagation environment among them. In this embodiment, as a method for adjusting the sneak propagation environment, control using two array antennas, selection switching of a plurality of antennas, rotation using a rotator, and the like are used, but other methods may be used.
[Calculation method of residual self-interference power]
Next, a method for calculating the residual self-interference power will be described. An analytical expression for the residual self-interference power E can be expressed as the following expression.

Here, each parameter of the formula (1) is as follows.
σ ² : Noise power
H: Response between transmitter and receiver antennas
G _T1 : Response of the transmission circuit in the wraparound path
G _T0 : Response of the cancellation signal path transmission circuit
G _R : Receiver circuit response √L: Attenuation of cancellation signal path
I: Residual self-interference component Note that the third term of equation (1) is sufficiently small in a high SNR environment and can be ignored.

FIG. 5 shows parameters for calculating the residual self-interference power. 5 shows the same configuration as that of relay station 101 described in FIG. In FIG. 5, the response between the transmission / reception antennas in the wraparound path is H, the response of the transmission circuit (transmission signal conversion unit 307) on the transmission side from the antenna 202 is G _T1 , and the transmission circuit on the cancellation signal path side (transmission signal conversion unit 311). ) Is G _T0 , the response of the reception circuit (reception signal conversion unit 303) is G _R , and the attenuation amount of the cancel signal path is √L. Here, it is assumed that each of the above parameters is measured by the communication path estimation unit 405, the cancellation response calculation unit 407, and the like by a known technique. Note that the responses of the transmission circuit and the reception circuit may be measured in advance and stored in the memory 313.

  Here, in this embodiment, the residual self-interference power is obtained from the analytical expression (1), but the residual self-interference power is obtained by transmitting a training signal for residual self-interference power measurement after the wraparound cancellation system is established. There is also a way to ask for. However, when the residual self-interference power measurement training signal is transmitted, there arises a problem that the overhead increases.

FIG. 6 shows a comparative example between measurement of residual self-interference power using a training signal and calculation of residual self-interference power using an analytical expression. Here, FIG. 6A shows an example of measuring the residual self-interference power using the training signal, and FIG. 6B shows an example of analytically deriving the residual self-interference power. 6 (a) and 6 (b), the horizontal axis indicates time, TR is a training signal, N _R (N _R : positive integer) is a response characteristic of a wraparound path, and propagation environment is estimated. The number of adjustments is shown respectively. That is, in the example of FIG. 6, the response characteristic of the wraparound path is estimated for N _R different propagation environments. M (M: positive integer) is a code indicating the transmission order (number of transmissions) of the training signals, and the order of the training signals is indicated as TR-1, TR-2,..., TR-M. write.

In the case of measuring the residual self-interference power with the training signal shown in FIG. 6A, first, the relay station 101 outputs the training signal TR-0 from the transmission signal conversion unit 311 and returns the response of the cancel signal path. presume. Next, relay station 101 transmits training signal TR-1 from antenna 202 to estimate the response of wraparound path 1. Further, relay station 101 transmits training signal TR-3 from antenna 202, and measures the residual self-interference power of wraparound path 1. Thereafter, the relay station 101 repeats the process of estimating the sneak path _NR times and the process of measuring the residual self-interference power of the sneak path _NR times. Finally, the relay station 101 transmits the training signal TR- (M-1) from the antenna 202, performs a process of estimating the response characteristic of the _NR wraparound path, and transmits the training signal TR-M from the antenna 202. and transmitted, it performs a process of measuring the residual self-interference power N _R th sneak paths. Thus, when measuring the residual self-interference power by the training signal, each time to estimate the N _R times the sneak path to sneak path N _R, it is necessary to measure the residual self-interference power each round of sneak paths.

On the other hand, when analytically deriving the residual self-interference power shown in FIG. 6B, first, the relay station 101 outputs the training signal TR-0 from the transmission signal conversion unit 311 to estimate the cancel signal path. To do. Next, the relay station 101 transmits the training signal TR-1 from the antenna 202 and estimates the wraparound path 1. The processing so far is the same as the measurement of the residual self-interference power with the training signal shown in FIG. However, in the case of FIG. 6B, since the relay station 101 analytically derives the residual self-interference power without measuring the residual self-interference power using the training signal, the estimation of the sneak path is continuously performed. It can be carried out. Thereby, even-numbered training signals TR-2, TR-4, TR-6,..., TR- (N _R +1),. Thus, the process of estimating the residual self-interference power becomes unnecessary, and the overhead time can be reduced. In the example of FIG. 6, if analytically derive the residual self-interference power is treated with N _R th training signal TR-N timing _R ends T1 is finished, the measurement of the residual self-interference power due to the training signal Is performed until timing T2 when the M-th training signal TR-M ends.

  Thus, since the relay station 101 according to the present embodiment derives the residual self-interference power analytically, overhead can be reduced as compared with the case where the residual self-interference power is measured using the training signal.

  FIG. 7 shows a processing procedure from selecting a propagation environment that minimizes the residual self-interference power to performing full-duplex relay processing.

In step S101, the relay station 101 estimates the response Y ₀ of the cancel signal path by the following equation.

In step S102, the relay station 101, while adjusting the propagation environment, the following equation to estimate the response Y ₁ of a plurality of sneak paths.

  Then, the relay station 101 stores the estimation result in the memory 313 or the like in association with the setting contents of the propagation environment.

  In step S103, the relay station 101 obtains each residual self-interference power value from the responses of a plurality of sneak paths for each propagation environment stored in the memory 313 or the like, and determines the response of the sneak path that minimizes the residual self-interference power. Select the corresponding propagation environment.

  In step S104, the relay station 101 calculates a cancellation response F from the response of the sneak path that minimizes the residual self-interference power, using the following equation.

Here, W0 and W1 are additive noise (variance σ2).

  In step S105, the relay station 101 sets the propagation environment corresponding to the response of the sneak path in which the residual self-interference power is minimized, cancels the sneak signal using the cancellation response F, and performs full-duplex relay. carry out. Here, the residual self-interference component I after the cancellation application is expressed by the following equation.

  In this way, the residual self-interference power E after applying the cancellation shown in Expression (1) can be obtained.

  FIG. 8 shows an example of the transmission signal of the base station 102 and the transmission signal of the relay station 101 corresponding to the processing procedure shown in FIG. In FIG. 8, the horizontal axis indicates time.

In FIG. 8, before the relay station 101 performs full-duplex communication relay, at timing T10, the relay station 101 outputs the training signal TR-0 from the transmission signal conversion unit 311 so that the internal cancellation signal path Estimate response characteristics. Then, as described with reference to FIG. 6, the relay station 101, in a period from the timing T11 to T12, the N _R times of the training signal from the training signal TR-1 while changing the propagation environment up to the training signal TR-N _R Transmitting from the antenna 202 , N _R response characteristics from the wraparound path 1 to N _R are estimated. Then, the relay station 101 calculates the residual self-interference power for each of the N _R response characteristics, selects the propagation environment of the wraparound path that minimizes the residual self-interference power, and sets the selected propagation environment. Further, the relay station 101 calculates a response characteristic F for cancellation from the response characteristic of the sneak path corresponding to the selected propagation environment, and sets the calculated response characteristic F for cancellation. Then, relay station 101 starts full-duplex communication relay of the frame of the desired signal transmitted by base station 102 at timing T13, and retransmits the frame of the desired signal to destination station 103 at timing T14. Note that the delay between the timing T13 and the timing T14 is caused by processing such as demodulation processing and cyclic redundancy check in the relay station 101.

In this way, the relay station 101 according to the present embodiment can set a propagation environment in which the residual self-interference power is reduced, and can relay the frame received from the base station 102 to the destination station 103 in full-duplex communication. it can.
[effect]
FIG. 9 shows parameters of computer simulation for verifying the effect of full-duplex communication relay performed by the relay station 101 according to the present embodiment. In FIG. 9, the average SNR of the radio signal received by the relay station 101 from the base station 102 is 35 dB. Further, the responses G _T0 , G _T1 , and G _R of the transmission / reception circuits have a lognormal distribution, an amplitude of 0.5 dB, and a uniform distribution ∈ [0, 2π). The simulation was performed for three cases where the K-factor of Rician fading was K = 0, 4, and 10.

FIG. 10 shows the result of the computer simulation at K = 0. In FIG. 10, the horizontal axis represents the residual self-interference power (interference), the vertical axis represents the cumulative distribution function (CDF), and N _R represents the number of adjustments of the wraparound propagation environment. In the example of FIG. 10, six types of results with N _R from 1 to 6 are shown. The simulation result of FIG. 10 shows that the residual self-interference power decreases as N _R increases, and the characteristics improve.

FIG. 11 shows the result of the computer simulation at K = 4. FIG. 11 is the same diagram as FIG. 10, but the K-factor is different. The simulation result of FIG. 11 shows that the residual self-interference power decreases as N _R increases and the characteristics are improved as in FIG. 10, but the characteristics are greatly improved as compared with FIG.

FIG. 12 shows the result of the computer simulation at K = 10. Note that FIG. 12 is the same diagram as FIG. 10 and FIG. 11, but the K-factor is different. Similar to FIGS. 10 and 11, the simulation result of FIG. 12 shows that the residual self-interference power decreases as the N _R increases, and the characteristics are improved. However, the characteristics are improved as compared with FIGS. large.

  As described above, the relay station 101 according to the present embodiment can reduce residual self-interference power and realize full-duplex communication relay by adjusting the propagation environment using an array antenna.

DESCRIPTION OF SYMBOLS 100 ... Wireless communication system; 101 ... Relay station; 102 ... Base station; 103 ... Destination station; 201 ... Antenna; 202, 202 (1), 202 (2) ... Antenna 203 ... Demodulation-modulation unit; 204 ... Round-off cancel unit; 205 ... Adder; 300 ... Digital circuit unit; 301 ... Reception-side propagation environment adjustment unit; 303: Reception signal conversion unit; 304 ... AD conversion unit; 305 ... Demodulation-modulation unit; 306 ... DA conversion unit; 307 ... Transmission signal conversion unit; Side propagation environment adjustment unit; 309... Cancel response multiplication unit; 310 ... DA conversion unit; 311 ... transmission signal conversion unit; 401 ... communication path equalization unit; 403: Transmission signal generation unit; 404: Transmission Training signal controller; 405 ... channel estimating unit; 406 ... cancel response calculation unit; 407 ... residual self-interference power calculation unit

Claims (6)

In a wireless relay device that transmits a radio signal received from a receiving antenna from a transmitting antenna at the same frequency,
An adjustment unit for adjusting a propagation environment of at least one of the transmission antenna and the reception antenna;
A plurality of the propagation environment, which is adjusted by the adjustment section, and from said transmitting antenna transmits a training signal, estimator for their respective estimating the response of a wraparound path to the receiving antenna,
Based on the response of the plurality of sneak paths estimated by the estimation unit and the response of the cancellation signal path inside the own apparatus, each residual self-interference power in the plurality of propagation environments is calculated , And selecting the propagation environment that minimizes the residual self-interference power , setting the adjustment unit so as to be the selected propagation environment, and receiving the reception from the transmission antenna based on the response of the sneak path in the propagation environment A wireless relay device comprising: a calculation unit that calculates a cancel response for canceling a sneak signal to the antenna. The wireless relay device according to claim 1,
The calculation unit , based on the response of the wraparound path and the response of the cancellation signal path, a response H between the transmission antenna and the reception antenna of the wraparound path, and a transmission circuit that transmits a radio signal from the transmission antenna and response G _T1, and response G _T0 transmission circuit before crisis Yanseru signal path, the attenuation √L of the cancellation signal path, the response G _R of a receiver circuit for receiving a radio signal from the receiving antenna, the noise power seeking and sigma ^2, the residual self-interference power E is calculated by the following equation

A wireless relay device characterized by that. In the wireless relay device according to claim 1 or 2,
The adjustment unit adjusts the propagation environment by at least one control of control of a radio signal radiation direction by an array antenna, selection or switching control of a plurality of antennas, and control of a radiation direction by an antenna rotation mechanism. A wireless relay device. A wraparound cancellation method in a wireless relay device that transmits a radio signal received from a receiving antenna from a transmitting antenna at the same frequency,
An adjustment process for adjusting a propagation environment of at least one of the transmission antenna and the reception antenna;
A plurality of the propagation environment, which is adjusted by the adjustment process, the estimating process by transmitting a training signal from the transmitting antenna, to their respective estimating the response of a wraparound path to the receiving antenna,
Calculating respective residual self-interference powers in the plurality of propagation environments based on responses of the plurality of sneak paths estimated by the estimation process and responses of cancellation signal paths in the own device; And selecting the propagation environment that minimizes the residual self-interference power , performing the adjustment process so as to be the selected propagation environment, and based on the response of the sneak path in the propagation environment, from the transmitting antenna to the receiving antenna And a calculation process for calculating a cancel response for canceling the sneak signal. In the wraparound cancellation method according to claim 4 ,
In the calculation process, based on the response of the sneak path and the response of the cancellation signal path, a response H between the transmission antenna and the reception antenna of the sneak path, and a transmission circuit that transmits a radio signal from the transmission antenna and response G _T1, and response G _T0 transmission circuit before crisis Yanseru signal path, the attenuation √L of the cancellation signal path, the response G _R of a receiver circuit for receiving a radio signal from the receiving antenna, the noise power seeking and sigma ^2, the residual self-interference power E is calculated by the following equation

A wraparound canceling method characterized by that. In the wraparound cancellation method according to claim 4 or claim 5 ,
In the adjustment process, the propagation environment is adjusted by at least one of control of a radiation direction of a radio signal by an array antenna, selection or switching control of a plurality of antennas, and control of a radiation direction by an antenna rotation mechanism. How to cancel wraparound.

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