JP2013110510A - Radio communication device, radio communication method, and radio communication program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid a deterioration in estimation accuracy and achieve a stable and high degree of signal separation in a radio communication device separating a transmission signal and a reception signal.SOLUTION: A radio communication device separates a transmission signal and a reception signal, and comprises: an antenna for transmitting and receiving a signal; transmission means for transmitting a transmission signal via the antenna; propagation path estimation means for estimating the phase amplitude response of a signal having sneaked from a transmission side into a reception side in a propagation path estimation section; replica generation means for generating a wraparound signal replica on the basis of the estimated phase amplitude response and the transmission signal; subtraction means for subtracting the wraparound signal replica from a reception signal received via the antenna; and receiving means for performing reception processing of the reception signal after the subtraction. The radio communication device further comprises: auto-correlation calculation means for calculating the worst value of an auto-correlation characteristic of the transmission signal within a prescribed delay time; and propagation path estimation section determination means for determining that a section where the worst value of the auto-correlation characteristic is equal to or less than a threshold value is to be the propagation path estimation section.

Description

  The present invention relates to a wireless communication device, a wireless communication method, and a wireless communication program that realize separation of transmission and reception signals.

  In general, in wireless communication devices, when transmission and reception operate simultaneously, reception sensitivity deteriorates due to saturation of the receiver's LNA (Low Noise Amplifier) and leakage of out-of-band leakage components into the reception band due to the sneaking of the transmission signal to the reception side. cause. Therefore, in a general wireless system in which only one system is implemented in one wireless device, transmission / reception signals are separated using an element that physically separates time or frequency according to a duplex system.

  When the duplex method is FDD (Frequency Division Duplex), since different frequency bands are fixedly assigned to the uplink and downlink, the transmission / reception signals are mainly separated using a duplexer or a bandpass filter. When the duplex method is TDD (Time Division Duplex), different time slots are assigned to the uplink and downlink, so the transmitter / receiver is connected to the antenna via the RF switch, so that the transmission signal is sent to the receiver. I try not to run around.

  However, in a software radio apparatus that implements a plurality of radio systems on software on one radio apparatus, a duplex system and various radio systems with different frequencies operate. Therefore, transmission and reception signals are separated at a fixed time and frequency. A duplexer or RF switch cannot be used. For this reason, software radio apparatuses are required to have a technique for separating transmitted and received signals without using a duplexer or an RF switch.

  FIG. 5 shows a conventional wireless communication apparatus that realizes separation of a transmission / reception signal without using an RF switch or a duplexer by subtracting a sneak signal replica that wraps around the reception side to separate the transmission signal and the reception signal. For example, it is a figure which shows the structure of nonpatent literature 1). This wireless communication apparatus includes a modulation unit 501, a transmission unit 502, a distributor 503, a transmission / reception shared circuit 504, an antenna 505, a replica generation unit 506, a subtraction unit 507, a reception unit 508, a propagation path estimation unit 509, and a demodulation unit 510. Has been.

  In the wireless communication apparatus illustrated in FIG. 5, modulation is performed by the modulation unit 501 to generate a digital transmission signal, and conversion to an analog signal and frequency conversion are performed by the transmission unit 502. The transmission signal frequency-converted by the distributor 503 is distributed into two, and one is output to the transmission / reception shared circuit 504 and the other is output to the replica generation unit 506. The shared transmission / reception circuit 504 outputs the transmission signal supplied from the distributor 503 to the antenna 505 and outputs the reception signal received by the antenna 505 to the subtraction unit 507. The replica generation unit 506 generates a wraparound signal replica based on the propagation path information of the wraparound signal estimated by the propagation path estimation unit 509. The subtraction unit 507 subtracts the output signal of the replica generation unit 506 from the output signal of the transmission / reception shared circuit 504. The receiving unit 508 performs frequency conversion and conversion to a digital signal on the received signal. A propagation path estimation unit 509 estimates a propagation path based on the output signal of the reception unit 508. The demodulator 510 demodulates the output signal from the receiver 508.

  Next, the operation of the wireless communication apparatus shown in FIG. 5 will be described in detail. In order to simplify the description, in the following description, it is assumed that the time from 0 to L is a propagation path estimation period, and no signal replica is generated during the propagation path estimation period.

The transmission unit 502 performs frequency conversion according to equation (1). Here, x ₁ (t) is an output signal of the modulation unit 501.

The distributor 503 distributes the output signal y ₁ (t) of the transmission unit 502 according to the equation (2). Here, the distribution ratio of the distributor 503 is set to 1: 1.

The transmission / reception shared circuit 504 outputs the transmission signal supplied from the distributor 503 to the antenna 505 and outputs the reception signal received by the antenna 505 to the subtraction unit 507 according to the equation (3). Here, R is a complex amplitude response of a signal that is input from distributor 504 and leaks into subtractor 507, N is the number of signals that are transmitted from antenna 505, reflected from nearby objects, and received again by antenna 505, τ _n is the delay time of the signal, h _n is the phase amplitude response of the signal, and y ₀ (t) is the original received signal received by the antenna 505. Note that a circulator or a hybrid is generally used for the transmission / reception shared circuit 504, and the leakage amount R is about -20 to -30 [dB] in any case.

The replica generation unit 506 generates a sneak signal replica y ₄ (t) according to the equation (4). Here, to R (~ is the subsequent stick character's head, hereinafter the _{same), ~τ m, ~h m,} M are inputted from the respective distributor 504, the signal leaking to the signal of the subtraction unit 507 complex Estimated value of amplitude response, estimated value of delay time of sneak signal transmitted from antenna 505, reflected by nearby object, and received again by antenna 505, estimated value of phase amplitude response of the signal, replica generation section 506 This is the number of sneak signals to be generated. These estimation methods will be described later.

The subtraction unit 507 subtracts the output signal of the replica generation unit 506 from the output signal of the transmission / reception shared circuit 504 according to the equation (5).

The receiving unit 508 performs frequency conversion according to equation (6).

ここでＴは相関値計算区間である。なお、伝搬路推定時、すなわち０≦ｔ≦Ｌの間は回り込み信号レプリカｙ_４（ｔ）＝０であるため、伝搬路推定で用いる周波数変換後の信号ｚ_１（ｔ）、相関値Ｄ（τ）はそれぞれ（８）式、（９）式の通りである。

The propagation path estimation unit 509 calculates the correlation value D (τ) according to the equation (7).

Here, T is a correlation value calculation section. Note that, during propagation path estimation, that is, during 0 ≦ t ≦ L, the sneak signal replica y ₄ (t) = 0, so that the signal z ₁ (t) after frequency conversion used in propagation path estimation and the correlation value D ( τ) is as shown in equations (8) and (9), respectively.

The propagation path estimation unit 509 further searches for M + 1 peak positions of the correlation value D (τ), and sets the second and subsequent positions as (˜τ ₁ ) to (˜τ _N ). Further, the value of the peak, respectively ~R = D _(0), and _{~h m = D (~τ m)} . In general, since the correlation value D (τ) includes an erroneous response and a noise component, a threshold value is often provided when searching for the peak position.

このとき、相関値Ｄ（τ）は遅延時間τが一致した回り込み信号のみが抽出され、図６に示すようにＤ（τ）はτ＝０，τ_１・・・τ_ＮのＮ＋１個のピークを持ち、それぞれの値はＲおよびｈ_ｍとなる。したがって、生成する回り込み信号の数Ｍが回り込み信号の総数Ｎと同じかそれ以上であり、ｘ_１（ｔ）の自己相関特性が理想的であれば、Ｒおよびｈ_ｍは誤差なく推定できる。そして、受信部５０７への入力信号ｙ_５（ｔ）は、（１１）式となり、回り込み信号成分をゼロにすることができ、デュプレクサやＲＦスイッチを用いずに送受信信号の分離を実現することができる。

Next, a propagation path estimation result when the autocorrelation characteristic of x ₁ (t) is ideal will be described. The ideal autocorrelation characteristic is defined by equation (10).

At this time, only the sneak signal having the same delay time τ is extracted as the correlation value D (τ), and D (τ) is N + 1 peaks of τ = 0, τ ₁ ... Τ _N as shown in FIG. the Have, each value is R and h _m. Accordingly, it is equal to or greater than the total number N of the number M wraparound signals generated echo signal, if the ideal autocorrelation properties of x 1 _(t), R and h _m can no error estimation. Then, the input signal y ₅ (t) to the receiving unit 507 is expressed by equation (11), and the sneak signal component can be made zero, so that transmission / reception signal separation can be realized without using a duplexer or an RF switch. it can.

Yonezawa, Yamazaki, Ishizu, Chiba, “Removal of sneak around relay station in digital terrestrial broadcasting SFN system,” ITE Technical Report 23 (73), 11-16, 1999-11-18

As described above, if the autocorrelation characteristics are ideal, the propagation path can be correctly estimated, and the transmission signal and the reception signal can be separated. However, since the transmission signal used for estimating the propagation path is a signal for performing communication, the autocorrelation characteristic is generally poor. Therefore, in the conventional wireless communication device, the estimation accuracy is deteriorated and a predetermined signal separation degree cannot be obtained. FIG. 7 shows an example of the correlation value D (τ) in the case where the autocorrelation value becomes α at Δτ, that is, the autocorrelation characteristic as shown in the equation (12).

  As is clear from FIG. 7, when the autocorrelation characteristic is not ideal (that is, when the autocorrelation characteristic is bad), an erroneous response peak appears at a position different from the original peak, and the propagation path is estimated at the wrong position. There is a problem of end.

  The present invention has been made in view of such circumstances, and avoids deterioration in estimation accuracy in a wireless communication apparatus that separates a transmission signal and a reception signal by subtracting a sneak signal replica leaking into the reception side. An object of the present invention is to provide a wireless communication device, a wireless communication method, and a wireless communication program that can stably realize a high degree of signal separation.

  The present invention relates to an antenna for transmitting and receiving a signal, a transmission means for transmitting a transmission signal via the antenna, and a propagation path estimation for estimating a phase amplitude response of a signal that wraps around from a transmission side to a reception side in a propagation path estimation section. Means, replica generating means for generating a sneak signal replica based on the estimated phase amplitude response and the transmission signal, subtracting means for subtracting the sneak signal replica from the received signal received via the antenna, and A wireless communication apparatus that separates transmission / reception signals, and includes: , Further comprising: a propagation path estimation section determining means for determining a section where the worst value of the autocorrelation characteristic is equal to or less than a threshold as the propagation path estimation section. It is characterized in.

  The present invention is characterized in that the delay time is T, the threshold is β, the carrier frequency of the transmission signal is fc, the gain of the antenna is G, and the delay time T is determined by equation (15). .

  The present invention includes two each of the replica generation means and the subtraction means, and generates the replica for each of the signal before the reception process and the signal after the reception process. The transmission / reception signal is separated using a pair of means and a subtraction means.

  The present invention provides a training signal generating means for generating a predetermined training signal, a variable attenuator for suppressing transmission of the training signal from the antenna, and a nonlinear characteristic for estimating a nonlinear characteristic of the receiving means based on the training signal. An estimation unit; and a nonlinear correction unit configured to correct the nonlinear characteristic of the reception unit based on the estimated nonlinear characteristic. The training signal generation unit includes a linear operation of the transmission unit, and the reception unit includes: The training signal having a non-linear operation amplitude is generated, and the non-linear characteristic estimating unit estimates the non-linear characteristic of the receiving unit.

  According to the present invention, a second variable attenuator for restricting a wraparound of the training signal to the receiving unit, a second nonlinear characteristic estimating unit for estimating a nonlinear characteristic of the transmitting unit based on the training signal, and an estimation A second non-linear correction unit that corrects the non-linear characteristic of the transmission unit based on the non-linear characteristic, and the training signal generation unit generates the training signal having a large amplitude at which the transmission unit performs a non-linear operation, The second variable attenuator sets a value at which the receiving unit does not saturate, and the second nonlinear characteristic estimating unit estimates the nonlinear characteristic of the transmitting unit.

  The present invention relates to an antenna for transmitting and receiving a signal, a transmission means for transmitting a transmission signal via the antenna, and a propagation path estimation for estimating a phase amplitude response of a signal that wraps around from a transmission side to a reception side in a propagation path estimation section Means, replica generating means for generating a sneak signal replica based on the estimated phase amplitude response and the transmission signal, subtracting means for subtracting the sneak signal replica from the received signal received via the antenna, and A wireless communication method in a wireless communication apparatus for separating a transmission / reception signal, comprising: a reception unit configured to perform reception processing on the reception signal, wherein the self-correlation characteristic within a predetermined delay time of the transmission signal A correlation calculation step, and a channel estimation section that determines a section in which the worst value of the autocorrelation characteristic is equal to or less than a threshold as the channel estimation section And having a determining step.

  The present invention relates to an antenna for transmitting and receiving a signal, a transmission means for transmitting a transmission signal via the antenna, and a propagation path estimation for estimating a phase amplitude response of a signal that wraps around from a transmission side to a reception side in a propagation path estimation section. Means, replica generating means for generating a sneak signal replica based on the estimated phase amplitude response and the transmission signal, subtracting means for subtracting the sneak signal replica from the received signal received via the antenna, and An autocorrelation calculating step of calculating a worst value of an autocorrelation characteristic within a predetermined delay time of the transmission signal in a computer on a radio communication apparatus that separates transmission / reception signals, and receiving means that performs reception processing on the reception signal And a channel estimation section determination step for determining a section where the worst value of the autocorrelation characteristic is equal to or less than a threshold as the channel estimation section. Characterized in that to perform the flop.

According to the present invention, by determining the propagation path estimation section in consideration of the autocorrelation characteristics, the erroneous response at the time of propagation path estimation can be suppressed to a certain level or less. Thus, an effect that a high degree of signal separation can be realized is obtained.
In addition, by sharing the generation of the wraparound signal replica between the analog unit and the digital unit, it is possible to realize a high signal separation degree while suppressing the apparatus cost.
In addition, by correcting the nonlinear characteristics of the receiver, it becomes possible to operate even at high input levels where the receiver operates nonlinearly, and the number of signal replicas generated and subtracted by the analog unit can be reduced, reducing the device cost. Can be realized.
Further, by correcting the nonlinear characteristic of the transmission unit, the transmission unit can be operated in a non-linear manner, so that the apparatus cost can be reduced.

It is a block diagram which shows the structure of the 1st Embodiment of this invention. It is a block diagram which shows the structure of the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the 3rd Embodiment of this invention. It is a block diagram which shows the structure of the 4th Embodiment of this invention. It is a block diagram which shows the structure of the radio | wireless communication apparatus by a prior art. It is a simulation result of the conventional multiuser receiving apparatus and the multiuser receiving apparatus according to the present invention, and is a diagram showing the complementary cumulative probability of SINR of the output signal y _m (t) of the signal separation circuit. It is a simulation result of the conventional multiuser receiving apparatus and the multiuser receiving apparatus according to the present invention, and is a diagram showing the complementary cumulative probability of SINR of the output signal y _m (t) of the signal separation circuit.

<First Embodiment>
Hereinafter, a wireless communication apparatus according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment. As shown in FIG. 1, the wireless communication apparatus includes a modulation unit 101, a transmission unit 102, a distributor 103, a transmission / reception shared circuit 104, an antenna 105, a replica generation unit 106, a subtraction unit 107, a reception unit 108, a propagation path estimation unit 109, It comprises a demodulator 110, an autocorrelation calculator 111, and a propagation path estimation interval determiner 112.

  Next, the operation of the wireless communication apparatus shown in FIG. 1 will be described with reference to FIG. The wireless communication apparatus modulates a signal to be transmitted by the modulation unit 101, generates a digital transmission signal, and performs conversion to an analog signal and frequency conversion by the transmission unit 102. Then, the transmission signal frequency-converted by the distributor 103 is distributed into two, and one is output to the transmission / reception shared circuit 104 and the other is output to the replica generation unit 106. The shared transmission / reception circuit 104 outputs the transmission signal supplied from the distributor 103 to the antenna 105 for transmission, and outputs the reception signal received by the antenna 105 to the subtraction unit 107.

  The replica generation unit 106 generates a wraparound signal replica based on the propagation path information estimated by the propagation path estimation unit 109. The subtraction unit 107 subtracts the output signal of the replica generation unit from the output signal of the shared transmission / reception circuit 104. The receiving unit 108 performs frequency conversion and digital signal conversion on the received signal. The output signal of the reception unit 108 is estimated by the propagation path estimation unit 109 and demodulated by the demodulation unit 110. The autocorrelation detection unit 111 calculates the autocorrelation of the transmission signal output from the modulation unit 101, and the propagation path estimation interval determination unit 112 performs propagation path estimation based on the autocorrelation value calculated by the autocorrelation calculation unit 111. Determine the interval.

  Next, detailed operations of the autocorrelation calculation unit 111 and the propagation path estimation interval determination unit 112 will be described using mathematical expressions. The modulation unit 101, transmission unit 102, distributor 103, transmission / reception shared circuit 104, replica generation unit 106, subtraction unit 107, reception unit 108, propagation path estimation unit 109, and demodulation unit 110 shown in FIG. Are similar to those of the modulation unit 501, the transmission unit 502, the distributor 503, the transmission / reception shared circuit 504, the replica generation unit 506, the subtraction unit 507, the reception unit 508, the propagation path estimation unit 509, and the demodulation unit 510 shown in FIG. Then, detailed description is abbreviate | omitted.

The autocorrelation detection unit 111 calculates the worst value of the autocorrelation characteristics in the correlation value calculation section T according to the equation (13).

The propagation path estimation interval determination unit 112 detects a time t ₀ when the correlation value calculated by the autocorrelation calculation unit 111 satisfies the expression (14), and sets t ₀ to t ₀ + L as the propagation path estimation interval. That is, in the autocorrelation characteristic, when an erroneous response peak appears at a position different from the original peak, the value of _Cmax increases, indicating that the autocorrelation characteristic is poor. Based on the fact that this value is a certain value or less, by not performing channel estimation during other periods, it is possible to avoid degradation in channel estimation accuracy due to erroneous responses. Here, β is the same value as the threshold value used when searching for the peak position of the correlation value D (τ) in the propagation path estimation unit 109, and is determined according to the signal separation of transmission / reception to be achieved. By determining the propagation path estimation section in this way, the maximum value of erroneous response at the time of propagation path estimation can be suppressed to β or less.

The correlation value calculation section T used in the propagation path estimation unit 109 is set based on the equation (15). By setting as shown in the equation (15), it is possible to avoid the occurrence of a sneak wave due to the short correlation value calculation section T while suppressing the occurrence of an erroneous response due to the correlation value calculation section T being too long.

The reason is as follows. The attenuation Q of the signal transmitted from the antenna 105, reflected by the object of the distance d, and received by the antenna 105 again is the best propagation state that can be seen between the antenna and the object (meaning the sneak in the transmitted signal) In the worst case, it is expressed by the equation (16) using the Friis formula.

Here, c is the speed of light. Further, the time Δt required to reciprocate the distance d is as shown in equation (17).

Substituting equation (16) into equation (17) yields equation (18).

  In order not to detect a response outside the correlation value calculation section T, the attenuation amount Q needs to be equal to or less than the threshold value β at the worst. Therefore, when Q = β is established, Equation (15) is derived.

  As explained in detail above, by determining the propagation path estimation section in consideration of the autocorrelation characteristics, the error response becomes less than the threshold value β during propagation path estimation. High signal separation can be achieved.

<Second Embodiment>
Next, a radio communication apparatus according to the second embodiment of the present invention will be described. FIG. 2 is a block diagram showing a configuration of the wireless communication apparatus according to the second embodiment of the present invention. 2 includes a modulation unit 101, a transmission unit 102, a distributor 103, a transmission / reception shared circuit 104, an antenna 105, a replica generation unit 106, a subtraction unit 107, a reception unit 108, a propagation path estimation unit 109, and a demodulation unit. 110, an autocorrelation calculation unit 111, a propagation path estimation interval determination unit 112, a second replica generation unit 201, and a second subtraction unit 202.

  Next, the operation of the wireless communication apparatus shown in FIG. 2 will be described with reference to FIG. The radio communication apparatus shown in FIG. 2 performs modulation by the modulation unit 101 to generate a digital transmission signal, and the transmission unit 102 performs conversion to an analog signal and frequency conversion. Then, the transmission signal frequency-converted by the distributor 103 is distributed into two, and one is output to the transmission / reception shared circuit 104 and the other is output to the replica generation unit 106. The transmission / reception shared circuit 104 outputs the transmission signal supplied from the distributor to the antenna 105 and outputs the reception signal received by the antenna 105 to the subtraction unit 107. The replica generation unit 106 generates a wraparound signal replica based on the propagation path information estimated by the propagation path estimation unit 109.

  The subtraction unit 107 subtracts the output signal of the replica generation unit 106 from the output signal of the shared transmission / reception circuit 104. The receiving unit 108 performs frequency conversion and conversion to a digital signal on the received signal, and the propagation path estimation unit 109 estimates the propagation path. The second replica generation unit 201 generates a replica of the sneak signal that was not generated by the replica generation unit 106 among the sneak signals estimated by the propagation path estimation unit 109. The second subtraction unit 202 subtracts the output signal of the second replica generation unit 201 from the output signal of the reception unit 108. The demodulator 110 performs demodulation based on the output signal of the second subtractor 202. The autocorrelation detection unit 111 calculates the autocorrelation of the transmission signal output from the modulation unit 101, and the propagation path estimation interval determination unit 112 performs propagation path estimation based on the autocorrelation value calculated by the autocorrelation calculation unit 111. Determine the interval.

  The wireless communication device shown in FIG. 2 is different from the wireless communication device shown in FIG. 1 in that the replica generation of the sneak signal estimated by the propagation path estimation unit 109 is shared by the second replica generation unit 201 and the replica generation unit 106. It is. The operations of the second replica generation unit 201 and the second subtraction unit 202 are the same as those of the replica generation unit 106 and the subtraction unit 107 described above, respectively.

  Since the replica generation unit 106 described above handles an analog signal, the replica generation unit 106 includes an analog element group such as a set of phase shifters, delay lines, and variable attenuators for each generated sneak signal replica. Therefore, the cost increases in proportion to the number M of sneak signal replicas to be generated. In addition, since the accuracy of the sneak signal replica generated due to manufacturing errors of these elements is low, the signal separation of transmission and reception cannot be increased beyond a certain level.

  On the other hand, since the second replica generation unit 201 that handles a signal after digital conversion is configured with a digital circuit, the cost is low even when the number of sneak signal replicas to be generated increases, and the sneak signal replica generation accuracy is also very high. Very expensive. However, if the receiving unit 108 is saturated, it cannot be operated correctly.

  Therefore, in the wireless communication apparatus shown in FIG. 2, a sneak signal replica is generated by the replica generation unit 106 for a sneak signal having a very large signal level such as a signal sneaking from the shared circuit shown in the first term of the equation (7). The signal is suppressed by the subtracting unit 107, transmitted from the antenna 105 shown in the second term of the equation (7), reflected on a nearby object, and received again by the antenna 105, but there are many numbers one by one. With respect to a sneak signal having a low level, a sneak signal replica is generated by the second replica generation unit 201 and is suppressed by the second subtraction unit 202, whereby a high signal separation degree can be realized while suppressing the apparatus cost.

<Third Embodiment>
Next, a wireless communication apparatus according to the third embodiment of the present invention is described. FIG. 3 is a lock diagram showing the configuration of the wireless communication apparatus according to the third embodiment of the present invention. 3 includes a modulation unit 101, a transmission unit 102, a distributor 103, a transmission / reception shared circuit 104, an antenna 105, a replica generation unit 106, a subtraction unit 107, a reception unit 108, a propagation path estimation unit 109, and a demodulation unit. 110, autocorrelation calculation unit 111, propagation path estimation interval determination unit 112, second replica generation unit 201, second subtraction unit 202, training signal generation unit 301, variable attenuator 302, nonlinear characteristic estimation unit 303, nonlinear characteristic correction Part 304.

  Next, the operation of the wireless communication apparatus shown in FIG. 3 will be described with reference to FIG. In the wireless communication apparatus shown in FIG. 3, modulation is performed by the modulation unit 101 and the training signal generation unit 301, a digital transmission signal is generated, and conversion to an analog signal and frequency conversion are performed by the transmission unit 102. Then, the transmission signal frequency-converted by the distributor 103 is distributed into two, and one is output to the transmission / reception shared circuit 104 and the other is output to the replica generation unit 106. The transmission / reception shared circuit 104 outputs the transmission signal supplied from the distributor to the antenna 105 and outputs the reception signal received by the antenna 105 to the subtraction unit 107. A variable attenuator 302 is connected between the transmission / reception shared circuit 104 and the antenna 105 to attenuate the input signal by a set value. The replica generation unit 106 generates a wraparound signal replica based on the propagation path information estimated by the propagation path estimation unit 109.

  The subtraction unit 107 subtracts the output signal of the replica generation unit 106 from the output signal of the shared transmission / reception circuit 104. The receiving unit 108 performs frequency conversion and digital signal conversion on the received signal. The nonlinear characteristic estimation unit 303 estimates the nonlinear characteristic using the output signal of the receiving unit 108, and the nonlinear characteristic correction unit 304 corrects the nonlinear characteristic. The second replica generation unit 201 generates a replica of the sneak signal that was not generated by the replica generation unit 106 among the sneak signals estimated by the propagation path estimation unit 109. The second subtraction unit 202 subtracts the output signal of the second replica generation unit 201 from the output signal of the nonlinear characteristic correction unit 304. The demodulator 110 performs demodulation based on the output signal of the second subtractor 202. The autocorrelation detection unit 111 calculates the autocorrelation of the transmission signal output from the modulation unit 101, and the propagation path estimation interval determination unit 112 performs propagation path estimation based on the autocorrelation value calculated by the autocorrelation detection unit 111. Determine the interval.

  The wireless communication device shown in FIG. 3 differs from the wireless communication device shown in FIG. 2 in that the training signal generator 301, the variable attenuator 302, the nonlinear characteristic estimation unit 303, and the nonlinear characteristic correction unit 304 are used. The point is to estimate and correct the nonlinear characteristic. Note that a digital transmission signal is generated by the training signal generation unit 301 during a period in which the nonlinear characteristic is estimated, and by the modulation unit 101 during other periods. As the training signal generated by the training signal generation unit 301, a signal that covers a range from a sufficiently small level to a level at which the reception unit 108 operates nonlinearly but does not saturate is used.

  The attenuation amount of the variable attenuator 302 is set to a sufficiently large value during the period for estimating the non-linear characteristics, and set to 0 during the other periods. Since the transmission from the antenna is suppressed by setting the attenuation amount of the variable attenuator 302 connected to the antenna 105 to a sufficiently large value in this way, the training signal generation unit 301 performs nonlinearity during the period for estimating the nonlinear characteristics. An arbitrary training signal suitable for characteristic estimation can be generated, and the nonlinear characteristic can be estimated easily and with high accuracy using the training signal.

  At this time, since the variable attenuator 302 also suppresses the reception of unnecessary signals other than the training signal from the antenna, the nonlinear characteristic can be estimated with high accuracy. In addition, a known method such as a polynomial approximation method or a method using a lookup table can be used for the estimation of the nonlinear characteristic in the nonlinear characteristic estimation unit 303 and the correction of the nonlinear characteristic in the nonlinear characteristic correction unit 304.

  The second replica generation unit 201 and the second subtraction unit 202 can completely suppress the remaining sneak signal if the reception unit 108 is in the linear operation region. Therefore, in the wireless communication apparatus illustrated in FIG. 2, it is necessary to lower the sneak signal to a level at which the reception unit 108 operates linearly by the second replica generation unit 201 and the second subtraction unit 202. Therefore, it is necessary to increase the number and precision of the sneak signal replicas generated by the second replica generation unit 201 to a certain level or more, and the cost of the second replica generation unit 201 cannot be decreased to a certain level or more.

  Therefore, in the wireless communication apparatus shown in FIG. 3, the nonlinear correction characteristic estimation unit 303 uses a training signal generation unit 301 that can generate an arbitrary signal and a variable attenuator 302 that suppresses transmission and reception of signals from the antenna 105. The non-linear characteristic 108 is estimated with high accuracy, and is corrected by the non-linear characteristic correcting unit 304, thereby reducing the number of sneak signal replicas generated by the second replica generating unit 201 and the required accuracy. Thereby, compared with the radio | wireless communication apparatus shown in FIG. 2, a high signal-separation degree is further realizable, suppressing apparatus cost.

<Fourth Embodiment>
Next, a wireless communication apparatus according to the fourth embodiment of the present invention is described. FIG. 4 is a block diagram showing a configuration of a wireless communication apparatus according to the fourth embodiment of the present invention. 4 includes a modulation unit 101, a transmission unit 102, a distributor 103, a transmission / reception shared circuit 104, an antenna 105, a replica generation unit 106, a subtraction unit 107, a reception unit 108, a propagation path estimation unit 109, and a demodulation unit. 110, autocorrelation calculation unit 111, propagation path estimation interval determination unit 112, second replica generation unit 201, second subtraction unit 202, training signal generation unit 301, variable attenuator 302, nonlinear characteristic estimation unit 303, nonlinear characteristic correction Unit 304, second variable attenuator 401, second nonlinear characteristic estimation unit 402, and second nonlinear characteristic correction unit 403.

  Next, the operation of the wireless communication apparatus shown in FIG. 4 will be described with reference to FIG. In the wireless communication apparatus shown in FIG. 4, modulation is performed by the modulation unit 101 and the training signal generation unit 301 to generate a digital transmission signal, and conversion to an analog signal and frequency conversion are performed by the transmission unit 102. The second nonlinear characteristic estimation unit 402 estimates the nonlinear characteristic of the transmission unit 102 using the output signal of the reception unit 108, and the second nonlinear characteristic correction unit 403 corrects the nonlinear characteristic of the transmission unit 102. Then, the transmission signal frequency-converted by the distributor 103 is distributed into two, and one is output to the transmission / reception shared circuit 104 and the other is output to the replica generation unit 106. The shared transmission / reception circuit 104 outputs the transmission signal supplied from the distributor 103 to the antenna 105 and outputs the reception signal received by the antenna 105 to the subtraction unit 107. A variable attenuator 302 is connected between the transmission / reception shared circuit 104 and the antenna 105 to attenuate the input signal by a set value.

  A second variable attenuator 302 is connected between the transmission / reception shared circuit 104 and the subtraction unit 107, and attenuates the input signal by a set value. The replica generation unit 106 generates a wraparound signal replica based on the propagation path information estimated by the propagation path estimation unit 109. The subtraction unit 107 subtracts the output signal of the replica generation unit 106 from the output signal of the shared transmission / reception circuit 104. The receiving unit 108 performs frequency conversion and digital signal conversion on the received signal. The nonlinear characteristic estimation unit 303 estimates the nonlinear characteristic using the output signal of the receiving unit 108, and the nonlinear characteristic correction unit 304 corrects the nonlinear characteristic of the output signal of the receiving unit 108.

  The second replica generation unit 201 generates a replica of the sneak signal that was not generated by the replica generation unit 106 among the sneak signals estimated by the propagation path estimation unit 109. The second subtraction unit 202 subtracts the output signal of the second replica generation unit from the output signal of the nonlinear characteristic correction unit 304. The demodulator 110 performs demodulation based on the output signal of the second subtractor 202. The autocorrelation detection unit 111 calculates the autocorrelation of the transmission signal output from the modulation unit 101, and the propagation path estimation interval determination unit 112 performs propagation path estimation based on the autocorrelation value calculated by the autocorrelation detection unit 111. Determine the interval.

  The wireless communication device shown in FIG. 4 is different from the wireless communication device shown in FIG. 3 in that the second variable attenuator 401, the second nonlinear characteristic estimation unit 402, and the second nonlinear characteristic correction unit 403 are used for transmission. The nonlinear characteristic of the unit 102 is estimated and corrected. Note that a digital transmission signal is generated by the training signal generation unit 301 during a period in which the nonlinear characteristic of the transmission unit 102 is estimated, and by the modulation unit 101 during other periods. As the training signal generated by the training signal generation unit 301, a signal that covers from a sufficiently small level to a level at which the transmission unit 102 performs non-linear operation but does not saturate is used. The attenuation amount of the second variable attenuator 401 is set to a value that does not saturate the receiving unit 108 during the period in which the nonlinear characteristic is estimated, and is set to 0 during other periods.

  In the wireless communication apparatus shown in FIG. 3, the non-linear characteristic of the receiving unit 108 is corrected by the non-linear characteristic correcting unit 304, so that the remaining sneak signal can be completely suppressed even at a high reception level where the receiving unit 108 operates in a non-linear manner. it can. However, when the transmission unit 102 operates in a non-linear manner, the sneak signal replica generated by the second replica generation unit 201 is different from the sneak signal actually received by the reception unit 108, and thus the sneak signal cannot be completely suppressed. Therefore, in the wireless communication apparatus shown in FIG. 3, it is necessary to use the transmission unit 102 that performs linear operation, and the cost cannot be reduced beyond a certain level.

  Therefore, in the wireless communication apparatus shown in FIG. 4, the second nonlinear estimator 402 uses the second variable attenuator 401 that adjusts the reception level so that the receiver 108 does not saturate, and the nonlinear characteristic of the transmitter 102 is increased. By estimating the accuracy and correcting by the second nonlinear correction unit 403, the sneak signal can be completely suppressed even if the transmission unit 102 operates nonlinearly. Thereby, compared with the radio | wireless communication apparatus shown in FIG. 3, apparatus cost can be suppressed further.

  As described above, in a wireless communication apparatus that performs transmission and reception simultaneously, there is a problem in that interference occurs when a transmission signal wraps around a reception circuit. In the prior art, a wraparound interference is removed by generating a replica of an interference signal from a transmission signal and subtracting the replica of the interference signal from a reception signal. However, in this technique, when the autocorrelation of the transmission signal is bad, there is a problem that the accuracy of interference removal is low because a false detection may occur in the correlation detection at the time of propagation path estimation. In the wireless communication apparatus described above, the autocorrelation of the transmission signal is calculated, and the correlation detection of the propagation path estimation is performed only during the period when the autocorrelation is not bad. In addition, by limiting the processing period of cross-correlation detection to a period in which the propagation loss of reflected waves from nearby objects may exceed the threshold β, the estimation of reflected waves necessary to achieve a predetermined signal separation degree The occurrence of false responses was suppressed while avoiding oversight. With this configuration, it is possible to avoid erroneous detection that occurs when the autocorrelation of the transmission signal is bad and to improve the accuracy of interference removal.

  Note that a program for realizing the function of the processing unit in FIG. 1 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed to execute wireless communication processing. You may go. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Further, the “computer-readable recording medium” refers to a volatile memory (RAM) in a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In addition, those holding programs for a certain period of time are also included.

  The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, what is called a difference file (difference program) may be sufficient.

  As mentioned above, although embodiment of this invention has been described with reference to drawings, the said embodiment is only the illustration of this invention, and it is clear that this invention is not limited to the said embodiment. is there. Accordingly, additions, omissions, substitutions, and other modifications of components may be made without departing from the spirit and scope of the present invention.

  In a wireless communication apparatus that separates a transmission signal and a reception signal by subtracting a sneak signal replica leaking into the reception side, it is also possible to apply a use in which it is indispensable to stably realize a high signal separation degree.

  DESCRIPTION OF SYMBOLS 101 ... Modulation part, 102 ... Transmission part, 103 ... Divider, 104 ... Transmission / reception shared circuit, 105 ... Antenna, 106 ... Replica generation part, 107 ... Subtraction part, 108: receiving unit, 109 ... propagation path estimation unit, 110 ... demodulation unit, 111 ... autocorrelation calculation unit, 112 ... propagation path estimation interval determination unit, 201 ... second Replica generating unit 202 ... second subtracting unit 301 ... training signal generating unit 302 ... variable attenuator 303 ... nonlinear characteristic estimating unit 304 ... nonlinear characteristic correcting unit 401 ..Second variable attenuator, 402... Second nonlinear characteristic estimation unit, 403... Second nonlinear characteristic correction unit

Claims (7)

An antenna for transmitting and receiving signals;
Transmitting means for transmitting a transmission signal via the antenna;
Propagation path estimation means for estimating a phase amplitude response of a signal sneaking from the transmission side to the reception side in the propagation path estimation section;
Replica generating means for generating a wraparound signal replica based on the estimated phase amplitude response and the transmission signal;
Subtracting means for subtracting the sneak path replica from the received signal received via the antenna;
Receiving means for performing a reception process on the received signal after subtraction, and a wireless communication device that separates transmission and reception signals,
Autocorrelation calculating means for calculating a worst value of autocorrelation characteristics within a predetermined delay time of the transmission signal;
A wireless communication apparatus, further comprising: a propagation path estimation section determining unit that determines, as the propagation path estimation section, a section in which the worst value of the autocorrelation characteristic is equal to or less than a threshold value. The delay time is T, the threshold is β, the carrier frequency of the transmission signal is fc, and the gain of the antenna is G.
The delay time T is

The wireless communication device according to claim 1, wherein the wireless communication device is determined by the following. Two each of the replica generation means and the subtraction means,
The transmission / reception signal is separated using a pair of the replica generation unit and the subtraction unit for each of the signal before the reception process and the signal after the reception process. The wireless communication apparatus according to claim 1, wherein the wireless communication apparatus is a wireless communication apparatus. Training signal generating means for generating a predetermined training signal;
A variable attenuator for suppressing transmission of the training signal from the antenna;
Nonlinear characteristic estimating means for estimating nonlinear characteristics of the receiving means based on the training signal;
A non-linear correction means for correcting the non-linear characteristic of the receiving means based on the estimated non-linear characteristic;
The training signal generating means generates the training signal having an amplitude at which the transmitting means operates linearly and the receiving means operates nonlinearly, and the nonlinear characteristic estimating means estimates the nonlinear characteristics of the receiving means. The wireless communication apparatus according to claim 3, wherein: A second variable attenuator for restricting wraparound of the training signal to the receiving means;
Second nonlinear characteristic estimation means for estimating nonlinear characteristics of the transmission means based on the training signal;
Second nonlinear correction means for correcting the nonlinear characteristic of the transmission means based on the estimated nonlinear characteristic;
The training signal generating means generates the training signal having a large amplitude at which the transmitting means operates nonlinearly, the second variable attenuator sets a value at which the receiving means does not saturate, and the second nonlinear characteristic estimation The wireless communication apparatus according to claim 4, wherein the unit estimates a nonlinear characteristic of the transmission unit. An antenna for transmitting and receiving signals;
Transmitting means for transmitting a transmission signal via the antenna;
Propagation path estimation means for estimating a phase amplitude response of a signal sneaking from the transmission side to the reception side in the propagation path estimation section;
Replica generating means for generating a wraparound signal replica based on the estimated phase amplitude response and the transmission signal;
Subtracting means for subtracting the sneak path replica from the received signal received via the antenna;
A wireless communication method in a wireless communication device for separating a transmission / reception signal, comprising: reception means for performing reception processing on the reception signal after subtraction;
An autocorrelation calculating step of calculating a worst value of autocorrelation characteristics within a predetermined delay time of the transmission signal;
A wireless communication method comprising: a propagation path estimation section determining step for determining a section where the worst value of the autocorrelation characteristic is equal to or less than a threshold as the propagation path estimation section. An antenna for transmitting and receiving signals;
Transmitting means for transmitting a transmission signal via the antenna;
Propagation path estimation means for estimating a phase amplitude response of a signal sneaking from the transmission side to the reception side in the propagation path estimation section;
Replica generating means for generating a wraparound signal replica based on the estimated phase amplitude response and the transmission signal;
Subtracting means for subtracting the sneak path replica from the received signal received via the antenna;
A reception unit that performs reception processing on the received signal after subtraction, and a computer on a wireless communication device that separates transmission and reception signals,
An autocorrelation calculating step of calculating a worst value of autocorrelation characteristics within a predetermined delay time of the transmission signal;
A radio communication program, comprising: performing a channel estimation section determining step of determining a section in which the worst value of the autocorrelation characteristic is equal to or less than a threshold as the channel estimation section.

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