JP6016289B2 - Signal separation device - Google Patents

Description

  The present invention relates to a technique for separating an interference communication signal used on a receiving side of a wireless communication apparatus.

  In recent years, in a wireless communication system, improvement in frequency use efficiency is required for effective utilization of limited radio wave resources. For that purpose, it is desirable to transmit in a state where a plurality of signals are mixed in the same frequency, and the receiver needs a function of easily separating the interference signals.

  When the radio waves that have interfered with each other arrive from different directions, it is possible to separate the interference signals based on the arrival directions. For example, Patent Document 1 discloses a technique for performing signal separation by independent component analysis.

  Further, Patent Document 2 proposes a method of bidirectional communication at the same frequency in order to improve the bandwidth utilization rate in satellite communication. In this communication method, two ground stations transmit signals in the same band to the same communication satellite, and the two signals are mixed and received in the satellite.

  Since the interference signal is directly frequency-converted and transmitted to the ground station, the ground station cannot perform signal separation based on the direction of arrival. Therefore, the ground station uses the transmission signal of its own station as a replica of one of the interference signals, and subtracts this from the received signal to separate the signals of the other stations.

  Patent Document 3 discloses a multiple access communication system in which the capacity is increased by removing interference inside and outside the cell. In the system, channels of the same frequency are used in adjacent cells or neighboring cells, while each receiver detects all signals by demodulating the received power in descending order and repeating the process of canceling its own signal. Making it possible.

  Patent Document 4 discloses a technique for simultaneously transmitting a burst mode high power video signal and a small power audio signal via the same frequency band in satellite digital video communication or the like. In this technology, a high-power signal in burst mode and a signal in which a low-power signal is superimposed are received, a high-power signal is detected from the received signal, and a replica of the high-power signal is generated only when a high-power signal is detected. To eliminate interference. According to the interference removal method, it is possible to prevent the replica signal of the high power signal from becoming an interference signal for the low power signal.

  Patent Document 5 discloses a signal separation technique that enables a signal to be separated and extracted with a small amount of calculation in a transmission method in which a large number of signals are multiplexed on the same frequency.

JP 2008-92363 A US Pat. No. 6,859,641 JP 2003-209879 A Japanese Patent Laid-Open No. 06-244746 JP 2007-97103 A

  However, in order to achieve signal separation by the signal separation technique according to the background art, a circuit for storing its own transmission signal as a replica may be required. In some cases, the transmission signal of the receiver cannot be stored as a replica due to the limitation of the memory capacity of the receiver, and there is a problem that it is not possible to separate an interference signal composed of a plurality of signals transmitted from the same direction.

  Further, in the signal separation technology according to the background art, there is a problem in that the accuracy of the replica generated for separating each signal from the interference signal including a plurality of signals transmitted from the same direction does not increase, and the signal separation cannot be performed appropriately. was there.

  In view of the above problems, the present invention provides a signal separation device and a signal separation method capable of separating a signal with high accuracy without depending on the arrival direction of each component of an interference signal for a receiver having no replica. The purpose is to provide.

  A signal separation device according to one aspect of the present invention includes a first signal separation unit that separates a signal from an interference signal including a plurality of signals in a first order, and a second signal that is different from the first order from the interference signal. The second signal separation means for separating the signals in this order, and a plurality of signals separated by the first signal separation means or a plurality of signals separated by the second signal separation means are selected and output Selecting means.

  According to the present invention, it is possible to provide a signal separation device and a signal separation method capable of separating a signal with high accuracy without depending on the arrival direction of each component of the interference signal for a receiver having no replica. Can do.

1 is a block diagram illustrating a configuration of a signal separation device according to a first embodiment. 3 is a block diagram showing a specific configuration of an adaptive canceller according to Embodiment 1. FIG. 6 is a block diagram illustrating a configuration of a signal separation device according to a second embodiment. FIG. FIG. 6 is a block diagram illustrating specific configurations of a first demodulator and a first modulator of a signal separation device according to a second embodiment. FIG. 10 is a block diagram illustrating a configuration of a signal separation device according to a third embodiment. FIG. 10 is a block diagram illustrating an overall configuration of a signal separation device according to a fourth embodiment. FIG. 10 is a block diagram illustrating a configuration of a first signal separation device according to a fourth embodiment. It is a block diagram which shows the structure of the signal separation apparatus of this invention. It is a flowchart figure which shows the flow of a process of the signal separation method of this invention. It is a block diagram which shows the structure of the signal separation apparatus of another form of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. The following description shows preferred embodiments of the present invention, and the scope of the present invention is not limited to the following embodiments. In the following description, the same reference numerals indicate substantially the same contents.

(Embodiment 1)
Embodiment 1 of the present invention will be described below with reference to the drawings. The signal separation device according to the first embodiment is a device that receives an interference signal output from a reception device arranged in the preceding stage, and separates and outputs a plurality of signals included in the interference signal.

  The reception device performs various reception processes such as filter processing, amplification processing, and mixing processing on the reception signal received by the antenna, and outputs the interference signal after the reception processing to the signal separation device.

  Since the receiving device receives a signal in which a plurality of signals are superimposed on the wireless transmission path, the interference signal includes a plurality of signals. In the following description, it is assumed that the first signal and the second signal are superimposed on the interference signal. However, the present invention is not limited to this, and more signals may be superimposed.

  Further, it is assumed that each signal included in the interference signal is subjected to error correction code processing and modulation processing on the transmission device side.

  FIG. 1 is a block diagram showing a configuration of a signal separation device 100 according to Embodiment 1 of the present invention.

  The signal separation device 100 includes a first demodulator 110, a first decoder 120, a first encoder 130, a first modulator 140, a first adaptive canceller 150, a second demodulator 160, and a second demodulator. And a decoder 170.

  The first demodulator 110 demodulates the first signal included in the interference signal. First demodulator 110 outputs the demodulated signal to first decoder 120.

  Here, the first demodulator 110 demodulates the first signal based on the signal strength from the interference signal including a plurality of signals. More specifically, the first demodulator 110 focuses on the signal strength of a plurality of signals included in the interference signal and demodulates the first signal having the highest strength.

  The first decoder 120 estimates the information sequence of the first signal by decoding the output from the first demodulator 110. The signal demodulated by the first demodulator 110 is subjected to error correction decoding by the decoder 120, thereby estimating a high-quality information sequence related to the first signal. The information sequence of the first signal decoded by the first decoder 120 is sent to various applications as received data, and is output to the first encoder 130.

  In the following description, it is assumed that the first demodulator 110 and the first decoder 120 together are means for estimating an information sequence of a first signal based on signal strength from an interference signal including a plurality of signals. Sometimes referred to as first information sequence estimation means.

  The first encoder 130 re-encodes the information sequence of the first signal decoded by the first decoder 120.

  The first modulator 140 re-modulates the information sequence estimated by re-encoding by the first encoder 130 to generate a replica of the first signal.

  In the following description, the first encoder 130 and the first modulator 140 are combined to be a replica of the first signal based on the information sequence of the first signal estimated by the first information sequence estimation means. The means for generating the first replica signal may be referred to as first replica generation means.

  The first adaptive canceller 150 estimates the difference in amplitude and phase between the first signal component in the interference signal and the first replica signal, and corrects the first replica signal so that the difference is minimized. The first adaptive canceller 150 extracts the second signal component by subtracting the corrected first replica signal from the interference signal. The first adaptive canceller 150 outputs the extracted second signal component to the second demodulator 160.

  Second demodulator 160 demodulates the second signal component extracted by first adaptive canceller 150 and outputs the demodulated signal to second decoder 170.

  The second decoder 170 performs error correction decoding on the signal demodulated by the second demodulator 160, thereby estimating a high-quality information sequence related to the second signal.

  In the following description, the second demodulator 160 and the second decoder 170 are combined to estimate the information sequence of the second signal from the output signal of the first adaptive canceller 150 obtained by subtracting the first replica signal from the interference signal. This means is sometimes referred to as second information sequence estimation means.

  Next, the operation of the first adaptive canceller 150 shown in FIG. 1 will be described with reference to FIG. The first adaptive canceller 150 performs a cancellation process for subtracting the first replica signal from the interference signal. FIG. 2 is a block diagram showing a configuration of the first adaptive canceller 150. The first adaptive canceller 150 includes a delay device 151, an adaptive filter 152, and an adder 153.

  Delay device 151 delays the input interference signal and outputs the delayed interference signal to adder 153. The delay unit 151 adds an amount of delay corresponding to the delay generated by the first demodulator 110, the first decoder 120, the first encoder 130, and the first modulator 140 to the interference signal, thereby adding to the interference signal. The time difference between the first signal component included and the replica signal is eliminated.

  The adaptive filter 152 corrects the amplitude and phase of the first replica signal that is the output from the first modulator 140. The adaptive filter 152 outputs the corrected first replica signal to the adder 153.

  The adder 153 removes the first signal component included in the mixed signal by subtracting the corrected first replica signal input from the adaptive filter 152 from the delayed interference signal input from the delay unit 151, and Extract signal components.

  As described above, the first adaptive canceller 150 receives the interference signal to be input for the time required from when the interference signal is input to the first information sequence estimation unit to when the first replica signal is output from the first replica generation unit. Delay unit 151 for delaying, adaptive filter 152 for correcting the amplitude and phase of the first replica signal, and adder 153 for subtracting the first replica signal corrected by adaptive filter 152 from the interference signal delayed by delay unit 151 And comprising.

  The first adaptive canceller 150 corrects the first replica signal based on the fact that the correlation between the first replica signal and the first signal component included in the interference signal is high and the correlation with the second signal component is low. The adaptive filter 152 automatically adjusts the filter coefficient so that the root mean square value (mean square error) of the difference between the first replica signal and the output of the adaptive filter 152 is minimized. This means that the mean square value of the difference between the first signal component and the replica is minimized, so that the first signal component can be removed from the interference signal.

  Note that the cancellation processing method for subtracting the first replica signal from the interference signal is not limited to the method in the first adaptive canceller 150, and the signal component of the first signal is removed using other cancellation processing methods. It can be configured.

  Also, by using an information sequence signal based on the output result of the decoder instead of the output signal from the demodulator, the signal is re-encoded and re-modulated to generate a replica of the first signal with high signal accuracy. Therefore, each signal included in the interference signal can be separated with high accuracy.

  In addition, by generating a replica based only on the intensity difference between the interference signals and separating the signal by subtracting the generated replica from the received signal, the interference signal does not depend on the arrival direction of each signal component. Can be separated.

(Embodiment 2)
Compared with the signal separation device 100 according to the first embodiment, the signal separation device 200 according to the second embodiment is characterized in that the carrier wave signal output from the demodulator is input to the modulator. Hereinafter, description will be given with reference to the drawings. However, a part of the description already given in the first embodiment will be omitted, and the difference from the first embodiment will be described.

  FIG. 3 is a block diagram showing a configuration of the signal separation device 200 according to the second embodiment. The signal separation device 200 includes a first demodulator 210, a first decoder 120, a first encoder 130, a first modulator 240, a first adaptive canceller 150, a second demodulator 160, and a second demodulator. And a decoder 170.

  The first demodulator 210 demodulates the first signal having the highest strength by paying attention to the signal strength of a plurality of signals included in the interference signal. Here, the first demodulator 210 outputs a carrier wave signal generated for demodulation to the first modulator 240.

  The first modulator 240 remodulates the information sequence of the first signal re-encoded by the first encoder 130 to generate a replica of the first signal. Here, the first modulator 240 receives the carrier signal generated by the first demodulator 210 for signal demodulation, and uses the input carrier signal to re-encode the signal re-encoded by the first encoder 130. Modulation processing is performed.

  By adopting such a configuration, the first adaptive canceller 150 at the subsequent stage can perform cancellation processing using a replica signal generated with higher accuracy, and therefore extracts the information sequence of the second signal with higher quality. Is possible.

  That is, the first adaptive canceller 150 corrects the replica signal of the first signal so that the difference from the first signal component included in the interference signal is minimized. At this time, if there is a large error in the carrier frequency of the two signals, a phenomenon that cannot be effectively corrected occurs. Therefore, in the present embodiment, by using the carrier signal of the first signal generated by the first demodulator 210 as the carrier signal of the replica signal generated by the first modulator 240, an error in the carrier frequency of the two signals. Is solved.

  Next, the operation of the first demodulator 210 and the first modulator 240 will be described in detail with reference to FIG. FIG. 4 is a block diagram showing the configuration of the first demodulator 210 and the first modulator 240 in the present embodiment.

  The first demodulator 210 includes a first multiplier 211 and a second multiplier 212, a first low-pass filter 213 and a second low-pass filter 214, a carrier regenerator 215, and a phase shifter 216. .

  The first multiplier 211 and the second multiplier 212 multiply the interference signal and the carrier wave, respectively. The first multiplier 211 demodulates the in-phase component of the interference signal before demodulation using the carrier wave generated by the carrier wave regenerator 215, and outputs the demodulated in-phase component signal to the first low-pass filter 213. The second multiplier 212 demodulates the quadrature component of the interference signal before demodulation using the carrier wave generated by the carrier regenerator 215, and outputs the demodulated quadrature component signal to the second low-pass filter 214.

  The first low-pass filter 213 blocks the high-frequency component of the in-phase component signal demodulated by the first multiplier 211 and outputs the demodulated in-phase component interference signal.

  The second low-pass filter 214 blocks the high-frequency component of the quadrature component signal demodulated by the second multiplier 212 and outputs the demodulated quadrature component interference signal.

  The carrier regenerator 215 regenerates the carrier signal of the first signal from the demodulated interference signals output from the first low pass filter 213 and the second low pass filter 214, respectively. The carrier regenerator 215 outputs the regenerated carrier signal to the first multiplier 211 and the phase shifter 216. The carrier regenerator 215 outputs the regenerated carrier signal to the first modulator 240.

  The phase shifter 216 shifts the phase of the carrier signal of the first signal by 90 °, and outputs the carrier signal after the phase shift to the second multiplier 212. Further, the phase shifter 216 outputs the carrier signal after the phase shift to the first modulator 240.

  As described above, the demodulator 210 repeats the loop for feeding back the carrier wave signal reproduced from the demodulated signal to the demodulation process, thereby following the fluctuation of the carrier frequency of the first signal and outputting the carrier wave signal with a small error. Is possible.

  Next, the first modulator 240 will be described in detail. The first modulator 240 includes a symbol converter 241, a third low-pass filter 242, a fourth low-pass filter 243, a third multiplier 244, and a fourth multiplier 245.

  The symbol converter 241 converts the information sequence of the first signal re-encoded by the first encoder 130 at the previous stage into symbol information for modulation. Of the modulation symbol information, the symbol converter 241 outputs symbol information related to the in-phase component to the third low-pass filter 242 and symbol information related to the quadrature component to the fourth low-pass filter 243.

  The third low-pass filter 242 and the fourth low-pass filter 243 respectively remove the high-frequency component of the symbol information input from the symbol converter 241 to perform waveform shaping, and each of the symbol information after waveform shaping is a third multiplier. 244 and the fourth multiplier 245.

  The third multiplier 244 multiplies the carrier signal generated by the carrier regenerator 215 of the first demodulator 210 by the symbol information of the in-phase component input from the third low-pass filter 242 to generate a modulated signal of the in-phase component. To do.

  The fourth multiplier 245 multiplies the carrier wave signal phase-shifted by the phase shifter 216 of the first demodulator 210 by the quadrature component symbol information input from the fourth low-pass filter 243 to generate a quadrature component modulation signal. To do. Thereafter, the in-phase component modulation signal and the quadrature component modulation signal, which are the outputs from the third multiplier 244 and the fourth multiplier 245, are combined into a first replica signal.

  As described above, the first modulator 240 modulates the carrier signal reproduced when the first demodulator 210 demodulates the first signal with the signal encoded by the first encoder 130, thereby Generate a replica signal. By using the carrier signal of the first signal reproduced by the first demodulator 210 to remodulate the information sequence of the first signal, a replica signal having a small carrier frequency error can be generated.

(Embodiment 3)
Compared with the signal separation device 200 according to the second embodiment, the signal separation device 300 according to the third embodiment is newly provided with a second adaptive canceller 350, a third demodulator 360, and a third decoder 370. The switch 380 is added to the configuration.

  The second adaptive canceller 350 receives the interference signal and the signal after cancellation processing output from the first adaptive canceller 150. Here, since the signal input from the first adaptive canceller 150 is a signal obtained by removing the signal component of the first signal from the interference signal, the signal can be regarded as a replica of the second signal.

  Therefore, in the following description, a signal output from the first adaptive canceller 150 is referred to as a second replica signal. The second adaptive canceller 350 performs a cancellation process for subtracting the second replica signal from the interference signal. The specific configuration of the second adaptive canceller 350 can be the same as that of the first adaptive canceller 150 described in FIG.

  The second adaptive canceller 350 outputs a signal in which the signal component of the first signal is more emphasized to the third demodulator 360 by subtracting the second replica signal regarded as a replica of the second signal from the interference signal. .

  The third demodulator 360 receives the signal in which the signal component of the first signal output from the adaptive canceller 350 is more emphasized, demodulates the first signal, and sends the demodulated signal to the third decoder 370. Output.

  Third decoder 370 estimates the information sequence of the first signal by decoding the demodulated signal input from third demodulator 360. The third decoder 370 outputs the estimated information sequence of the first signal to the switch 380, and outputs it to the subsequent signal processing apparatus as the finally determined information sequence of the first signal.

  In the following description, the information sequence of the first signal from the canceled signal obtained by subtracting the replica of the second signal from the interference signal including a plurality of signals by combining the third demodulator 360 and the third decoder 370. May be referred to as third information sequence estimation means.

  Therefore, the signal separation apparatus 300 according to Embodiment 3 has at least two estimation means, ie, first information sequence estimation means and third information sequence estimation means, as estimation means for estimating the information sequence of the first signal. It is characterized by having.

  The switch 380 is one of the estimation result of the information sequence of the first signal that is the output from the first decoder 120 and the estimation result of the information sequence of the first signal that is the output from the third decoder 120. One is selected and output to the first encoder 130. That is, the switch 380 switches so that the first encoder 130 is connected to either the first decoder 120 or the third decoder 370.

  Referring to FIG. 5, when the above is summarized, the signal separation device 300 includes a first information sequence estimation unit 310 that estimates an information sequence of a first signal from an interference signal including a plurality of signals, and the first signal. And a replica generation unit 320 that generates a first replica signal that is a replica of the first signal based on the information series. In addition, the signal separation device 300 generates a second replica signal that is a replica of the second signal by subtracting the first replica signal from the interference signal including a plurality of signals. The first adaptive canceller (first cancel unit) 150 And a second information sequence estimation unit 330 that estimates the information sequence of the second signal from the second replica signal. Further, the signal separation device 300 includes a second adaptive canceller (second cancellation unit) 350 that subtracts the second replica signal from the interference signal including a plurality of signals, and a second cancellation in which the second replica signal is subtracted from the interference signal. And a third information sequence estimation unit 340 that estimates an information sequence of the first signal from the output signal of the unit 350. Further, the signal separation device 300 includes a switch 380. The switch 380 selects one of the information sequence of the first signal estimated by the first information sequence estimation unit 310 or the information sequence of the first signal estimated by the third information sequence estimation unit 340. To the first replica generation unit 320. When a crosstalk signal is newly input to the signal separation device 300, the switch 380 outputs the information sequence of the first signal estimated by the first information sequence estimation unit 310 to the first replica generation unit 320. Thereafter, the information sequence of the first signal estimated by the third information sequence estimation unit 340 is switched to be output to the first replica generation unit 320. The estimation result fed back from the third information sequence estimation unit 340 has a higher probability that the information sequence of the first signal is estimated with higher accuracy than the estimation result in the first information sequence estimation unit 340. Because.

  As described above, in the signal separation device 300 according to the third embodiment, signal separation can be realized with high accuracy even when the signal strength of the interference signal is small. Specifically, in order to generate a highly accurate replica signal of the first signal, the information sequence of the first signal is estimated using the replica signal of the second signal that is the output of the first adaptive canceller 150. . By inputting the output to the switch 380, it is possible to generate the first replica signal based on the information sequence of the first signal with higher accuracy than the output of the first decoder 120. By repeating this process in a feedback manner, as a result, it is possible to realize highly accurate first and second information series signals.

  This signal separation method is particularly effective when the level difference between interference signals is small. When the level difference of the interference signal is equal to or lower than a predetermined reference, a highly accurate replica signal is generated by generating a replica of the first signal by feeding back the separated second signal as a replica signal. Can do.

  In addition, it further includes a determination unit that determines whether the level difference of the interference signal exceeds a predetermined reference value. When the level difference is less than the predetermined reference value in the determination unit, the second signal is A configuration using the signal separation method of generating a replica of the first signal by feeding back as a replica signal may be employed.

(Embodiment 4)
The signal separation device 1000 according to the fourth embodiment is characterized by having a plurality of signal separation functions for extracting information sequences from the interference signal in different orders. Hereinafter, description will be given with reference to the drawings. However, a part of the description already given in the first to third embodiments will be omitted, and the difference from the first to third embodiments will be described.

  FIG. 6 is a block diagram showing an overall configuration of a signal separation device 1000 according to the fourth embodiment. The signal separation device 1000 is roughly divided into a first signal separation device 400 that performs signal separation in a first order, a second signal separation device 500 that performs signal separation in a second order, and a first signal separation device 400. And a switcher 600 that switches and outputs the output from the second signal separation device 500.

  First, the first signal separation device 400 will be described. The first signal separation device 400 includes a first information sequence estimation unit 410, a first replica generation unit 420, a first cancellation processing unit 430, and a second information sequence estimation unit 440.

  First information sequence estimation section 410 estimates an information sequence of the first signal from an interference signal on which a plurality of signals are superimposed. First information sequence estimation section 410 outputs the estimated information sequence of the first signal to switch 600 and also outputs to first replica generation section 420.

  First replica generation section 420 generates a first replica signal from the information sequence of the first signal estimated by first information sequence estimation section 410 and outputs the generated first replica signal to first cancellation processing section 430. To do.

  First cancellation processing section 430 performs cancellation processing for removing the signal component of the first replica signal from the interference signal, and outputs the signal after the cancellation processing to second information sequence estimation section 440.

  Second information sequence estimation section 440 estimates the information sequence of the second signal from the signal after cancellation processing. Second information sequence estimation section 440 outputs the estimated information sequence of the second signal to switch 600.

  Next, the second signal separation device 500 will be described. The second signal demultiplexer 500 differs from the first signal demultiplexer 400 in the order in which the information sequence is extracted from the interference signal, and first estimates the information sequence of the second signal. Except for the above estimation order, the first signal separation device 400 and the second signal separation device 500 have the same functional configuration.

  Second signal separation apparatus 500 includes second information sequence estimation section 510, second replica generation section 520, second cancellation processing section 530, and first information sequence estimation section 540.

  Second information sequence estimation section 510 estimates an information sequence of the second signal from an interference signal on which a plurality of signals are superimposed, and switches the estimated information sequence of the second signal to switch 600 and a second replica generation section Output to 520.

  Second replica generation section 520 generates a second replica signal from the information sequence of the second signal estimated by second information sequence estimation section 510, and outputs the generated second replica signal to cancel processing section 530.

  Second cancellation processing section 530 performs cancellation processing for removing the signal component of the second replica signal from the interference signal, and outputs the signal after the cancellation processing to first information sequence estimation section 540.

  First information sequence estimation section 540 estimates the information sequence of the first signal from the signal after cancellation processing, and outputs the estimated information sequence of the first signal to switch 600.

  Note that the second information sequence estimation unit 510 and the first information sequence estimation unit 540 included in the second signal separation device 500 are the third and fourth information sequence estimation units when viewed as a whole of the signal separation device 1000. become. Therefore, in the following description, the second information sequence estimation unit 510 and the first information sequence estimation unit 540 included in the second signal separation apparatus 500 are referred to as a third information sequence estimation unit and a fourth information sequence estimation unit, respectively. There is.

  Next, the switching device 600 will be described. The switcher 600 has a function of selecting and outputting either a plurality of signals separated by the first signal separation device 400 or a plurality of signals separated by the second signal separation device 500, as will be described later. Therefore, in the following description, it may be called a selection unit.

  The switcher 600 appropriately switches the output from the first signal separation device 400 and the output from the second signal separation device 500. That is, the switcher 600 is configured such that the information sequence of the first signal previously estimated and extracted by the first signal separation device 400 or the first signal estimated and extracted later by the second signal separation device 500. One of the information series is selected, and the information series of the selected first signal is output to the subsequent stage. Similarly, the switcher 600 uses the information sequence of the second signal estimated and extracted later in the first signal separation device 400 or the second signal estimated and extracted earlier in the second signal separation device 500. Is selected, and the information sequence of the selected second signal is output to the subsequent stage.

  In this way, the switcher 600 can appropriately follow the fluctuation of the relative signal intensity by appropriately switching the output from the first signal separation device 400 or the second signal separation device 500.

  The switching function of the outputs from the two signal separation devices in the switcher 600 can be realized, for example, by comparing the communication quality of the first signal and the second signal and selecting the higher quality. As for the output of the switcher 600, the output of the communication quality estimator included in each of the first signal separation device 400 and the second signal separation device 500 is constantly monitored, so that the communication quality of the received interference signal has changed. Even when you get the best output.

  Next, an example of means for generating communication quality information will be described with reference to FIG.

  FIG. 7 is a block diagram showing the configuration of the first signal separation device 400 when a function for estimating the communication quality of the first signal is added. In FIG. 7, the first signal separation device 400 is further provided with a communication quality estimator 450.

  The first information sequence estimation unit 410 also demodulates the first signal included in the interference signal, and a decoder 412 that decodes the output of the demodulator 411 and estimates the information sequence of the first signal. And comprising. The demodulator 411 and the decoder 412 are substantially the same as the demodulator 210 and the decoder 220 in Embodiment 2, respectively, and thus description thereof is omitted.

  The first replica generation unit 420 includes an encoder 421 that re-encodes the information sequence of the first signal, and a modulator 422 that re-modulates the output of the encoder 421 and generates a replica signal. Composed. The encoder 421 and the modulator 422 are substantially the same as the encoder 230 and the modulator 240 in the second embodiment, respectively, and thus description thereof is omitted.

  Further, the cancel processing unit 430 can use the adaptive canceller 431. The configuration of adaptive canceller 431 is substantially the same as the configuration of first adaptive canceller 150 in the first embodiment, and thus the description thereof is omitted.

  The second information sequence estimation unit 440 also demodulates the output from the adaptive canceller 431, and the second decoding for estimating the second information sequence by decoding the output from the second demodulator 441. And a device 442. The second demodulator 441 and the second decoder 442 are substantially the same as the second demodulator 160 and the second decoder 170 in Embodiment 1, and thus the description thereof is omitted.

  Next, the communication quality estimator 450 will be described in detail. The communication quality estimator 450 estimates the communication quality of the first signal by calculating the bit unit difference between the output from the first demodulator 411 and the output from the first encoder 421. Communication quality estimator 450 outputs the estimated quality to switcher 600 as communication quality information of the first signal.

  When the communication quality of the first signal is high, the number of error bits corrected by the first decoder 412 is small, so that the difference between the output of the first demodulator 411 and the output of the first encoder 421 is also small. Conversely, when the communication quality is low, the difference between the outputs becomes large.

  Similarly to the first signal separation device 400 described above, the second signal separation device 500 also estimates the communication quality of the second signal to be demodulated first, and uses the estimated quality as the communication quality information of the second signal. It further includes a communication quality estimator 550 that outputs to 600. Other configurations are substantially the same as those of the first signal separation device 300, and thus description thereof is omitted.

  The switcher 600 receives the communication quality information of the first signal input from the communication quality estimator 450 included in the first signal separator 400 and the communication quality estimator 550 included in the second signal separator 500. The information sequence to be selected is determined based on the communication quality information of the second signal.

  As described above, the present embodiment employs a configuration in which a plurality of signal separation devices in the first embodiment or the second embodiment are arranged in parallel. Here, each signal separation device extracts a plurality of information series from the hybrid signal in a predetermined order.

  Specifically, the first signal separation device demodulates and decodes the first signal to estimate an information sequence related to the first signal, generates a replica, and relates to the second signal from a difference between the replica and the interference signal. Estimate information series. On the other hand, the second signal demultiplexer first demodulates and decodes the second signal to estimate the information sequence related to the second signal, generates a replica, and calculates the first from the difference between this and the interference signal. An information series related to the signal of is estimated.

  The outputs obtained from each of these two signal separation devices are relatively the output from the first signal separation device when the first signal strength is high, and the second output when the second signal strength is high. Each output from the signal separation device has a relationship that provides a desired estimation result. Therefore, the switcher (selector) compares the quality estimated by the first communication quality estimator (first quality estimator) with the quality estimated by the second communication quality estimator (second quality estimator). In the first signal separation device or the second signal separation device, a plurality of signals separated by the signal separation device having the better quality are selected and output.

  As described above, the switch selects and outputs one of the estimation results based on the quality information obtained by each signal separation device, and thereby the first signal information obtained as an output from the entire signal separation device. The sequence and the information sequence of the second signal can maintain high quality.

  As described above in each embodiment, according to the configuration of the signal separation device of the present invention, a signal replica is generated based on only the intensity difference between interference signals, and the signal is subtracted from the received signal. Therefore, even in a receiver that does not have a replica, it is possible to separate an interference signal that does not depend on the arrival direction of each signal component.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention. For example, each function described in each of the above embodiments may be realized by hardware, or may be realized by causing a CPU (Central Processing Unit) to execute a computer program. Further, the above-described program can be stored using various types of non-transitory computer readable media and supplied to a computer. Non-transitory computer readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (for example, flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (for example, magneto-optical disks), CD-ROM (Read Only Memory) CD-R, CD -R / W, semiconductor memory (for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (Random Access Memory)). The program may also be supplied to the computer by various types of transitory computer readable media. Examples of transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.

  Further, the present invention can be appropriately combined with the above-described embodiments. For example, the signal separation device that performs feedback processing according to the third embodiment may be configured as the first signal separation device and the second signal separation device according to the fourth embodiment.

  In the above description, the technique for separating the first signal and the second signal has been described, but the present invention is not limited to this. When a plurality of signals are further superimposed on the interference signal, the first to Nth signals can be separated.

  That is, as illustrated in FIG. 8, the signal separation device 1 according to the present invention described above includes a first information sequence estimation unit 11, a replica generation unit 12, a cancellation unit 13, and a second information sequence estimation unit 14. Are provided. The first information sequence estimation unit 11 estimates the information sequence of the first signal from the interference signal including a plurality of signals based on the signal strength. The replica generation unit 12 generates a first replica signal that is a replica of the first signal based on the information sequence of the first signal estimated by the first information sequence estimation unit 11. The cancel unit 13 subtracts the first replica signal from the interference signal. The second information sequence estimation unit 14 estimates the information sequence of the second signal from the output signal of the cancellation unit 13 obtained by subtracting the first replica signal from the interference signal.

  FIG. 9 is a flowchart showing the flow of processing of the signal separation method according to the present invention. When an interference signal including a plurality of signals is input, the first information sequence estimation unit 11 estimates the information sequence of the first signal from the interference signal based on the signal strength (step S101). Subsequently, the replica generation unit 12 generates a first replica signal that is a replica of the first signal based on the information sequence of the first signal estimated by the first information sequence estimation unit 11 (step S102). Next, the cancel unit 13 subtracts the first replica signal from the interference signal (step S103). Next, the second information sequence estimation unit 14 estimates the information sequence of the second signal from the output signal of the cancellation unit 13 obtained by subtracting the first replica signal from the interference signal (step S104).

  Here, as shown in FIG. 10, the signal separation device 1 is provided with a second replica generation unit 15, a second cancellation unit 16, and a third information sequence estimation unit 17. The second replica generation unit 15 generates a second replica signal that is a replica of the second signal based on the information sequence of the second signal estimated by the second information sequence estimation unit 14. The second cancel unit 16 subtracts the first replica signal generated by the replica generation unit 12 and the second replica signal generated by the second replica generation unit 15 from the interference signal. Then, the third information sequence estimation unit 17 estimates the information sequence of the third signal from the second signal and the output signal from the second cancellation unit 16. You may comprise in this way. Further, even when a plurality of signals are separated, it can be dealt with by additionally providing an Nth replica generation unit, an Nth cancellation unit, and an (N + 1) th information sequence estimation unit.

  In addition, the multistage signal separation device can be incorporated in the third or fourth embodiment. In addition, the present invention can take the following forms.

(Appendix 1)
First information sequence estimation means for estimating an information sequence of a first signal from an interference signal including a plurality of signals based on signal strength, and an information sequence of the first signal estimated by the first information sequence estimation means Replica generating means for generating a first replica signal that is a replica of the first signal based on the above, cancellation means for subtracting the first replica signal from the interference signal, and subtracting the first replica signal from the interference signal And a second information sequence estimating means for estimating an information sequence of the second signal from the output signal of the canceling means.
(Appendix 2)
The first information sequence estimating means includes first demodulating means for demodulating a first signal based on signal strength among interference signals including a plurality of signals, and the first demodulated by the first demodulating means. First decoding means for decoding a signal and estimating an information sequence of the first signal,
The replica generation means modulates a signal encoded by the first encoding means and a first encoding means for encoding the information sequence of the first signal estimated by the first decoding means. First modulation means for generating a first replica signal that is a replica of the first signal,
The second information sequence estimating means decodes the signal demodulated by the second demodulating means and second demodulating means for demodulating the output signal from the canceling means obtained by subtracting the first replica signal from the interference signal. And a second decoding means for estimating an information sequence of the second signal.
(Appendix 3)
The signal separation device according to appendix 2, wherein the first demodulation means demodulates a first signal which is a signal having the highest signal strength included in the interference signal.
(Appendix 4)
The first modulation means modulates the carrier wave signal reproduced when the first demodulation means demodulates the first signal with the signal encoded by the first encoding means, whereby the first replica 4. The signal separation device according to appendix 2 or 3, which generates a signal.
(Appendix 5)
The cancellation means delays the inputted interference signal by an amount of time required from when the interference signal is input to the first information sequence estimation means to when the first replica signal is output from the replica generation means. Means, correction means for correcting the amplitude and phase of the first replica signal, and addition means for subtracting the first replica signal corrected by the correction means from the interference signal delayed by the delay means. 5. The signal separation device according to any one of appendices 1 to 4.
(Appendix 6)
A second canceling unit for subtracting the output signal of the canceling unit from the interference signal; a third information sequence estimating unit for estimating again the information sequence of the first signal from the output signal of the second canceling unit; Either the information sequence of the first signal estimated by the information sequence estimation means or the information sequence of the first signal estimated by the third information sequence estimation means is selected and output to the replica generation means Switching means, and
When the switching means has selected the information sequence of the first signal estimated by the third information sequence estimation means, the replica generation means is estimated by the third information sequence estimation means Generating a first replica signal that is a replica of the first signal based on an information sequence of the first signal;
The signal separation device according to any one of appendices 1 to 5.
(Appendix 7)
First signal separation means for separating signals in a first order from interference signals including a plurality of signals, and second signal separation means for separating signals from the interference signals in a second order different from the first order And a selection means for selecting and outputting either the plurality of signals separated by the first signal separation means or the plurality of signals separated by the second signal separation means.
(Appendix 8)
The first signal separating means includes
First information sequence estimating means for estimating an information sequence of a first signal from the interference signal; and an information sequence of the first signal based on the information sequence of the first signal estimated by the first information sequence estimating means. First replica generation means for generating a first replica signal that is a replica; first cancellation means for subtracting the first replica signal from the interference signal; and the cancellation means for subtracting the first replica signal from the interference signal Second information sequence estimation means for estimating the information sequence of the second signal from the output signal of
The second signal separation means includes a second information sequence estimation means for estimating an information sequence of the second signal from the interference signal, and an information sequence of the second signal estimated by the second information sequence estimation means. A second replica generating means for generating a second replica signal that is a replica of the second signal based on the second signal, a second canceling means for subtracting the second replica signal from the interference signal, and the second signal from the interference signal. First information sequence estimation means for estimating an information sequence of the first signal from the output signal of the cancellation means from which the replica signal has been subtracted,
The selection means includes the information sequence of the first signal and the information of the second signal estimated by the first information sequence estimation means and the second information sequence estimation means included in the first signal separation means, respectively. The information sequence of the first signal and the information of the second signal estimated by the first information sequence estimation unit and the second information sequence estimation unit included in the second signal separation unit 8. The signal separation device according to appendix 7, which selects and outputs either a group of sequences.
(Appendix 9)
The first signal separation means further includes first quality estimation means for estimating the quality of the signals separated in the first order, and the second signal separation means is the quality of the signals separated in the second order. Further comprising second quality estimation means for estimating
The selection means includes a plurality of signals separated by the first signal separation means based on the quality estimated by the first quality estimation means and the quality estimated by the second quality estimation means, The signal separation device according to appendix 7 or 8, wherein one of the plurality of signals separated by the second signal separation means is selected and output.
(Appendix 10)
A first information sequence estimation step for estimating an information sequence of a first signal from an interference signal including a plurality of signals based on signal strength; and an information sequence of the first signal estimated in the first information sequence estimation step A replica generation step of generating a first replica signal that is a replica of the first signal based on the following: a cancellation step of subtracting the first replica signal from the interference signal; and subtracting the first replica signal from the interference signal And a second information sequence estimation step of estimating an information sequence of the second signal from the received signal.
(Appendix 11)
The replica generation unit generates the first replica signal using a carrier wave signal reproduced when the first information sequence estimation unit estimates the information sequence of the first signal. 2. The signal separation device according to item 1.
(Appendix 12)
The switching unit outputs the information sequence of the first signal estimated by the first information sequence estimation unit to the cancellation unit, and then inputs the information sequence of the first signal output to the cancellation unit The signal separation device according to appendix 6, wherein the first information sequence estimation unit is switched to the third information sequence estimation unit.
(Appendix 13)
The first information sequence estimating means included in the first signal separating means includes a first demodulating means for demodulating a first signal from the interference signal, and the first demodulated by the first demodulating means. First decoding means for decoding a signal and estimating an information sequence of the first signal,
The replica generation means included in the first signal separation means includes: first encoding means for encoding the information sequence of the first signal estimated by the first decoding means; and the first encoding means. First modulation means for modulating the encoded signal to generate a first replica signal that is a replica of the first signal, and
The second information sequence estimating means included in the second signal separating means includes second demodulating means for demodulating a second signal from the interference signal, and the second demodulated by the second demodulating means. Second decoding means for decoding a signal and estimating an information sequence of the second signal,
The replica generation means included in the second signal separation means includes a second encoding means for encoding the information sequence of the second signal estimated by the second decoding means, and a second encoding means. The signal separation device according to appendix 8, further comprising: a second modulation unit that modulates the encoded signal to generate a second replica signal that is a replica of the second signal.
(Appendix 14)
The first signal separation means estimates the quality of the first signal based on a bit unit difference between the output from the first demodulation means and the output from the first encoding means. Further comprising
The second signal separating means estimates the quality of the second signal based on a bit unit difference between the output from the second demodulating means and the output from the second encoding means. Further comprising
The selection means includes the first signal separated by the first signal separation means based on the quality estimated by the first quality estimation means and the quality estimated by the second quality estimation means. And appendix 13 for selecting and outputting either one of the second signal or the second signal and the first signal separated by the second signal separation means. The signal separation device as described.
(Appendix 15)
The selection means compares the quality estimated by the first quality estimation means with the quality estimated by the second quality estimation means, and the first signal separation means or the second signal separation means 15. The signal separation device according to any one of appendices 9, 13, and 14, wherein a plurality of signals separated by the signal separation means having the better quality are selected and output.
(Appendix 16)
A first signal separation step of separating a signal in a first order from an interference signal including a plurality of signals; and a second signal separation step of separating the signal from the interference signal in a second order different from the first order. And a selection step of selecting and outputting either the plurality of signals separated in the first signal separation step or the plurality of signals separated in the second signal separation step.

DESCRIPTION OF SYMBOLS 1 Signal separation apparatus 11 1st information sequence estimation part 12 Replica production | generation part 13 Cancellation part 14 2nd information sequence estimation part 15 2nd replica production | generation part 16 2nd cancellation part 17 3rd information sequence estimation part 100 Signal separation apparatus 110 1st Demodulator 120 First decoder 130 First encoder 140 Modulator 150 Adaptive canceller 151 Delay unit 152 Adaptive filter 153 Adder 160 Demodulator 170 Decoder 200 Signal separator 210 First demodulator 211 First multiplier 212 Second Multiplier 213 First low-pass filter 214 Second low-pass filter 215 Carrier regenerator 216 Phase shifter 220 First decoder 230 First encoder 240 First modulator 241 Symbol converter 242 Third low-pass filter 243 First 4 Low-pass filter 244 3rd multiplier 245 4th multiplier 300 Signal separation Device 310 first information sequence estimation unit 320 first replica generation unit 330 second information sequence estimation unit 340 third information sequence estimation unit 350 second adaptive canceller 360 third demodulator 370 third decoder 380 switch 400 first signal Separator 410 First information sequence estimator 411 First demodulator 412 First decoder 420 First replica generator 421 First encoder 422 First modulator 430 First cancellation processor 431 First adaptive canceller 440 Second information Sequence estimation unit 441 Second demodulator 442 Second decoder 450 First communication quality estimator 500 Second signal separation device 510 Second information sequence estimation unit 520 Second replica generation unit 530 Second cancellation processing unit 540 First information sequence Estimator 550 Second communication quality estimator 600 switch (selector)

Claims (3)

First signal separation means for separating signals in a first order from interference signals including a plurality of signals;
Second signal separation means for separating signals from the interference signal in a second order different from the first order;
Selection means for selecting and outputting either of the plurality of signals separated by the first signal separation means or the plurality of signals separated by the second signal separation means;
A signal separation device comprising: The first signal separating means includes
First information sequence estimation means for estimating an information sequence of a first signal from the interference signal;
First replica generation means for generating a first replica signal that is a replica of the first signal based on the information sequence of the first signal estimated by the first information sequence estimation means;
First cancellation means for subtracting the first replica signal from the interference signal;
Second information sequence estimation means for estimating an information sequence of a second signal from an output signal of the cancellation means obtained by subtracting the first replica signal from the interference signal;
With
The second signal separation means includes
Second information sequence estimation means for estimating an information sequence of the second signal from the interference signal;
Second replica generation means for generating a second replica signal that is a replica of the second signal based on the information sequence of the second signal estimated by the second information sequence estimation means;
Second cancellation means for subtracting the second replica signal from the interference signal;
First information sequence estimation means for estimating an information sequence of a first signal from an output signal of the cancellation means obtained by subtracting the second replica signal from the interference signal;
With
The selection means includes
A set of the information sequence of the first signal and the information sequence of the second signal respectively estimated by the first information sequence estimation unit and the second information sequence estimation unit included in the first signal separation unit; A set of the information sequence of the first signal and the information sequence of the second signal respectively estimated by the first information sequence estimation unit and the second information sequence estimation unit included in the second signal separation unit; Select one of these to output,
The signal separation device according to claim 1. The first signal separation means further comprises first quality estimation means for estimating the quality of signals separated in the first order,
The second signal separation means further comprises second quality estimation means for estimating the quality of the signals separated in the second order,
The selection means includes a plurality of signals separated by the first signal separation means based on the quality estimated by the first quality estimation means and the quality estimated by the second quality estimation means, Selecting and outputting one of a plurality of signals separated by the second signal separation means;
The signal separation device according to claim 1 or 2.

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