JPWO2006092830A1 - Receiver - Google Patents

Abstract

In a receiving apparatus having an interference signal component removal function, a good interference removal effect can be ensured while shortening the processing time required for estimating the transmission path of the interference signal transmission path or reducing the processing amount (scale). In a receiving apparatus including an analog signal processing unit that converts an analog signal obtained by down-converting a received signal into a digital signal, and a digital signal demodulating unit that demodulates the digital signal output from the analog signal processing unit, The desired signal parameter estimation unit (202) outputs a desired signal transmission path estimation unit (303) that outputs a transmission path estimation value of the desired signal as one of the predetermined parameters relating to the desired signal, and the transmission path estimation value of the desired signal is known. A replica generation unit (302) that generates a replica signal of the desired signal based on the signal, and a replica subtraction unit (301) that outputs a subtraction output obtained by subtracting the replica signal of the desired signal from the received signal as a desired signal replica removal signal; Is provided.

Description

  The present invention relates to a receiving apparatus, and more particularly to a receiving apparatus having a function of removing an interference signal component contained in a received signal.

  In digital wireless communication systems, co-channel interference is a major factor that degrades communication quality. Therefore, co-channel interference countermeasures in digital wireless communication systems are an important issue. For example, in a digital wireless communication system represented by an asynchronous cellular system between base stations, generally, frame synchronization is not achieved between a co-channel interference signal arriving at a receiver and a desired signal of the own system. Some measures against interference must be taken for unknown co-channel interference signals.

  For example, Patent Document 1 listed below is one of documents disclosing co-channel interference cancellation technology on the receiver side in such an environment. In the method disclosed in Patent Document 1, first, a transmission path estimation value related to a desired signal of the own system is estimated using a known sequence, while a transmission path estimation value of a co-channel interference signal is set to an arbitrary initial value. Temporarily set to the value. Next, these channel estimation values and the received signal are used, and the sequence estimation process considering the state of the interference signal is repeated a plurality of times, and the desired signal is transmitted while updating the channel estimation value of each channel. A signal sequence is estimated and output. As described above, the interference cancellation technique disclosed in Patent Document 1 repeatedly improves the estimation accuracy of the transmission path and the accuracy of the estimated sequence by repeatedly performing sequence estimation, and suppresses interference signal components. Like to do.

European Patent Application No. 1475933

  However, the conventional technique disclosed in Patent Document 1 has a problem in that it is necessary to repeat a sequence estimation process with a large amount of processing a plurality of times in order to suppress the interference signal component, which requires a very large amount of processing.

  Further, in the above prior art, regarding the transmission path estimation of the interference signal transmission path, since the transmission path must be estimated in the presence of both the desired signal and the interference signal, sufficient estimation accuracy cannot be obtained and good interference can be obtained. There was a problem that the removal effect could not be obtained.

  Furthermore, in the above prior art, the initial value of the transmission path estimation value for the interference signal transmission path is provisionally set to an arbitrary initial value, and the accuracy is gradually increased in the subsequent iterative sequence estimation processing. However, it has not been converged to a sufficient accuracy, and an estimated value for which a sufficient accuracy cannot be ensured due to processing time restrictions or the like must be used, and a good interference removal effect cannot be obtained.

  The present invention has been made in view of the above, and ensures a good interference removal effect while shortening the processing time required for the transmission path estimation of the interference signal transmission path or reducing the processing amount (scale). An object is to provide a possible receiving device.

  In order to solve the above-described problems and achieve the object, a receiving apparatus according to the present invention includes each of N (N is an integer of 1 or more) antennas that receive M (M is an integer of 1 or more) multiplexed signals. An analog signal processing unit that converts an analog signal obtained by down-converting each received signal into a digital signal, and a digital signal demodulation unit that demodulates the digital signal output from the analog signal processing unit. A signal demodulator that estimates a predetermined parameter related to a desired signal based on the digital signal and a known signal that is foresight information; and a signal demodulator that relates to an interference signal based on an output signal of the desired signal parameter estimator An interference signal parameter estimation unit for estimating a predetermined parameter, an output of the desired signal parameter estimation unit, and Or an equalizer that outputs, as demodulated data, an equalization processing output performed on the received signal based on the output of the interference signal parameter estimation unit, wherein the desired signal parameter estimation unit relates to the desired signal A desired signal transmission path estimation unit that outputs a transmission path estimation value of the desired signal as one of predetermined parameters, and generates a replica signal of the desired signal based on the transmission path estimation value of the desired signal and the known signal And a replica subtracting unit that outputs a subtracted output obtained by subtracting the replica signal of the desired signal from the received signal as a desired signal replica removal signal.

  According to the present invention, the replica subtraction unit, the replica subtraction unit, and the desired signal transmission path estimation unit are provided as means for estimating a predetermined parameter related to the desired signal based on the received signal and the known signal that is the foresight information. The desired signal parameter estimation unit outputs the output of the desired signal transmission path estimation unit as a desired signal transmission path estimation value, and outputs a subtraction output obtained by subtracting the desired signal replica signal from the received signal as a desired signal replica removal signal.

  According to the receiving apparatus of the present invention, since the transmission path estimation of the interference signal is performed using the subtraction output obtained by subtracting the replica of the desired signal, the transmission path of the desired signal is estimated when the transmission path estimation of the interference signal is performed. It is possible to estimate with high accuracy without being affected, and it is possible to provide good communication in which the influence of interference is suppressed.

FIG. 1 is a block diagram showing an overall configuration of a receiving apparatus according to first to fifth embodiments of the present invention. FIG. 2 is a block diagram showing the configuration of the digital signal demodulator according to the first embodiment of the present invention. FIG. 3 is a block diagram showing a configuration of a desired signal parameter estimation unit according to the first embodiment shown in FIG. FIG. 4 is a block diagram showing a configuration of the digital signal demodulator according to the second embodiment of the present invention. FIG. 5 is a block diagram showing a configuration of the desired signal parameter estimation unit according to the second exemplary embodiment shown in FIG. FIG. 6 is a block diagram showing the configuration of the digital signal demodulator according to the third embodiment of the present invention. FIG. 7 is a block diagram showing a configuration of the digital signal demodulator according to the fourth embodiment of the present invention. FIG. 8 is a block diagram showing a configuration of a desired signal parameter estimation unit according to the fourth embodiment shown in FIG. FIG. 9 is a block diagram showing the configuration of the digital signal demodulator according to the fifth embodiment of the present invention. FIG. 10 is a block diagram illustrating a configuration of an interference signal parameter estimation unit according to the fifth embodiment illustrated in FIG. 9. FIG. 11 is a block diagram showing an overall configuration of a receiving apparatus according to the sixth embodiment of the present invention. FIG. 12 is a block diagram showing the configuration of the digital signal demodulator according to the sixth embodiment shown in FIG. FIG. 13 is a block diagram showing the configuration of the desired signal parameter estimation unit according to the sixth embodiment shown in FIG.

Explanation of symbols

101, 1101 Antenna 102, 1102 Analog signal processing unit 103, 103a, 103b, 103c, 103d, 103e, 1103 Digital signal demodulation unit 201, 1201 Known signal storage memory 202, 401, 701, 1202 Desired signal parameter estimation unit 203, 901 , 1203 Interference signal parameter estimation unit 204, 902, 1204 Equalizer 301, 1301 Replica subtraction unit 302, 1302 Replica generation unit 303, 501, 1303 Desired signal transmission path estimation unit 601, 702, 1001, 1004 Switch 801 Interference signal Level estimation unit 1002 Blind channel estimation unit 1003 Transmission channel estimation unit

  Embodiments of a receiving apparatus according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this embodiment.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing an overall configuration of a receiving apparatus according to first to fifth embodiments of the present invention. FIG. 2 shows a configuration example of the digital signal demodulator 103 shown in FIG. 1, and is a block diagram showing a configuration of the digital signal demodulator 103a according to the first embodiment of the present invention. Further, FIG. 3 shows an example of the configuration of the desired signal parameter estimation unit 202 shown in FIG. 2, and is a block diagram showing the configuration of the desired signal parameter estimation unit 202 according to the first embodiment of the present invention.

  Here, the configuration of the receiving apparatus according to the first embodiment will be described. 1, the receiving apparatus according to the first embodiment of the present invention includes an antenna (receiving antenna) 101, an analog signal processing unit 102, and a digital signal demodulating unit 103. In FIG. 2, the digital signal demodulator 103 a shown in FIG. 1 includes a known signal storage memory 201, a desired signal parameter estimator 202, an interference signal parameter estimator 203, and an equalizer 204. 3, the desired signal parameter estimation unit 202 shown in FIG. 2 includes a replica subtraction unit 301, a replica generation unit 302, and a desired signal transmission path estimation unit 303.

  Next, the operation of the receiving apparatus according to the first embodiment will be described with reference to FIG. 1 and FIG. In FIG. 1, a signal (received signal) received by the antenna 101 is subjected to a process of down-converting a high-frequency analog signal into a baseband signal and a process of converting the analog signal into a digital signal by an analog signal processing unit 102. . The digital signal converted by the analog signal processing unit 102 is output to the digital signal demodulation unit 103 which forms the core of the invention of the first embodiment.

  In FIG. 2, the digital signal (received signal) output from the analog signal processing unit 102 is output to the desired signal parameter estimation unit 202 and the equalizer 204. The desired signal parameter estimation unit 202 uses a digital signal (received signal) output from the analog signal processing unit 102 and a known signal stored in advance in the known signal storage memory 201 to estimate a transmission path regarding a desired signal. (For example, in addition to the transmission path estimation value, estimation information such as timing of desired signal and received power) is estimated.

  In addition, the interference signal parameter estimation unit 203 uses a predetermined parameter related to the interference signal based on output information such as the transmission channel estimation value output from the desired signal parameter estimation unit 202 (for example, a transmission channel estimation value similar to the desired signal). And estimation information such as received power). Here, as a processing method of the interference signal parameter estimation unit 203, for example, any conventionally known blind estimation method can be applied.

  Further, the equalizer 204 outputs the digital signal (received signal) output from the analog signal processing unit 102 and the predetermined parameters related to the desired signal output from the desired signal parameter estimation unit 202 and the interference signal parameter estimation unit 203. Based on a predetermined parameter related to the interference signal, equalization processing is performed in consideration of the desired signal and the state of the interference signal, and demodulated data of the received signal is output. Here, as a processing method of the equalizer 204, for example, a maximum likelihood sequence estimation which is a known technique can be applied.

  By the way, the demodulated data which is the output data of the equalizer 204 includes information on the desired signal and the interference signal depending on conditions such as the strength of interference and the transmission path, and some implementations of the present invention. In this form, the output of the equalizer 204 may be fed back to perform parameter estimation regarding a desired signal or an interference signal. Therefore, in the following description, the output (demodulated data) of the equalizer 204 will be referred to as “determination value”.

  Next, the operation of desired signal parameter estimation section 202 shown in FIG. 3 will be described. In the figure, a received signal that is an input signal to the desired signal parameter estimation unit 202 is input to a replica subtraction unit 301 and a desired signal transmission path estimation unit 303. Similarly, a known signal that is an input signal to desired signal parameter estimation section 202 is input to replica generation section 302 and desired signal transmission path estimation section 303. The desired signal transmission path estimation unit 303 performs a transmission path estimation process of the desired signal based on these two input signals, for example, by applying a technique such as a least square method that has been widely used conventionally. The channel estimation value of the desired signal estimated at this time (hereinafter referred to as “desired signal channel estimation value”) is transmitted to the replica generation unit 302 and also output to the equalizer 204 shown in FIG. On the other hand, the replica generation unit 302 generates a replica of the desired signal using the known signal and the desired signal transmission path estimation value. The replica subtraction unit 301 performs a process of subtracting the replica of the desired signal generated by the replica generation unit 302 from the received signal, and the signal after the replica of the desired signal is removed is input to the interference signal parameter estimation unit 203 shown in FIG. Is output.

  The receiving apparatus configured as described above has the following advantages. That is, in the receiving apparatus of this embodiment, since the interference signal transmission path is estimated from the signal obtained by subtracting the replica of the desired signal, the interference signal transmission path estimation is not affected by the desired signal. It is possible to estimate well, and it is possible to perform highly accurate equalization processing in the subsequent equalizer, and as a result, it is possible to provide good communication in which the influence of interference is suppressed. In addition, since parameter estimation of interference signals is performed separately from equalization processing, it is not necessary to perform iterative sequence estimation as in the prior art, and it is possible to provide good communication with a smaller amount of computation. Become.

  As described above, according to the receiving apparatus of this embodiment, as means for estimating a predetermined parameter related to a desired signal based on a received signal and a known signal that is foresight information, a replica subtraction unit, a replica subtraction unit, and Since it is configured to include a desired signal transmission path estimation unit, and the subtracted output obtained by subtracting the replica signal of the desired signal from the received signal is output as a desired signal replica removal signal by these components, the interference signal Thus, it is possible to accurately estimate the transmission path without being influenced by the desired signal, and to provide good communication in which the influence of interference is suppressed. Further, in the processing of the above-described components, the parameter estimation of the interference signal is performed separately from the equalization processing, so that it is not necessary to repeat sequence estimation, and good communication can be provided with a smaller amount of computation. it can.

  In the receiving apparatus according to this embodiment, the known signal input to the desired signal parameter estimation unit 202 has been described as being provided from the known signal storage memory as shown in FIG. Instead, for example, a configuration may be adopted in which a known signal generation circuit or the like is separately provided and generated each time at a necessary timing.

  The desired signal parameter estimation unit 202 and the interference signal parameter estimation unit 203 are not limited to the component units that output the channel estimation values of the desired signal and the interference signal described in the present embodiment, Needless to say, the present invention includes other components such as a detection circuit.

Embodiment 2. FIG.
FIG. 4 is a block diagram showing the configuration of the digital signal demodulator 103b according to the second embodiment of the present invention, and FIG. 5 shows the configuration of the desired signal parameter estimation unit 401 according to the second embodiment shown in FIG. FIG. The difference from the first embodiment is that, as shown in FIGS. 4 and 5, feedback processing is performed so that the output of the interference signal parameter estimation unit 203 is output to the desired signal parameter estimation unit 401. is there. In addition, about the structure of each part, it is the same as that of Embodiment 1, or is equivalent, The same code | symbol is attached | subjected and shown to these parts.

  Next, the operation of the digital signal demodulator 103b shown in FIG. 4 will be described with reference to FIGS. First, in FIG. 5, a desired signal transmission path estimation unit 501 is based on at least three pieces of output information obtained by adding a transmission path estimation value of an interference signal to a received signal and a known signal (hereinafter referred to as “interference signal transmission path estimation value”). Thus, the transmission path of the desired signal is estimated. The replica generation unit 302 generates a replica of the desired signal based on the known signal and the desired signal transmission path estimation value, and outputs the generated desired signal replica to the replica subtraction unit 301. The replica subtraction unit 301 performs a process of subtracting the replica of the desired signal from the received signal, and outputs the signal after the replica of the desired signal is removed to the interference signal parameter estimation unit 203.

  In FIG. 4, the interference signal parameter estimation unit 203 uses a conventionally well-known method (for example, blind estimation), and performs interference based on a signal after replica removal of the desired signal output from the desired signal parameter estimation unit 401. A signal transmission path estimation value and the like are estimated and output to the equalizer 204 and the desired signal parameter estimation unit 401. Desired signal parameter estimation section 401 repeatedly performs desired signal parameter estimation based on the interference signal transmission path estimation value output from interference signal parameter estimation section 203.

  As described above, in this embodiment, as the interference signal transmission path estimation value used in the desired signal parameter estimation unit 401, a predetermined initial value such as “0” is input in the first process. On the other hand, in the second and subsequent processing, a configuration is adopted in which the interference signal transmission path estimation value output from the interference signal parameter estimation unit 203 is input, so that parameter estimation with higher accuracy is possible. As a result, a better interference cancellation effect can be obtained with the equalizer at the subsequent stage.

  As described above, according to the receiving apparatus of this embodiment, the desired signal transmission path estimation value and the interference signal transmission path estimation based on the received signal, the known signal that is the foresight information, and the interference signal transmission path estimation value output information. Since a predetermined parameter such as a value is estimated, highly accurate parameter estimation is possible, and a better interference removal effect can be obtained.

Embodiment 3 FIG.
FIG. 6 is a block diagram showing the configuration of the digital signal demodulator 103c according to the third embodiment of the present invention. The digital signal demodulator 103c shown in the figure receives the known signal output from the known signal storage memory 201 and the determination value output from the equalizer 204 in the configuration of the first embodiment. A switch 601 is provided as output switching means (first output switching means) for outputting one of them to the desired signal parameter estimation unit 202. In addition, about another structure, it is the same as that of Embodiment 1, or is equivalent, The same code | symbol is attached | subjected and shown to these parts.

  Next, the operation of the digital signal demodulator 103c shown in FIG. 6 will be described. In the figure, the switch 601 outputs the known signal output from the known signal storage memory 201 to the desired signal parameter estimation unit 202 at the processing timing for the known signal portion of the desired signal, and obtains the determination value by the equalizer 204. After the determination, the decision value from the equalizer 204 is output. In this way, the desired signal parameter estimation unit 202 performs parameter estimation of the desired signal based on the determination value from the equalizer 204 after the determination value by the equalizer 204 is obtained.

  As described above, in this embodiment, when the desired signal parameter estimation and the interference signal parameter estimation are performed, the output to the desired signal parameter estimation unit 202 according to the presence or absence of the determination value output from the equalizer 204. Therefore, it is possible to estimate the transmission path with high accuracy following the fluctuation of the transmission path, and to obtain a higher interference suppression effect.

  As described above, according to the receiving apparatus of this embodiment, predetermined parameters such as a desired signal transmission path estimation value and an interference signal transmission path estimation value are estimated based on a known sequence portion of a desired signal and demodulated data. Therefore, it is possible to estimate the transmission path with high accuracy following the fluctuation of the transmission path, and to obtain a higher interference suppression effect.

  In this embodiment, the example in which the configuration in which any one of the known signal or the determination value is output to the desired signal parameter estimation unit using the output switching unit is applied to the configuration of the first embodiment has been described. These configurations can also be applied to the configuration of the second embodiment, and the same effects as those of the second embodiment can be obtained.

Embodiment 4 FIG.
FIG. 7 is a block diagram showing the configuration of the digital signal demodulator 103d according to the fourth embodiment of the present invention, and FIG. 8 shows the configuration of the desired signal parameter estimation unit 701 according to the fourth embodiment shown in FIG. FIG. These digital signal demodulator 103d and desired signal parameter estimator 701 are configured as follows as an extension of the configuration of the first embodiment.

  That is, the digital signal demodulator 103d shown in FIG. 7 has the output of the desired signal parameter estimator 701 and the output of the interference signal parameter estimator 203 in the configuration of the digital signal demodulator 103a according to the first embodiment shown in FIG. And a switch 702 as output control means for controlling whether or not to output the output from the interference signal parameter estimation unit 203 to the equalizer 204. 8 is an interference signal level estimation unit that estimates and outputs the level of the interference signal in the configuration of the desired signal parameter estimation unit 202 according to the first embodiment shown in FIG. 801 is further provided. The configuration other than that shown here is the same as or equivalent to the configuration of the first embodiment, and these portions are denoted by the same reference numerals.

  Next, the operation of the digital signal demodulator 103d shown in FIG. 7 will be described with reference to FIGS. First, in FIG. 8, a desired signal transmission path estimation unit 303 performs transmission path estimation of a desired signal based on a received signal and a known signal. For example, the least square method can be applied as the transmission path estimation of the desired signal. The estimated desired signal transmission path estimation value is output to the replica generation unit 302 and also to the equalizer 204 shown in FIG. The replica generation unit 302 generates a replica of the desired signal based on the known signal and the desired signal transmission path estimation value, and outputs it to the replica subtraction unit 301. The replica subtraction unit 301 performs a process of subtracting a replica of the desired signal from the received signal, and outputs the output to the interference signal level estimation unit 801 and also to the interference signal parameter estimation unit 203. The interference signal level estimation unit 801 measures the level of the interference signal based on the received signal before subtraction subtraction of the desired signal and the output signal after replica subtraction of the desired signal, and the switch shown in FIG. 702 is output.

  Here, the interference signal level signal only needs to include an index indicating the strength of the co-channel interference signal arriving at the receiver. For example, the average signal power to interference power ratio, the average interference signal power, etc. Can be used.

  In FIG. 7, the interference signal parameter estimation unit 203 applies a technique such as blind estimation, for example, and estimates the interference signal transmission path based on the signal after the replica of the desired signal output from the desired signal parameter estimation unit 701 is removed. A parameter such as a value is estimated and output to the switch 702. The switch 702 receives the interference signal level signal output from the desired signal parameter estimation unit 701 and the interference signal transmission path estimation value output from the interference signal parameter estimation unit 203, and equalizes the interference signal transmission path estimation value. Whether or not to output to the device 204 is controlled.

  Here, the switch 702 holds a predetermined threshold value (referred to as “threshold value a”) relating to the interference signal level therein, for example, when the interference signal level signal exceeds the threshold value a. For example, an interference signal transmission path estimation value that is an output from the interference signal parameter estimation unit 203 is output to the equalizer 204. That is, the switcher 702 operates to control whether to output the output of the interference signal parameter estimation unit 203 to the equalizer 204 based on the output of the desired signal parameter estimation unit 701. The equalizer 204 performs an equalization process in consideration of the state of the interference signal based on the received signal, the output from the desired signal parameter estimation unit 701, and the output of the switch 702, and outputs a determination value. As apparent from the above, when the switch 702 determines that the interference signal level signal is lower than the threshold value a, the interference channel transmission path estimation value is output to the equalizer 204. First, the equalizer 204 performs equalization processing without considering the interference signal.

  As described above, according to the receiving apparatus of this embodiment, the switch that is the output control means outputs the output of the interference signal parameter estimation unit based on the interference signal level signal that is the output of the desired signal parameter estimation unit. Since whether or not to output to the equalizer is controlled, it is possible to eliminate the influence of the estimation error on the interference signal transmission path estimation value when the interference signal level is small, and provide good communication Is possible.

  In this embodiment, a configuration for controlling whether to output the output of the interference signal parameter estimation unit to the equalizer based on the interference signal level signal that is the output of the desired signal parameter estimation unit is described in the first embodiment. Although the example applied to this configuration has been described, these configurations can also be applied to the configurations of the second and third embodiments, and the same effects as those of the second and third embodiments can be obtained.

  Further, for example, before performing the interference signal parameter estimation, a determination similar to the threshold determination of the interference signal level signal in the switch 702 is performed, and the interference signal parameter estimation unit 203 is operated using the result as a trigger. It is good also as a structure. Further, the equalizer 204 itself may be provided with a threshold value judgment function so as to switch between considering or ignoring the state of the interference signal. Furthermore, the threshold value a of the interference signal level signal may be configured to be input from the outside instead of being held in the switch 702. Furthermore, the threshold value a need not be a fixed value, and may be configured to be input as a variable parameter from the outside.

Embodiment 5 FIG.
FIG. 9 is a block diagram showing the configuration of the digital signal demodulator 103e according to the fifth embodiment of the present invention, and FIG. 10 shows the configuration of the interference signal parameter estimation unit 901 according to the fifth embodiment shown in FIG. FIG. The digital signal demodulator 103e and the interference signal parameter estimator 901 are configured as follows as an extension of the configuration of the third embodiment.

  That is, in the configuration of the digital signal demodulator 103c according to the third embodiment shown in FIG. 6, the digital signal demodulator 103e shown in FIG. 9 has an output of the equalizer 902 (determination value of the interference signal) as an interference signal parameter. A feedback process that is output to the estimation unit 901 is added. In addition, about another structure, it is the same as that of Embodiment 3, or is equivalent, The same code | symbol is attached | subjected and shown to these parts.

  Also, the interference signal parameter estimation unit 901 shown in FIG. 10 includes a switch 1001 to which a signal after removal of a desired signal replica is input, a blind transmission path estimation unit 1002 and a transmission path estimation unit respectively connected to the switch 1001. 1003 and output switching means (second output switching means) for switching and controlling any one of the output signals output from the blind transmission path estimation section 1002 and the transmission path estimation section 1003 as the output of the interference signal parameter estimation section 901. Switcher 1004. Note that an interference signal determination value, which is a feedback output from the equalizer 902, is input to the transmission path estimation unit 1003.

  Next, the operation of the digital signal demodulator 103e shown in FIG. 9 will be described with reference to FIGS. First, in FIG. 10, the signal after replica removal of the desired signal output from the desired signal parameter estimation unit 202 is input to the switch 1001, and the switch 1001 uses the blind transmission path at the processing timing of the known signal portion of the desired signal. The data is output to the estimation unit 1002, and is output to the transmission path estimation unit 1003 at other timings. The blind transmission path estimation unit 1002 performs transmission path estimation of interference signals using a known blind estimation technique, and outputs the estimation result to the switch 1004. On the other hand, the transmission path estimation unit 1003 uses a technique such as a least-square method that has been widely known based on the output signal from the switch 1001 and the determination value of the interference signal output from the equalizer 902. Then, the transmission path of the interference signal is estimated, and the estimation result is output to the switch 1004. Note that the switch 1004 operates in conjunction with the switch 1001. That is, the signal from the blind transmission path estimation unit 1002 is output at the timing of processing the known signal portion of the desired signal, and the signal from the transmission path estimation unit 1003 is output at other timings. In this way, the output signal from the switch 1004 is output to the equalizer 902 as an interference signal transmission path estimation value.

  In FIG. 9, the equalizer 902 also outputs the determination value of the interference signal considered during the equalization process in addition to the determination value of the desired signal as a result of the equalization process. Note that as the equalizer 902, any equalizer that can perform an equalization process in consideration of the state of the interference signal can be applied. Also, the determination value, which is the output of the equalizer 902, is output to the interference signal parameter estimation unit 901, and is used to estimate the interference signal transmission path at a timing other than the known signal portion of the desired signal, as already described.

  As described above, according to the receiving apparatus of this embodiment, since both the determination value of the desired signal and the determination value of the interference signal are fed back, timing other than the known signal portion of the desired signal However, the transmission path estimation of the desired signal and the interference signal can be continuously performed, and the transmission path estimation with higher accuracy can be performed, and as a result, good interference cancellation characteristics can be obtained.

  In this embodiment, the example in which the configuration for feeding back the determination value of the interference signal is applied to the configuration of the third embodiment, but these configurations are applied to the configuration of the first, second, or fourth embodiment. It is also possible to obtain the same effects as those of these embodiments.

  In this embodiment, the signal after replica removal of the desired signal is switched using the switch 1001 when the signal is output to either the blind transmission path estimation unit 1002 or the transmission path estimation unit 1003. Since the switch 1004 has a function of controlling the output to the equalizer 902, the signal after the replica of the desired signal is removed without using the switch 1001 is sent to the blind channel estimation unit 1002 and the channel estimation unit 1003. It is good also as a structure which inputs into both directly.

Embodiment 6 FIG.
FIG. 11 is a block diagram showing an overall configuration of a receiving apparatus according to the sixth embodiment of the present invention. The receiving apparatus shown in the figure includes N antennas (receiving antennas) 1101-1 to 1101-N, N analog signal processing units 1102-1 to 1102-N, and digital signal demodulation. The unit 1103 is provided. Here, a feature of the receiving apparatus of this embodiment is that signals received by N receiving antennas are transmitted to a digital signal demodulating unit, and equalization processing is performed in consideration of the state of an interference signal.

  Further, the signals arriving at the N antennas may be signals simultaneously transmitted from a plurality of antennas on the transmitter side (not shown), such as so-called MIMO (Multiple Input Multiple Output) transmission. In the following description, the desired signal and the interference signal are M multiplexed signals transmitted substantially simultaneously from M (M is an integer of 1 or more) antennas on the transmitter side, and these M multiplexed signals are received by the receiving device. The case where the antennas 1101-1 to 1101-N arrive at will be described as an example.

  Next, configurations of the digital signal demodulator and the desired signal parameter estimator according to the sixth embodiment will be described with reference to FIGS. 11 and 12. FIG. 12 is a block diagram showing the configuration of the digital signal demodulator 1103 according to the sixth embodiment shown in FIG. 11, and FIG. 13 shows the desired signal parameter estimation according to the sixth embodiment shown in FIG. 3 is a block diagram showing a configuration of a unit 1202. FIG.

  First, the digital signal demodulator 1103 shown in FIG. 12 is configured to include a known signal storage memory 1201, a desired signal parameter estimator 1202, an interference signal parameter estimator 1203, and an equalizer 1204. The connection configuration is shown in FIG. It is the same as or equivalent to the digital signal demodulator 103a according to the first embodiment shown in FIG. However, since desired system parameter estimation section 1202 and equalizer 1204 receive N system received signals, they have a function for processing the N system received signals.

  Further, desired signal parameter estimation section 1202 shown in FIG. 13 is configured to include replica subtraction section 1301, replica generation section 1302, and desired signal transmission path estimation section 1303, and the connection configuration thereof is the embodiment shown in FIG. 1 is the same as or equivalent to the desired signal parameter estimation unit 202. Further, similarly to the digital signal demodulator 1103, it has a function for processing N-system received signals.

  Next, the operation of the digital signal demodulator 1103 shown in FIG. 12 will be described with reference to FIGS. First, in FIG. 13, desired signal transmission path estimation section 1303 performs transmission path estimation of a desired signal based on the N-system received signal and the known signal. When M multiplexed signals are received using N antennas 1101-1 to 1101-N, there are M × N transmission paths for the desired signal, and it is necessary to estimate all of them. Can be executed by adopting a method using, for example, an orthogonal code as a known signal. The replica generation unit 1302 generates N replicas corresponding to each of the N received signals based on the desired signal transmission path estimation value output from the desired signal transmission path estimation unit 1303 and the input known signal. The result is output to the subtraction unit 1301. The replica subtracting unit 1301 performs a process of subtracting N kinds of replicas generated by the replica generating unit 1302 from the input N system received signals. As a result of these processes, the desired signal transmission path estimation value is output to the equalizer 1204 shown in FIG. 12, and the N-system signal after removal of the replica of the desired signal is the interference signal parameter estimation unit 1203 shown in FIG. Is output.

  In FIG. 12, the interference signal parameter estimation unit 1203 uses a conventionally well-known method (for example, blind estimation) to estimate the transmission path estimation value of the interference signal based on the N-system signal after replica removal of the desired signal. Are estimated and output to the equalizer 1204. The equalizer 1204 performs demodulation processing in consideration of the state of the interference signal based on the N-system received signal, the desired signal transmission path estimation value, and the interference signal transmission path estimation value.

  As described above, according to the receiving apparatus of this embodiment, even when M multiplexed signals transmitted from the transmitter side are received using N antennas, the same as in Embodiment 1 An effect can be obtained.

  In the receiving apparatus of this embodiment, the example in which the configuration for receiving the transmitted M multiplexed signal using N antennas is applied to the configuration of the digital signal demodulator according to the first embodiment has been described. These configurations can be applied to the configuration of the digital signal demodulator according to the second to fifth embodiments, and the same effects as those of the embodiments can be obtained.

  In addition, the receiving apparatus of this embodiment includes a single digital signal demodulating unit that processes N received signals obtained by combining the outputs of N analog signal processing units connected to N antennas. However, it is also possible to prepare a digital signal demodulator for each receiving antenna and synthesize the demodulated data output from each digital signal demodulator.

  As described above, the receiving apparatus according to the present invention is useful as a receiving apparatus applicable to a mobile communication environment in which co-channel interference due to an interference signal causes a problem.

Claims (9)

An analog signal processing unit that converts an analog signal obtained by down-converting each received signal from N (N is an integer of 1 or more) antennas that receive M (M is an integer of 1 or more) multiple signals; In a receiving apparatus comprising: a digital signal demodulator that demodulates a digital signal output from the analog signal processor;
The digital signal demodulator is
A desired signal parameter estimator for estimating a predetermined parameter related to a desired signal based on the digital signal and a known signal which is foresight information;
An interference signal parameter estimation unit that estimates a predetermined parameter related to an interference signal based on an output signal of the desired signal parameter estimation unit;
An equalizer that outputs, as demodulated data, an equalization processing output performed on the received signal based on the output of the desired signal parameter estimation unit and / or the output of the interference signal parameter estimation unit;
With
The desired signal parameter estimation unit includes:
A desired signal transmission path estimation unit that outputs a transmission path estimation value of the desired signal as one of the predetermined parameters related to the desired signal;
A replica generation unit that generates a replica signal of the desired signal based on the estimated channel of the desired signal and the known signal;
A replica subtraction unit that outputs a subtraction output obtained by subtracting the replica signal of the desired signal from the received signal as a desired signal replica removal signal;
A receiving apparatus comprising:   The receiving apparatus according to claim 1, wherein the desired signal parameter estimating unit estimates a predetermined parameter related to the desired signal by further using an output of the interference signal parameter estimating unit. The digital signal demodulator includes a first output switching unit to which the known signal and the determination value output from the equalizer are input,
The receiving apparatus according to claim 1, wherein the first output switching unit outputs any one of the known signal and the determination value to the desired signal parameter estimation unit.   The receiving apparatus according to claim 3, wherein the first output switching unit switches a signal to be output to the desired signal parameter estimation unit in accordance with the presence or absence of a determination value output from the equalizer. The digital signal demodulator comprises output control means for receiving the output of the desired signal parameter estimator and the output of the interference signal parameter estimator, respectively.
The output control means controls whether or not to output the output of the interference signal parameter estimation unit to the equalizer based on the output of the desired signal parameter estimation unit. Receiver device. The desired signal parameter estimation unit further includes an interference signal level estimation unit that outputs an interference signal level signal obtained by estimating an interference signal level based on the received signal and the replica subtraction unit,
The receiving apparatus according to claim 5, wherein the interference signal level signal is input to the output control unit.   The receiving apparatus according to claim 3, wherein the interference signal parameter estimation unit estimates a predetermined parameter related to the interference signal by further using the determination value output from the equalizer. The interference signal parameter estimator is
A blind channel estimation unit that blindly estimates an interference signal channel estimation value based on the desired signal replica removal signal output from the replica subtraction unit;
A transmission path estimation unit that estimates an interference signal transmission path estimation value based on the desired signal replica removal signal and a determination value of the interference signal output from the equalizer;
Second output switching means to which the outputs of the blind channel estimation unit and the channel estimation unit are input;
With
The receiving apparatus according to claim 7, wherein the second output switching means outputs either the output of the blind transmission path estimation unit or the output of the transmission path estimation unit to the equalizer. 9. The second output switching unit switches a signal to be output to the equalizer based on information on an interference signal included in a determination value output from the equalizer. Receiver.

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