JPH10308725A - Reception equipment and interference removing reception equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce device scale while improving multipath characteristic by generating the replica candidates of demodulated signal, finding the residual signal power values of plural replica candidates and received signal and performing demodulation by selecting the replica candidate having the bottom residual signal power value. SOLUTION: A convolusion integrator 16 generates received signal replicas from a transmission signal, which does not contain any information component, generated by a spreading code generation part 14 and the delay profile of transmission line from a transmission line response estimate part 13. A multiplier 17 prepares signal candidates to be received from the received signal replicas. The received signal replica and the signal candidate become residual signals as the difference from the received signal through a subtracter 18 and the signal having lower residual signal power value is outputted as the discriminated result through a power computing element 19 and an integrator 110 by a minimum value discriminator 111. Thus, interference removal can be more surely performed in a little circuit scale and delay time in discriminating processing can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a receiver for a code division multiple access (CDMA) system and a receiver for interference cancellation.

[0002]

2. Description of the Related Art In a CDMA cellular system, since the total amount of interference increases as the number of multiplexed users increases, various interference canceling receivers have been proposed for the purpose of increasing user capacity and improving communication quality.

[0003] Among them, as a receiving apparatus such as a spread spectrum communication system, there is a receiving apparatus using a matched filter having a weight coefficient of a spreading code for each tap of a transversal filter. This receiving apparatus uses an output of a matched filter corresponding to each spread code for interference removal. This matched filter is prepared for each received signal for each user.

[0004] A receiving apparatus using this matched filter has an advantage that a despread output can be obtained for each sample clock, but requires a weight multiplier for each tap, and is particularly applied to a system using a long spreading code. In this case, there is a disadvantage that the apparatus scale becomes large.

[0005] As another receiving apparatus, a spread code synchronized with the code of the received signal is generated inside the apparatus, multiplied by the received signal, and the signal resulting from the multiplication is integrated over the code period, thereby performing the inverse operation. There is a correlation receiver that performs spreading.

[0006] In recent years, the height of buildings tends to be high, and it is necessary to improve the influence of multipath as a receiving apparatus.

However, if a circuit for implementing path diversity reception in order to improve the multipath characteristics is to be constituted by the above-mentioned correlation receiving apparatus or receiving apparatus using a matched filter, any of the above-mentioned apparatuses is required to receive signals for each path. However, there is a disadvantage that the size of the circuit increases because synthesis must be performed thereafter.

[0008]

As described above, the conventional receiving apparatus described above has the following problems.

[0009] Since a coefficient multiplier is required for each tap of each matched filter, there is a problem that the circuit size of the receiving apparatus itself increases, especially when path diversity is performed in a system using a long spreading code. Further, when the number of users increases in the future, there is a problem that the user multiplexing characteristic (interference elimination characteristic) deteriorates, and the calculation for interference elimination takes much time, and the determination is delayed.

Further, if a circuit for realizing diversity reception is to be constructed in order to improve the multipath characteristics, there is a problem that the scale of the entire apparatus increases.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide a receiving apparatus and an interference canceling receiving apparatus which can reduce the size of the apparatus while improving the multipath characteristics. .

It is another object of the present invention to provide a receiving apparatus and an interference canceling receiving apparatus capable of obtaining good user multiplexing characteristics even when the number of users increases.

It is a further object of the present invention to provide a receiving apparatus and an interference canceling receiving apparatus which can reduce the delay time of the determination processing.

[0014]

In order to achieve the above object, a receiving apparatus according to the first aspect of the present invention provides a receiving apparatus in which a plurality of wireless communication apparatuses perform multiplex communication using different spreading codes within the same frequency band. In a receiving apparatus for demodulating a received signal of a code division multiple access (CDMA) method, an RF receiving means for frequency-converting the received signal to obtain a baseband signal;
Channel response estimating means for estimating the channel response received by the baseband signal for each spreading code, code synchronizing means for synchronizing each spreading code with respect to the baseband signal, and the channel response estimating means Using the transmission path response estimation value for each spreading code estimated by the above, timing information of each spreading code when synchronized by the code synchronization means, and information symbol candidates set by the modulation scheme. Replica signal generation means for generating a replica signal of a received signal; subtraction means for calculating each residual signal from a difference between each replica signal generated by the replica signal generation means and the baseband signal; A residual signal power measuring means for periodically measuring the power of the signal,
Minimum power determining means for outputting, as a demodulation result, one of the information symbol candidates which has generated the residual signal having the lowest power value among the power values of the residual signals obtained by the residual signal power measuring means. Have.

According to a second aspect of the present invention, in the receiving apparatus according to the first aspect, the replica signal generating means converts each spread code synchronized with the received signal from timing information obtained from the code synchronizing means. A spreading code generating means for generating, a filter for limiting a frequency band of each spreading code generated by the spreading code generating means and generating a transmission signal containing no information component, and excluding an information component generated by the filter A convolution integrator for generating a received signal replica containing no information component from a transmission signal and a transmission path response estimation value for each spreading code estimated by the transmission path response estimating means; and information generated by the convolution integrator. A received signal replica containing no component is branched, and replica signals of a plurality of received signals having a predetermined phase difference are generated according to a modulation scheme. ; And a phase difference signal generating means for outputting to the serial subtraction means.

According to a third aspect of the present invention, in the receiving apparatus according to the second aspect, the phase difference signal generating means multiplies a received signal replica not containing one of the branched information components by a predetermined coefficient. And a multiplier for providing a phase difference with the other.

According to a fourth aspect of the present invention, in the receiving apparatus according to the second aspect, the phase difference signal generating means assigns the first coefficient to a received signal replica that does not include one of the branched information components. A first multiplier that multiplies the received signal replica having the first phase difference and a second coefficient that multiplies the received signal replica that does not include the other branched information component by a second coefficient to have a second phase difference A second multiplier for generating a received signal replica, and further splitting the received signal replica having the respective phase difference output from the first and second multipliers, one of the split signals and the baseband And an adder for adding the signal.

According to a fifth aspect of the present invention, in the receiving apparatus according to the second aspect, the phase difference signal generating means includes a received signal replica not including one of the branched information components and the baseband signal. , A first shift register for delaying the received signal replica that does not include the other branched information component for a fixed time, and a second shift register for delaying the baseband signal for a fixed time. , The received signal replica delayed and output from the first shift register is further branched, and the second
And a second adder for further branching the baseband signal output delayed from the shift register and adding one of the branched ones. According to a sixth aspect of the present invention, there is provided an interference cancellation receiving apparatus which receives and demodulates a code division multiple access (CDMA) signal in which a plurality of wireless communication devices perform multiplex communication using different spreading codes within the same frequency band. RF receiving means for frequency-converting the received signal to obtain a baseband signal; transmission path response means for estimating a transmission path response received by the baseband signal for each spreading code; Code synchronization means for synchronizing each spread code with respect to the band signal; transmission path response estimation value estimated by the transmission path response estimation means; and timing information of each spread code when synchronized by the code synchronization means. And a replica signal generating means for generating a replica signal of the received signal corresponding to each user, and each transmission path response estimation value obtained by the transmission path response estimation means. Receiving power sorting means for sorting the received signals of the respective users in the order of the calculated received power by calculating the power of the received signals of the respective users; and the replica signal converting the received signals of the users in the order sorted by the received power sorting means. A subsequence estimating means for outputting a demodulation result by removing interference while demodulating by using a residual signal including information components corresponding to the remaining users,
Delay means for respectively delaying the demodulation result output from the partial sequence estimation means and the replica signal generated by the replica signal generation means; and the demodulation result and the replica signal delayed by the delay means and the baseband signal. A pre-interference removing unit that removes an interference component of a previous information symbol and inputs the same to the partial sequence estimating unit, a residual signal output from the partial sequence estimating unit, the demodulation result, and the transmission Post-detection means for performing re-demodulation of the remaining reception signal using each transmission path response estimation value obtained by the channel response estimation means and a replica signal of the reception signal for each user generated by the replica signal generation means; Is provided.

According to a seventh aspect of the present invention, there is provided an interference cancellation receiving apparatus in which a plurality of wireless communication apparatuses perform multiplex communication using different spreading codes within the same frequency band (CD).
In a receiving apparatus for receiving and demodulating a signal of the MA) system, a first antenna for receiving the signal of the CDMA system, and a frequency conversion of a received signal received by the first antenna to obtain a baseband signal First RF receiving means; first transmission path response estimating means for estimating, for each spreading code, a transmission path response received by the baseband signal frequency-converted by the first RF receiving means; Code synchronization means for synchronizing each spread code with respect to a band signal, a second antenna for receiving the CDMA signal, and frequency conversion of a received signal received by the first antenna to convert a baseband signal A second RF receiving means for obtaining, and a second estimation means for estimating, for each spreading code, a transmission path response received by the baseband signal frequency-converted by the second RF receiving means. A channel response estimating unit, a first channel response estimation value estimated by the first channel response estimating unit, and timing information of each spread code when synchronized by the code synchronizing unit. A first replica signal generating means for generating a first replica signal of the received signal corresponding to each user using the second transmission path response estimation value estimated by the second transmission path response estimation means; A second replica signal generating means for generating a second replica signal of a received signal corresponding to each user by using timing information of each spreading code synchronized by the code synchronizing means; And demodulating the received signal of the user in a predetermined order using the respective transmission path response estimation values and the first and second replica signals, removing interference, outputting a demodulation result, and outputting the remaining users. To Subsequence estimating means for outputting first and second residual signals including information components to be processed, and first delay means for delaying respective replica signals generated by the first and second replica signal generating means And second delay means for delaying the demodulation result output from the partial sequence estimating means; and a demodulation result delayed by the first and second delay means, a first replica signal, and the baseband signal. A first pre-interference removing unit that removes an interference component of an immediately preceding information symbol and inputs the result to the partial sequence estimating unit;
And a demodulation result delayed by the second delay means, a second replica signal and the baseband signal,
A second pre-interference removing unit that removes an interference component of a previous information symbol and inputs the result to the partial sequence estimation unit; a first and a second residual signal output from the partial sequence estimation unit; The demodulation result, the first and second transmission path response estimation values obtained by the first and second transmission path response estimation means, and the user-specific values generated by the first and second replica signal generation means for each user A post-detection unit for performing re-demodulation of the remaining reception signal using the first and second replica signals of the reception signal.

In a receiving apparatus of a code division multiple access (CDMA) system, if the condition of the transmission path, that is, a delay profile in the transmission path can be correctly obtained, the ideal receiving signal waveform excluding a phase element due to information modulation is obtained in the receiving apparatus. (Received signal replica) can be obtained. Further, by performing all possible phase modulation on the received signal replica, signal candidates to be received without adding noise or interference signals can be generated. Therefore, the difference (residual signal) between these received signal replica candidates and the received signal is obtained,
The power of each residual signal is obtained, path diversity reception can be performed by selecting the best replica candidate from the power value, and a circuit for performing the above series of processing includes a subtractor, an adder,
The processing can be performed at high speed and the circuit scale can be reduced by using an integrator, a shift register, or the like.

Therefore, according to the present invention, a replica candidate of a demodulated signal is generated, and a residual signal power value of a plurality of replica candidates and a received signal is obtained. Demodulation is performed by selecting a replica candidate having.

That is, instead of counting, multiplying and adding each tap in a matched filter when performing despreading,
Since demodulation is performed in synchronization with information symbols by subtraction and power measurement, a high-speed multiplier is not required, and matched filters for the number of paths are not required for path diversity reception, which simplifies the receiver. it can.

According to the first to fifth aspects of the present invention, the received signal is divided into a plurality of parts, the residual signal power is obtained in parallel, and the replica candidate having the minimum power value is output from the divided signal power. The speed can be increased, and the delay time required for the determination can be reduced.

According to the third to fifth aspects of the present invention, since the path diversity receiving circuit is realized by a simple configuration such as an adder, a subtractor, and a shift register, it is possible to reduce the size of the device while improving the multipath characteristics. it can.

According to the sixth aspect of the present invention, the generation of the residual signal and the determination of the replica candidate can be repeated in a small loop by delaying the replica candidate and the estimation result and using the result for interference removal of the previous received signal. It is possible to reliably perform interference cancellation with a small circuit scale, thereby obtaining an excellent user multiplexing characteristic (interference cancellation characteristic) in response to an increase in the number of users.

According to the seventh aspect of the present invention, in addition to the effect of the sixth aspect of the present invention, since the antenna diversity receiving circuit is realized with a simple configuration, the scale of the apparatus can be reduced while improving the multipath characteristics. .

[0027]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a receiver applied to a BPSK modulation method in a spread spectrum communication system or a CDMA system as a first embodiment of an interference cancellation receiver according to the present invention.

As shown in FIG. 1, the receiving apparatus includes an antenna 10, an RF receiving section 11, a code synchronizing section 12, a transmission path response estimating section 13, a spreading code generating section 14, a band limiting filter 15, a convolution integrator 16 , A multiplier 17 as a phase difference signal generating means, a subtractor 18, a power calculator 19, an integrator 1
10, a minimum value judging device 111 and the like. A replica signal generation unit includes the spreading code generation unit 14, the band limiting filter 15, the convolution integrator 16, the multiplier 17, the subtractor 18, and the like. The RF receiver 11 converts the frequency of a signal received by the antenna 10 into a baseband signal. The RF receiver 11 has an A / D converter inside. The code synchronizer 12 detects the timing of the spread code of the received signal and outputs timing information to the spread code generator 14 and each integrator 110. The transmission path response estimating unit 13 measures the complex delay profile (transmission path response estimation value) of the propagation path received by the received signal using the known signal portion of the sampled received signal. The spreading code generator 14 generates a spreading code synchronized with the received signal from the obtained timing information. The band limiting filter 15 limits the band of the spread code and generates a transmission signal containing no information component.
The convolution integrator 16 generates a received signal replica containing no information component from the transmission signal containing no information component and the delay profile of the transmission path. The multiplier 17 multiplies the received signal replica containing no information component by a coefficient -1 as an information symbol. In FIG. 1, a multiplier for multiplying by +1 as a coefficient is omitted. Power calculator 1
9 and the integrator 110 constitute a residual power measuring means. The minimum value determiner 111 receives the input of the residual signal power value corresponding to each information symbol candidate, and outputs a candidate having a smaller value as a determination result.

In the case of the receiving apparatus of the first embodiment, when a signal transmitted from a base station of a spread spectrum communication system or a CDMA system is received by an antenna 10, the received signal (received signal) is converted to an RF receiving unit. 11
Is converted to a baseband signal by the RF receiver 1
The digital signal is sampled by the A / D converter in 1 and converted into a digital signal. In response to this signal, the code synchronization section 12 detects the timing of the spread code of the received signal and transmits the timing information to the spread code generation section 14. The spreading code generator 14 generates a spreading code synchronized with the received signal from the obtained timing information. This spread code is band-limited by the band-limiting filter 15 to generate a transmission signal containing no information component.

On the other hand, the transmission path response estimator 13 measures the complex delay profile (transmission path response estimation value) of the propagation path received by the received signal using the known signal portion of the sampled received signal. As another method of realizing transmission path response estimation, there is a method of feeding back the demodulation result and removing the phase uncertainty due to the information component from the received signal to estimate the state of the transmission path response. These two transmission path response estimation methods are used separately depending on the type of information, timing, and the like.

The convolution integrator 16 generates a received signal replica containing no information component from the transmission signal containing no information component and the delay profile of the transmission path. For example, when the modulation scheme is BPSK, the received signal has two types of phase uncertainties, “0” (the coefficient as an information symbol is +1) and “π” (the coefficient as an information symbol is −1). The multiplier 17 multiplies the received signal replica containing no information component by a coefficient corresponding to each phase, in this case, -1 to prepare a candidate signal to be received. For these ideal received signal candidates, a subtractor 18 generates a residual signal that is a difference from the received signal, and a power calculator 19 and an integrator 110 reduce the power of each residual signal in an information symbol period. The measurement is performed, and the measurement result is output to the minimum value determination unit 111.

The minimum value determiner 111 receives the input of the residual signal power value corresponding to each information symbol candidate, selects the candidate with the smaller residual signal power value, and outputs it as a determination result.

As described above, according to the receiving apparatus of the first embodiment, the path diversity receiving circuit converts the received signal of the BPSK modulation method into a convolution integrator 16, a multiplier 17,
It can be realized with a simple configuration such as the subtractor 18, the power calculator 19, the integrator 110, and the minimum value determiner 111.

Next, a receiving apparatus according to a second embodiment will be described with reference to FIG.

FIG. 2 is a diagram showing a configuration of a receiving apparatus applied to the QPSK modulation method.

As shown in the figure, this receiving apparatus includes an antenna 20, an RF receiving unit 21, a code synchronizing unit 22, a transmission line response estimating unit 23, a spreading code generating unit 24, a band limiting filter 25, and a convolution integrator 26. , A multiplier 27a as a first multiplier, a multiplier 27b as a second multiplier, subtractors 28 and 210, adders 29 and 211, and a power calculator 21.
2, an integrator 213, a minimum value determiner 214, and the like. Spreading code generator 24, band limiting filter 2
5, convolution integrator 26, multiplier 27, adder 29, 2
11 and the like constitute a replica signal generating means.

In the case of the receiving apparatus of the second embodiment, a received signal of a spread spectrum communication system or a CDMA system is frequency-converted into a baseband signal by an RF receiving section 21, sampled by an A / D converter and converted to a digital signal. Is converted to The signal synchronization unit 2
2 detects the timing of the spread code of the received signal and transmits the timing information to the spread code generator 24. The spread code generator generates a spread code synchronized with the received signal from the obtained timing information. The spread code is band-limited by the band-limiting filter 25 to generate a transmission signal containing no information component. On the other hand, the transmission path response estimator 23 measures the complex delay profile of the propagation path received by the received signal using the known signal portion of the sampled received signal. As another method of realizing the transmission path response estimation, there is a method of estimating the state of the transmission path response by feeding back the demodulation result and removing the phase uncertainty due to the information component from the received signal, as in the first embodiment. Use them properly.

The convolution integrator 26 generates a received signal replica containing no information component from the transmission signal containing no information component and the delay profile of the transmission path.

In the case of the QPSK modulation method, the received signal includes "π / 4", "3π / 4", "-3π / 4", "-π /
4 ". There are four types of phase uncertainties,
/ 4 "and" -3π / 4 ", and" 3π / 4 "and" -π
/ 4 "differ only in phase by 180 degrees, so that the subtracters 28 and 210 for calculating the difference are added to the adder 2
The same processing can be performed only by changing to 9, 211.

Therefore, the multiplier 27a multiplies the received signal replica not containing the information component by the coefficient (1 / route 2, -1 / route 2) corresponding to each phase, and determines the candidate of the signal to be received. prepare. In the multiplier 27b,
A received signal replica containing no information component is multiplied by a coefficient (1 / route 2, 1 / route 2) corresponding to each phase to prepare a signal candidate to be received. As another embodiment, replica candidates can be prepared by multiplying coefficients corresponding to all phases.

The replica signal candidate generated by the multiplier 27a is branched into two, and one of these two ideal replica signal candidates is input to the subtracter 28, and the residual signal representing the difference from the received signal is obtained. A signal is generated. The other of the two ideal replica signal candidates is input to the adder 29, and a residual signal that is a sum with the received signal is generated.
On the other hand, the replica signal candidate generated by the multiplier 27b also branches into two in the same manner as described above, and one of the two replica signal candidates is input to the subtractor 210, and the residual signal that is the difference from the received signal is obtained. Generated. The other of the two is input to the adder 211 to generate a residual signal that is a sum with the received signal.

As a result, four residual signals are generated and input to the respective power calculators 212.

Each power calculator 212 and integrator 213 measure the power of each residual signal at the information symbol period (timing information), and individually output to the minimum value determiner 214.

The minimum value determiner 214 receives the input of the residual signal power value corresponding to each information symbol candidate,
An information symbol candidate having a low power value is selected from a plurality of input residual signal power values and output as a determination result.

According to the receiving apparatus of the second embodiment, Q
The path diversity receiving circuit for the received signal of the PSK modulation method is configured by a convolution integrator 26, multipliers 27a and 27b,
It can be realized by a simple configuration such as the subtracters 28 and 210, the adders 29 and 211, the power calculator 212, the integrator 213, and the minimum value determiner 214.

Next, a receiving apparatus according to a third embodiment will be described with reference to FIG.

FIG. 3 is a diagram showing a configuration of a receiving apparatus applied to the BPSK modulation method.

As shown in the figure, this receiving apparatus includes an antenna 30, an RF receiving unit 31, a code synchronizing unit 32, a transmission line response estimating unit 33, a spreading code generating unit 34, a band limiting filter 35, a convolution integrator 36 , A shift register 37 as a first shift register, a shift register 38 as a second shift register, subtractors 39 and 310, an adder 311 as a first adder, and an adder 312 as a second adder. , Power calculator 313, integrator 314, adder 3
15, 316, a minimum value judging device 317 and the like. A replica signal generation unit includes the spread code generation unit 34, the band limiting filter 35, the convolution integrator 36, the shift registers 37 and 38, the adders 311, 312, and the like. The shift register 37 delays the received signal replica containing no information component from the convolution integrator 36 by half the information symbol period, and subtracts the subtracted signal from the replica 310 by the adder 3.
12 is output. The shift register 38 delays the baseband signal (received signal) by half the information symbol period and outputs the delayed signal to the subtractor 310 and the adder 312. The subtractor 310 adds a received signal replica that does not include an input information component and is input with a time delay of half the information symbol period and a baseband signal (received signal). The adder 312 subtracts a baseband signal (received signal) from a received signal replica that does not include an input information component and is input after being delayed by half the information symbol period. The adders 315 and 316 combine the in-phase and residual signals obtained by adding and subtracting the received signal and the replica signal separately from each other, and output the final residual signal power value.

In the case of the receiving apparatus of the third embodiment, a received signal of a spread spectrum communication system or a CDMA system is frequency-converted into a baseband signal by an RF receiver 31, sampled by an A / D converter, and converted into a digital signal. Is converted to The signal synchronization unit 3
In 2, the spread code timing of the received signal is detected, and the timing information is output to the spread code generation unit 34.

The spreading code generator 34 generates a spreading code synchronized with the received signal from the obtained timing information.
The spread code is band-limited by the band-limiting filter 35 to generate a transmission signal containing no information component.

On the other hand, the transmission path response estimating section 33 measures the complex delay profile (transmission path response estimation value) of the transmission path received by the received signal using the known signal portion of the sampled reception signal. As another method of realizing the transmission path response estimation, there is a method of estimating the state of the transmission path response by feeding back the demodulation result and removing the phase uncertainty due to the information component from the received signal. We use properly depending on. In the convolution integrator 36, a received signal replica containing no information component is generated from the transmission signal containing no information component and the delay profile of the transmission path. This ideal received signal replica is divided into two, one of which is delayed as it is, and the other is delayed by a half of the information symbol period via the shift register 37.

On the other hand, the received signal is similarly divided into two to generate a signal that is not delayed and a signal that is delayed by half the information symbol period.

These signals are divided into the first half and the second half of the information symbol period, and the residual signal power can be calculated in parallel. Note that the number of divisions is not limited to two. By increasing the number of divisions further, the number of adders, subtractors, and residual signal power measuring devices increases, but
The signal can be output in a short cycle, and the processing can be speeded up.

The received signal and received signal replica not subjected to the delay and the received signal and received signal replica subjected to the delay are respectively subjected to subtractors 39 and 310 and adders 311 and 3 respectively.
12 separately generate residual signals, and the power calculator 3
13 and the integrator 314 measure the power of each residual signal in a half cycle of the information symbol, and the measurement result is output to the adders 315 and 316.

In the adders 315 and 316, the received signal and the residual signal obtained by addition and subtraction of the replica signal are separately synthesized, and the final residual signal power value is calculated from the minimum value determining unit. 317 is output.

The minimum value determiner 317 receives the input of the residual signal power value corresponding to each information symbol candidate,
At the timing of the synchronization signal from the code synchronization unit 32, the candidate with the smaller residual signal power value is output as the determination result.

As described above, according to the receiving apparatus of the third embodiment, the path diversity receiving circuit converts the received signal of the BPSK modulation system into a convolution integrator 36, shift registers 37 and 38, subtractors 39 and 310, and an adder. Vessels 311, 3
12, power calculator 313, integrator 314, adder 31
5, 316, a minimum value determiner 317, and the like. Further, in the case of the receiving device of the third embodiment, the number of adders and subtractors increases, but the number of parallel processes increases, and the replica candidate can be determined at higher speed than in the first embodiment. The delay time required for the determination process is reduced.

Since the example of the third embodiment is a BPSK modulation method, two types of phase uncertainties of “0” and “π” of the received signal are added to adders 311 and 312 or subtractors 39 and 310 later. , But this is, for example, QPSK
In the case of the modulation system, as shown in FIG.
27b, a received signal replica containing no information component is multiplied by a coefficient corresponding to each phase to prepare a signal candidate to be received. Next, an interference cancellation receiving apparatus according to a fourth embodiment of the present invention will be described with reference to FIGS.

FIG. 4 is a block diagram showing the configuration of the interference cancellation receiver in the DS-CDMA system, and FIG. 5 is a diagram showing the specific configuration of the partial sequence estimator of the interference cancellation receiver of FIG. DS is an abbreviation for Direct Sequence (direct spreading modulation).

As shown in FIG. 4, the interference cancellation receiving apparatus includes an antenna 40, an RF receiving section 41, a code synchronizing section 42,
Channel response estimator 43, replica generator 44, previous bit interference remover 46, subsequence estimator 47, subsequent detector 4
8, a delay unit (delay1) 49, a delay unit (delay2) 410, and the like. The RF receiver 41 is an antenna 40
To obtain a baseband signal from the received signal received by the base station. The received signal may be an analog signal or a digital signal.
An A / D converter is provided in 1 to perform A / D conversion to obtain a digital signal. The code synchronization section 42 performs synchronization supplementation and holding of the spread code of each user from the baseband signal input from the RF reception section 41. The transmission path response estimation section 43 estimates the transmission path response received by each user based on the baseband signal supplied from the RF reception section 41 and the timing information from the code synchronization section 42. The replica generation unit 44 includes a transmission path response estimation unit 43
The replica signal of each user is generated from the transmission path response for each user obtained in step (1) and the information of the spreading sequence of each user. The received power sorting section 45 calculates the received power from the transmission path response (delay profile) of each user, associates the actual number of the user with the order of the received power, and obtains the order information for each user into the partial sequence estimating section 47. To communicate. The delay unit (delay1) 49 delays the replica signal generated at the previous time by one symbol, and outputs the delayed signal to the previous bit interference removing unit 46. The delay unit (delay2) 410 delays the transmission bit estimation result generated at the previous time by one symbol, and outputs the result to the previous bit interference removal unit 46. The previous bit interference removing unit 46 removes interference of the previous bit. The partial sequence estimating unit 47 performs sequence estimation on the received signal of the highest group of the order information notified from the received power sorting unit 45 while dividing some users, for example, all users to be received into some groups. , And outputs the estimation result to the subsequent detection unit 48. The sequence estimation is to state all combinations of users in a group, to select a surviving path for sequence estimation among the grouped states, and to demodulate. Subsequence estimation unit 4
Reference numeral 7 removes the demodulated portion of the received signal from the received signal and outputs the remainder as a residual signal to the subsequent detection section 48.
The post-stage detector 48 demodulates the remaining users using the transmission path response (delay profile), code timing information, the estimation result, and the residual signal, outputs the demodulation result, and outputs the output of the internal matched filter to the code synchronization unit. The signal is output (feedback) to the transmission line response estimating unit 43 and the transmission line response estimating unit 43.

As an example of the subsequence estimation unit 47,
As shown in FIG. 5, the shift register 51 and the switch 5
2. A plurality of shift registers 53 for the user, a reference signal generator 57, a plurality of subtracters 55, a plurality of signal power calculators 5
4, a minimum value selector 58, switches 510 and 511, a sequence estimation controller (CONTROL) 59, and the like. The shift register 51 stores the sampling rate (CLK1) of the received signal.
And has a delay amount of about three information symbols. The shift register 51 temporarily holds the input signal (received signal-previous bit interference removal signal) as data. The switch 52 transfers the contents of the shift register 51 to the shift register 53 at the information symbol period under the control of the sequence estimation control section 59. The reference signal generator 57 generates a plurality of received signal replica candidates from the replica signals of all users obtained from the replica generator 44, the order information of the sorting result, and the user grouping information obtained from the sequence estimation controller 59. The reference signal generator 57 generates different received signal replica candidates in synchronization with the shift of the switch 510, and uses the subtractor 56 to generate a residual signal corresponding to each received signal replica candidate. The signal power calculator 54 calculates the power of each user. The minimum value selector 58 selects the minimum value from the respective signal power calculation results and outputs it as an estimation result.
The switch 511 outputs the finally selected residual signal. A sequence estimation control unit (CONTROL) 59 controls the above units and outputs user grouping information and control signals.

In the case of the interference cancellation receiving apparatus of the fourth embodiment, when an RF signal (analog radio wave) is transmitted from the base station of the CDMA system, the RF signal is transmitted to the antenna 4.
When the RF signal is received by the RF receiving unit 41 through 0, the received signal is frequency-converted by the RF receiving unit 41 to be dropped into a baseband signal, sampled by an A / D converter in the RF receiving unit 41, and converted into a digital signal. Is converted. This digital signal is output to the code synchronization section 42, the transmission path response estimation section 43, and the previous bit interference removal section 46.

When the digital signal is input to the code synchronization section 42, the code synchronization section 42 detects the timing of the spread code of the received signal and transmits the timing information to the transmission path response estimation section 43. The transmission path response estimating unit 43 measures the complex delay profile (transmission path response value) of the transmission path received by the reception signal of each user using the known signal portion (known symbol) of the sampled reception signal.

As a method of estimating a channel response using a portion other than a known symbol, a result obtained by demodulating a received signal in a subsequent stage is fed back, a phase uncertainty due to an information component is removed from the received signal, and the channel response is estimated. Although there is a method of estimating the state, any one of them is used depending on the frame configuration of the received signal or the transmission state. The replica generation unit 44 obtains information corresponding to each user from the code timing information obtained by the code synchronization unit 42 and the delay profile information of the transmission path received by each user's received signal obtained by the transmission path response estimation unit 43. Generate a replica signal containing no component.

On the other hand, the received power sorting section 45
The received power is calculated from the delay profile of each user, and the number of the actual user and the order of the received power are corresponded,
This information is output to subsequence estimation section 47.

In the preceding bit interference removing unit 46, the delay unit (de
lay1) 49 and a replica signal of the received signal of each user input through the delay unit (delay2) 410, and the transmission sequence estimation result of each user of the subsequence estimation unit 43 input through the delay unit (delay2) 410. A composite replica signal one symbol before the symbol to be reproduced is generated and removed from the received signal.
The delay unit (delay1) 49 and the delay unit (delay2) 41
In the case of 0, the delay amount is adjusted so that the replica signal generated at the previous time and the estimation result are output with a shift of one symbol in the furnishing.

The signal from which the previous bit interference has been removed by the preceding bit interference removing section 46 is introduced into the partial sequence estimating section 47, and the partial sequence estimating section 47 performs a partial sequence estimating operation (interference removing receiving operation). .

In this case, the previous bit interference elimination signal input to the subsequence estimation unit 47 is introduced into the shift register 51 and temporarily held therein, and the switch 52 is switched at an appropriate timing.
Is transferred to the shift register 53 and set.
The signal initially set in the shift register 53 is fed back to the subtractor 55 and the adder 56 via the switch 510.

On the other hand, in the reference signal generation section 57, the replica signals of all users obtained from the replica generation section 44, the reception power sorting result obtained from the reception power sorting section 45, and the sequence estimation control section (CONTROL) 59 A plurality of received signal replica candidates are generated based on the obtained user grouping information. As the received signal replica candidates, all combinations of the users in each group over two symbol times are generated. Also, the interference elimination processing is 1
Each time the step ends, a received signal replica candidate of a different group is generated in synchronization with the contents of the shift register 53.

In the reference signal generator 57, different received signal replica candidates are generated in synchronization with the shift of the switch 510, and the subtractor 55 and the adder 56 described above use the residual error corresponding to each replica candidate. A signal is generated.

The residual signal generated by the reference signal generator 57 is again introduced into the shift register 53, and the power of the content of the shift register 53 is measured by the signal power calculator 54. These power measurement results are introduced to the minimum value determiner 58.

The minimum value determiner 58 selects a residual signal having the lowest power and a combination of information symbol candidates that have generated the residual signal based on the power measurement result. With respect to this residual signal, the switch with the lowest power is again fed back to the next step by the switch 510 (feedback signal). An estimation result for one group is output from the combination of the information symbol candidates.

After the next step, sequence estimation in the next group is performed in the same procedure as described above except that the residual signal is used, and this sequence estimation operation is performed until the last user is estimated, or is determined in advance. Up to the number of steps set. After these series of operations are completed, the switch 511 is turned on by a control signal from the sequence estimation control unit (CONTROL) 59, and the final residual signal is output to the subsequent detection unit 48.
, And the received signal is transferred to the shift register 51 again in order to perform symbol determination at the next time.

As described above, the partial sequence estimating unit 47
The primary demodulation results of all users are output to the subsequent detection unit 48 as the estimation result of the partial sequence. Further, a residual signal generated from a signal obtained by synthesizing the estimation result and the replica signal of the received signal of each user and the received signal is output to the subsequent detection unit 48.

In the subsequent detection section 48, the partial sequence estimation section 47
The estimation result is corrected by using the residual signal and the estimation result obtained in the above and the replica signal of each user, and the corrected result is used as the final output, and at the same time, each user's The output of the matched filter is transmitted to the code synchronization section 42 and the transmission path response estimation section 43.

As described above, the DS-CD of the fourth embodiment
According to the interference cancellation receiving apparatus in the MA system, the partial sequence estimator 47 removes the previous bit interference and outputs the estimation result, the estimation result is corrected by the subsequent detection unit 48, and the corrected result is used as the final output. By doing so, interference cancellation reception can be realized more reliably with a simple circuit configuration, and the user capacity of the system can be improved.

Next, an interference cancellation receiving apparatus according to a fifth embodiment of the present invention will be described with reference to FIGS.
FIG. 6 is a block diagram illustrating a configuration of an antenna diversity receiver according to a fifth embodiment of the present invention, and FIG. 7 is a diagram illustrating a specific configuration of a partial sequence estimation unit of the antenna diversity receiver of FIG.

As shown in FIG. 6, an antenna 60a as a first antenna for receiving a CDMA signal, and a first RF reception for converting a frequency of a received signal received by the antenna 60a to obtain a baseband signal An RF unit 61 as means, a code synchronization unit 62 for synchronizing each spread code with respect to the baseband signal, and a transmission path response a received by the baseband signal frequency-converted by the RF unit 61 for each spread code. Channel response estimating unit 63 as first channel response estimating means for estimating, and a channel response a as a first channel response estimation value estimated by the channel response estimating unit 63 and a code synchronization unit. A first replica signal a of the received signal corresponding to each user is generated using the timing information (code timing information) of each spreading code synchronized by 62. A replica generation unit 64 as a first replica signal generation unit, an antenna 60b as a second antenna for receiving a signal of the CDMA system, and a frequency conversion of a reception signal received by the antenna 60b to convert a baseband signal RF section 68 as second RF receiving means to be obtained, and second transmission path response estimating means for estimating a transmission path response received by the baseband signal frequency-converted by this RF section 68 for each spreading code. , A transmission path response b as a second transmission path response estimated value estimated by the transmission path response estimation section 69, and each spread when synchronized by the code synchronization section 62. Replica generation as second replica signal generation means for generating a second replica signal b of the received signal corresponding to each user using the code timing information And 610, a replica signal delayed by the delay-out (delay1) 612 b
And the baseband signal from the RF unit 68 and the delay
2) Based on the demodulation result delayed by 67, the previous bit interference as the first pre-interference canceling means, which removes the interference of the previous bit, which is the immediately preceding received signal, and inputs the result to subsequence estimation section 614 The demodulator 611 and the transmission path responses a and b and the replica signals a and b are used to demodulate a user's received signal in a predetermined order while removing interference and outputting a demodulation result.
First and second containing information components corresponding to the remaining users
A subsequence estimating unit 614 that outputs a residual signal of the following, a delay (delay1) 66 as a first delay unit that delays the replica signal a generated by the replica generating unit 64,
Replica signal b generated by replica generation section 610
(Delay1) as first delay means for delaying
612, a reception power sorting unit 613 that calculates reception power from the individual transmission path responses a and b, associates the actual user number with the order of the reception intensity, and notifies this information to the partial sequence estimation unit 614. , A delay (delay2) 67 as a second delay unit for delaying the demodulation result output from the partial sequence estimator 614, a replica signal a delayed by the delay (delay1) 66, and a base from the RF unit 61. Based on the band signal and the demodulation result delayed by the delay (delay2) 67, the first pre-interference cancellation that removes the interference of the previous bit, which is the immediately preceding received signal, and inputs the interference to the partial sequence estimation unit 614 The preceding bit interference removing unit 65 as a means, the replica signal b delayed by the delay unit (delay1) 612, the baseband signal from the RF unit 68, and the delay unit (delay2)
Based on the demodulation result delayed by 67, the interference of the previous bit, which is the immediately preceding received signal, is removed, and the partial sequence estimation unit 6
14, a previous bit interference canceller 611 as a second interference canceler, the residual signals a and b output from the partial sequence estimator 614, demodulation results, transmission path responses a and b, and each user And a subsequent-stage detection unit 615 that re-demodulates the remaining received signals by using the replica signals a and b of the received signal and outputs the demodulation result.

The post-stage detecting section 615 includes a matched filter for each user inside, and feeds back the output of each matched filter to the corresponding channel response estimating sections 63 and 69. An A / D converter is provided inside each of the RF units 61 and 68. The delay units (delay1) 66 and 612 and the delay unit (delay2) 67 adjust the amount of delay so that the replica signal generated at the previous time and the estimation result are output with one symbol offset.

The branch a includes the antenna 60a and the RF unit 6
1, a transmission path response estimation unit 63, a replica generation unit 64, a previous bit interference removal unit 65, a delay (delay1) 66, and the like. The branch b is connected to the antenna 60b, R
F unit 68, channel response estimation unit 69, replica generation unit 61
0, previous bit interference canceller 611, delay (delay1) 61
2 and the like.

As shown in FIG. 7, the partial sequence estimating section 614 has a shift register 7 as a configuration on the branch a side.
1, a switch 72, a plurality of shift registers 7 for a user
3, a plurality of signal power calculators 74, a plurality of adders 75, a plurality of subtracters 76, a reference signal generator 77, a switch 71
8, 720 and the like.

Further, as a configuration on the branch b side, a shift register 78, a switch 79, a plurality of shift registers 710 for a user, a plurality of signal power calculators 711, a plurality of adders 712, a plurality of subtracters 713, a reference signal generation Part 71
4, switches 719 and 721, and the like.

The subsequence estimating section 614 calculates the total amount of power for each shift of the plurality of power calculation results separately output from the signal power calculators 74 and 711 of the branches a and b. And a minimum value selector 716 that compares the total amount of power for each shift by the adder 715 and selects the minimum value among them, and outputs a minimum value selection signal. The minimum value selection output from the minimum value selector 716 A sequence estimation control unit (CONTROL) that selects one of the replica candidates of the received signal based on the signal and outputs it as an estimation result
717 and the like.

In the case of the antenna diversity receiver according to the fifth embodiment, the received signal of the spread spectrum communication system or the CDMA system received on the branch a side is frequency-converted by the RF unit 61 into a baseband signal.
It is sampled by an A / D converter inside the RF unit 61 and converted into a digital signal. In response to this signal, the code synchronization unit 62 detects the timing of the spread code of the received signal,
The timing information is transmitted to the transmission path response estimation unit 63. The transmission path response estimator measures the transmission path response a (complex delay profile of the transmission path) received by each user's reception signal using the known signal portion of the sampled reception signal of the branch a. As a transmission path response estimation method using a portion other than the known symbol, a method of estimating a state of a transmission path response by removing a phase uncertainty due to an information component from a received signal by feeding back a demodulation result from a subsequent detection unit 615. Here, the estimation method is properly used depending on the frame configuration and transmission state of the received signal.

The replica generation section 64 transmits the code timing information obtained by the code synchronization section 62 and the complex delay profile information of the transmission path received by each reception signal obtained by the transmission path response estimation section 63 in the branch a, that is, the transmission From the road response a, a replica signal containing no information component corresponding to each user is generated.

Further, in received power sorting section 613,
Receiving the transmission path response a of each user, the reception power is calculated for each user, the number of the actual user is made to correspond to the order of the reception strength, and this information is used as the partial sequence estimation unit 614.
Output to

The previous bit interference removing section 65 has a delay (delay)
1) Estimation is performed using the received signal replica a of each user on the branch a side input through 66 and the transmission bit estimation result of each user of the subsequence estimator 614 input through the delay (delay 2) 67. A composite replica signal one symbol before the symbol to be performed is generated, removed from the received signal (baseband signal) of the branch a input from the RF unit 61, and input to the partial sequence estimator 614.

On the other hand, the spread spectrum communication system or CDMA received by the antenna 60b on the branch b side
The received signal of the system is frequency-converted into a baseband signal by an RF unit 68, sampled by an A / D converter in the RF unit 68, and converted into a digital signal. The spread code timing information obtained by the code synchronization unit is transmitted to the transmission path response estimation unit 69, and among the received signals of the branch b,
The transmission path response b, which is the complex delay profile of the transmission path received by each user's received signal, is measured using the known signal portion. Also, as a method of realizing transmission path response estimation using a part other than a known symbol, there is a method of estimating a state of a transmission path response by feeding back a demodulation result and removing a phase uncertainty due to an information component from a received signal, Here, different estimation methods are used depending on the frame configuration and transmission state of the received signal.

The replica generation section 610 transmits the code timing information obtained by the code synchronization section 62 and the complex delay profile information of the transmission path received by each reception signal obtained by the transmission path response estimation section 69 in the branch b. From the road response b, a replica signal b containing no information component corresponding to each user is generated.

Receiving power sorting section 613 receives the transmission path response b of each user, calculates the receiving power, associates the actual user number with the order of the receiving strength, and estimates this information as a partial sequence. Output to the unit 614.

The previous bit interference removal unit 611 outputs the delay (dela
y1) The estimation is performed by using the received signal replica b of the branch b of each user input through 612 and the transmission bit estimation result of each user of the subsequence estimator 614 input through the delay (delay2) 67. A composite replica signal one symbol before the symbol to be reproduced is generated and removed from the received signal (baseband signal) of branch b.

Then, the received signal from which the interference of the previous bit has been removed is input to subsequence estimation section 614, and interference removal reception is performed.

In this case, the partial sequence estimating section 614 introduces the signal received at the branch a and from which the interference of the previous bit has been removed into the shift register 71. The shift register 71 operates at the sampling rate (CLK1) of the received signal and has a delay amount of about three information symbols. The switch 72 transfers the contents of the shift register 71 to the shift register 73 at the information symbol period under the control of the sequence estimation control unit 717.

On the other hand, the reference signal generator 77 for the branch a
Generates a plurality of received signal replica candidates from the replica signals of all users obtained from the replica generation unit 64 for branch a and the user grouping information obtained from the sequence estimation control unit 717 based on the sorting result. All combinations of the received signal replica candidates over two symbol times of the users in each group are generated. Also, each time the interference removal is completed by one step, a received signal replica candidate of a different group is generated in synchronization with the contents of the shift register 73.

The signal first introduced into the shift register 73 is a baseband signal, which is fed back via the switch 718 and introduced into each of the first adder 75 and the first subtractor 76. After the second time, the switch 718 shifts to the second.

In reference signal generator 77, switch 718
In synchronization with this shift, different received signal replica candidates are generated, and the respective received signal replica candidates are output to the first adder 75 and the subtractor 76. The first adder 75 and the subtractor 76 respectively output the received signal replica candidates. Are added or subtracted, and a residual signal corresponding to each replica candidate is generated, and introduced into the first shift register 73. Then, the first signal power calculator 74 operates the first shift register 73.
Is measured. Thereafter, the residual signal is changed to the second and subsequent adders 7 according to the shift of the switch 718.
5. The power is fed back to the subtractor 76, and the power measurement is sequentially performed.

On the other hand, similarly to the branch a, the signal received by the antenna 60b on the branch b side and from which the interference of the previous bit has been removed is introduced into the shift register 78. This shift register also operates at the sampling rate (CLK1) of the received signal, and has a delay amount of about three information symbols. The switch 79 synchronizes with the switch 72 to transfer the contents of the shift register 78 to the shift register 710 at the information symbol period under the control of the sequence estimation control section 717.

On the other hand, the reference signal generator 71 on the branch b side
In 4, a plurality of received signal replica candidates are generated from replica signals of all users obtained from the replica generation unit 610 for branch b and user grouping information obtained from the sequence estimation control unit 717 based on the sorting result. You. As for the received signal replica candidate, all combinations of the users in each group over two symbol times are generated as in the case of the branch a. Also, every time the interference removal is completed by one step, a received signal replica candidate of a different group is generated in synchronization with the contents of the shift register 79.

The signal first introduced into the shift register 71 is fed back via the switch 719,
It is introduced to the second adder 712 and the subtractor 713.

On the other hand, the reference signal generator 714
In synchronization with the 19th shift, different received signal replica candidates are generated and input to the first adder 712 and the subtractor 713, and the first adder 712 and the subtractor 713 correspond to each replica candidate. A residual signal is generated, and the generated residual signal is introduced into the first shift register 710, and the power of the content of the shift register 710 is measured by the first signal power calculator 711. After that, the data is shifted to the second and subsequent ones similarly to the branch a side.

In this way, the branch a side and the branch b
The residual signal power determined on the side is added to an adder 715.
, Power values corresponding to the same combination of information symbols are combined and introduced into the minimum value determiner 716.

The minimum value determiner 716 selects the combination of the residual signal having the lowest power and the information symbol candidate that has generated the residual signal, and notifies the combination to the sequence estimation controller 717. The switch 718 and the switch 719 again use the candidate having the lowest power as the feedback to the next step.

The sequence estimation control section 717 receives the notification of the combination of the residual signal having the smallest power and the information symbol candidate from the minimum value determiner 716, and outputs the estimation result for one group.

In the next step, sequence estimation in the next group is performed in the same procedure. This operation is performed until the estimation of the last user is completed or up to a predetermined number of steps. Further, after these series of operations are completed, the switch 7 is controlled by the control signal of the sequence estimation control unit 717.
20, the switch 721 is turned on, and the final residual signal of each of the branch a and the branch b is output to the subsequent detection unit 615. Further, the received signal is transferred to the shift registers 73 and 710 again in order to determine the symbol at the next time.

That is, subsequence estimation section 614 uses the primary demodulation result of all users as the estimation result, and calculates the residual of the signal obtained by combining the estimation result with the replica signal of each user and the received signal. The difference signal is output to the subsequent detection unit 615.

[0107] Subsequent detection section 615 includes subsequence estimation section 6
The estimation result is corrected by using the residual signal and the estimation result obtained in step 14 and the replica signal of each user, and the corrected result is used as the final output. The output of the matched filter of the user is output to the code synchronization unit 62.
Then, the signals are fed back to the transmission path response estimation units 63 and 69.

As described above, according to the antenna diversity receiving apparatus of the fifth embodiment, sequence estimating section 614 includes shift registers 71 and 73, switches 72, 718 and 72.
0, a signal power calculator 74, an adder 75, a subtractor 76, a reference signal generation unit 77, and other simple circuit components. At the same time, interference cancellation reception can be realized, and the circuit scale can be reduced. Multipath characteristics can be improved. Also, it can cope with an increase in the user capacity of the system. In the fifth embodiment, the number of diversity branches is two, that is, the branches a and b.
The number is not limited to three, and may be three or more. In this case, the configuration from the RF unit to the previous bit interference removing unit is increased according to the number of branches.

As described above, each of the above-described embodiments can be implemented in combination. Also, the components of the receiving device of each of the above embodiments need not be physically separated, and can be realized on a single or a plurality of signal processors.

[0110]

As described above, according to the present invention, the replica signal and the estimation result are delayed, interference of the previous received signal is eliminated, and the result is input to the transmission path response estimating means to generate the residual signal. Since the replica candidate is repeatedly estimated, interference removal can be performed more reliably with a small circuit scale,
Thereafter, good user multiplexing characteristics can be obtained even when the number of users increases.

According to the present invention, the received signal power is obtained in parallel by branching the received signal a plurality of times, and the obtained residual signal power is used for the determination processing. Therefore, the delay time of the determination processing can be reduced.

Further, according to the present invention, since a circuit for implementing diversity reception including path diversity reception is formed by a simple circuit, the circuit scale can be reduced while improving multipath characteristics.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a BPSK modulation type receiving apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a QPSK modulation type receiving apparatus according to a second embodiment of the present invention.

FIG. 3 is a diagram illustrating a configuration of a BPSK modulation type receiving apparatus according to a third embodiment of the present invention.

FIG. 4 is a diagram illustrating a configuration of an interference cancellation receiving apparatus according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing a specific example of a subsequence estimation unit of the interference cancellation reception apparatus in FIG. 4;

FIG. 6 is a diagram illustrating a configuration of a diversity interference cancellation receiving apparatus according to a fifth embodiment of the present invention.

FIG. 7 is a diagram showing a specific example of a subsequence estimation unit of the diversity interference cancellation receiving apparatus of FIG. 6;

[Explanation of symbols]

11, 21, 31, 41, 61, 68 ... RF receiving section, 1
2, 22, 32, 42, 62 ... code synchronization section, 13, 2
3, 33, 43, 63, 69 ... channel response estimation unit, 1
4, 24, 34... Spreading code generator, 15, 25, 35.
Band limit filters, 16, 26, 36: convolution integrators, 17, 27a, 27b: multipliers, 18, 28, 21
0, 39, 310, 56, 76, 713 ... subtractor, 1
9, 212, 313 Power calculator, 110, 213, 3
14: integrator, 111, 214, 317: minimum value determiner, 29, 311, 312, 315, 316, 55, 7
5,712,715 ... adder, 37,38,51,5
3, 71, 73, 78, 710 shift register, 4
4, 64, 610: replica signal generator, 45, 613
... Received power sorting section, 46, 65, 611 Previous bit interference removal section, 47, 614 Subsequence estimation section, 4
8,615... Latter-stage detector, 49,410,66,67,
612 delay unit, 52, 510, 511, 718, 71
9, 720, 721 ... switch, 54, 74, 711 ...
Signal power calculators, 57, 77, 714... Reference signal generators, 59, 717...

Claims (7)

[Claims] 1. A receiving apparatus for demodulating a reception signal of a code division multiple access (CDMA) system in which a plurality of wireless communication devices perform multiplex communication using different spreading codes in the same frequency band, RF receiving means for converting and obtaining a baseband signal; transmission path response estimating means for estimating a transmission path response received by the baseband signal for each spreading code; synchronization of each spreading code with respect to the baseband signal A code synchronization unit that performs the transmission channel response estimation value for each spreading code estimated by the channel response estimation unit, and timing information and a modulation method of each spreading code when synchronized by the code synchronization unit. Replica signal generating means for generating a replica signal of each received signal using the set information symbol candidate, and the replica signal generating means Subtraction means for calculating each residual signal from the difference between each generated replica signal and the baseband signal; residual signal power measurement means for periodically measuring power for each residual signal; Minimum power determining means for outputting, as a demodulation result, one of the information symbol candidates which has generated the residual signal having the lowest power value among the power values of the residual signals obtained by the signal power measuring means. A receiving device characterized by the above-mentioned. 2. The receiving device according to claim 1, wherein the replica signal generating unit generates spreading code synchronized with a received signal from timing information obtained from the code synchronizing unit, A filter for restricting the frequency band of each spread code generated by the spread code generation means and generating a transmission signal containing no information component; a transmission signal containing no information component generated by the filter; and the transmission path response estimation means. A convolutional integrator that generates a received signal replica that does not include an information component from the channel response estimation value for each spreading code estimated by the above, and branches the received signal replica that does not include the information component generated by the convolutional integrator And generating a replica signal of a plurality of received signals having a predetermined phase difference according to the modulation method and outputting the replica signal to the subtraction means. Receiving apparatus characterized by comprising a No. generation means. 3. The receiving apparatus according to claim 2, wherein the phase difference signal generating means multiplies the received signal replica not including one of the branched information components by a predetermined coefficient to have a phase difference from the other. A receiving device comprising a multiplier. 4. The receiving apparatus according to claim 2, wherein said phase difference signal generating means multiplies a first received signal replica that does not include one of the branched information components by a first coefficient to have a first phase difference. A first multiplier for generating a received signal replica, and a second multiplier for multiplying a received signal replica not containing the other branched information component by a second coefficient to generate a received signal replica having a second phase difference. A multiplier, and an adder for further splitting the received signal replica having the respective phase difference output from the first and second multipliers, and adding one of the split ones and the baseband signal. A receiving device, comprising: 5. The receiving apparatus according to claim 2, wherein the phase difference signal generating means includes: a first adder that adds a received signal replica not including one of the branched information components and the baseband signal. A first shift register that delays a received signal replica that does not include the other branched information component for a certain time; a second shift register that delays the baseband signal for a certain time; and a delay from the first shift register. A second adder that further branches the received signal replica output as a result, further branches the baseband signal output with delay from the second shift register, and adds one of the branched ones. A receiving circuit comprising: 6. An interference cancellation receiver for receiving and demodulating a code division multiple access (CDMA) signal in which a plurality of wireless communication devices perform multiplex communication using different spreading codes in the same frequency band, RF receiving means for frequency-converting a received signal to obtain a baseband signal; transmission path response means for estimating a transmission path response received by the baseband signal for each spreading code; A code synchronization unit for synchronizing codes, and each user using a channel response estimation value estimated by the channel response estimation unit and timing information of each spreading code when synchronized by the code synchronization unit. A replica signal generating means for generating a replica signal of the received signal corresponding to the transmission signal response estimation value of each user based on the transmission path response estimation value obtained by the transmission path response estimation means. Received power sorting means for sorting the received signals of each user in the order of the received power calculated by calculating the signal power, and demodulating the received signals of the user using the replica signal in the order sorted by the received power sorting means. While demodulating the output while removing interference,
A partial sequence estimating unit that outputs a residual signal including an information component corresponding to the remaining users; and a demodulation result output from the partial sequence estimating unit and a replica signal generated by the replica signal generating unit are delayed. A delay unit, based on the demodulation result delayed by the delay unit, the replica signal, and the baseband signal, to remove an interference component of a previous information symbol and to input a pre-interference removal signal to the subsequence estimation unit Means, a residual signal output from the partial sequence estimating means, a demodulation result, a transmission path response estimation value obtained by the transmission path response estimating means, and a user generated by the replica signal generating means. And a post-stage detecting means for performing re-demodulation of the remaining received signal by using the replica signal of the received signal. . 7. An interference cancellation receiving apparatus for receiving and demodulating a code division multiple access (CDMA) signal in which a plurality of wireless communication devices perform multiplex communication using different spreading codes in the same frequency band, A first antenna for receiving a CDMA signal, a first RF receiver for frequency-converting a received signal received by the first antenna to obtain a baseband signal, and a first RF receiver. First channel response estimating means for estimating the channel response received by the frequency-converted baseband signal for each spreading code, code synchronizing means for synchronizing each spreading code with respect to the baseband signal, A second antenna for receiving the CDMA signal; and a second RF reception for frequency-converting a received signal received by the first antenna to obtain a baseband signal Means, a second transmission path response estimating means for estimating, for each spreading code, a transmission path response received by the baseband signal frequency-converted by the second RF receiving means, and the first transmission path response A first replica of a received signal corresponding to each user using the first transmission path response estimation value estimated by the estimation means and timing information of each spreading code synchronized by the code synchronization means. A first replica signal generating means for generating a signal, a second transmission path response estimation value estimated by the second transmission path response estimating means, and each spread when synchronized by the code synchronization means. Second replica signal generation means for generating a second replica signal of the received signal corresponding to each user using the code timing information; the first and second transmission channel response estimation values and the first and A demodulation result is output while demodulating a user's received signal in a predetermined order using the second replica signal and a demodulation result is output, and a first signal including information components corresponding to the remaining users is output.
Partial sequence estimating means for outputting a second residual signal and a second residual signal; first delay means for delaying each replica signal generated by the first and second replica signal generating means; A second delay means for delaying the demodulation result output from the first and second base stations, based on the demodulation result delayed by the first and second delay means, the first replica signal, and the baseband signal. A first pre-interference removing unit that removes an interference component of the information symbol and inputs the result to the partial sequence estimating unit; a demodulation result delayed by the first and second delay units and a second replica signal; A second pre-interference removing unit that removes an interference component of the immediately preceding information symbol based on the baseband signal and inputs the result to the partial sequence estimating unit; and an output from the partial sequence estimating unit. The first and second residual signals obtained, the demodulation result, the first and second transmission path response estimation values obtained by the first and second transmission path response estimation means, and the first and second And a second-stage detecting means for performing re-demodulation of the remaining received signal by using the first and second replica signals of the received signal for each user generated by the replica signal generating means. Removal receiver.