JP2003008549A - CDMA receiver - Google Patents

Abstract

[PROBLEMS] To improve tentative decision processing accuracy in the first stage, and to improve tentative decision processing accuracy and replica signal generation accuracy in the first and second stages and thereafter, CDMA reception that can greatly improve demodulation characteristics. To get a chance. A CDMA receiver equipped with a multi-stage interference canceller according to the present invention includes, as an interference cancellation stage, a physical channel having a lower processing order than a physical channel being processed from a received signal or a residual signal in units of physical channels. Subtracts the interference replica signal with likelihood, generates a symbol replica and an interference replica signal using the subtraction result, and subtracts the interference replica signal generated from the received signal or the residual signal to output an updated residual signal. The first stage 1 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver used for mobile communication, satellite communication, indoor communication and the like, and in particular, spread signals corresponding to a plurality of physical channels are superimposed on the same frequency band. The present invention relates to a CDMA receiver capable of removing interference of other physical channels other than the physical channel for each physical channel from the received signal and individually outputting demodulated signals of all physical channels.

[0002]

2. Description of the Related Art A conventional CDMA receiver will be described below. In CDMA communication, all physical channels share the same frequency band by assigning individual spreading codes to a plurality of physical channels. At this time, the other physical channel signal becomes an interference component due to the cross-correlation of the spread codes assigned to each physical channel, and the reception characteristic is deteriorated.

A CDMA receiver equipped with a multi-stage type interference canceller has been studied as one of the techniques for reducing the interference caused by the cross-correlation. This CDMA
The receiver tentatively determines the received signal for each physical channel and generates an interference signal replica based on the tentative determination result. Then, by subtracting the interference replica from the received signal, the signal power to interference power ratio (SIR: Signal-to-Inter) for the subsequent physical channels is subtracted.
(Ference Ratio) to improve the reception characteristics.

As a document relating to a CDMA receiver equipped with the above-mentioned multi-stage interference canceller, Yoshida and Gogawa “Sequential channel estimation type CDMA multi-stage interference canceller utilizing symbol replica processing” (IEICE, Radio Communication System) Technical Report of Research Group, RCS96-17
1, February 1997). Hereinafter, this will be described as a conventional technique.

FIG. 15 is a diagram showing the configuration of the above conventional CDMA receiver. In FIG. 15, 101-1 is the first
101-2 is the second stage, 1
01-M is the M-th stage, 111-1 to 111-
N, 121-1 to 121-N, 131-1 to 131-N
Is an interference cancellation processing unit (ICU: Interference).
Cancel Unit), 112-1 to 11
2-N, 122-1 to 122-N, 132-1, 132
-2, ... are delay devices (Delay), 113-1 to
113-N, 123-1 to 123-N, 133-1, 1
33-2, ... are subtractors.

FIG. 15 shows a receiver for receiving N (N ≧ 1 integer) physical channels and having M stages (M ≧ 1 integer). Each stage is configured in series according to the reception level of the physical channel signal corresponding to N ICUs, and demodulation and interference replica generation processing are performed in order from the higher level.

FIG. 16 is a diagram showing the internal structure of the ICU. In FIG. 16, reference numeral 201 denotes a despreading unit, 2
Reference numerals 02 and 212 are adders, 203 is a transmission path characteristic estimation unit, 204 and 208 are multipliers, and 205 and 2
11 is a delay device, 206 is a Rake combiner,
207 is a determiner, 209 is a subtractor, 210
Is a diffusion unit.

The operation of the conventional CDMA receiver will be described below. In the first stage 101-1,
The residual signal is input to ICU 111-1, and a symbol replica and a spread signal related thereto are output. Here, the residual signal becomes the received signal. Further, since it is the first stage, there is no input of the symbol replica of the previous stage. In the delay device 112-1, the received signal is ICU111-
A delay of 1 processing time is given. The subtractor 113-1 calculates the ICU 111 from the received signal output from the delay device 112-1.
The -1 output spread signal is subtracted and the updated residual signal is output.

The residual signal after the update is ICU111-
2 and the delay device 112-2, and thereafter, the same processing as above is repeatedly executed for each physical channel. The subtractor 113-n subtracts the spread signal output from the ICU 111-n from the residual signal output from the delay device 112-n, and outputs the updated residual signal.

Next, the ICU 12 at the top of the second stage
1-1 receives the residual signal output from the subtracter 113-n and the symbol replica output from the ICU 111-1 at the highest stage of the first stage, outputs the updated symbol replica, and outputs the symbol replica of the current stage. It outputs a spread signal related to the difference from the symbol replica of the previous stage.

Thereafter, the same processing as described above is repeatedly executed on all physical channels and all stages. In addition, the ICU 131-1 of the M-th stage 101-M
In ~ 131-N, it is not necessary to re-estimate the symbol replica, and the demodulation processing result is output as the demodulated signal of each physical channel.

Next, the operation of each ICU will be described. Each ICU corresponds to K (K ≧ 1 integer) multipath transmission lines.

In the despreading section 201, the k-th (K ≧ k ≧ 1)
The integer) of the received signal is despread at the timing synchronized with the path. The adder 202 adds the despread signal to the symbol replica in path units of the relevant physical channel estimated in the previous stage. This symbol replica is a product of the judgment value in the previous stage and the transmission path characteristic estimated value, and takes a different value for each path. It should be noted that the ICU 111-1 of the first stage 101-1 does not have a preceding stage, and therefore has no symbol replica.

In the transmission path characteristic estimating section 203, the adder 20
The transmission path characteristics are estimated using the two outputs. The multiplier 204 multiplies the output of the adder 202 by the complex conjugate of the transmission path characteristic estimated value. The delay unit 205 delays the output of the multiplier 204 by a time required for Rake combining.

The Rake combiner 206 Rake combines the outputs of the delay device 205 for each path. In the judging device 207,
A transmission symbol is determined from the signal after Rake combining.

The multiplier 208 multiplies the decision symbol by the transmission path characteristic estimation value of the corresponding path. The multiplication result is sent to the next stage in path units as a symbol replica at the current stage. Subtractor 209
Then, the symbol replica of the previous stage is subtracted from the output of the multiplier 208. The spreading unit 210 uses the spreading code of its own physical channel at the timing synchronized with the path,
The output of the subtractor 209 is spread. The delay unit 211 gives a predetermined delay to the spread signal in order to match the output timing of each path. The adder 212 synthesizes the outputs of the delay devices 211 corresponding to the K paths.

[0017]

However, the above
In the conventional CDMA receiver, in the first stage, the provisional determination is performed in a state where the SIR is bad without removing the signal replica of the other physical channel whose processing order is lower than that of the own physical channel signal. However, there is a problem that the accuracy of the generated replica is deteriorated.

Further, as a result of the tentative decision error in the first stage,
There is a problem that the provisional determination and replica generation accuracy after the second stage are deteriorated and the demodulation characteristics of the CDMA receiver are deteriorated.

The present invention has been made in view of the above, and the demodulation characteristic is significantly improved by improving the accuracy of the temporary judgment processing in the first stage and the accuracy of the temporary judgment and the replica signal generation in the second and subsequent stages. CD that can be improved
The purpose is to obtain an MA receiver.

[0020]

[Means for Solving the Problems]
To achieve the object, in a CDMA receiver according to the present invention, an interference canceling stage for canceling interference caused by cross-correlation of spreading codes individually assigned to a plurality of physical channels, and an interference canceling stage. A multi-stage type interference canceller having a second stage for demodulating each subsequent physical channel signal is mounted, and the first stage of the interference cancellation stage is shorter than the total symbol length of the CDMA received signal. Likelihood replica generating means for generating an interference replica signal with likelihood, which is a replica signal based on the despread value of a partial signal having a length, and a received signal or residual signal, rather than a physical channel signal being processed. First subtraction means for subtracting the interference-added replica signal of a physical channel signal having a low processing order, and a symbol level for each physical channel using the subtraction result. Interference replica generating means for generating a Rika and an interference replica signal related thereto, second subtracting means for subtracting the interference replica signal of the corresponding physical channel from the received signal or the residual signal, and outputting an updated residual signal, In the serial configuration, the interference cancellation process and the demodulation process are performed in order from the physical channel having the highest processing order, and the sequentially updated residual signal is propagated.

In a CDMA receiver according to the next invention, an interference removal stage for removing interference caused by cross-correlation of spreading codes individually assigned to a plurality of physical channels, and each of the interference removal stages after the interference removal. A multi-stage type interference canceller having a second stage for demodulating a physical channel signal is mounted, and the first stage of the interference canceling stage has a length shorter than the total symbol length of the CDMA received signal. From a likelihood-equipped replica generation unit that generates a likelihood-added interference replica signal that is a replica signal based on the despread value of a partial signal that has, and a received signal or a residual signal,
Physically using the first subtraction means for subtracting the likelihood-added interference replica signal of the physical channel having a lower processing rank than the physical channel being processed, and the subtraction result and the transmission path estimation value sent from the second stage. First interference replica generating means for generating a determination symbol and an interference replica signal for each channel, and second for outputting an updated residual signal by subtracting the interference replica signal of the corresponding physical channel from the received signal or the residual signal. And a subtraction means for performing interference removal processing and demodulation processing in order from a physical channel having a higher processing order, and a serial configuration for propagating a sequentially updated residual signal.

The CDMA receiver according to the next invention is characterized in that the processing order in the interference elimination stage is in the order of increasing reception level of each physical channel.

In the CDMA receiver according to the next invention, an interference removal stage for removing interference caused by the cross-correlation of spreading codes individually assigned to a plurality of physical channels, and each of the interference removal stages after the interference removal. A multi-stage type interference canceller having a second stage for demodulating a physical channel signal is mounted, and the first stage of the interference canceling stage has a length shorter than the total symbol length of the CDMA received signal. Likelihood replica generator for generating an interference replica signal with likelihood, which is a replica signal based on the despread value of a partial signal, and an interference replica with likelihood of a physical channel other than the physical channel being processed from the received signal First subtraction means for subtracting a signal, and using the subtraction result, generate a symbol replica and an interference replica signal related thereto in units of physical channels Interference subtraction means for subtracting interference replica signals of a plurality of physical channels from the received signal and outputting an updated residual signal, the interference is removed simultaneously for all physical channels. It is characterized by a parallel configuration for performing processing and demodulation processing.

In the CDMA receiver according to the next invention, an interference canceling stage for canceling interference caused by cross-correlation of spreading codes individually assigned to a plurality of physical channels, and each of the interference canceling stages after the interference canceling. A multi-stage type interference canceller having a second stage for demodulating a physical channel signal is mounted, and the first stage of the interference canceling stage has a length shorter than the total symbol length of the CDMA received signal. Likelihood replica generator for generating an interference replica signal with likelihood, which is a replica signal based on the despread value of a partial signal, and an interference replica with likelihood of a physical channel other than the physical channel being processed from the received signal The first subtraction means for subtracting the signal, and the judgment result for each physical channel using the subtraction result and the transmission path estimation value sent from the second stage. And a second subtraction means for subtracting interference replica signals of a plurality of physical channels from the received signal and outputting an updated residual signal, all of which are provided. It is characterized by a parallel configuration in which the interference removal processing and the demodulation processing are performed simultaneously on the physical channels.

In the CDMA receiver according to the next invention, the reception level of each physical channel in the interference canceling stage is set in the descending order of the receiving level of each physical channel, and in the interference canceling process of each physical channel, The interference replica signal with likelihood of a physical channel signal having a lower reception level and a lower transmission rate than the physical channel signal to be processed is removed from the received signal.

In the CDMA receiver according to the next invention, the reception level of each physical channel in the interference cancellation stage is set in the descending order of the reception level of each physical channel, and is the processing target in the interference cancellation process. It is characterized in that the interference replica signal with likelihood of a physical channel signal having a higher reception level and a lower transmission rate than the physical channel signal is removed from the received signal.

In the CDMA receiver according to the next invention, an interference removal stage for removing interference caused by the cross-correlation of spreading codes individually assigned to a plurality of physical channels, and each of the interference removal stages after the interference removal. A multi-stage type interference canceller having a second stage for demodulating a physical channel signal; and the interference cancellation stage is divided into a plurality of groups based on a predetermined standard, Each group of stage 1
Replica generating means with likelihood for generating an interference replica signal with likelihood which is a replica signal based on the despread value of a partial signal having a length shorter than the total symbol length of the CDMA received signal, and a received signal or residual signal From the group to which the physical channel being processed belongs, the first subtraction means for subtracting the likelihood-added interference replica signal of the physical channel, and the subtraction result and the transmission path estimation value sent from the second stage. First interference replica generating means for generating a determination symbol and an interference replica signal for each physical channel by using, and residuals updated by subtracting interference replica signals of a plurality of physical channels in the group from the received signal or the residual signal. Second subtraction means for outputting a signal, and within the group, interference removal processing and demodulation processing are performed simultaneously for all physical channels. And a parallel configuration in which, between the groups is characterized by a series arrangement of propagating residual signal that have been updated in order from the physical channel upper group.

In the CDMA receiver according to the next invention, an interference canceling stage for canceling interference caused by cross-correlation of spreading codes individually assigned to a plurality of physical channels, and each of the interference canceling stages after canceling the interference. A multi-stage type interference canceller having a second stage for demodulating a physical channel signal; and the interference cancellation stage is divided into a plurality of groups based on a predetermined standard, Each group of stage 1
Replica generating means with likelihood for generating an interference replica signal with likelihood which is a replica signal based on the despread value of a partial signal having a length shorter than the total symbol length of the CDMA received signal, and a received signal or residual signal , A first subtraction unit for subtracting the likelihood-added interference replica signal of the physical channel of a lower group than the group to which the physical channel being processed belongs, and a symbol replica and an interference replica related thereto in physical channel units using the subtraction result. An interference replica generating unit that generates a signal; and a second subtracting unit that subtracts interference replica signals of a plurality of physical channels in the group from a received signal or a residual signal and outputs an updated residual signal, the group The inside has a parallel configuration that performs interference removal processing and demodulation processing on all physical channels at once, and between groups, Position, characterized in that a series arrangement of propagating residual signal that have been updated in order from the physical channels of the group.

In the CDMA receiver according to the next invention, group division in the interference removal stage is determined based on the reception level order of each physical channel signal,
In the interference cancellation processing of the physical channel belonging to the group with high reception level, the interference replica signal with likelihood of the physical channel signal belonging to the group with low reception level and low transmission rate is removed from the received signal or the residual signal. And

In the CDMA receiver according to the next invention, group division in the interference cancellation stage is determined based on the reception level order of each physical channel signal,
In the interference cancellation processing of the physical channel belonging to the group with high reception level, the interference replica signal with likelihood of the physical channel signal belonging to the group with high reception level and low transmission rate is removed from the received signal or the residual signal. And

In the CDMA receiver according to the next invention, the group division in the interference removal stage is determined based on the reception level order of each physical channel signal,
The interference cancellation processing of the physical channels belonging to the group having a high reception level is characterized by removing the likelihood-added interference replica signals of the physical channel signals belonging to the same group and having a low transmission rate from the reception signal or the residual signal.

The CDMA receiver according to the next invention is characterized in that the interference replica signal with likelihood of the pilot channel or the common control channel is removed from the received signal or the residual signal.

In the CDMA receiver according to the next invention, in the first stage of the interference elimination stage, there is further provided a weighting means for weighting the likelihood-added interference replica signal to be subtracted by the first subtraction means. It is characterized by being provided.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION CDMA according to the present invention
An embodiment of a receiver will be described in detail with reference to the drawings.
The present invention is not limited to this embodiment.

Embodiment 1. FIG. 1 shows C according to the present invention.
It is a figure which shows the structure of Embodiment 1 of a DMA receiver. In FIG. 1, 1 is the first stage, 2 is the 1.1st stage, 3 is the second stage, 11-1, 1
1-2, ..., 14-1, 14-2, ... 14-N, 23-
1, 23-2, ..., 23-N, 33-1, 33-2 ,.
Is a subtracter, and 12-1, 12-2, ..., 12-N,
21-1, 21-2, ... 21-N, 31-1, 31-
2, ..., 31-N are interference removing units (ICUs), and
-1, 13-2, ..., 13-N, 22-1, 22-2
, 22-N, 23-1, 23-2, ... are delay devices (De
, 15-N are likelihood replica generators, and 16 is an adder. In addition, each IC
The configuration and operation of U are the same as in FIG. 16 described above.

The CDMA receiver is a receiver equipped with a multi-stage type interference canceller.
This is an M stage (integer of M ≧ 1) configuration capable of receiving received signals corresponding to a number of (N ≧ 1 integer) physical channels.
Specifically, the interference replica of the physical channel is removed from the received signal received in the first stage 1 for each physical channel, and the interference replica removal process is repeated in the 1.1st stage and thereafter. By demodulating the final residual signal in the second stage 3, the demodulated signal (1), the demodulated signal (2), ..., The demodulated signal (N) are output for each physical channel.

The received signal here is a signal in which spread signals spread by individual spreading codes assigned to N physical channels are superimposed on the same frequency band. Further, each stage other than the second stage 3 may be configured to cancel n (N is an integer of N ≧ n ≧ 1) interference among N physical channels to be subjected to interference cancellation processing.

Further, the first stage 1 is provided with ICU 12-1, so that it can individually support N physical channels.
First interference removal processing block including delay device 13-1, subtractors 11-1, 14-1, ICU 12-2, delay device 13-2, subtractors 11-2, 14-2, with likelihood A second interference cancellation processing block including a replica generation unit 15-2, ..., ICU 12-N, delay device 13-N, subtracter 1
4-N, the N-th including the likelihood-added replica generation unit 15-N
And an interference removal processing block.

In addition, the 1.1st stage 2 described above is provided with the ICU 21- so that it can individually support N physical channels.
1, a delay unit 22-1, a first interference removal processing block including a subtractor 23-1, an ICU 21-2, a delay unit 22
-2, a second interference cancellation processing block including a subtractor 23-2, ..., An NCU interference cancellation processing block including an ICU 21-N, a delay device 22-N, and a subtractor 23-N,
It is configured to include. It should be noted that the structure after the 1.2th stage is the same as that of the 1.1st stage, and the description thereof is omitted. The operation of the stages other than the first stage is not limited to this. However, in the second stage 3, the delay device and subtractor for the final physical channel are deleted.

Here, the operation of the CDMA receiver of the first embodiment configured as described above will be described. First,
In the first stage 1, the ICU 12-1 receives a signal obtained by removing the likelihood-added interference replica signal of a physical channel other than itself from the received signal. The ICU 12-1 outputs a symbol replica and an interference replica signal related to the symbol replica. At this time, the delay unit 13-1 delays the received signal by the processing time related to the generation of the interference replica signal. Thereafter, the subtractor 14-1 subtracts the interference replica signal from the output signal of the delay device 13-1 and outputs the result as the residual signal of the first interference processing block.

The subtractor 11-2 outputs a signal obtained by removing the likelihood-added interference replica signal of the physical channel having a processing order lower than that of the residual signal of the first interference processing block. The ICU 12-2 outputs the symbol replica, the interference replica signal related thereto, and the likelihood-added interference replica signal in cooperation with the likelihood-added replica generation unit 15-2. The delay unit 13-2 delays the residual signal of the first interference processing block by a processing time relating to generation of an interference replica signal. Then, the subtractor 14-2 subtracts the interference replica signal output from the ICU 12-2 from the output signal from the delay unit 13-2, and outputs the result as the residual signal of the second interference processing block.

Thereafter, in the first stage 1, the same processing is repeated to generate interference replica signals and remove interference replica signals from the residual signal of the preceding stage for all physical channels. The ICU 12-N outputs a likelihood-added interference replica signal in conjunction with the likelihood-added replica generation unit 15-N, and further outputs a symbol replica and an interference replica signal related thereto. The delay device 13-N outputs the residual signal of the preceding stage delayed by the processing time related to the generation of the interference replica signal. The subtractor 15-N subtracts the symbol replica signal output from the ICU 12-N from the residual signal of the preceding stage, and outputs the result as the residual signal of the Nth interference processing block.

The interference-added replica signal with likelihood input to the subtractor 11-1 is an interference-replica signal with likelihood of a physical channel having a lower processing order than the physical channel of ICU 12-1.
This is the signal added by the adder 16. Also, the subtractor 11-
The two-input likelihood-added interference replica signal is the sum of likelihood-added interference replica signals of the physical channel having a processing order lower than that of the ICU 12-2. Further, the likelihood-added interference replica signal may be the sum of the physical channel signals whose processing order is lower than that of the interference replica signal, or the sum of some of them. The transmission path information of the likelihood-added interference replica signal may be the transmission path information of the previous symbol, or the transmission path information itself may be the likelihood-added information. However, since the signal component of the physical channel signal of ICU 12-1 having a higher processing order than the physical channel signal of ICU 12-2 is not included in the residual signal of the first interference processing block, the physical channel of ICU 12-1 is not included. It is not necessary to generate the interference replica signal with likelihood of the signal.

Here, a method of generating the replica signal with likelihood will be described. In the prior art, the CDMA signal is provisionally determined based on the integral value obtained by despreading over the symbol length,
A replica signal is generated based on the temporary determination result. On the other hand, the likelihood-added replica signal is a replica signal that is tentatively determined based on an integral value obtained by despreading a partial signal in a section shorter than the symbol length of the CDMA signal, and is generated based on the tentative determination result. . Since the conventional replica signal is a replica signal of the entire despread symbol section, in order to be input to the ICU corresponding to another physical channel,
It is necessary to delay the received signal or the residual signal input to the ICU by the replica signal generation time. On the other hand, the replica signal with likelihood is a replica signal corresponding to the signal in the remaining section of the symbol length based on the tentative determination result by the integral value obtained by despreading only the signal in the section shorter than the symbol length, and the remaining Since it is generated at the same time as the signal in the section, there is no need to delay the received signal or the residual signal input to the ICU corresponding to the other physical channel, and the circuit scale and the processing delay can be reduced.

The likelihood replica signal has a symbol length of a, an integral value of the symbol length a is b, an interval length for likelihood replica generation is c (c <a), and an integral value of the interval length c. Let d be the following, for example. However, the method is not limited to the following.

(1) If the integrated value d in the despreading section c is not less than the threshold value {(c / a) × b}, the replica signal with likelihood based on the tentative determination result at that time is effective. Then, weighting is performed with a coefficient {(c / a) × b}. on the other hand,
If it is less than the threshold value, the reliability of the intermediate result is low and the replica signal with likelihood in the section c is not generated.

(2) Let e be the standard deviation value between the ideal despreading result and the actual despreading result, and if the value of e is less than or equal to the threshold value, then the replica signal with likelihood is set to the coefficient (1-e ). On the other hand, if it is larger than the threshold value, the reliability of the despreading result is low, and the replica signal with likelihood is not generated.

Next, an example of the operation in the 1.1st stage 2 will be described. However, the operation is not limited to this. The ICU 21-1 uses the residual signal of the Nth interference processing block in the previous stage and the ICU 12- of the previous stage.
One-output symbol replica and are received. And I
The CU 21-1 outputs an interference replica signal regarding the symbol replica in the 1.1st stage 2 and the difference between the determination symbol in the 1.1st stage 2 and the symbol replica in the previous stage. At this time, in the delay device 23-1, the residual signal of the Nth interference processing block in the previous stage is changed to I
It is delayed by the processing time relating to the generation of the interference replica signal of the CU 21-1 output. After that, the processing of the other ICUs in stage 1.1 stage 2 is performed in the same manner as above.

As described above, from the 1.1st stage 2 to the 2nd stage
Up to the stage before the stage 3, the residual signal is updated / propagated in units of each physical channel, so that the determination process of the temporary determination symbol can be performed in a state where the interference component is smaller. Therefore, the accuracy of the decision symbol and the interference signal replica is improved as it goes to the subsequent stage.

Next, an example of the operation in the second stage 3 will be shown. However, the operation is not limited to this.
ICU 31-1 receives the residual signal from the preceding stage and the symbol replica from the preceding stage ICU,
The demodulated signal (1) and the interference replica signal are output. At this time, the delay unit 32-1 delays the residual signal from the previous stage by the processing time related to the generation of the interference replica signal by the ICU 31-1. Then, the subtractor 33-1
Then, the interference replica signal output from the ICU 31-1 is subtracted from the output signal from the delay device 32-1 and the residual signal is output as a result.

After that, the processes in the other ICUs of the second stage 3 are also performed in the same manner as described above, and as a result, demodulated signals (2) to (N) are output, respectively.

As described above, in the second stage 3, since the residual signal is updated / propagated for each physical channel, the demodulated signal can be generated in a state with less interference components and good SIR.

As described above, in the CDMA receiver according to the present embodiment, when the interference cancellation processing is performed on the physical channel signal having the higher processing order in the first stage, the physical channel signal having the processing order lower than that of the physical channel is processed. The interference replica signal with likelihood is removed from the received signal to improve the SIR. This makes it possible to improve the interference cancellation characteristics of all physical channels in the first stage.
As a result, the interference removal characteristics and the demodulation characteristics in each subsequent stage can be significantly improved.

Embodiment 2. FIG. 2 shows C according to the present invention.
It is a figure which shows the structure of Embodiment 2 of a DMA receiver. In FIG. 2, 1b is the first stage, and 2b is the first stage.
1 stage, 3b is the second stage, 12b
-1, 12b-2, ..., 12b-N, 21b-1, 21
b-2, ..., 21-N, 31-1, 31-2, ..., 31
-N is ICU, and 34b-1, 34b-2, ... 34
b-N is a storage device. The same components as those in the first embodiment described above are designated by the same reference numerals and the description thereof will be omitted.

The operation of the CDMA receiver according to the second embodiment will be described below. Here, only the operation different from the first embodiment described above will be described. In the present embodiment, the ICUs 31b-1 to 31b-N of the second stage 3b are used.
The transmission path is estimated at the storage device 3 and the estimation result is stored in the storage device 3.
4b-1 to 34b-N are stored. Storage device 34b-1
34b-N, the channel estimation value is supplied to the corresponding ICU of the previous stage (1b, 2b, ...). It should be noted that each transmission path estimation value may be the same value in all stages or may be different in each stage.

Further, each IC of the first embodiment described above
In U, the symbol replicas (judgment symbol × transmission path estimated value) are output, but in the ICUs of the stages other than the second stage 3b of the present embodiment, the judgment symbols are output.

Here, the operation of each ICU of this embodiment will be described. FIG. 3 is a diagram showing the configuration of the ICU of each stage other than the second stage. In FIG. 3, 30
1 is a despreading unit, 302 is an adder, 304,
306 and 310 are multipliers, 305 and 312 are delay units, 307 is a Rake combiner, 308 is a determiner, 309 is a subtractor, 311 is a spreading unit, and 313 is an adder. It is a vessel. Each ICU corresponds to K (K ≧ 1 integer) multipath transmission lines.

In the despreading section 301, the k-th (K ≧ k ≧ 1)
The integer) of the received signal is despread at the timing synchronized with the path. The multiplier 306 receives the determination symbol of the previous stage and the transmission path characteristic estimation value for each path obtained in the second stage, and outputs the multiplication result. In the adder 302, the signal after despreading is multiplied by the multiplier 306.
Add the output multiplication results. It should be noted that in each ICU of the first stage 1b, there is no preceding stage, so there is no decision symbol.

The multiplier 304 multiplies the output of the adder 302 by the complex conjugate of the transmission path characteristic estimation value for each path.
In the delay device 305, Rak is output to the output of the multiplier 304.
e A delay corresponding to the time required for combining (matched with the path having the maximum delay amount) is given.

The Rake combiner 307 Rake combines the output of the delay device 305 for each path. In the judging device 308,
A transmission symbol is determined from the signal after Rake combining. This decision symbol is output to the ICU of each physical channel in the next stage as a decision symbol in the current stage. The subtractor 309 subtracts the decision symbol of the previous stage from the decision symbol of the current stage and outputs the difference. In the ICU of the first stage 1b, Rak
The output value of the e combiner 307 and the output value of the determiner 308 are output to each likelihood-added replica generator.

The multiplier 310 multiplies the subtraction result by the transmission path characteristic estimation value of the corresponding path. The spreading unit 311 spreads the output of the multiplier 310 at the timing synchronized with the path, using the spreading code assigned to itself. The delay unit 312 gives a predetermined delay to the spread signal in order to match the output timing of each path. In the adder 313, the delay unit 3 corresponding to the K paths is
The 12 outputs are combined and a spread signal related to the difference between the symbol determination values of the current stage and the previous stage is output.

On the other hand, FIG. 4 is a diagram showing the configuration of the second stage ICU. In FIG. 4, reference numeral 303 is a transmission line characteristic estimation unit. Each ICU has K (K
It corresponds to a multipath transmission line of ≧ 1). Here, only the differences from FIG. 3 will be described.

In FIG. 3, the transmission path characteristic estimation value is given from the outside, whereas in FIG.
03 estimates the transmission path and uses the result in the ICU. Then, the estimated transmission path value is output to the outside of the ICU (storage device).

As described above, in the present embodiment, the transmission path characteristic estimation processing is performed only by the ICU in the second stage, so that the circuit scale can be significantly reduced as compared with the first embodiment described above. , The processing delay can be greatly reduced. Further, in the present embodiment, since the transmission path estimation value is obtained in a state where the interference signal of the other physical channel is removed in the second stage, the estimation accuracy of the transmission path can be significantly improved. Further, since the error in the transmission path characteristic estimation value is reduced due to the significant reduction in the processing delay, it is possible to generate a more accurate interference replica signal with likelihood in the first stage. Further, in the present embodiment, only the decision symbol value is transmitted, so that the circuit scale can be reduced also here.

Embodiment 3. In the interference replica removal processing for each physical channel in each stage of the above-described first and second embodiments, the physical channel processing order is determined in descending order of reception level. However, the physical channel processing order measurement may be performed by a matched filter, or may be calculated from the transmission rate and required quality. Further, the processing order may be the same for all stages or may be updated for each stage.

For example, when a physical channel signal having a lower processing order has a lower transmission rate than a physical channel signal having a higher processing order, the physical channel signal having a lower processing order is 1 more.
Since the chip length per symbol is long, a physical channel having a high processing order performs the tentative determination process by subtracting the likelihood-added interference replica signal of the physical channel signal having a low processing order from the residual signal.

As described above, in the case of making a tentative decision on a physical channel signal having a high processing order, the likelihood-added interference replica signal of a physical channel signal having a low processing order is removed, so that the accuracy of the tentative decision making process and interference replica generation is high. Can be improved. Further, since the interference replica generation accuracy of the physical channel having a high processing order is improved, the tentative determination processing of the physical channel signal having a low processing order and the interference replica generation accuracy are also improved. Can be improved. Furthermore, because the interference removal characteristics of all physical channels in the first stage are improved, the interference removal characteristics of all physical channels in and after the second stage are also improved, so that the demodulation processing characteristics of all physical channels can be finally improved. .

Fourth Embodiment FIG. 5 shows C according to the present invention.
It is a figure which shows the structure of Embodiment 4 of a DMA receiver. In FIG. 5, 1d is the first stage, and 2d is the first stage.
1 stage, 3d is the second stage, 18
d, 24d, ... Are delay devices (Delay), and
d, 25d, ... Are subtractors. The same components as those in the first and second embodiments described above are designated by the same reference numerals and the description thereof will be omitted. The configuration and operation of each ICU are the same as in FIG. 16 described above.

The CDMA receiver is a receiver equipped with a multi-stage type interference canceller.
This is an M stage (integer of M ≧ 1) configuration capable of receiving received signals corresponding to a number of (N ≧ 1 integer) physical channels.
Specifically, the interference replicas are removed from the received signal received in the first stage 1d all at once in the previous physical channels, and the interference replica removal process is repeated even in the 1.1st stage 2d and thereafter to obtain the final replica. By demodulating the residual signal in the second stage 3d, the demodulated signal (1), the demodulated signal (2), ...
Is output.

Note that the received signal here is a signal in which spread signals spread by individual spreading codes assigned to N physical channels are superposed on the same frequency band, as described above. . Further, each stage other than the second stage 3d may be configured to cancel n (N is an integer of N ≧ n ≧ 1) interference among N physical channels to be subjected to interference cancellation processing.

Further, the first stage 1d is provided with the ICU 12- so that it can individually support N physical channels.
1, a first interference cancellation processing block including a subtracter 11-1, and a second interference cancellation processing block including an ICU 12-2, a subtractor 11-2, and a replica generator with likelihood 15-2. ..., ICU 12-N, likelihood replica generator 1
And an Nth interference cancellation processing block including 5-N. In this first stage 1d, N ICs
U has a parallel configuration in which received signals are input at the same time, and all physical channels simultaneously perform interference cancellation processing. It should be noted that the method of generating the interference replica signal with likelihood is the same as in the first embodiment described above.
Is the same as.

Also, the 1.1 st stage 2d is configured so that the ICU 21-1 can individually support N physical channels.
A first interference cancellation processing block comprising:
, A second interference cancellation processing block having -2, ..., I
And a Nth interference cancellation processing block including CU21-N. It should be noted that the configuration after the 1.2th stage is the same as that of the 1.1st stage 2d, and the description thereof is omitted. However, the delay device is removed in the second stage 3d.

Here, the operation of the CDMA receiver of the fourth embodiment configured as described above will be explained. First,
In the first stage 1d, the ICU 12-1 receives a signal obtained by removing a likelihood-added interference replica signal of a physical channel other than itself from the received signal by the subtractor 11-1. ICU
12-1 outputs a symbol replica and an interference replica signal related thereto.

Further, another ICU 12 of the first stage 1d
Even with -2, ..., A signal obtained by removing the interference replica signal with likelihood of the physical channel other than itself from the received signal by the subtractor 11-2 is received. Each ICU outputs a symbol replica and an interference replica signal related to it. However, IC
U12-N directly receives the received signal and outputs a symbol replica and an interference replica signal related thereto.

The interference replica signal with likelihood input to the subtractor 11-1 is a signal obtained by adding all interference replica signals with likelihood in physical channels other than the physical channel of ICU 12-1 by the adder 16. Further, the likelihood-added interference replica signal input to the subtractor 11-2 is the sum of likelihood-added interference replica signals of the physical channel whose reception level is lower than that of the ICU 12-2. Also, the likelihood-added interference replica signal may be the sum of physical channel signals other than itself, or the sum of some of them.

The delay unit 18d delays the received signal in accordance with the interference replica signal having the longest processing delay in the processing time for generating the interference replica signals of all the ICUs of the first stage 1d. Thereafter, the subtractor 19d simultaneously subtracts all the interference replica signals from the output signal of the delay device 18d, and outputs the updated residual signal.

Next, after the first stage 2d, all the ICUs 21-1 to 21-N simultaneously receive the residual signal from the first stage 1d, and further,
The symbol replica from the first stage 1d is received for each corresponding physical channel. In this state, in each ICU,
Each outputs the symbol replica of the current stage and the interference replica signal related to it.

In the delay unit 24d, the first stage 2d
In the processing time related to the generation of the interference replica signals of all ICUs, a delay is given to the residual signal from the first stage 1d in accordance with the interference replica signal having the largest processing delay. Thereafter, the subtractor 25d simultaneously subtracts all interference replica signals from the output signal of the delay device 24d, and outputs the updated residual signal. Similar processing is repeatedly executed in the subsequent stages. It should be noted that the circuit configuration and operation after the above-mentioned 1.1 stage 2d is an example, and the present invention is not limited to this.

Finally, in the second stage 3d, all the ICUs 31-1 to 31-N simultaneously receive the residual signals from all the stages and further receive the symbol replica from the preceding stage for each corresponding physical channel. .
In this state, each ICU has demodulated signals (1) to
(N) is output.

As described above, in the CDMA receiver of the present embodiment, from the first stage to the stage before the second stage,
The residual signal is updated / propagated for each physical channel unit, and a temporary determination symbol is generated in a state where there are fewer interference components. As a result, the interference removal characteristic is improved as it goes to the subsequent stage, so that the demodulation characteristic in the second stage can be greatly improved. Further, the interference removal processing for each physical channel is performed in parallel in each stage, and the demodulation processing is also performed in parallel in the second stage, so that the processing speed can be increased and the circuit scale can be reduced. Further, in the present embodiment,
The likelihood-added replica of another physical channel signal is removed in the first stage, and the SIR of the received signal is improved in the interference removal processing of each physical channel in the first stage. This makes it possible to improve the provisional determination processing of the first stage and the accuracy of interference replica generation, and as a result,
The interference removal characteristics and demodulation characteristics after the stage can also be improved.

Embodiment 5. FIG. 6 shows C according to the present invention.
It is a figure which shows the structure of Embodiment 5 of a DMA receiver. In FIG. 6, 1f is the first stage, and 2f is the first.
One stage, 3f is the second stage. In addition,
The same components as those in the first, second, or fourth embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

The operation of the CDMA receiver according to the fifth embodiment will be described below. Here, only the operation different from the above-described fourth embodiment will be described. In the present embodiment, the ICUs 31b-1 to 31b-N of the second stage 3f are used.
The transmission path is estimated at the storage device 3 and the estimation result is stored in the storage device 3.
4b-1 to 34b-N are stored. Storage device 34b-1
.. 34b-N, the channel estimation value is supplied to the corresponding ICU of the preceding stage (1f, 2f, ...). It should be noted that each transmission path estimation value may be the same value in all stages or may be different in each stage.

Further, each IC of the first embodiment described above
In U, each symbol replica (judgment symbol × transmission path estimated value) was output, but in the ICUs of each stage other than the second stage 3f of the present embodiment, each judgment symbol is output. The configuration and operation of each ICU of the first stage 1f, the 1.1th stage 2f, ... Are similar to those of FIG. 3 described above, and the configuration and operation of each ICU of the second stage 3f are This is similar to FIG. 4 described above. Further, the method of generating the interference-added replica signal with likelihood is similar to that of the first embodiment described above.

As described above, in the present embodiment, the transmission path characteristic estimation processing is performed only in the second stage ICU, so that the circuit scale can be greatly reduced as compared with the fourth embodiment described above. , The processing delay can be greatly reduced. Further, in the present embodiment, since the transmission path estimation value is obtained in a state where the interference signal of the other physical channel is removed in the second stage, the estimation accuracy of the transmission path can be significantly improved. Further, since the error in the transmission path characteristic estimation value is reduced due to the significant reduction in the processing delay, it is possible to generate a more accurate interference replica signal with likelihood in the first stage. Further, in the present embodiment, since only the decision symbol value is transmitted, the circuit scale can be reduced also here.

Sixth Embodiment In the interference replica removal processing for each physical channel in each stage of the above-mentioned Embodiments 4 and 5, the order of reception levels is determined in descending order of reception level. However, the reception level ranking may be calculated from the matched filter, the transmission rate, the required quality, and the like. Also, the reception level ranking is
It may be the same for all stages or may be updated for each stage.

For example, in the interference cancellation processing of the physical channel having the higher receiving level rank, when the physical channel signal having the lower receiving level ranking has a lower transmission rate than the physical channel signal having the higher receiving level ranking, the physical channel signal having the lower receiving level ranking is used. Since the chip length per symbol is longer, the interfering replica signal with likelihood of a physical channel signal with a lower reception level rank and a lower transmission rate is removed from the received signal or the residual signal, and the physical channel signal with a higher reception level is obtained. Is performed. In this way, when the physical channel with the higher reception level rank performs the interference cancellation processing, the likelihood-based interference replica signal of the physical channel signal with the lower reception level rank is removed, so that the accuracy of the provisional determination processing and the interference replica generation is improved. Can be improved. Further, since the interference cancellation characteristics of the physical channel having the higher reception level rank are improved, the provisional determination processing of the physical channel signal having the lower reception level rank and the interference replica generation accuracy are also improved.
It is possible to improve the interference cancellation characteristics of all physical channels of the stage. Furthermore, since the interference cancellation characteristics of all physical channels in the first stage are improved, the interference cancellation characteristics of all physical channels in and after the 1.1st stage are also improved. Therefore, the demodulation processing characteristics of all physical channels are finally improved. You can

Further, since the physical channel signal having the lower transmission rate has a longer chip length per symbol, the interference replica signal with likelihood of the physical channel signal having the higher reception level rank and the lower transmission rate is received signal or residual error. It is also possible to remove the signal from the signal and perform provisional determination processing of the physical channel signal having a high transmission rate. In this case, since the interference replica signal with likelihood of the physical channel signal with the higher reception level rank is subtracted from the received signal or the residual signal, it is more than the case where the interference replica signal with likelihood of the physical channel signal with the lower reception level rank is subtracted. However, the interference removal effect is large, and the demodulation processing characteristics of all physical channels can be further improved.

Seventh Embodiment FIG. 7 shows C according to the present invention.
It is a figure which shows the structure of Embodiment 7 of a DMA receiver. In FIG. 7, 1h is the first stage, and 2h is the first stage.
1 stage, 3h is the second stage, 4h,
6h and 8h are the first divided groups, and 5h, 7h and 9
h is the L-th division group, and is 43, 44, 51, 6
1, 62, 71, 81, 82 and 91 are the same as those in FIG.
CU, 45, 53, 63, 72, 83 are delay devices (Delay), 46, 55, 64, 73, 84
Is a subtractor, 52 is a likelihood replica generator,
54 is an adder.

The CDMA receiver is a receiver equipped with a multi-stage type interference canceller.
This is an M stage (integer of M ≧ 1) configuration capable of receiving received signals corresponding to a number of (N ≧ 1 integer) physical channels.
Specifically, the interference replica of the previous physical channel is removed from the received signal received in the first stage 1h, and the interference replica removal process is repeated in the 1.1st stage 2h and thereafter to obtain the final residual signal. By demodulating the difference signal in the second stage 3h, a demodulated signal is output for each physical channel.

Note that the received signal here is a signal in which spread signals spread by individual spreading codes assigned to N physical channels are superimposed on the same frequency band, as described above. . Further, each stage other than the second stage 3h may be configured to cancel n (N is an integer of N ≧ n ≧ 1) interference among N physical channels to be subjected to interference cancellation processing.

The first stage 1h is divided into a first divided group 4h to an L-th (N> L ≧ 1 integer) divided group 5h. The first division group 4h includes a number of ICUs 43, 44, ... Equal to the corresponding physical channels,
The L-th divided group 5h is configured to include the same number of ICUs 51, ... As the corresponding physical channels.

In the first divided group 4h, ICU43
Subtracts the likelihood-added interference replica signal from the received signal
The signal removed by is received, and the symbol replica and the interference replica signal related thereto are output. Similarly, for other I
The CUs 44, ... Also receive the signals obtained by removing the interference replica signals with likelihood from the received signals by the subtractors 42, ..., And output the symbol replicas and the interference replica signals related thereto, respectively. The delay unit 45 delays the received signal in accordance with the interference replica signal having the largest processing delay in the processing time related to the generation of the interference replica signal of the first division group 4h. After that, the subtractor 46 simultaneously subtracts all the interference replica signals from the output signal of the delay device 45, and outputs the updated residual signal.

In the L-th division group 5h, the same operation as that of the first division group 4h is performed, and each ICU and each likelihood-equipped replica generator corresponding thereto output the likelihood-added interference replica signal in cooperation with each other. Then, in the adder 54,
Combine all likelihood-based interference replica signals. The method for generating the likelihood-added interference replica signal is the same as that in the first embodiment described above.

The first division group 6h after the first stage 2h has a parallel configuration in which the residual signals from the first stage 1h are simultaneously input to the ICUs 61, 62, ... Perform removal processing. ICU
At 61, the residual signal and the symbol replica output from the ICU 43 are input, and the symbol replica and the interference replica signal related thereto are output. The ICU 62 inputs the residual signal and the symbol replica of the ICU 44 output,
The symbol replica and the interference replica signal related to it are output. The delay unit 63 delays the residual signal in accordance with the interference replica signal having the largest processing delay in the processing time related to the generation of the interference replica signal of the first division group 6h. Then, in the subtractor 64,
All the interference replica signals are simultaneously subtracted from the output signal of the delay unit 63, and the updated residual signal is output.

The operation of the L-th divided group 7h is similar to that of the first divided group 6h. Also, regarding the stages before the second stage to the second stage, the first.
It is similar to 1 stage 2h. Regarding the number of divisions and combinations of groups, there is a method of making all stages the same or a method of updating each stage. Further, the circuit configuration and operation after the 1.1 stage 2h are examples, and the present invention is not limited to this.

Finally, in the first divided group 8h of the second stage 3h, a parallel configuration is adopted in which the residual signals from the 1.1th stage 2h are simultaneously received by the ICUs 81, 82, ... And further for each corresponding physical channel. Receive the symbol replica from the previous stage. In this state, each ICU
Respectively output demodulated signals.

As described above, in the CDMA receiver of the present embodiment, from the first stage to the stage before the second stage,
The residual signal is updated / propagated for each physical channel, and the temporary determination symbol is generated in a state where there are fewer interference components. As a result, the interference removal characteristic is improved as it goes to the subsequent stage, so that the demodulation characteristic in the second stage can be greatly improved. Further, in each stage, physical channel signals having the same reception level or physical channel signals having close reception levels are processed in parallel, and physical channel signals having different reception levels are processed in series.
Furthermore, the demodulation processing characteristic can be improved as compared with the fourth embodiment. Further, in the present embodiment, the likelihood-added replicas of the other physical channel signals of the lower group are removed in the first stage, and the SIR of the received signal is improved in the interference removal processing for each physical channel in the first stage. As a result, it is possible to improve the accuracy of the first-stage provisional determination processing and the interference replica generation. As a result, the first.
The interference removal characteristics and demodulation characteristics after the first stage can also be improved.

Eighth Embodiment FIG. 8 shows C according to the present invention.
It is a figure which shows the structure of Embodiment 8 of a DMA receiver. In FIG. 8, 1j is the first stage, and 2j is the first stage.
1 stage, 3j is the second stage, 4j,
6j and 8j are first divided groups, and 5j, 7j and 9
j is the L-th division group, and 43j, 44j, 51
Reference numerals j, 61j, 62j, 71j are ICUs similar to those in FIG. 3, 81j, 82j, 91j are ICUs similar to those in FIG. 4, and 85j, 86j, 92j are storage devices. In addition,
The same components as those in the seventh embodiment described above are designated by the same reference numerals and the description thereof will be omitted.

The operation of the CDMA receiver according to the eighth embodiment will be described below. Here, only the operation different from the above-described seventh embodiment will be described. In the present embodiment, the ICUs 81j, 82j, ..., 9 of the second stage 3j are
, 1j, ... Estimate the transmission path, and store the estimation results in the storage devices 85j, 86j ,. In each storage device, the corresponding I of the previous stage (1j, 2j, ...)
The channel estimation value is supplied to the CU. It should be noted that each transmission path estimation value may be the same value in all stages or may be different in each stage.

Further, each IC of the first embodiment described above
In U, the symbol replicas (judgment symbol × transmission path estimated value) are output, but in the ICUs of the stages other than the second stage 3j of the present embodiment, the judgment symbols are output. The configuration and operation of each ICU of the first stage 1j, the 1.1th stage 2j, ... Are similar to those of FIG. 3 described above, and the configuration and operation of each ICU of the second stage 3j are This is similar to FIG. 4 described above. Further, the method of generating the interference-added replica signal with likelihood is similar to that of the first embodiment described above.

As described above, in the present embodiment, the transmission path characteristic estimation processing is performed only in the second stage ICU, so that the circuit scale can be significantly reduced as compared with the seventh embodiment described above. , The processing delay can be greatly reduced. Further, in the present embodiment, since the transmission path estimation value is obtained in a state where the interference signal of the other physical channel is removed in the second stage, the estimation accuracy of the transmission path can be significantly improved. Further, since the error in the transmission path characteristic estimation value is reduced due to the significant reduction in the processing delay, it is possible to generate a more accurate interference replica signal with likelihood in the first stage. Further, in the present embodiment, since only the decision symbol value is transmitted, the circuit scale can be reduced also here.

Ninth Embodiment In the interference replica removal processing for each physical channel in the above-mentioned Embodiments 7 and 8, the reception level order is determined in descending order of reception level. However, the physical channel reception level ranking may be calculated by a matched filter, transmission rate, required quality, and the like.

Here, each stage is divided into groups based on the above-mentioned reception level ranking. The reception level ranking and group division may be the same for all stages or may be updated for each stage.

For example, in the tentative determination process for each physical channel signal, the likelihood-added interference replica signal of the physical channel signal of another group whose transmission rate is lower than that of the own physical channel signal is removed from the received signal or the residual signal. Since the physical channel signal having the lower transmission rate has a longer chip length per symbol, the interference replica signal with likelihood of the physical channel signal having the lower transmission rate than the own physical channel signal is subtracted from the residual signal to obtain the own physical channel signal. Is performed.

In the tentative determination process of each physical channel signal, the likelihood-added interference replica signals of the physical channel signals of other groups having lower transmission rates and higher reception level ranks than the own physical channel signal are removed from the residual signal. It may be that. 1 for physical channel signals with low transmission rate
Since the chip length per symbol is long, the interference replica signal with likelihood of a physical channel signal having a transmission rate lower than that of the own physical channel signal is subtracted from the residual signal to perform temporary determination processing of the own physical channel signal.

Further, in the tentative determination process for each physical channel signal, if another physical channel signal in the same division group has a lower transmission rate than the own physical channel signal, the residual signal gives an interference replica with likelihood of that physical channel signal. The signal may be removed. Since the physical channel signal with the lower transmission rate has a longer chip length per symbol,
A temporary determination process of the own physical channel signal is performed by subtracting the likelihood-added interference replica signal of the physical channel signal having a lower transmission rate than the own physical channel signal from the residual signal.

By removing the likelihood-added interference replica signal of the other physical channel signal as described above, the provisional determination processing characteristic and the interference replica generation processing characteristic of the own physical channel signal can be improved. It is possible to improve the interference replica generation processing characteristics of all physical channels in the first stage,
Furthermore, the interference replica generation processing characteristics of all physical channels after the 1.1st stage can be improved, and as a result, the demodulation processing characteristics of all physical channels can be improved. In addition, when removing the likelihood-added interference replica signals of the physical channel signals of other groups whose transmission rate is lower than that of the own physical channel signal and whose reception level is higher than the own physical channel signal, the interference cancellation effect is large, and The demodulation processing characteristic can be further improved.

Embodiment 10. In addition, the first embodiment
9 to 9, the likelihood-added interference replica signal of the pilot channel or the common control channel may be removed from the received signal or the residual signal. Since the pilot channel and the common control channel have higher power levels than the physical channel signals, the demodulation characteristics of the physical channel signal can be significantly improved.

Eleventh Embodiment 9, 10, 11,
12, FIG. 13 and FIG. 14 are diagrams showing the configuration of the eleventh embodiment of the CDMA receiver according to the present invention. 9 is the configuration of FIG. 1, FIG. 10 is the configuration of FIG. 2, FIG. 11 is the configuration of FIG. 5, FIG. 12 is the configuration of FIG. 6, and FIG. 13 is the configuration of FIG.
FIG. 14 shows a circuit configuration in which weighting units are added to the configuration of FIG.

In FIG. 9, 1a is a first stage, and 17a-1, 17a-2, ... Are weighting sections.
In FIG. 10, 1c is the first stage. In FIG. 11, 1e is the first stage. In FIG.
1g is the first stage. In FIG. 13, 1i is the first stage, 4i is the first division group, and
7i is a weighting unit. In FIG. 14, 1k is the first
It is a stage, and 4k is a first divided group. The same components as those in the first to tenth embodiments described above are designated by the same reference numerals, and the description thereof will be omitted.

The operation of the eleventh embodiment will be described below by taking the configuration of FIG. 9 as an example. Here, only the operation different from the first embodiment described above will be described. In the first stage 1a, the weighting unit 17a-1 uses the ICU.
The result of combining the interference-added replica signals of the physical channels other than the physical channel 12-1 is weighted by a predetermined coefficient α. Then, the subtractor 11-1 subtracts the weighted signal from the received signal.

Similarly, in the weighting section 17a-2, the IC
The synthesis result of the likelihood-added interference replica signal of the physical channel whose processing order is lower than that of U12-2 is weighted by a predetermined coefficient α. Then, the subtractor 11-2 subtracts the weighted signal from the residual signal of the first interference processing block. After that, similar processing is performed for all physical channels other than the physical channel having the lowest processing order.

The weighting factors α may all have the same value or different values. Further, it may be a fixed value or a variable value.

As described above, in the present embodiment, as compared with the above-described first to tenth embodiments, it is possible to reduce the interference in the subsequent replica generation processing when the likelihood-added interference replica signal has an error. Therefore, the demodulation characteristics can be further improved.

[0115]

As described above, according to the present invention, when the interference canceling process is performed on the physical channel signal having the high processing order in the first stage, the physical channel having the processing order lower than that of the physical channel being processed. The interference replica signal with likelihood of the channel signal is removed from the received signal to improve the SIR. This makes it possible to improve the interference cancellation characteristics of all physical channels in the first stage.
As a result, it is possible to significantly improve the interference removal characteristics and the demodulation characteristics in each subsequent stage.

According to the next invention, since the transmission path characteristic estimation processing is performed only in the second stage ICU, the circuit scale can be greatly reduced and the processing delay can be greatly reduced.
Has the effect. In addition, since the transmission channel estimation value is obtained in a state in which the interference signal of the other physical channel is removed in the second stage, it is possible to significantly improve the estimation accuracy of the transmission channel.

According to the next invention, when a physical channel signal having a high processing order is provisionally determined, the likelihood-determined interference replica signal of the physical channel signal having a low processing order is removed to perform the provisional determination processing and the interference replica. The effect is that the accuracy of generation can be improved. Further, by improving the interference replica generation accuracy of the physical channel having a high processing order, the provisional determination processing and the interference replica generation accuracy of the physical channel signal having a low processing order are also improved, and as a result, the first stage and the 1.2th stage and thereafter. Since the interference cancellation characteristics of all physical channels are also improved, the demodulation processing characteristics of all physical channels can be finally improved.

According to the next invention, the residual signal is updated / propagated in each physical channel unit from the first stage to the stage before the second stage, and the temporary decision symbol is generated in a state where the interference component is smaller. As a result, the interference removal characteristic is improved as it goes to the subsequent stages, so that the demodulation characteristic in the second stage can be significantly improved. Further, the interference removal processing for each physical channel is performed in parallel in each stage, and the demodulation processing is performed in parallel in the second stage as well, so that the processing speed can be increased and the circuit scale can be reduced. .

According to the next invention, since the transmission path characteristic estimation processing is performed only by the second stage ICU, the circuit scale can be greatly reduced and the processing delay can be greatly reduced.
Has the effect. In addition, since the transmission channel estimation value is obtained in a state in which the interference signal of the other physical channel is removed in the second stage, it is possible to significantly improve the estimation accuracy of the transmission channel.

According to the next invention, when the physical channel having the higher reception level rank performs the interference cancellation processing, the temporary decision processing is performed by removing the likelihood-added interference replica signal of the physical channel signal having the lower reception level rank. Also, it is possible to improve the accuracy of interference replica generation. Further, since the interference cancellation characteristics of the physical channels having the higher reception level rank are improved, the tentative determination processing of the physical channel signals having the lower reception level rank and the interference replica generation accuracy are also improved. Therefore, the interference cancellation of all the physical channels in the first stage is performed. The effect is that the characteristics can be improved. Furthermore, because the interference cancellation characteristics of all physical channels in the first stage are improved, the interference cancellation characteristics of all physical channels in and after the 1.2th stage are also improved, so that the demodulation processing characteristics of all physical channels are finally improved. There is an effect that it is possible.

According to the next invention, since the interference replica with likelihood of the physical channel signal having the higher reception level rank is subtracted from the reception signal or the residual signal, the interference replica with the likelihood of the physical channel signal having the lower reception level rank is added. As compared with the case where the signal is subtracted, the effect of removing interference is greater, and the demodulation processing characteristics of all physical channels can be further improved.

According to the next invention, the residual signal is updated / propagated in units of physical channels from the first stage to the stage before the second stage, and the temporary decision symbol is generated in a state where the interference component is smaller. As a result, the interference removal characteristic is improved as it goes to the subsequent stages, so that the demodulation characteristic in the second stage can be significantly improved. Further, in each stage, physical channel signals having the same reception level or physical channel signals having close reception levels are processed in parallel, and physical channel signals having different reception levels are processed in series, so that both the processing speed and the demodulation processing characteristic can be improved. There is an effect that it can.

According to the next invention, since the transmission path characteristic estimation processing is performed only by the ICU in the second stage, the circuit scale can be greatly reduced and the processing delay can be greatly reduced.
Has the effect. In addition, since the transmission channel estimation value is obtained in a state in which the interference signal of the other physical channel is removed in the second stage, it is possible to significantly improve the estimation accuracy of the transmission channel.

According to the next invention, it is possible to improve the provisional determination processing characteristic and the interference replica generation processing characteristic of the own physical channel signal by removing the likelihood-added interference replica signal of the other physical channel signal. Produce an effect.
Further, the interference replica generation processing characteristics of all physical channels in the first stage can be improved, and further, the interference replica generation processing characteristics of all physical channels in the 1.2th and subsequent stages can be improved. Thus, it is possible to improve the demodulation processing characteristics of all physical channels.

According to the next invention, when a likelihood-added interference replica signal of a physical channel signal of another group having a lower transmission rate and a higher reception level rank than its own physical channel signal is removed from the residual signal, interference cancellation is performed. The effect is great, and the demodulation processing characteristics of all physical channels can be further improved.

According to the next invention, it is possible to improve the provisional decision processing characteristic and the interference replica generation processing characteristic of the own physical channel signal by removing the likelihood-added interference replica signal of the other physical channel signal. Produce an effect.

According to the next invention, since the power level of the pilot channel and the common control channel is higher than that of each physical channel signal, the demodulation characteristic of the physical channel signal can be greatly improved.

According to the next invention, interference in the replica generation process thereafter when an interference replica signal with likelihood has an error can be reduced, so that the demodulation characteristic can be further improved. Has the effect.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a first embodiment of a CDMA receiver according to the present invention.

FIG. 2 is a diagram showing a configuration of a second embodiment of a CDMA receiver according to the present invention.

FIG. 3 is a diagram showing a configuration of an ICU in each stage other than the second stage.

FIG. 4 is a diagram showing a configuration of a second stage ICU.

FIG. 5 is a diagram showing the configuration of a fourth embodiment of a CDMA receiver according to the present invention.

FIG. 6 is a diagram showing the configuration of a fifth embodiment of a CDMA receiver according to the present invention.

FIG. 7 is a diagram showing the configuration of a CDMA receiver according to a seventh embodiment of the present invention.

FIG. 8 is a diagram showing the configuration of an eighth embodiment of the CDMA receiver according to the present invention.

FIG. 9 is a diagram showing the structure of an eleventh embodiment of a CDMA receiver according to the present invention.

FIG. 10 is a diagram showing the configuration of an eleventh embodiment of a CDMA receiver according to the present invention.

FIG. 11 is a diagram showing the configuration of an eleventh embodiment of a CDMA receiver according to the present invention.

FIG. 12 is a diagram showing the configuration of an eleventh embodiment of a CDMA receiver according to the present invention.

[Fig. 13] Fig. 13 is a diagram showing the structure of an eleventh embodiment of a CDMA receiver according to the present invention.

[Fig. 14] Fig. 14 is a diagram illustrating the configuration of an eleventh embodiment of a CDMA receiver according to the present invention.

FIG. 15 is a diagram showing a configuration of a conventional CDMA receiver.

FIG. 16 is a diagram showing an internal configuration of an ICU.

[Explanation of symbols]

1, 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1
h, 1i, 1j, 1k first stage, 2, 2b, 2d,
2f, 2h, 2j Stage 1.1, 3, 3b, 3
d, 3f, 3h, 3j second stage, 4h, 4i, 4
j, 4k, 6h, 6j, 8h, 8j 1st division group, 5h, 5j, 7h, 7j, 9h, 9j Lth division group, 11-1, 11-2, 14-1, 14-2, 14
-N, 23-1, 23-2, 23-N, 33-1, 33
-2 subtractor, 12-1, 12-2, 12-N, 12b
-1,12b-2,12b-N, 21-1,21-2
21-N, 21b-1, 21b-2, 21-N, 31-
1, 31-2, 31-N, 43, 43j, 44, 44
j, 51, 51j, 61, 61j, 62, 62j, 7
1, 71j, 81, 81j, 82, 82j, 91, 91
j Interference removal unit (ICU), 13-1, 13-2, 13
-N, 22-1, 22-2, 22-N, 23-1, 23
-2 delay device, 15-2,15-N likelihood replica generator, 16 adder, 17a-1, 17a-2, 47i
Weighting unit, 18d, 24d, 45, 53, 63, 7
2,83 delay device (Delay), 19d, 25d subtractor, 34b-1, 34b-2, 34b-N, 85j,
86j, 92j storage device, 52 likelihood replica generator, 54 adder, 301 despreader, 302 adder, 304, 306, 310 multiplier, 305, 312
Delay device, 307 Rake combiner, 308 decision device,
309 Subtractor, 311 Spreading unit, 313 Adder.

Claims (14)

[Claims] 1. An interference removal stage for removing interference caused by cross-correlation of spreading codes individually assigned to a plurality of physical channels, and a second stage for demodulating each physical channel signal after interference removal. , A CDMA (Code Divisio) equipped with a multi-stage interference canceller equipped with
n multiple access) In the receiver, the first stage of the interference cancellation stage is a replica signal based on a despread value of a partial signal having a length shorter than the entire symbol length of the CDMA received signal, and the interference with likelihood. Likelihood replica generating means for generating a replica signal, and first subtracting means for subtracting a likelihood-added interference replica signal of a physical channel signal having a processing order lower than that of the physical channel signal being processed from the received signal or the residual signal. And an interference replica generation unit that generates a symbol replica and an interference replica signal related thereto in physical channel units using the subtraction result, and is updated by subtracting the interference replica signal of the corresponding physical channel from the received signal or the residual signal. A second subtraction means for outputting the residual signal, and Demodulates, CDMA receiver, characterized in that a series arrangement of propagating are sequentially updated residual signal. 2. An interference removal stage for removing interference caused by cross-correlation of spreading codes individually assigned to a plurality of physical channels, and a second stage for demodulating a plurality of physical channel signals after interference removal. In a CDMA receiver equipped with a multi-stage type interference canceller, the first stage of the interference cancellation stage is a despread value of a partial signal having a length shorter than the total symbol length of the CDMA received signal. Likelihood replica generating means for generating an interference replica signal with likelihood that is a replica signal based on the received signal or residual signal, and an interference replica signal with likelihood of a physical channel having a lower processing order than the physical channel being processed. The first subtraction means for subtracting the subtraction value and the transmission path estimation value sent from the second stage and the second stage are used to determine the physical channel unit. First interference replica generating means for generating the symbol and the interference replica signal, and second subtracting means for subtracting the interference replica signal of the corresponding physical channel from the received signal or the residual signal and outputting the updated residual signal , A CDMA receiver having a serial configuration in which interference cancellation processing and demodulation processing are performed in order from a physical channel having a higher processing order, and a sequentially updated residual signal is propagated. 3. The CDMA receiver according to claim 1, wherein the processing order in the interference removal stage is set in order of increasing reception level of each physical channel. 4. An interference removal stage for removing interference caused by cross-correlation of spreading codes individually assigned to a plurality of physical channels, and a second stage for demodulating each physical channel signal after interference removal. In a CDMA receiver equipped with a multi-stage type interference canceller, the first stage of the interference cancellation stage is a despread value of a partial signal having a length shorter than the total symbol length of the CDMA received signal. A likelihood-added replica generation unit that generates a likelihood-added interference replica signal that is a replica signal based on the received signal; and a first subtraction unit that subtracts the likelihood-added interference replica signal of a physical channel other than the physical channel being processed from the received signal. , An interference replica generation means for generating a symbol replica and an interference replica signal related thereto in units of physical channels using the subtraction result Second subtraction means for outputting an updated residual signal by subtracting interference replica signals of a plurality of physical channels from the received signal, and performing interference cancellation processing and demodulation processing on all physical channels at the same time. CD characterized by a parallel configuration
MA receiver. 5. An interference removal stage for removing interference caused by cross-correlation of spreading codes individually assigned to a plurality of physical channels, and a second stage for demodulating each physical channel signal after interference removal. In a CDMA receiver equipped with a multi-stage type interference canceller, the first stage of the interference cancellation stage is a despread value of a partial signal having a length shorter than the total symbol length of the CDMA received signal. A likelihood-added replica generation unit that generates a likelihood-added interference replica signal that is a replica signal based on the received signal; and a first subtraction unit that subtracts the likelihood-added interference replica signal of a physical channel other than the physical channel being processed from the received signal. , A decision symbol and an interference replica signal are provided for each physical channel using the subtraction result and the channel estimation value sent from the second stage. And a second subtraction means for subtracting interference replica signals of a plurality of physical channels from the received signal and outputting an updated residual signal, for all physical channels. A CD characterized by a parallel configuration that performs simultaneous interference removal processing and demodulation processing
MA receiver. 6. The reception level ranking of each physical channel in the interference cancellation stage is set in descending order of the reception level of each physical channel, and in the interference cancellation processing of each physical channel, the reception level is higher than that of the physical channel signal to be processed. The CDMA receiver according to claim 4 or 5, wherein the likelihood-added interference replica signal of the physical channel signal having a low transmission rate is removed from the received signal. 7. The reception level of each physical channel in the interference cancellation stage is set in descending order of the reception level of each physical channel, and in the interference cancellation processing, the reception level is higher than the physical channel signal to be processed and the transmission rate is higher. The CDMA receiver according to claim 4 or 5, wherein the interference-added replica signal of the physical channel signal having a low power consumption is removed from the received signal. 8. An interference canceling stage for canceling interference caused by cross-correlation of spreading codes individually assigned to a plurality of physical channels, and a second stage for demodulating each physical channel signal after interference cancellation. In a CDMA receiver equipped with a multi-stage type interference canceller, the interference cancellation stage is divided into a plurality of groups based on a predetermined standard, and each group of the first stage of the interference cancellation stage is CDMA. From a received signal or a residual signal, a likelihood-added replica generation unit that generates a likelihood-added interference replica signal that is a replica signal based on the despread value of a partial signal having a length shorter than the total symbol length of the received signal , A first reduction for subtracting the likelihood-added interference replica signal of a physical channel in a lower group than the group to which the physical channel being processed belongs Means, first interference replica generating means for generating a determination symbol and an interference replica signal in physical channel units using the subtraction result and the transmission path estimation value sent from the second stage, the received signal or the residual error Second subtraction means for outputting an updated residual signal by subtracting interference replica signals of a plurality of physical channels in the group from the signal, and in the group, interference cancellation processing is simultaneously performed for all physical channels. And a parallel configuration for performing demodulation processing, and a serial configuration for propagating a residual signal updated in order from a physical channel of an upper group between groups. 9. An interference removal stage for removing interference caused by cross-correlation of spreading codes individually assigned to a plurality of physical channels, and a second stage for demodulating each physical channel signal after interference removal. In a CDMA receiver equipped with a multi-stage type interference canceller, the interference cancellation stage is divided into a plurality of groups based on a predetermined standard, and each group of the first stage of the interference cancellation stage is CDMA. From a received signal or a residual signal, a likelihood-added replica generation unit that generates a likelihood-added interference replica signal that is a replica signal based on the despread value of a partial signal having a length shorter than the total symbol length of the received signal , A first reduction for subtracting the likelihood-added interference replica signal of a physical channel in a lower group than the group to which the physical channel being processed belongs Means, an interference replica generation means for generating a symbol replica and an interference replica signal related thereto in physical channel units using the subtraction result, and subtracting interference replica signals of a plurality of physical channels in the group from the received signal or the residual signal. A second subtraction means for outputting the updated residual signal; and a parallel configuration in which all physical channels simultaneously perform interference cancellation processing and demodulation processing in the group, and between groups, the physical group of the upper group is connected. CD having a serial configuration for propagating the residual signal updated in order from the channel
MA receiver. 10. The group division in the interference cancellation stage is determined based on the reception level order of each physical channel signal, and in the interference cancellation processing of the physical channel belonging to the group having a high reception level, the group is divided into a group having a low reception level and The CDMA receiver according to claim 8 or 9, wherein an interference replica signal with likelihood of a physical channel signal having a low transmission rate is removed from a received signal or a residual signal. 11. The group division in the interference cancellation stage is determined based on the reception level ranking of each physical channel signal, and in the interference cancellation processing of the physical channel belonging to the group having a high reception level, the group division belongs to a group having a high reception level. The CDMA receiver according to claim 8 or 9, wherein an interference replica signal with likelihood of a physical channel signal having a low transmission rate is removed from a received signal or a residual signal. 12. The group division in the interference cancellation stage is determined based on the reception level ranking of each physical channel signal, and in the interference cancellation processing of the physical channels belonging to the group having a high reception level, the transmission rate of the physical channels belonging to the same group is determined. The CDMA receiver according to claim 8 or 9, wherein the likelihood-added interference replica signal of the low physical channel signal is removed from the received signal or the residual signal. 13. The CDMA receiver according to claim 1, wherein an interference replica signal with likelihood of a pilot channel or a common control channel is removed from a received signal or a residual signal. . 14. The first stage of the interference elimination stage further comprises weighting means for weighting the likelihood-added interference replica signal to be subtracted by the first subtraction means. The CDMA receiver according to any one of 1 to 13.