JP2003143034A - Communication terminal device and spread code number estimating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To estimate the number of spread codes multiplexed on a received signal, even if the shift amount of a common midamble and the number of spread codes are not in one-to-one correspondence. SOLUTION: A despreading section 202 correlates a data portion of the received signal with each spread code stored in a spread code table 201 for applying despreading. A spread code sorting section 203 arranges the spread codes, in the order of descending levels after inverse-spreading. A spread code number estimating section 204 estimates the number of spread codes multiplexed on the received signal, on the basis of the level of each spread code after despreading and a midamble code determined by a midamble code determining device 103. The section 203 selects the spread codes, in the order of descending levels after despreading only the estimated number of spread codes.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a CDMA (Code D
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication terminal device and a spread code number estimation method used in an ivision multiple access) wireless communication system to estimate the number of spread codes multiplexed in a received signal.

[0002]

2. Description of the Related Art Joint detection (hereinafter referred to as "JD") is a method for demodulating a received signal.
Say. ). For this JD, see "Interferenc
e Cancellation vs. Channel Equalization and Joint
Detection for the Downlink of C / TDMA Mobile Radio
Concepts '' (Bernd Steiner, Proceedings of EPMCC Conf
erence Germany 1997, No.145, pp.253-260) or `` E
FFICIENT MULTI-RATE MULTI-USER DETECTION FOR THE A
SYNCHRONOUS WCDMA UPLINK '' (HR Karimi, VTC'99, pp.5
93-597) and the like.

JD performs a matrix operation using a system matrix in which a convolution operation result of a channel estimation value of each user and a spreading code assigned to each user is arranged in a matrix, and the matrix operation result is the data portion of a received signal. Interference due to multipath fading,
This is a demodulation method for extracting a demodulated signal by removing various interferences such as inter-symbol interference and multiple access interference. Therefore, JD
Has the feature that the reliability of demodulated data is higher than that of RAKE combining, which is generally used at present, and has recently received attention.

In order to execute JD, the number of spreading codes multiplexed in the received signal (hereinafter referred to as "spreading code number").
It is necessary to estimate). Where 3GPP specification TS2
In 5.221v4.2.0, there are 16 types of spreading codes used, and the common midamble (Mida
mble) shift amount is assigned. In addition, the allocation rule is described in TS25.221 Annex C of the same specification.

FIG. 8 is a diagram showing the relationship between the number of spreading codes and the number of midamble codes when there are 16 types of common midambles (K _cell = 16). FIG. 9 is a diagram showing the relationship between the number of spreading codes and the number of midamble codes when there are eight types of common midambles (K _cell = 8). In FIG. 10, four types of common midambles (K _cell =
It is a figure which shows the correspondence of the midamble code and the spreading code number in the case of 4). As shown in FIGS. 8 to 10,
When K _cell = 16, one type of spreading code corresponds to one midamble code, and when K _cell = 8, two types of spreading code correspond to one midamble code. However, when K _cell = 4, four kinds of spreading codes correspond to one midamble code. The base station inserts a midamble code corresponding to the number of spread codes to be multiplexed into transmission data and transmits it to the communication terminal apparatus.

FIG. 11 is a diagram showing a method of creating a midamble code when there are 16 types of common midambles. As shown in FIG. 11, the midamble is generated by cutting out a part of a known basic code string having a predetermined chip period (456 chips) while shifting W chips. For example, the midamble code # 1 (shift amount 1) is W = 5 after the basic code.
The 7-chip part and the 455 chips from the beginning of the basic code are connected. In addition, the midamble code # 2 (shift amount of 2) is 2 after the basic code.
A portion of × W = 114 chips and a portion of 455-W = 398 chips from the beginning of the basic code are connected. That is, the midamble code # 2 is obtained by shifting the midamble code # 1 backward by W. The method of creating the midamble code is described in TS25.221 (v4.2.0) section 5.2.3.

Therefore, when performing wireless communication based on the above standard, as shown in FIG.
Since the signal S _i transmitted at (i = 1, 2, 3) has a slot configuration in which a common midamble is inserted between data, the reception device of the communication terminal device determines that the midamble part of the reception signal is received. The shift amount of the common midamble can be estimated by taking the correlation between and the basic code. When the midamble code and the number of spreading codes have a one-to-one correspondence (K _cell = 16),
If the midamble code is known, the number of spreading codes will be uniquely obtained. For example, if it is determined that the common midamble is the midamble code # 1, it is determined from FIG. 8 that the number of spreading codes is 1.

The receiving device of the communication terminal device performs despreading processing on all spreading codes usable in the slot,
Spreading codes are selected in descending order of despreading code by the number of spreading codes determined above, and JD is performed using the selected spreading code.

[0009]

However, when the shift amount of the common midamble and the number of spreading codes do not have a one-to-one correspondence (K _cell = 4 or K _cell = 8), the shift amount of the common midamble is large. The number of spreading codes cannot be calculated by itself. In the prior art, no effective spreading code number estimation method in this case has been proposed.

The present invention has been made in view of the above points, and the number of spreading codes multiplexed in a received signal even when the shift amount of the common midamble and the number of spreading codes do not have a one-to-one correspondence. It is an object of the present invention to provide a communication terminal device and a spreading code number estimation method capable of estimating the number of bits.

[0011]

A communication terminal apparatus of the present invention is provided with a determination means for determining a known code multiplexed on a received signal and all spreading codes possibly multiplexed on the received signal. Despreading means for performing despreading processing, spreading code selection means for selecting a spreading code multiplexed on the received signal based on the known code and the level after despreading in the despreading means, and this spreading code selection Demodulation means for demodulating the data portion of the received signal using the channel estimation value of the spreading code selected by the means.

The determination means in the communication terminal apparatus of the present invention calculates the shift amount of the received signal whose known signal is the midamble with respect to the basic code of the midamble, and uses the midamble code to be used based on the shift amount of the midamble. Take the configuration to judge.

The spreading code selecting means in the communication terminal apparatus of the present invention narrows down the candidates for the number of spreading codes based on the used midamble code, and the spreading code order and candidates are sorted in descending order of the level after despreading. The configuration is such that the spreading code is selected in relation to the number of spreading codes.

With these configurations, the number of spreading codes is narrowed down based on the shift amount of the common midamble, and the levels after despreading in each spreading code are compared to finally estimate the number of spreading codes. Therefore, even when the shift amount of the common midamble and the number of spreading codes do not have a one-to-one correspondence, it is possible to estimate the number of spreading codes multiplexed in the received signal and select the spreading code. Then, it is possible to accurately demodulate.

The spreading code selecting means in the communication terminal device of the present invention divides the spreading codes after sorting into groups based on the number of candidate spreading codes, and calculates the average value of the levels after despreading for each group. A configuration is adopted in which the spreading code is selected according to the magnitude relationship between the difference between the average values of the levels between the two groups and the threshold value.

With this configuration, by comparing the level average values with the number of candidate spreading codes as a boundary, even if the shift amount of the common midamble and the number of spreading codes do not have a one-to-one correspondence, reception is performed. The number of spreading codes multiplexed in the signal can be estimated.

The spreading code selecting means in the communication terminal device of the present invention is the despreading level of the spreading code whose sorting order is the same as the number of candidate spreading codes and the spreading code of the next sequence. The difference between the spread level is calculated, and the spread code is selected according to the magnitude relationship between the difference and the threshold value.

With this configuration, by comparing the levels before and after the number of candidate spreading codes as a boundary, even when the shift amount of the common midamble and the number of spreading codes do not have a one-to-one correspondence. It is possible to estimate the number of spreading codes multiplexed in the received signal.

The spreading code selecting means in the communication terminal device of the present invention calculates the difference in level after despreading between two spreading codes in consecutive order, and determines the spreading code order and candidates that maximize this difference. The spreading code is selected according to the size relation with the number of spreading codes.

With this configuration, by comparing the order in which the level difference is maximum and the candidate, even if the shift amount of the common midamble and the number of spreading codes do not have a one-to-one correspondence, they are multiplexed in the received signal. It is possible to estimate the number of spreading codes used.

The spreading code selecting means in the communication terminal apparatus of the present invention is configured to select the spreading code in consideration of the order of the spreading codes of its own station.

With this configuration, the processing time until the number of spreading codes is estimated can be shortened by considering the order of spreading codes of the own station.

The demodulating means in the communication terminal apparatus of the present invention generates a matrix using the spreading code and the channel estimation value selected by the spreading code selecting means, and uses the generated matrix and the received signal to perform joint detection. Take a configuration to perform an option.

With this structure, demodulated data with high reliability can be obtained by the joint detection even when the shift amount of the common midamble and the number of spreading codes do not have a one-to-one correspondence.

The base station apparatus of the present invention has a configuration for performing wireless communication with any one of the above communication terminal apparatuses.

With this configuration, demodulated data with high reliability can be obtained in the downlink, so that high quality wireless communication can be performed.

The spread code number estimating method of the present invention comprises the steps of calculating the shift amount of the basic code of the midamble multiplexed in the received signal, and determining the midamble code based on the shift amount of the midamble. A step of narrowing down candidates for the number of spreading codes based on the midamble code; a step of performing despreading processing on all spreading codes that may be multiplexed in the received signal; and a step of performing despreading processing. The number of spreading codes multiplexed in the received signal from the process of sorting the codes in descending order of the level after despreading, and the relationship between the sorted spreading code order, the level after despreading, and the number of candidate spreading codes. And the step of estimating.

According to this method, the number of spreading codes is narrowed down based on the shift amount of the common midamble, and the levels after despreading in each spreading code are compared to finally estimate the number of spreading codes. Therefore, even when the shift amount of the common midamble and the number of spreading codes do not have a one-to-one correspondence, it is possible to estimate the number of spreading codes multiplexed in the received signal.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION When the present inventor performs despreading processing (correlation processing + RAKE combining processing) on the same spreading code as the spreading code of the spread signal multiplexed on the received signal, the The present invention has been made paying attention to the fact that the level is significantly higher than that in other spreading codes.

That is, the essence of the present invention may be multiplexed on the spread signal multiplexed on the received signal after narrowing down the candidates for the number of spread codes based on the shift amount of the common midamble. The despreading process is performed for all of a certain spreading code, and the number of spreading codes is finally estimated by comparing the levels after despreading in each spreading code.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(Embodiment 1) FIG. 1 is a block diagram showing a configuration of a communication terminal apparatus according to Embodiment 1 of the present invention. The communication terminal device shown in FIG. 1 includes a wireless receiver 101,
The midamble correlator 102, the midamble code determiner 103, the path selector 104, the spreading code selector 105, and the JD demodulator 106 are mainly included.

Radio receiver 101 frequency-converts a radio frequency received signal having the slot configuration shown in FIG. 12 into a baseband. Then, the radio receiver 101 uses the spread code selector 10 to convert the data portion of the received signal converted to the baseband (hereinafter referred to as “received baseband signal”).
5 and the JD demodulator 106 and outputs the midamble part of the received baseband signal to the midamble correlator 102.
Output to.

The midamble correlator 102 performs a correlation process between the basic code and the midamble portion of the received baseband signal to create a delay profile corresponding to each midamble shift amount, and determines the delay profile from the midamble code determiner. Output to 103.

The midamble code determiner 103 determines the midamble code based on the shift amount of the maximum correlation value of the delay profile, and the determination result is the path selector 10
4 and spread code selector 105.

The path selector 104 refers to the determination result of the midamble code determiner 103 and the delay profile, selects a path exceeding a predetermined threshold as a path used for matrix calculation for interference cancellation, and selects the selected path. (Less than,
The position of the “selected path” and the channel estimation value of the path are output to the spreading code selector 105 and the JD demodulator 106.

The spread code selector 105 selects a spread code to be used for JD based on the correlation result between the data part of the received signal and each spread code and the midamble code determined by the midamble code determiner 103. The selection result is output to the JD demodulator 106.

The JD demodulator 106 is the spread code selector 1
A matrix is generated by a predetermined process using the channel estimation value of the selected path in the spreading code selected in 05, and the joint matrix is generated using the generated matrix and the received baseband signal.
Detection is performed and desired reception data is extracted by demodulating while removing interference.

Next, the internal configuration of spreading code selector 105 according to the present embodiment will be explained using the block diagram of FIG. The spreading code selector 105 includes a spreading code table 201, a despreading unit 202, and a spreading code sorting unit 2
03 and a spreading code number estimation unit 204.

The spreading code table 201 stores all spreading codes that may be multiplied by the spreading signal multiplexed on the received signal. The despreading unit 202 performs despreading by correlating the data portion of the received signal with each spreading code stored in the spreading code table 201 at the timing of the path selected by the path selector 104, and spreading. The code and the level after despreading in each spreading code are output to the spreading code sorting unit 203. Despreading section 202 averages the levels after despreading over a plurality of symbols, and the average value thereof is spread code sorting section 20.
It may be output to 3.

The spreading code sorting unit 203 is a despreading unit 2
The spreading codes output from No. 02 are arranged in descending order of despreading level. Further, the spreading code sorting unit 203 selects the spreading code to be used for JD in the descending order of the level after despreading by the number of spreading codes estimated by the spreading code number estimating unit 204, and selects the selected spreading code from the JD demodulator. To 106.

Spreading code number estimating section 204 receives the received signal based on the despreading level of each spreading code output from spreading code sorting section 203 and the midamble code determined by midamble code determining section 103. Then, the number of spread codes multiplexed in is estimated, and the estimation result is output to the spread code sorting unit 203.

Next, the flow of the spreading code number estimating method in spreading code number estimating section 204 will be described with reference to the flowchart of FIG. In FIG. 3, the constant P is a numerical value indicating the number of candidates for the number of spreading codes corresponding to the midamble code determined by the midamble code determiner 103, and in the examples of FIGS. 8, 9, and 10. When K _cell = 8, P = 2, and when K _cell = 4, P = 4. Further, N (i) indicates the number of spreading codes that are candidates (i is a natural number), and in the examples of FIGS. 8, 9, and 10, N (i) = K
_cell * (i-1) + m (m is a midamble code number). Here, N (0) = 0. For example, K
_{When cell} = 8 (P = 2) and m = 3, the spreading code number candidate N (i) is N (1) = 3 or N (2) = 11.

First, the midamble code determiner 103
A candidate N (i) for the number of spreading codes is acquired based on the midamble code determined in (ST (= step) 301).

Next, the average value L of the levels from the first (highest) level to the N (1) th level after despreading.
_AVE (1) is calculated (ST302, ST303). Further, the level after despreading is from N (1) + 1st to N (2).
The average value L _AVE (2) of the level up to the th is calculated (ST304).

The average value L _AVE (1) and the average value L _AVE
It is determined whether the difference Δ (1) from (2) = L _AVE (1) −L _AVE (2) is larger than a preset threshold Th (ST305).

In ST305, the difference Δ (1) is the threshold value T.
If it is larger than h, the process proceeds to ST308. On the other hand, S
When the difference Δ (1) is less than or equal to the threshold Th at T305, i is incremented (ST306, ST30
7) Then, the process from ST303 is performed again. Below, ST3
In step 05, the difference Δ becomes larger than the threshold value Th, or in ST306, until i = P−1, ST
The processing from 302 to ST307 is repeated.

Then, in ST305, the difference Δ (i)
Is larger than the threshold Th, or ST306
If i = P−1 in N, then N at that time
It is estimated that (i) is the number of spreading codes (ST30).
8).

The above series of processing (ST301 to ST30
8), the spreading code number estimation unit 204 can estimate the spreading code number. Then, spreading code number estimating section 204 outputs the estimation result to spreading code sorting section 203.

In ST303 of FIG. 3, the 1st to N (i) th levels may be calculated as the average value L _AVE (i).

Next, a specific example of the spreading code number estimating method in spreading code number estimating section 204 will be described with reference to FIG. FIG. 4 is a diagram showing an example of the relationship between the rank j (horizontal axis) and the level L (vertical axis) after despreading when sorting in descending order of the level after despreading. In FIG. 4, K _cell =
4 (P = 4) and m = 3, in which case N
(1) = 3, N (2) = 7, N (3) = 11, N (4)
= 15.

The spreading code number estimating unit 204 firstly performs the inverse expansion.
Levels from the 1st to the 3rd level after dispersion
Average L_AVE(1) and the level after despreading is 4th to 7th
Average value L of the level up to_AVE(2) and calculated
And Δ (1) = L_AVE(1) -L _AVE(2) and threshold Th
Compare the magnitude relationship of.

As a result, for example, if Δ (1) is less than or equal to the threshold value Th, the spreading code number estimating unit 204 next determines the average value of the fourth to seventh levels after despreading. L _AVE (2) and the average value L _AVE (3) of the level from the 8th to the 11th after despreading
Is calculated, and the magnitude relationship between Δ (2) = L _AVE (2) −L _AVE (3) and the threshold Th is compared.

As a result, for example, if Δ (2) is larger than the threshold value Th, the spreading code number estimating unit 204
It is estimated that N (2) = 7 is the number of spreading codes, and the estimation result (= 7) is output to the spreading code sorting unit 203. The spreading code sorting unit 203 selects seven spreading codes in descending order of the level after despreading, and selects the selected spreading code by JD.
Output to the demodulator 106.

As described above, according to the present embodiment, the candidates of the number of spreading codes are narrowed down based on the shift amount of the common midamble, the spreading codes are sorted in descending order of the level after despreading, and the spreading becomes the candidates. By comparing the level averages with the number of codes as a boundary, the number of spreading codes multiplexed in the received signal is estimated even when the shift amount of the common midamble and the number of spreading codes do not have a one-to-one correspondence. be able to.

(Embodiment 2) Embodiment 2 is different from Embodiment 1 in the spreading code number estimation method in the spreading code number estimating section. The configuration of the communication terminal apparatus according to the present embodiment is the same as that of FIG. 1 described in the first embodiment, and the internal configuration of the spreading code selector according to the present embodiment is the same as that described in the first embodiment. Since it is the same as that of 2, the description is omitted.

The flow of the spreading code number estimating method in spreading code number estimating section 204 of the present embodiment will be explained below using the flowchart of FIG. In addition, in FIG.
The constant P is a numerical value indicating the number of candidates for the number of spreading codes corresponding to the midamble code determined by the midamble code determiner 103, and when K _cell = 8 in the examples of FIGS. 8, 9 and 10. When P = 2 and K _cell = 4, P
= 4. Further, N (i) indicates the number of spreading codes that are candidates (i is a natural number), and in the examples of FIGS. 8, 9 and 10, N (i) = K _cell × (i−1) + m (m Is the midamble code number). Here, N (0) = 0. Further, the j-th level after despreading when the spreading codes are sorted in descending order of the level after despreading is L (j).

First, the midamble code determiner 103
A candidate N (i) for the number of spreading codes is acquired based on the midamble code determined in (ST501).

Next, the level L after the N (1) th despreading
(N (1)) is searched (ST502, ST503).
Moreover, the level L (N
Search (1) +1) (ST504).

Then, the level L (N (1)) and the level L
Difference from (N (1) +1) Δ (1) = L (N (1)) −
It is determined whether L (N (1) +1) is larger than a preset threshold Th (ST505).

In ST505, the difference Δ (1) is the threshold value T.
If it is larger than h, the process proceeds to ST508. On the other hand, S
When the difference Δ (1) is less than or equal to the threshold Th at T505, i is incremented (ST506, ST50
7) Then, the process from ST302 is performed again. Below, ST5
In step 05, the difference Δ becomes larger than the threshold value Th, or in ST506, until i = P−1, ST
The processing from 503 to ST507 is repeated.

Then, in ST505, the difference Δ (i)
Is larger than the threshold Th, or ST506
If i = P−1 in N, then N at that time
It is estimated that (i) is the number of spreading codes (ST50
8).

The above series of processes (ST501 to ST50)
8), the spreading code number estimation unit 204 can estimate the spreading code number. Then, spreading code number estimating section 204 outputs the estimation result to spreading code sorting section 203.

As described above, according to the present embodiment, the candidates for the number of spreading codes are narrowed down based on the shift amount of the common midamble, the spreading codes are sorted in descending order of the level after despreading, and the spreading as a candidate is performed. By comparing the levels before and after the number of codes as a boundary, the number of spreading codes multiplexed in the received signal is estimated even when the shift amount of the common midamble and the number of spreading codes do not have a one-to-one correspondence. can do.

In the above-mentioned first and second embodiments,
Although the threshold value Th used when estimating the number of spreading codes is described as being fixed in advance, the present invention is not limited to this, and the threshold value Th may be variable and may be obtained by an appropriate calculation formula. For example, the average value of the paths other than the selected path is set as the noise level, and the value obtained by multiplying the ratio of the maximum value of the despread level and the noise level by a predetermined coefficient is set as the threshold value.

(Third Embodiment) The third embodiment is different from the first embodiment in the spreading code number estimating method in the spreading code number estimating section. The configuration of the communication terminal apparatus according to the present embodiment is the same as that of FIG. 1 described in the first embodiment, and the internal configuration of the spreading code selector according to the present embodiment is the same as that described in the first embodiment. Since it is the same as that of 2, the description is omitted.

The flow of the spreading code number estimating method in spreading code number estimating section 204 of the present embodiment will be explained below using the flowchart of FIG. In addition, in FIG.
The constant P is a numerical value indicating the number of candidates for the number of spreading codes corresponding to the midamble code determined by the midamble code determiner 103, and when K _cell = 8 in the examples of FIGS. 8, 9 and 10. When P = 2 and K _cell = 4, P
= 4. Further, N (i) indicates the number of spreading codes that are candidates (i is a natural number), and in the examples of FIGS. 8, 9 and 10, N (i) = K _cell × (i−1) + m (m Is the midamble code number). Here, N (0) = 0. Further, the j-th level after despreading when the spreading codes are sorted in descending order of the level after despreading is L (j). The constant J is the type of spreading code that may be used, that is, the type of spreading code stored in the spreading code table 201 (3GPP specification TS25.2).
In 21v4.2.0, J = 16).

First, the midamble code determiner 103
A candidate N (i) for the number of spreading codes is acquired based on the midamble code determined in (ST601).

Next, the j-th despread level L (j)
The difference Δ (j) = L a (j) -L (j + 1 ) is calculated for all j, corresponding to the maximum difference Δ _max j = k and the j + 1 th level despread L (j + 1) It is detected (ST602 to ST608).

Next, the magnitude relationship between Δ _max and a predetermined threshold Th is compared (ST609). Then, if Δ _max is larger than the threshold value Th in ST609, the magnitude relationship between N (i) and k is sequentially compared from i = 1 (ST609-
ST613), when N (i)> k, or
When i = P-1, the number of spreading codes is estimated as N (i) (ST615). On the other hand, in ST609 Δ
_{If max} is less than the threshold Th, i = P is set (ST6
14), the number of spreading codes is determined to be N (i) (ST61
5).

The above series of processes (ST601 to ST61)
According to 5), the spreading code number estimation unit 204 can estimate the spreading code number. Then, spreading code number estimating section 204 outputs the estimation result to spreading code sorting section 203.

As described above, according to the present embodiment, the candidates for the number of spreading codes are narrowed down based on the shift amount of the common midamble, the spreading codes are sorted in descending order of the level after despreading, and the spreading as a candidate is performed. By comparing the number of codes and the order of maximum level difference, the number of spreading codes multiplexed in the received signal even when the shift amount of the common midamble and the number of spreading codes do not have a one-to-one correspondence. Can be estimated.

(Embodiment 4) Here, each communication terminal device naturally knows its spreading code (spreading code multiplied by the signal addressed to itself and transmitted from the base station).
Then, when the spreading codes are sorted in descending order of the level after despreading, the order of spreading codes of the local station is equal to or less than the number of multiplexed spreading codes.

In the fourth embodiment, the processing time of the method for estimating the number of spreading codes described in the first embodiment is shortened by considering the order of spreading codes of its own station. The configuration of the communication terminal apparatus according to the present embodiment is the same as that of FIG. 1 described in the first embodiment, and the internal configuration of the spreading code selector according to the present embodiment is the same as that described in the first embodiment. Since it is the same as that of 2, the description is omitted.

The flow of the spreading code number estimating method in spreading code number estimating section 204 of the present embodiment will be explained below using the flow chart of FIG. The flow chart of FIG. 7 is obtained by adding ST701 and ST702 between ST302 and ST303 of FIG. 3 described in the first embodiment.
In FIG. 7, j _own is the order of the spreading code of the own station when the spreading codes are sorted in descending order of the level after despreading. When there are a plurality of spreading codes at the time station, it is assumed that the spreading code has the smallest level after despreading.

In ST701 and ST702, N (i) ≧
Increment i until j _own . For example, if j _own = 5 in the case of FIG. 4 above, i = 2 when proceeding to ST303, and it is not necessary to perform the processing of ST303 to ST307 for i = 1.

As described above, according to the present embodiment, the processing time of the spreading code number estimation method described in the first embodiment can be shortened by considering the order of spreading codes of the own station. .

Similarly, S in FIG. 5 explained in the second embodiment.
ST701 and ST702 between T502 and ST503
Can be added, the processing time of the spreading code number estimation method described in the first embodiment can be shortened. Further, by adding ST701 and ST702 between ST609 and ST610 of FIG. 6 described in the third embodiment, it is possible to reduce the processing time of the spreading code number estimation method described in the first embodiment.

In the present embodiment, when the spreading code is output from the spreading code sorting section 203 of FIG. 2 to the JD demodulator 106, the spreading code lower than the despreading level of the spreading code of the own station by X dB is used. It may be removed from the selection.

In each of the above embodiments, the case where the spreading code is selected on the basis of the level after despreading has been described. However, in the present invention, the spreading code is selected after despreading and subjected to synchronous detection or RAKE demodulation processing. You may make it use a level.

Further, although the communication terminal apparatus of each of the above-mentioned embodiments carries out demodulation using joint detection, the present invention is not limited to this, and it is possible to carry out demodulation using other matrix operations. Even if there is, the same effect can be obtained.

[0082]

As described above, according to the present invention,
After narrowing down the candidates for the number of spreading codes based on the shift amount of the common midamble, despreading processing is performed on all spreading codes that may be multiplied by the spreading signal multiplexed on the received signal, and each spreading code is spread. Estimating the number of spreading codes multiplexed in the received signal even when the shift amount of the common midamble and the number of spreading codes do not have a one-to-one correspondence by comparing the levels of the codes after despreading. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a communication terminal device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration of a spread code selector according to the above embodiment.

FIG. 3 is a flowchart showing a flow of a spreading code number estimation method of the communication terminal apparatus according to the above embodiment.

FIG. 4 is a diagram showing an example of a relation between a rank j and a level L after despreading when sorting in descending order of the level after despreading.

FIG. 5 is a flowchart showing a flow of a spreading code number estimation method for a communication terminal apparatus according to Embodiment 2 of the present invention.

FIG. 6 is a flowchart showing a flow of a spreading code number estimation method for a communication terminal apparatus according to Embodiment 3 of the present invention.

FIG. 7 is a flowchart showing a flow of a spreading code number estimation method for a communication terminal apparatus according to Embodiment 4 of the present invention.

FIG. 8: 16 types of common midamble (K _cell = 1
The figure which shows the relationship between the midamble code and the number of spreading codes in the case of 6)

FIG. 9 is a diagram showing a relationship between a midamble code and the number of spreading codes when there are eight types of common midambles (K _cell = 8).

FIG. 10: Four common midambles (K _cell = 4)
Diagram showing the correspondence between the midamble code and the number of spreading codes in case of

FIG. 11 is a diagram showing a method of creating a midamble code when there are 16 types of common midambles.

FIG. 12 is a diagram showing a slot configuration when a common midamble is inserted between data.

[Explanation of symbols]

101 wireless receiver 102 midamble correlator 103 Midamble code determiner 104 path selector 105 Spread code selector 106 JD demodulator 201 Spread code table 202 despreader 203 Spread Code Sorting Unit 204 Spread code number estimation unit

Claims (10)

[Claims] 1. A determining means for determining a known code multiplexed on a received signal, a despreading means for performing a despreading process on all spreading codes that may be multiplexed on the received signal, and the known method. Spreading code selecting means for selecting a spreading code multiplexed on the received signal based on the code and the level after despreading in the despreading means,
And a demodulation unit for demodulating the data portion of the received signal using the channel estimation value of the spreading code selected by the spreading code selection unit. 2. The determining means calculates a shift amount of a received signal whose known signal is a midamble with respect to a basic code of the midamble, and determines a used midamble code based on the shift amount of the midamble. The communication terminal device according to claim 1, which is characterized in that. 3. The spreading code selecting means narrows down the candidates for the number of spreading codes based on the midamble code used, sorts the spreading codes in descending order of the level, and the number of spreading codes to be candidates. 3. The communication terminal device according to claim 2, wherein the spreading code is selected from the relationship. 4. The spreading code selecting means divides the spreading codes after sorting into groups based on the number of candidate spreading codes, calculates the average value of the levels after despreading for each group, and calculates the average between the two groups. 4. The communication terminal device according to claim 3, wherein the spreading code is selected according to the magnitude relationship between the difference between the average values of the levels and the threshold value. 5. The spreading code selection means includes a despreading level of a spreading code whose sorted order is the same as the number of candidate spreading codes and a despreading level of a spreading code of the next order. 4. The communication terminal device according to claim 3, wherein the spread code is selected according to the magnitude relationship between the difference and the threshold value. 6. The spreading code selecting means calculates a difference in level after despreading between two spreading codes whose order is continuous, and the order of the spreading code having the maximum difference and the number of candidate spreading codes. 4. The communication terminal device according to claim 3, wherein the spreading code is selected according to the magnitude relationship with. 7. The communication terminal device according to claim 4, wherein the spreading code selecting unit selects the spreading code in consideration of the order of spreading codes of the own station. 8. The demodulating means generates a matrix using the spreading code and the channel estimation value selected by the spreading code selecting means, and uses the generated matrix and the received signal to perform a joint
The communication terminal device according to any one of claims 1 to 7, which performs detection. 9. A base station device, which performs wireless communication with the communication terminal device according to claim 1. Description: 10. A step of calculating a shift amount of a basic code of a midamble multiplexed in a received signal, a step of determining a midamble code based on the shift amount of the midamble, and a step of determining a midamble code based on the midamble code. And narrowing down the number of spreading code candidates,
A step of performing despreading processing on all of the spreading codes that may be multiplexed in the received signal, a step of sorting the despreading processed spreading codes in descending order of the level after despreading, and a step of sorting the spread codes. A method for estimating the number of spreading codes, which comprises estimating the number of spreading codes multiplexed in a received signal from the relationship between the order, the level after despreading and the number of candidate spreading codes.