JP2003273779A - Receiver for direct spread spectrum communication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform always stable receiving operation without deteriorating receiving characteristics to a variation in multiplexed transmission path in the path search method of a direct spread spectrum communication. <P>SOLUTION: This receiver is provided with: receiving means 1, 2 and 3 for receiving a direct spread spectrum signal; a filter 4 for removing noise component outside of a transmission band from the received direct spread spectrum signal; a path search part 5 for searching a path from the direct spread spectrum signal outputted from the filter; and a RAKE mixing part 6 for performing RAKE mixing. The path search part 5 obtains the correlation power value of each delay time with a spread code to generate the delay profile, detects a first path from this delay profile, removes an impulse response component on the basis of the transmission function of the filter 4 with the first pulse as reference from the delay profile, and thereafter decides a plurality of paths while performing processing of detecting a second path from the delay profile from which the impulse response component is removed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving apparatus such as a mobile phone system which employs a direct spread spectrum communication system, and more particularly to a path search system for assigning multipath fingers in a mobile radio system.

[0002]

2. Description of the Related Art DS-CDMA (Direct Sequence-Code)
Division Multiple Access) communication method is a method in which a plurality of receivers perform communication at the same frequency using different spreading codes. In mobile communication, a multipath propagation path (multipath) is formed due to the influence of buildings and topography between a base station and a receiver. In the multiple wave propagation path, each wave interferes with each other and causes quality deterioration in the receiver.
In the DMA system, reception quality can be improved by separating these multiple waves and performing RAKE combining.
The process of separating each path from the multipath propagation path is path search. Each path separated by the path search is assigned to each RAKE finger, and the waves of each path are extracted and combined.

When selecting a path, the receiving device first creates a delay profile. In general, a delay profile is a correlation power value between a known common pilot signal included in a received signal and a spread code (scramble code),
It is generated by calculating the delay time with a slight shift. The receiving device is assigned a plurality of path search fingers used to perform a path search in parallel by shifting the delay time and a plurality of detected paths, and a plurality of RAKE used for RAKE combining. It is equipped with fingers. In the receiving device, a delay profile is periodically generated by a path search finger, as many paths as RAKE fingers are selected from the delay profile, and each of these paths is assigned to a RAKE finger. As a method of selecting this path, for example, a method disclosed in Japanese Patent Laid-Open No. 2001-237739, in which local maxima are first detected from the delay profile, and then paths are selected in descending order of power value from these maxima is known. Has been.

[0004]

In mobile communication,
A roll-off filter or the like is used for the purpose of removing noise components such as overshoot and ringing outside the transmission band from the received signal. The impulse response of the roll-off filter has a waveform as shown in FIG. 12 when, for example, 4 times oversampling is performed. When converted into a power value, a waveform as shown in FIG. 13 is obtained. That is, the power leaks to the points other than the sampling point having the maximum power (the leakage power becomes 0 every 4 samples from the maximum sampling point). When a delay profile is created in the receiving device, the shape of the delay profile has a waveform similar to this impulse response if the number of multipaths is 1. When selecting a path from this delay profile, as in the method disclosed in Japanese Patent Laid-Open No. 2001-237739, if a maximum point is simply selected, a total of three sample points, sample point 0 and sample point ± 6, are selected as different paths. May be done. Originally, it is only necessary to select the sample point 0, but if the sample points ± 6 are also selected, these sample points have low S / N.
If RAKE combining is performed, there is a problem that reception characteristics are deteriorated.

The present invention has been made in view of the above circumstances, and provides a receiving apparatus for direct spread spectrum communication that can always obtain good receiving characteristics without being affected by the impulse response component of a filter. The purpose is to

[0006]

In order to solve the above-mentioned problems, a first receiving device according to the present invention comprises a receiving means for receiving a direct spread spectrum signal, and a device outside the transmission band from the received direct spread spectrum signal. A filter that removes noise components and a correlation power value for each delay time of the direct spread spectrum signal and spread code output from this filter are calculated to generate a delay profile, and the first path is detected from this delay profile. Processing for removing the impulse response component based on the transfer function of the filter based on the first path from the delay profile, and then detecting the second path from the delay profile from which the impulse response component has been removed And a plurality of paths determined by the path search means for determining a plurality of paths while performing Direct sequence spread spectrum signal received with the calculated correlation power value of the spread code, the calculated correlation power value, characterized in that a RAKE combining means for RAKE combining.

According to the first receiving apparatus of the present invention, the first path is determined from the delay profile obtained by the path search unit, and then based on the transfer function of the filter with the first path as a reference. Since a plurality of paths are determined by determining the next path after removing the impulse response component, only the sampling point 0 of the impulse response waveform is included in the determined path. Is not included. Therefore, it is possible to prevent the deterioration of the reception characteristics.

A second receiving device according to the present invention is a receiving means for receiving a direct spread spectrum signal, a filter for removing a noise component outside the transmission band from the received direct spread spectrum signal, and an output from this filter. A delay profile is generated by obtaining a correlation power value of each direct spread spectrum signal and a spread code for each delay time, and a plurality of paths are determined from this delay profile, and a path search means between the determined plurality of paths. And the correlation power value between the direct spread spectrum signal and the spread code received for each of the plurality of paths determined by the path search means is calculated, and the calculated correlation value between each path is calculated. If the correlation value is smaller than the predetermined threshold value, each path is RAKE-combined and the calculated correlation value is equal to or larger than the predetermined threshold value. In this case, RAKE only one path
RAKE combining means for combining is provided.

According to the second receiver of the present invention, R
When performing AKE combining, a correlation value between the detected paths is calculated, and when the calculated correlation value is smaller than a predetermined threshold value, both paths are regarded as separate paths, and these are treated as separate paths. If the correlation value calculated by RAKE combining is equal to or greater than a predetermined threshold value, both paths are the same path, and the relationship between sample point 0 and sample point ± n that appears due to the influence of the impulse response of the filter Since the path having the higher correlation power value is RAKE-combined, it is possible to prevent an erroneous path from being RAKE-combined. This makes it possible to prevent deterioration of reception characteristics.

In these receiving devices, RAKE
A block error rate detecting means for detecting the block error rate of the combined output is provided, and the process of removing the impulse response component of the filter from the delay profile described above, or the process of selecting the RAKE combining path based on the correlation value between the paths, It may be performed only when the block error rate exceeds a predetermined threshold value. By doing so, the processing load can be reduced and power consumption can be suppressed.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a block diagram showing the configuration of a receiver for direct spread spectrum communication according to the first embodiment of the present invention. As shown in FIG. 1, this receiving device includes an antenna 1 for receiving a signal, an RF unit 2 for converting a direct spread spectrum signal received via the antenna 1 into a baseband signal, and an RF unit 2 for the RF unit 2. An A / D converter 3 for converting the output from an analog signal to a digital signal, and a filter 4 for limiting the band of the baseband signal converted to the digital signal to remove noise components outside the transmission band such as ringing and overshoot. , A path search unit 5 for performing a correlation calculation between a common pilot signal included in a received signal and a scramble code for path search, and a RAKE combining unit 6 for decoding data on each detected path to perform RAKE combining. And an error correction unit 7 that performs error correction on the output of the RAKE combining unit 6, path search and decision control, path allocation, and RAKE reception. A controller 8 that performs the control or the like, and is constituted by a memory 9 for storing a delay profile or the like for the path determination.

FIG. 2 is a block diagram showing a specific configuration of the path search unit 5. The path search unit 5 has Pf path search fingers 10. Each path search finger 1
Reference numeral 0 denotes a common pilot correlator 11 for synchronous detection that performs a correlation calculation between a received signal and a scramble code, and a scramble code generator 12 that supplies a scramble code as a spread code to the common pilot correlator 11.
And a power measuring device 13 for measuring the correlation power between the received signal and the scramble code. In the path search unit 5, the DSP (Digital Signal Processor) 14 that writes the correlation power values output from the Pf power measuring devices 13 and the delay time in the memory 15 as a delay profile and determines the path from the delay profile. And D
A memory 15 for storing the delay profile written by the SP 14 is included. Note that a matched filter may be used instead of the correlator 11 to perform the path search.

FIG. 3 is a block diagram showing a specific structure of the RAKE combining section 6. The RAKE combining unit 6 has Rf RAKE fingers 20. Each RAKE finger 2
At 0, a common pilot correlator 21 for synchronous detection that performs a correlation calculation between the received signal and the scramble code, a data correlator 22 for demodulating data of each path from the received signal, and these correlator 21 , 22 are provided with a scrambling code generator 23 for supplying a scrambling code which is a common spreading code, and a channelizing code generator 24 for supplying a channelizing code which is an individual spreading code to the data correlator 22. There is. Also, each RA
The KE finger 20 is provided with a power measuring device 25 for measuring the power value based on the correlation value from the common pilot correlator 21 and estimating the transmission line response. RAKE
The synthesizer 6 also performs complex multiplication of the estimated transmission path response and the correlation value from the data correlator 22 to generate demodulated data, and allocates the demodulated data to each RAKE finger 20. The DSP 25 for compensating for the delay time corresponding to the selected path and performing the in-phase synthesis by matching the data timings of all the RAKE fingers 20 and this DS.
A memory 26 for storing data necessary for the processing of P25 is provided.

Next, the operation of the receiving apparatus thus configured will be described. FIG. 4 is a diagram schematically showing the configuration of the received signal. In the received signal, the data DATA1, which is spread with the channelizing code different for each user,
, 2, and a common pilot signal which is a known signal are multiplexed. In addition, each base station generates a transmission signal using a scramble code that is different for each base station.

In this receiving apparatus, the path search unit 5 and the RAKE combining unit 6 operate independently. Path search unit 4
Sets the phase of the scramble code generator 12 according to an instruction from the controller 8, and calculates the correlation value with the common pilot signal included in the received signal by the common pilot correlator 11. The power measuring device 13 measures the correlation power value from the correlation value. The power meter 13 vector averages the correlation result of the common pilot signal over a plurality of symbols, and can be configured by a DSP, a shift register, an adder, a multiplier, or the like.

The DSP 14 includes each path search finger 10
The correlation power value calculated in step 3 is written in the memory 15. The content written in the memory 15 is the correlation power value for each delay time of each path. This is referred to herein as the current "instantaneous delay profile". For example, as shown in FIG. 5, the path search fingers 10 calculate the correlation power value of the common pilot signal in parallel by slightly shifting the start timing of the correlation calculation in the delay time axis τ direction. Path P to received signal
1, P2, P3 are included, the instantaneous delay profiles obtained at time t _n-1 and time t _n are delay times corresponding to the head positions of the paths P1, P2, P3, respectively.
The peak correlation power value is obtained.

On the other hand, in the RAKE combining section 6, each path is assigned to each RAKE finger 20 by an instruction from the controller 8, and the channelizing code generator 24 and the scramble code generator 23 respectively generate the scramble code and the channelization code. The phase is set, and the despread processing of the received data is executed. At the same time, the DSP 26 estimates the transmission line response and applies the result to the data. Further, the DSP 26 measures the power value using the correlation value information from the finger for channel response estimation and writes it in the memory 27. The contents written in the memory 27 are the delay time of the path assigned to each finger 20 and the correlation power value.

Next, the path search method according to the first embodiment using the receiving apparatus according to this embodiment will be described. FIG. 6 is a flowchart of the path search according to this embodiment, and FIG. 7 is a timing chart of the same path search.
Now, it is assumed that the path search cycle is 50 ms. The controller 8 outputs a search command to the path search unit 5 every 50 ms to make the processing of FIG. 6 a star. At this time, the memory 9 stores a delay profile calculated in the past (referred to as “cumulative delay profile” in order to distinguish this from the “instantaneous delay profile” to be created), and the controller is stored. 8 is a memory 9
Each correlation power value of the cumulative delay profile stored in (1) is multiplied by a coefficient (1-α) (where 0 <α <1) to update the contents of the memory 9 (S11).

Next, the path search section 5 generates an instantaneous delay profile (S12). That is, the path search unit 5 measures the correlation power value for each delay time based on the search command from the controller 8. The DSP 14 writes the result in the memory 15. When the calculation of the correlation power value for the path search window width for generating the delay profile is completed, the writing to the memory 15 is completed. That is, DSP
The memory 14 stores the power values within these window widths and the delay time information corresponding to each power value in the memory 15. Each sample stored in the memory 15 is shown in FIG.

Next, the DSP 14 is shown in FIG.
Of the stored samples, the sample P1 having the maximum power value and its delay time T1 are searched, and this is selected as the first pass. Next, the power value corresponding to the characteristic of the filter 4 used (for example, the characteristic of the roll-off filter) is subtracted from the power value corresponding to the vicinity of the sample point selected as the first pass. That is, as shown in FIG. 8B, when the delay time of the sample point having the maximum value P1 is T1, (P1 * C
1) to (P1 * C2) for T1 ± 2 sample points
To (P1 * C3) for the sample points of T1 ± 3,
(P1 * C5) for T1 ± 5 sample points,
(P1 * C6) for sample points of ± 6, T1 ± 7
Subtract (P1 * C7) from the sample points of. However, Ci is a coefficient according to the shape of the impulse response response waveform of the filter 4, and 0 <Ci <1
Is. The correlation power value for each delay time after performing this operation has a form as shown in FIG. And
The DSP 14 repeats the same operation as described above for the next largest sample P2 and its delay time T2, selects, for example, 10 paths, and writes this in the memory 15 (S1).
3).

The controller 8 sequentially takes in the correlation power values and delay times for these 10 paths and writes them in the memory 9. At this time, each correlation power value of the instantaneous delay profile is multiplied by the coefficient α (S14). And memory 9
The cumulative delay profile (multiplied by the coefficient (1-α)) and the instantaneous delay profile (multiplied by the coefficient α) written in are added for each delay time (S15), The result is written in the memory 9 as a new cumulative delay profile (S16). However, the addition here is the addition of paths having the same delay time. From the information thus updated, a path satisfying the threshold value and having a RAKE finger number Rf or less is selected (S17, 18, 19). The path satisfying the threshold value here has, for example, a path having a power peak included within TH1 [dB] from the correlation power peak value of the path having the maximum power, or a correlation power value of TH2 [dB] or more. Means a path.

According to the present embodiment, the influence of the impulse response component of the filter can be removed for each path in the process of determining the path from the delay profile, so that the path detection accuracy is improved. be able to. Here, α is 0 in order to secure the stability of communication.
It is desirable to set <α <0.5.

Incidentally, the removal of the impulse response component of the filter in step S13 of the path search described above may be carried out only when the reception quality is deteriorated. In this case, the criterion for judgment is the bit error rate (B
ER) and block error rate (BLER) can be used. When the BLER is used, the controller 8 monitors the BLER obtained by the error correction processing of the error correction unit 7 shown in FIG. 1, and the BLER is a predetermined threshold value (for example, 1
%) Is exceeded, the impulse response component removal processing of the filter in step S13 is executed. By performing such processing, it is possible to suppress the power consumption when the reception status is good.

(Second Embodiment) Next, a receiver for direct spread spectrum communication according to a second embodiment of the present invention will be described. FIG. 9 is a flowchart of path search in the receiving apparatus according to the second embodiment of the present invention, FIG.
0 is a timing chart of the same path search. In this embodiment, the memory 9 is logically divided into three storage areas (memory 1, memory 2, memory 3). The operation of the path search unit 5 in steps S11 to S16 of FIG. 9 is basically the same as that of the first embodiment, and thus the description of the overlapping parts will be omitted. The cumulative delay profile is
It is stored in the memory 1. In the present embodiment, the RAKE combining unit 6 calculates the correlation power value of each path in parallel with the generation and updating of the cumulative delay profile by the path search unit 5. FIG. 10 shows the calculation timing. DS
P26 writes the average correlation power value from the power measuring device 25, which estimates the channel response, in the memory 2 every 10 ms, for example, in parallel with the path search at 50 ms intervals.
Then, after 10 ms has elapsed, the DSP 26 determines that the memory 2
To the correlation power value written in (hereinafter, this will be the "cumulative correlation power value") by the coefficient (1-β) (where 0 ≦ β ≦
1) is multiplied to update the contents of the memory 2 (S21).
On the other hand, the DSP 26 causes the RAKE combiner 6 to calculate the correlation power value for the path currently assigned (referred to as “instantaneous correlation power value”) (S22), and multiplies the obtained instantaneous correlation power value by the coefficient β. Yes (S23). Then, the cumulative correlation power value (coefficient (1
−β)) and the instantaneous correlation power value (multiplied by the coefficient β) are added together for paths having the same delay time (S24), and the result is stored as a new correlation power value in the memory 2. The contents are updated (S25).

That is, as shown in FIG. 10, the memory 1 is updated every 50 ms, and the memory 2 is updated every 10 ms. The allocation change to the RAKE finger 20 is also performed every 50 ms in synchronization with the update of the memory 1. That is, the result of adding the correlation power values of both the memory 1 and the memory 2 is written in the memory 3 as a new cumulative delay profile (S26). However, the addition of the memory 1 and the memory 2 is performed between the paths having the same delay time. And
From the cumulative delay profile in the memory 3 generated in this way, a path satisfying the threshold and having the number of RAKE fingers Rf or less is selected (S16, S17, S1).
8). The path satisfying the threshold here means, for example, from the correlation power peak value of the path having the maximum power, TH1 [d
B], a path having a power peak included within, or TH2
It means a path having a correlation power value of [dB] or more.

According to the second embodiment, the cumulative delay profile is generated by using the correlation power value of each path in the RAKE combiner 6, which is calculated more frequently than the path search cycle. , It becomes possible to perform a path search that better reflects the actual communication status. In order to realize a more stable receiving operation, β is preferably 0.5 <β ≦ 1.

(Third Embodiment) Next, a path search method according to a third embodiment of the present invention will be described. In this embodiment, instead of the path search processing by removing the impulse response component of the filter in the path search unit 5,
Alternatively, in combination therewith, the correlation value between the respective paths calculated by the RAKE combining unit 6 is calculated, and when the calculated correlation value is smaller than a predetermined threshold value, the respective paths are RAKE combined,
When the calculated correlation value is equal to or larger than a predetermined threshold value, only one path is RAKE-combined.
That is, 2 detected as different paths by the path search unit 5.
When two paths are actually the same path, the correlation value between the signals of both paths is high. On the other hand, when the two paths are different paths, the correlation value between the signals of both paths is low.
This embodiment focuses on this point.

FIG. 11 is a flowchart of RAKE combining by the receiving apparatus according to the third embodiment. Now, it is assumed that the paths designated by the path search unit 5 are three paths (delay times are T1, T2, T3, respectively). The DSP 26 of the RAKE combiner 6 stores the output signals R1 (t), R2 (t), and R3 (t) from the common pilot correlator 21 for each path in the memory 27 (S31), The correlation values C12, C13, C23 of are calculated (S32). When the correlation value Cij is smaller than the predetermined threshold value (S3
3) RAKE combining is performed assuming that there is no correlation between the paths (S34). On the other hand, when the correlation value Cij is greater than or equal to the predetermined threshold value (S33), it is determined that there is a correlation between the paths, only one path is selected (S35), and RAKE combining is performed (S34). For example, when the correlation value C12 is equal to or larger than the threshold value and the correlation value C13 and the correlation value C23 are smaller than the threshold value, the power values of the path 1 and the path 2 are compared, and the larger path is detected. The path 3 and RAKE will be combined.

Next, a method of calculating the correlation value Cij and a concrete example of the threshold value will be described. Since the correlation value Cij is a numerical value in the range of -1 to 1, the numerical value in the range of 0 <TH <1 is selected as the above-mentioned predetermined threshold value TH.

(Correlation value calculation method 1) If the average amplitudes of path 1, path 2 and path 3 are A1, A2 and A3 respectively,

[0031]

[Equation 1] A1 = {Σ | R1 (t) |} / N A2 = {Σ | R2 (t) |} / N A3 = {Σ | R3 (t) |} / N

It can be expressed as However, t = 1, 2,
…, N. Dispersion B1 and B of path 1, path 2 and path 3
2 and B3 are as shown in Equation 2.

[0033]

## EQU00002 ## B1 = .SIGMA. {| R1 (t) | -A1} ² / N B2 = .SIGMA. {| R2 (t) | -A2} ² / N B3 = .SIGMA. {| R3 (t) | -A3} ² / N

Further, the covariance Dij between the path i and the path j
Becomes like Equation 3.

[0035]

[Equation 3]   D12 = Σ {(| R1 (t) | -A1) (| R2 (t) | -A2)} / N   D13 = Σ {(| R1 (t) | -A1) (| R3 (t) | -A3)} / N   D23 = Σ {(| R2 (t) | -A2) (| R3 (t) | -A3)} / N

From this, the correlation value Ci between the path i and the path j
j is as in Expression 4.

[0037]

[Equation 4] C12 = D12 / √ (B1 × B2) C13 = D13 / √ (B1 × B3) C23 = D23 / √ (B2 × B3)

At this time, for example, if Cij> 0.5, it is determined that there is a correlation, and only one path (the path with the smaller average power) is cut off.

(Correlation value calculation method 2) If the average powers of the path 1, the path 2, and the path 3 are P1, P2, and P3, respectively, P1, P2, and P3 are expressed as in Equation 5, respectively.

[0040]

P1 = {Σ | R1 (t) | ² } / N P2 = {Σ | R2 (t) | ² } / N P3 = {Σ | R3 (t) | ² } / N

Here, the output signals R1, R2 and R3 of the common pilot correlator 21 are

[0042]

[Equation 6] r1 (t) = R1 (t) / √P1 r2 (t) = R2 (t) / √P2 r3 (t) = R3 (t) / √P3

By normalizing as described above, the correlation value Cij between the path i and the path j is calculated as follows.

[0044]

[Equation 7] C12 = Σ {r1 (t) × r2 (t) *} / N C13 = Σ {r1 (t) × r3 (t) *} / N C23 = Σ {r2 (t) × r3 (t) *} / N

However, * is a conjugate complex number. At this time, for example, if Cij> 0.5, it is determined that there is a correlation,
Only one path (the path with the smaller average power) is disconnected.

Also in this embodiment, it is possible to effectively prevent erroneous RAKE combining of the path due to the impulse response component of the filter. In this embodiment as well, the controller 8 monitors the BLER from the error correction unit 7 and calculates the correlation value between paths when the BLER exceeds a predetermined threshold value, for example, 1%. , The power consumption can be reduced.

[0047]

As described above in detail, according to the present invention, in the direct spread spectrum communication system, the RAKE
Since it is possible to improve the detection accuracy of the path assigned to the finger or the accuracy of the RAKE combining, it is possible to improve the reception characteristic.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a receiver for direct spread spectrum communication according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a path search unit in the receiving device.

FIG. 3 is a block diagram of a RAKE combining unit in the receiving device.

FIG. 4 is a diagram showing a configuration of a received signal received by the receiving device.

FIG. 5 is a diagram showing a delay profile obtained by path search from the received signal.

FIG. 6 is a flowchart showing a path search procedure according to the first embodiment.

FIG. 7 is a timing chart of the same path search.

FIG. 8 is a diagram for explaining a process of removing an impulse response component in the same path search.

FIG. 9 is a flowchart showing a path search procedure according to the second embodiment.

FIG. 10 is a timing chart of the same path search.

FIG. 11 is a flowchart showing a path search procedure according to the third embodiment.

FIG. 12 is a graph showing an impulse response waveform of a filter.

FIG. 13 is a graph showing a power waveform of the impulse response of the filter.

[Explanation of symbols]

1 ... antenna 2 ... R / F section 3 ... A / D converter 4 ... Filter 5 ... Path search section 6 ... RAKE receiver 7 ... Error correction section 8 ... Controller 9 ... Memory 10 ... Path search finger 11,21 ... Correlator for common pilot 12, 23 ... Scramble code generator 13, 25 ... Electric power measuring device 14, 26 ... DSP 15, 27 ... Memory

Claims (4)

[Claims] 1. A receiving means for receiving a direct spread spectrum signal, a filter for removing a noise component outside a transmission band from the received direct spread spectrum signal, a direct spread spectrum signal and a spread code output from this filter. Generate a delay profile by obtaining the correlation power value for each delay time of, to detect the first path from this delay profile, from the delay profile to the transfer function of the filter with reference to the first path After removing the impulse response component based on the impulse response component, a path search means for determining a plurality of paths while performing a process of detecting the second path from the delay profile from which the impulse response component has been removed, and the path search means The correlation power value of the direct spread spectrum signal and spread code received for each of the multiple paths Calculate and calculate the calculated correlation power value as R
A receiver for direct spread spectrum communication, comprising: RAKE combining means for performing AKE combining. 2. A block error rate detecting means for detecting a block error rate of the RAKE-combined output, further comprising: the path search means, if the detected block error rate is less than a predetermined value. The plurality of paths are determined based on the delay profile obtained from the correlation power value of the direct spread spectrum signal and the spread code output from each of the delay times, and the detected block error rate becomes a predetermined value or more. Then, after detecting the first path from the generated delay profile, after removing the impulse response component based on the transfer function of the filter with respect to the first path from the delay profile,
2. The direct spread spectrum communication receiver according to claim 1, wherein a plurality of paths are determined while performing a process of detecting a second path from the delay profile from which the impulse response component has been removed. 3. A receiving means for receiving a direct spread spectrum signal, a filter for removing a noise component outside the transmission band from the received direct spread spectrum signal, a direct spread spectrum signal and a spread code output from this filter. A delay profile is generated by obtaining the correlation power value for each delay time of, and a plurality of paths are determined from this delay profile, and the path search means between the determined plurality of paths and the path search means are determined. Calculate the correlation power value between the direct spread spectrum signal received for each of the multiple paths and the spread code, and calculate the correlation value between the calculated paths, and the calculated correlation value is the predetermined threshold value. When the calculated correlation value is equal to or larger than a predetermined threshold value, only one path is R-combined. A receiver for direct spread spectrum communication, comprising: RAKE combining means for performing AKE combining. 4. A block error rate detecting means for detecting a block error rate of the RAKE-combined output is further provided, wherein the RAKE combining means performs a path search when the detected block error rate is below a predetermined value. Calculating the correlation power value of the direct spread spectrum signal and the spread code received for each of the plurality of paths determined by the means,
The calculated correlation power value is RAKE-combined, and when the detected block error rate is equal to or more than a predetermined value, the calculated correlation value between the time series of each path is calculated, and the calculated correlation value is When it is smaller than a predetermined threshold value, each path is RAKE-combined, and when the calculated correlation value is equal to or larger than a predetermined threshold value, only one path is RAKE-combined. The receiver for direct spread spectrum communication according to claim 3.