JP4816949B2 - CDMA receiver, profile synthesis path search method and program - Google Patents

Description

The present invention relates to a CDMA (Code Division Multiple Access) receiver, and more particularly to a profile synthesis path search method.

Conventionally, a CDMA reception having a finger part and a searcher part for finding a reception timing having a high level from a correlation value after addition calculated using a correlator group and an adder group and determining a reception timing to be received by the finger part An apparatus is known (for example, Patent Document 1).

  FIG. 7 is a block diagram showing a detailed configuration of a conventional profile synthesis searcher unit.

The reception data a for each branch is input to the delay profile calculation unit 61. The delay profile calculation unit 61 calculates a delay profile d for each branch and outputs it to the profile synthesis unit 62. The profile synthesizing unit 62 multiplies the level of the delay profile d for each branch by the AGC correction coefficient j for each branch specified by the radio unit 66 to correct the relative level to the absolute level, and then synthesizes the level of the delay profile d ( The combined profile e is output to the peak detection / noise calculation unit 63. The peak detection / noise calculation unit 63 detects reception timings having a high level from the post-combination profile e for the designated number of peaks, and outputs the peak timing f common to each branch and the peak level g to the threshold processing unit 64. Further, the peak detection / noise calculation unit 63 calculates the average level of the remaining profile e excluding the peak timing f, and outputs the average level to the threshold processing unit 64 as a noise level h common to each branch. The threshold value processing unit 64 performs threshold value processing for selecting a path above the various threshold values from the peak level g and the noise level h (for example, when the peak level is greater than the noise level by a dB value), A path that is equal to or greater than the threshold value is output to the path allocation unit 65 as a search path timing i. The path allocation unit 65 allocates a search path timing i common to each branch to each branch, and outputs it as a finger path timing b to a finger unit (not shown). However, when the difference in the value of the AGC correction coefficient j is extremely large in the AGC correction coefficient j for each branch instructed by the radio unit 66, the branch having a large value is determined as an invalid branch and no path is assigned.
JP 2002-314460 A

  This conventional profile synthesis path search method has an advantage that a stable profile can be obtained in a short time. However, when the levels are synthesized (added), it is necessary to apply an AGC correction coefficient to correct the absolute level. There is a problem in that it is necessary to perform a multiplication process that requires a larger amount of processing than addition and subtraction. In addition, the notification of the AGC correction coefficient from the radio unit 66 is indispensable, and there is a problem that the device configuration is not simplified. The reason is that threshold processing is performed on a peak common to each branch using a noise level common to each branch.

  An object of the present invention is to provide a CDMA receiver and a profile synthesis path search method that omits the AGC correction coefficient notification from the radio unit, which is essential in the profile synthesis path search method, and simplifies the device configuration. It is in.

The CDMA receiver of the present invention
Delay profile calculation means for inputting received data for each branch and calculating a delay profile for each branch from the received data;
Profile synthesis means for synthesizing the level of the delay profile for each branch;
Peak detection processing means for detecting a high level of reception timing from the profile after synthesis for a specified number of peaks and outputting a peak timing common to each branch;
Noise calculation means for outputting a peak level corresponding to a peak timing common to each branch to a delay profile for each branch before synthesis, and calculating a noise level for each branch by removing the peak timing common to each branch ,
Threshold processing is performed for selecting a path above the various thresholds from the peak timing, the peak level, and the noise level for each branch, and a search path timing that is a path above the threshold is output for each branch. Threshold processing means;
A searcher unit including path search means for assigning the search path timing to each branch and outputting the search path timing to the finger unit as finger path timing.

  In the present invention, the peak of the invalid branch is determined by removing the peak common to each branch from the profile for each branch before synthesis, calculating the noise level for each branch, and performing threshold processing for each branch. It is deleted by value processing and is not assigned as a path.

According to the present invention, it is possible to omit the AGC correction process and the AGC correction coefficient notification from the radio unit, and there is an effect that the apparatus configuration is simplified. The reason is that the peak of the invalid branch is determined by removing the peak common to each branch from the profile for each branch before synthesis, calculating the noise level for each branch, and performing threshold processing for each branch. This is because it is deleted by value processing and is not assigned as a path.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of a CDMA receiver according to an embodiment of the present invention. As shown in FIG. 1, the CDMA device 10 includes a finger unit 11, a searcher unit 12, a RAKE combining unit 13, and a decoding unit 14.

  The reception data a for each branch input to the CDMA receiver 10 is input to the finger unit 11 and the searcher unit 12 respectively. The searcher unit 12 obtains the correlation level while gradually shifting the despreading timing of the reception data a, searches for the optimal (high correlation level) reception timing, and determines the reception timing to be received by the finger unit 11 as the peak timing b ( Hereinafter, each finger of the finger part 11 is instructed at finger path timing).

  The finger unit 11 despreads the received data a at the reception timing indicated by the finger path timing b, and performs detection processing. The outputs of the finger units 11 are respectively input to the RAKE combining unit 13 and added, and the added data is decoded by the decoding unit 14. Here, each finger of the finger unit 11 is prepared according to the number of branches and the number of paths processed by the CDMA receiver 10, and the number of fingers is fixed for each branch. If the number of branches M = 2 and the number of fingers per branch N = 5, a maximum of 10-path RAKE combining is possible.

  FIG. 2 is a block diagram showing a detailed configuration of the searcher unit 12 of FIG. The searcher unit 12 includes a delay profile calculation unit 21, a profile synthesis unit 22, a peak detection processing unit 23, a noise calculation unit 24, a threshold processing unit 25, and a path allocation unit 26.

  As shown in FIG. 2, the reception data a for each branch is input to the delay profile calculation unit 21, and the delay profile calculation unit 21 calculates the delay profile d for each branch, and the profile synthesis unit 22 and the noise calculation unit 24 Output.

FIG. 3 is a block diagram showing a detailed configuration of the delay profile calculator 21 of FIG.
As shown in FIG. 3, the reception data a is input to each correlator of the correlator group 32, and each correlator performs despreading at a slightly different reception timing. The correlation value c that is the output of the correlator is input to each adder of the adder group 33. Each adder adds (integrates) the correlation value a specified number of times (which can be changed as a parameter), and outputs an added correlation value (delay profile) d. The spread code generator 34 generates a spread code for despreading by the correlator 32 and outputs it to the search delay circuit 35. The search delay circuit 35 shifts the correlation pattern (spread code) little by little (for example, 0.5 chips). The profile synthesizing unit 22 synthesizes (adds) the level of the delay profile d for each branch and outputs the post-synthesis profile e to the peak detection processing unit 23. The peak detection processing unit 23 detects the reception timing from the highest level in the post-combination profile e in the order of the designated number of peaks, and outputs the peak timing f common to each branch to the noise calculation unit 24 and the threshold processing unit 25. . The noise calculation unit 24 outputs a peak level g corresponding to the peak timing f common to each branch to the threshold processing unit 25 for the delay profile d for each branch before synthesis. In addition, the noise calculation unit 24 removes the peak timing f common to each branch (detected timing corresponding to the number of specified peaks) to obtain the noise level h for each branch, and the peak level from the pre-synthesis delay profile. Calculation is performed by averaging the removed portions, and the result is output to the threshold processing unit 25. The threshold processing unit 25 selects a path higher than the threshold from the peak timing f, peak level g, and noise level h for each branch (when the peak level is greater than the noise level by a predetermined dB or more). Path detection), and for each branch, a path i (hereinafter referred to as search path timing) equal to or higher than a threshold value is output to the path allocation unit 26. Here, the peak level g and the noise level h exist for each branch. By having a noise level for each branch, invalid branch paths are deleted during threshold processing. The path allocation unit 26 allocates the search path timing i for each branch, and outputs it to the finger unit 11 as the finger path timing b.

  Next, the operation of this embodiment will be described in detail with reference to FIG. 2, FIG. 4, and FIG. FIG. 4 is a flowchart showing the operation of the searcher unit 12. FIG. 5 shows an example of searcher processing when the number of branches M = 2.

  First, the delay profile calculation unit 21 calculates the delay profile d for each branch from the reception data a for each branch, and outputs it to the profile synthesis unit 22 and the noise calculation unit 24 (Step 101 in FIG. )).

  The profile synthesizing unit 22 synthesizes (adds) the level of the delay profile d for each branch, and outputs the synthesized profile e to the peak detecting unit 23 (step 102 in FIG. 4).

  The peak detection processing unit 23 detects reception timings having a high level from the post-combination profile e for the specified number of peaks, and outputs the peak timing f common to each branch to the noise calculation unit 24 and the threshold processing unit 25 (see FIG. Step 103 of FIG. 4, FIG. 5 (2)).

  The noise calculation unit 24 outputs a peak level g corresponding to the peak timing f common to each branch to the threshold processing unit 25 for the delay profile d for each branch before synthesis. The noise calculation unit 24 calculates the noise level h for each branch by removing the peak timing f common to each branch, and outputs it to the threshold processing unit 25 (step 104 in FIG. 4, FIG. 5 (3)). ).

  The threshold value processing unit 25 performs threshold value processing for selecting a path having various threshold values or more from the peak timing f, peak level g, and noise level h for each branch. The search path timing h is output to the path allocation unit 26 (step 105 in FIG. 4, FIG. 5 (4)).

  The path allocation unit 26 allocates the search path timing i for each branch, and outputs it to the finger unit 11 as the finger path timing b (step 106 in FIG. 4).

  Next, another embodiment of the present invention will be described in detail with reference to the drawings.

  Referring to FIG. 6, in the present embodiment, when the received signal is a communication signal, the SIR estimation can be sufficiently performed in the finger unit 11, and the path of the invalid branch is not used for RAKE combining. In the case of a signal, it is different from the above-described embodiment in that a peak equal to or higher than the threshold is assigned to each branch as a path regardless of the valid branch and the invalid branch.

  The level of the delay profile for each branch is synthesized (added) (step 101), and the reception timing with a high level is detected from the post-synthesis profile for the specified number of peaks (step 102). If the received signal is a communication signal (DPCCH reception) in step 100, the noise calculation unit 24 removes the peak timing common to each branch from the combined profile, and calculates the noise level common to each branch (step 107). The threshold processing unit 25 performs threshold processing for selecting a path above various thresholds from the peak timing, peak level, and noise level common to each branch (step 108), and the path allocation unit 26 exceeds the threshold. Are assigned to each branch as a path (step 109). If the received signal is a burst signal (reception of PRACH) in step 100, the same processing as in FIG. 4 is performed (steps 104, 105, 106).

  As a result, when the received signal is a communication signal, it is possible to further reduce the amount of processing required for noise calculation processing and threshold processing.

  The function of the searcher unit may be to record a program for realizing the function on a computer-readable recording medium, and cause the computer to read and execute the program recorded on the recording medium. Good. The computer-readable recording medium refers to a recording medium such as a flexible disk, a magneto-optical disk, and a CD-ROM, and a storage device such as a hard disk device built in a computer system. Further, the computer-readable recording medium is a medium that dynamically holds the program for a short time (transmission medium or transmission wave) as in the case of transmitting the program via the Internet, and in the computer serving as a server in that case Such as a volatile memory that holds a program for a certain period of time.

It is a block diagram which shows the structure of the CDMA receiver of one Embodiment of this invention. It is a block diagram which shows the detailed structure of the searcher part in FIG. It is a block diagram which shows the detailed structure of the delay profile calculation part in a searcher part. It is a flowchart which shows operation | movement of a searcher part. It is a figure which shows an example of a process of a searcher part. It is a flowchart which shows operation | movement of the example of other embodiment of this invention. It is a block diagram which shows the detailed structure of the conventional profile synthetic | combination searcher part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 CDAMA receiver 11 Searcher part 12 Finger part 13 RAKE combining part 14 Decoding part 21 Delay profile calculation part 22 Profile combining part 23 Peak detection processing part 24 Noise calculation part 25 Threshold processing part 26 Path allocation part 32 Correlator group 33 Adder group 34 Spread code generator 35 Search delay circuit 100-109 steps

Claims (6)

In the CDMA receiver,
Delay profile calculation means for inputting received data for each branch and calculating a delay profile for each branch from the received data;
Profile synthesis means for synthesizing the level of the delay profile for each branch;
Peak detection processing means for detecting a high level of reception timing from the profile after synthesis for a specified number of peaks and outputting a peak timing common to each branch;
Noise calculation means for outputting a peak level corresponding to a peak timing common to each branch to a delay profile for each branch before synthesis, and calculating a noise level for each branch by removing the peak timing common to each branch ,
Threshold processing is performed for selecting a path above the various thresholds from the peak timing, the peak level, and the noise level for each branch, and a search path timing that is a path above the threshold is output for each branch. Threshold processing means;
A CDMA receiving apparatus comprising: a searcher unit including: path allocation means that allocates the search path timing for each branch and outputs the search path timing to the finger unit as finger path timing.   When the received signal is a communication signal, the noise calculating means removes the peak timing common to each branch from the combined profile to calculate a noise level common to each branch, and the threshold processing means is a peak common to each branch. 2. The CDMA according to claim 1, wherein threshold processing for selecting a path higher than a threshold from timing, peak level, and noise level is performed, and the path allocation means allocates a peak higher than the threshold as a path to each branch. Receiver device. A profile synthesis path search method in a CDMA receiver comprising:
Inputting received data for each branch and calculating a delay profile for each branch from the received data;
Synthesizing the level of the delay profile for each branch;
A step of detecting a high-level reception timing for a specified number of peaks from a post-combination profile and outputting a peak timing common to each branch;
Outputting a peak level corresponding to a peak timing common to each branch to a delay profile for each branch before synthesis, and calculating a noise level for each branch by removing the peak timing common to each branch;
Threshold processing is performed for selecting a path above the various thresholds from the peak timing, the peak level, and the noise level for each branch, and a search path timing that is a path above the threshold is output for each branch. Steps,
Assigning the search path timing for each branch and outputting to the finger part as finger path timing;
A profile synthesis path search method comprising:   4. The profile synthesis path search method according to claim 3, further comprising a step of assigning a peak equal to or higher than a threshold value as a path to each branch regardless of whether the received signal is a communication signal, regardless of whether the branch is a valid branch or an invalid branch. In the CDMA receiver,
A procedure for inputting received data for each branch and calculating a delay profile for each branch from the received data;
A procedure for synthesizing the level of the delay profile for each branch;
A procedure to detect the specified number of peaks for high level reception timing from the profile after synthesis, and to output the peak timing common to each branch,
A procedure for outputting a peak level corresponding to a peak timing common to each branch with respect to a delay profile for each branch before synthesis, and calculating a noise level for each branch by removing a peak timing common to each branch;
Threshold processing is performed for selecting a path above the various thresholds from the peak timing, the peak level, and the noise level for each branch, and a search path timing that is a path above the threshold is output for each branch. Procedure and
A procedure for assigning the search path timing for each branch and outputting the finger path timing to the finger part;
Profile synthesis path search program for causing a computer to execute.   6. The profile synthesis path search program according to claim 5, wherein when the received signal is a communication signal, the computer further executes a procedure for assigning a peak equal to or higher than the threshold value as a path to each branch regardless of the valid branch and the invalid branch. .

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