JP2007300529A - Cdma receiving device and its path timing update control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify the control of parallel de-spreading of a common redundant hard resource by reducing the number (circuit scale) of redundant hard resources which perform de-spreading when updating the path timing, in CDMA receiving device and its path timing update control method. <P>SOLUTION: A path timing reported by a searcher portion 3-1 is stored in a buffer memory 3-21, and a slot number for which de-spreading is performed by individual resources 3-41 to 3-4M is acquired from a slot counter 3-24, and a slot having a number which is the acquired slot number plus the number of slots L which need processing for preparing path updating is determined as a path update slot. Then, a de-spreading code of the path update slot is created by a slot boundary code initial value generating circuit 3-25. Using an initial value of the de-spreading code, only one slot de-spreading of the path update slot is performed in a new path timing by a redundant resource 3-3, and subsequent de-spreading is continuously performed by the individual resources to restore the redundant resource. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a CDMA (Code Division Multiple Access) receiving apparatus and a path timing update control method thereof, and more particularly, to simultaneously receive signals from a plurality of users' mobile terminals in a CDMA mobile radio communication system. The present invention relates to a CDMA receiver including a multiuser despreading circuit that demodulates and a path timing update control method thereof.

  FIG. 4 shows a basic configuration of the CDMA receiver. The baseband unit of the CDMA receiver passes the received signal through the bandpass filter 4-1, and then separates the received signal into an in-phase component and a quadrature component by a QPSK (Quadrature Phase Shift Keying) demodulator 4-2. Are passed through a low-pass filter 4-3 to remove a high-frequency component, converted into a digital signal by an analog-digital converter 4-4, and input to a searcher unit 4-5 and a despreading unit 4-6.

  The searcher unit 4-5 measures the correlation between the received signal and the spread code, detects the peak (path timing) of the delay profile of the received signal, and notifies the despreading unit 4-6 of the detection result of the path timing. . The despreading unit 4-6 performs despreading processing on the received signals of a plurality of paths received in the multipath environment according to the path timing information.

  The signal of each path subjected to the despreading process by the despreading unit 4-6 is input to the synchronous detection unit 4-7. The synchronous detection unit 4-7 performs the synchronous detection and performs the maximum ratio combining process of the signals of each path. And output as demodulated data.

  FIG. 5A shows the basic configuration of the searcher unit. The searcher unit first calculates a correlation value with the spread code obtained from the code generator 5-2 using the matched filter 5-1, for the in-phase component and the quadrature component of the received signal. The correlation values of the in-phase component and the quadrature component obtained here are passed through the in-phase addition circuit 5-3, the power conversion circuit 5-4, the power addition circuit 5-5, and the delay profile holding unit 5-6, as shown in FIG. It is converted into delay profile information as shown in (b).

  The path timing detection circuit 5-7 compares the levels of the delay profiles obtained from the delay profile holding means 5-6, and sequentially passes a predetermined number of paths from the path with the highest reception level (Path1 to Path4 in the example of FIG. 5B). ), And notifies each despreading unit 4-6 of the path timing. The despreading unit 4-6 starts the despreading process at the path timing notified from the searcher unit 4-5, and demodulates the data.

  Since the path timing and the number of effective paths detected by the searcher unit 4-5 constantly change with the passage of time, it is necessary to make the despreading process in the despreading processing unit 4-6 follow the change in path timing. As means for making the despreading process follow the change in path timing, there are an autonomous tracking system using a DLL (Delay Locked Loop) circuit and a parallel despreading processing system using redundant hardware resources.

(1) Autonomous tracking method using a DLL (Delay Locked Loop) circuit The autonomous tracking method using a DLL circuit starts despreading according to path timing information from a searcher unit, sets a path, and then receives a received signal of the path as a DLL. The signal is input to the circuit, and the timing of the despreading process is adjusted by following the path timing variation by the DLL circuit. The DLL circuit obtains a correlation between a set of despread codes having a time difference and the received signal, calculates a phase difference between the despread code and the received signal based on the correlation, and tracks the timing of the despread code.

  FIG. 6A shows a configuration of a despreading processing unit of a self-supporting tracking system using a DLL circuit. In the figure, only one finger is shown for the sake of simplicity. In the despreading processing unit, the despreading code generator 6-1 is loaded with the despreading code (initial value) at the beginning of the frame at the path timing at the beginning of the frame detected by the searcher unit. 1 despread code sequentially generated from −1 and the received signal are multiplied by a first multiplier 6-21 and a second multiplier 6-22, respectively, and despread Processing is performed, the difference of the despreading result is calculated to the subtractor 6-3, and the output of the subtractor 6-3 is passed through the loop filter 6-4 so as to minimize the difference. In addition to the generator 6-5, the voltage control clock generator 6-5 adjusts the phase of the clock signal of the despread code generator 6-1.

  (B1) to (b3) in FIG. 6 show the results of despreading processing between two despread codes having a time difference and the received signal, and the difference between them. FIG. 4B1 shows the correlation with the despread code output from the tap n of the despread code generator 6-1 having n shift registers, and FIG. 2B2 shows the tap shifted by one chip. The correlation with the despread code output from (n−1) is shown, and FIG.

  As shown in (b1) and (b2) of the figure, the highest correlation is obtained at the timing of (−Tc / 2) and (Tc / 2), respectively, and as shown in (b3) of FIG. Adjust the phase of the clock signal of the despreading code generator 6-1 so that it is minimized, and despread the code obtained by giving a delay of (Tc / 2) to the despreading code output from the tap (n-1) By using it as a code, a despreading code is generated by following an intermediate timing between two despreading codes having a time difference and the timing at which the highest correlation is obtained, and always follows the fluctuation of the path timing within one chip. Continue the continuous despreading process.

(2) Parallel despreading processing method using redundant hard resources The parallel despreading processing method using redundant hard resources periodically detects the path timing in the searcher unit, and the despreading processing unit periodically notifies the searcher unit. By applying the new path timing and resetting the initial value (frame head value) of the despreading code, it is possible to cope with path timing fluctuations. Therefore, the despreading process at the old path timing and the despreading process at the new path timing may overlap in time.

  In such a case, the despreading process at the new path timing is started using redundant resources common to each user. The individual resource for each user takes over the result of the despreading process from the redundant resource when the despreading process at the old path timing is completed and restores the redundant resource. Thereafter, the new path timing is set for each individual resource. Continue the despreading process at.

  FIG. 7A shows the configuration of the despreading processing unit of the redundant hard resource method (only for one finger). The searcher unit (not shown) periodically performs a path search for the received signal from each user, detects the path timing of the frame head of each received signal, and notifies the despreading processing unit. The path timing information of all users is notified to the despreading processing control unit 7-1, and when the time overlap of the despreading processing data occurs at the time of updating the path timing, the redundant resource 7-2 reverses at the new path timing. Start the diffusion process.

  The despreading process in the redundant resource 7-2 is performed when the processing for one frame at the old path timing in the individual resources 7-31 to 7-3M corresponding to each user is completed. 2 is taken over, the redundant resource 7-2 is restored, and the subsequent despreading process is continuously performed by the individual resources 7-31 to 7-3M. As described above, the redundant resource 7-2 is commonly used for the received signals of a plurality of users in the execution of the despreading parallel processing that is instantaneously required when the path timing of the received signal of each user is updated. .

  In the case of the redundant hard resource method, the despreading process is restarted every time the path timing is updated, and the correlation between the old path timing setting and the new path timing setting is not required. Is simplified. Note that the maximum time for parallel processing by the individual resources 7-31 to 7-3M and the redundant resources 7-2 for each user is determined by the search window width time Tsw (see FIG. 5B). From several tens of us to several hundreds of us.

  FIG. 7B shows an operation example of parallel despreading processing by the redundant hard resource method. In the redundant hard resource method, since the path update timing is the head of each received signal frame, there is a maximum of one frame from the notification of the new path timing from the searcher unit to the execution of path update at the new path timing. A corresponding waiting time of 10 ms occurs, and during that time, the redundant hard resource 7-2 is reserved and secured, and a wait is made until the path update timing at the head of the frame arrives.

  On the other hand, when there is a restriction on the path update cycle for the received signal of each user and it is essential to perform path update within a predetermined time, the number of users performing parallel processing using the shared redundant resource 7-2 is If the number is large, the above-mentioned maximum waiting time becomes a bottleneck for sharing, and it may happen that the constraint condition of the path update cycle cannot be satisfied. In order to prevent such a situation, it is necessary to provide a large number of redundant resources sufficient to satisfy the constraint condition of the path update cycle and increase the processing capacity of the parallel path update process.

As a prior art document related to the present invention, the following Patent Document 1 discloses that when the delay profile of a communication channel changes due to movement of a mobile terminal or due to a change in the environment of a transmission path, etc. In order to adjust the timing for multiplying the spread signal by the spread code, the delay profile of the communication channel is periodically monitored by the path detector, and the timing signal is generated based on the result and provided to the despread demodulator. A spread demodulator is a receiver that continuously demodulates a spread signal while adjusting the multiplication timing in accordance with the timing signal, and describes a receiver that can simultaneously receive spread signals respectively transmitted through a plurality of channels. ing.
JP 2000-151558 A

  In the autonomous tracking method using the DLL circuit of (1) described above, a DLL circuit is required for each finger, and the configuration of the despread code generator 6-1 is complicated, so that the circuit scale is large. . Furthermore, in a radio wave environment in which paths frequently appear / disappear, such as the Birth_death model, there is a tendency for the characteristics to deteriorate because the path lock is frequently lost in the DLL circuit.

  In the redundant hardware resource method (2) described above, since path setting is performed periodically, the characteristic degradation is less than in the DLL method, but despreading is performed in parallel at the new path timing and the old path timing at the time of path update. In the past, the path update process was performed at the beginning of the frame of the received signal, so there was a waiting time of up to one frame from the notification of the new path timing to the arrival of the frame head timing. The shared redundant hard resource is occupied by one path update process, and a plurality of redundant resources must be provided to satisfy the constraint condition of the path update cycle for the received signals from a plurality of users. .

  In particular, a multi-user demodulator that simultaneously receives and demodulates signals from a large number of users, such as a radio base station (BTS) of a mobile radio communication system, secures a large number of redundant resources, Contention control is necessary to share and use with many users.

  In this case, in order to increase the use efficiency of a large number of redundant resources, when there is no overlap between the despreading process assignment control to each redundant resource and the despreading process of the old path timing and the new path timing, Since a restoration process for delivering the result of the despreading process is required for a large number of redundant resources, the control circuit becomes complicated.

  The present invention reduces the number of redundant hard resources (circuit scale), which is a problem in the redundant hard resource method, by improving the multiple use efficiency of redundant hard resources, and the path frequently appears in a redundant hard resource configuration with a small circuit scale. An object of the present invention is to configure a despreading processing circuit that operates stably even in a radio wave environment that disappears. Another object of the present invention is to simplify the control of parallel despreading processing using shared redundant hardware resources.

  In order to solve the above-described problems, the CDMA receiver of the present invention (1) performs despreading processing by updating the path timing of each received signal with respect to the CDMA received signal transmitted from the mobile terminals of a plurality of users. In the CDMA receiving apparatus that performs the despreading process in the individual resource that performs the despreading process corresponding to the user among the plurality of slots obtained by subdividing the radio frame of the received signal when the update path timing is notified to each user. A slot having a number obtained by adding the number of processing required slots for path update preparation to the number of the slot being executed is determined as a path update slot, and the start timing of the path update slot is corrected based on the update path timing Unit path update timing calculation means, and despreading with an initial value of a despread code corresponding to the path update slot The despreading code generation means for generating a code string and the despreading process for the received signals of a plurality of users are used in common, and the despreading process for the path update slot is performed by the slot unit path update timing calculation means. And redundant resources for performing the despreading code generated by the despreading code generating means at the start timing of the calculated path update slot.

  (2) When the notification of the update path timing is received, the despreading process of the path update slot is always performed with the redundant resource, and the despreading process of the slot after the path update slot is performed for each user. A despreading processing control means to be implemented with individual resources is provided.

  (3) When the notification of the update path timing is received, it is determined whether or not the update path timing is shifted forward. Only when the update path timing is shifted forward, the despreading process of the path update slot is performed as the redundancy. When the update path timing is shifted backward or is not shifted, the despreading processing of the slot after the path update slot is performed on the individual resource corresponding to each user. The despreading processing after the path update slot is performed at the start timing of the path update slot calculated by the slot unit path update timing calculation means and by the despread code sequence generated by the despread code generation means. It is characterized by comprising despreading processing control means for controlling as described above.

  Further, the path timing update control method of the CDMA receiver of the present invention includes (4) despreading processing by updating the path timing of each received signal with respect to the CDMA received signal transmitted from the mobile terminals of a plurality of users. In the path timing update control method of the CDMA receiver that performs the user de-spreading processing among the plurality of slots obtained by subdividing the radio frame of the received signal when the update path timing notification is received for each user A slot with a number obtained by adding the number of processing slots required for path update preparation to the number of the slot for which despread processing is performed in the individual resource is determined as a path update slot, and the start timing of the path update slot is determined by the update path A slot unit path update timing calculating step for correcting based on the timing; and the path update slot A despreading code generation step for generating a despreading code sequence having an initial value of a despreading code corresponding to a user and a notification of the update path timing, which is commonly used for despreading processing for a plurality of users The despreading process of the path update slot is performed with a redundant resource at the start timing of the path update slot calculated in the slot unit path update timing calculation step and with the despread code generated in the despread code generation step. And a despreading process control step for always performing the despreading process of the slot after the path update slot with the individual resource corresponding to each user.

  In addition, (5) when the notification of the update path timing is received, it is determined whether or not the update path timing is shifted forward. Only when the update path timing is shifted forward, it is commonly used for a plurality of users. The despreading process of the path update slot with the despread code generated in the despread code generation step at the start timing of the path update slot calculated in the slot unit path update timing calculation step Is always performed, and the despreading processing of the slot after the path update slot is performed on the individual resource corresponding to each user, and when the update path timing is shifted backward or not, the individual resource is used. The despreading processing after the path update slot is the path calculated in the slot unit path update timing calculation step. At the beginning timing of the update slot, and it characterized in that it comprises a despreading processing control step of controlling to perform in the despreading code generating despread code string generated in step.

  In the parallel despreading processing method using redundant hard resources, the present invention performs redundant hard resource parallel processing in units of slots so that path updating is performed at slot boundaries instead of frame boundaries as in the prior art. Resource waiting time is reduced, and the number of redundant hard resources (circuit scale) can be reduced. In addition, since parallel despreading processing is performed with fewer redundant hardware resources, redundant hardware resource sharing control can be simplified.

  In addition, when a notification of the new path timing is received, the despreading process of the path update slot is always performed with the redundant resource, and the despreading process of the slot after the path update slot is performed with the individual resource corresponding to each user. Thus, redundant hardware resource sharing control can be further simplified.

  In addition, when the update path timing is received, only when the update path timing is shifted forward, the despreading processing of the path update slot is performed with the redundant resource, and the update path timing is not shifted forward. Since the frequency of applying the redundant resource can be reduced by controlling the despreading processing of the path update slot with the individual resource, the number of required redundant hard resources (circuit scale) can be further reduced.

  A despreading processing circuit that operates stably even in an environment where a path frequently appears / disappears with a redundant hard resource configuration having a small circuit scale by improving the multiple use efficiency of redundant hard resources by applying the present invention. Is possible. In addition, since shared control of redundant resources is simplified, the circuit scale of the control circuit can be reduced. In addition, even when the paths overlap, the despreading process by the stable and reliable parallel processing is performed, so that the despreading process without data loss is possible.

According to the present invention, path updating by the conventional redundant hard resource method, in which path updating is performed at the head of each received signal frame, is performed at the boundary of each slot obtained by subdividing one frame, and the redundant hard resource is determined in slot units. Perform parallel despreading processing. In order to perform path update at slot boundaries,
[1] Generation of despread code from slot boundary for path update
[2] It is necessary to calculate the path update timing based on the slot position during the current despreading process.

[1] Generation of despreading code from slot boundary for path update Normal despreading code generation is a process of generating despreading code initial value data of a despreading code at the head of a frame set for each user from an upper layer. In general, a despread code is continuously generated by cyclically shifting data stored in the shift register sequentially. When initialization is performed during the generation of the despreading code by such a despreading code generator, the initial value of the despreading code at the head of the frame is input again to the shift register of the despreading code generator. .

  In the present invention, a despread code at the slot boundary for path update is generated, and the despread code is input to the shift register of the despread code generator for initialization. Means for generating a despread code initial value. One of the following two configurations can be used as a means for generating the initial value of the despread code for each slot. The despreading code corresponding to the path update slot generated by the following configuration is input as an initial value to the shift register of the despreading code generator, so that the despreading code corresponding to the path update slot is the initial value. A despread code generation means for generating a code string can be configured.

(I) Using the free time from the setting of the initial value of the despreading code to the start of the despreading process, setting the despreading code at the head of the frame in the despreading code generator and setting the despreading code generator up to the frame length Operate, extract the shift register initial value at the slot boundary where the path is updated, and hold it internally. In this way, 14 types of despread codes from slot 2 to slot 15 can be set. The despread code in slot 1 is the despread code (initial value) at the beginning of the frame.

(Ii) A logical operation expression (tap extraction position) for generating the shift register initial value at the slot boundary from the frame head initial value is calculated in advance from the despread code generator polynomial generated by the despread code generator. To do. The calculated logical operation expression is internally held as a circuit, and the slot boundary initial value is calculated from the frame head initial value. Also in this case, 14 types of despreading codes of slot 2 to slot 15 are calculated, and the despreading code of slot 1 becomes the despreading code (initial value) at the head of the frame.

An example of calculating the tap extraction position for generating the slot boundary initial value will be described below. here,
M-sequence code generator polynomial: x ^ 25 + x ^ 3 + 1,
Shift register: [a24, a23, ..., a1, a0],
When a0 of the shift register is output,
The output after each step from now is
Output after 0 step = a0
Output after one step = a1
Output after 2 steps = a2
...
Output after 24 steps = a24
Output after 25 steps = (output after 0 steps) exor (output after 3 steps)
...
Output after 50 steps = (output after 25 steps) exor (output after 28 steps)
= (Output after 0 steps) exor (output after 3 steps) exor (output after 3 steps) exor (output after 6 steps)
= (Output after 0 steps) exor (Output after 6 steps)

  Therefore, from the theory of M-sequence code, the internal register value after X chip shift can be calculated by linear calculation by the above arithmetic processing. Since the slot length is 2560 chips, the tap extraction position at the slot boundary may be calculated as (2560 × K) steps (K = 1 to 14). In the above formula, “exor” means an exclusive OR operation.

[2] Calculation of path update timing based on despread slot position currently being processed In the present invention, in order to reduce the waiting time from notification of a new path timing to the start of parallel despread processing by redundant hardware resources, A process of correcting the path update timing is performed according to the despread slot position in the middle.

  The searcher unit detects the new path timing at the head of the frame of each received signal and notifies the despreading processing unit. The despreading processing unit corresponds to the time required to generate the despreading code from the slot boundary where the path update of [1] described above is performed on the slot number on which the despreading process is performed when the new path timing is notified. The slot having the slot number L (L ≧ 1) to be added is determined as the path update slot, and the new path timing at the head of the frame notified from the searcher unit is corrected to the timing at the position of the path update slot.

  This correction can be performed simply by adding the offset timing from the frame head to the path update slot position to the new path timing at the head of the frame. For example, the offset is added to the new path timing at the head of the notified frame. The timing one frame before the calculated timing is calculated as the path update slot timing.

  Further, the despreading processing unit notifies the searcher unit of the despreading slot number currently being processed, and the searcher unit determines the path update slot position from the despreading slot number being processed, and the path update slot position It is also possible to have a configuration for notifying the path update timing. In this way, slot unit path update timing calculation means can be configured.

  FIG. 1 shows an example of an operation sequence of the first embodiment of parallel despreading processing using redundant resources. In the first embodiment, for example, as shown in FIG. 1A, when the new path timing is advanced and shifted forward, for example, the despreading processing of the slot 14 is performed with the individual resource corresponding to the first user. If the notification of the new path timing is received during the process, number 1 (14 + 2 = 16 is obtained by adding 2 as the slot number L to the slot number 14, but the slot number is up to 15, so the number 16 Slot corresponding to the number 1) is determined to be a slot boundary for starting the path update process, and the despreading process with the individual resource for the slot 15 and the despreading process with the redundant resource for the slot 1 are performed in parallel. When the despreading process for slot 1 is completed, the despreading process is continuously performed with the individual resource corresponding to the first user from slot 2 onward.

  Also, as shown in FIG. 1B, when the new path timing is delayed and shifted backward, the despreading processing of, for example, the slot 10 is being performed with the individual resource corresponding to the second user. When the notification of the new path timing is received, it is determined that the slot of number 12 obtained by adding 2 as the slot number L to the slot number 10 is the slot boundary for starting the path update process, and is individually assigned to the slot 11. A despreading process is performed using resources, and a despreading process using redundant resources is performed on the slot 12. When the despreading process for the slot 12 is completed, the despreading process is continuously performed with the individual resource corresponding to the second user from the slot 13 onward.

  In addition, as shown in FIG. 1C, when the new path timing does not change and there is no shift, for example, while performing the despreading process of the slot 4 with the individual resource corresponding to the third user, Assuming that the notification of the new path timing is received, it is determined that the slot No. 6 obtained by adding 2 as the slot number L to the slot number 4 described above is the slot boundary for starting the path update process, and the individual resource for the slot 5 is determined. Then, the despreading process is performed, and the despreading process with redundant resources is performed on the slot 6. When the despreading process for the slot 6 is completed, the despreading process is continuously performed with the individual resources corresponding to the third user from the slot 7 onward.

  Further, as shown in FIG. 1D, when the new user's new path timing is shifted forward, the despreading processing of, for example, the slot 12 is performed with the individual resource corresponding to the fourth user. If the notification of the new path timing is received while the slot number 12 is received, it is determined that the slot No. 14 obtained by adding 2 as the above-mentioned slot number L to the slot number 12 is the slot boundary for starting the path update process. When the despreading process with the individual resource for the slot 14 and the despreading process with the redundant resource for the slot 14 are performed in parallel, and when the despreading process for the slot 14 is completed, the individual corresponding to the fourth user is started from the slot 15 onward. Continue despreading with resources.

  FIG. 1E shows the slot number processed by the redundant resource and the occupation state of the redundant resource. As shown in the figure, in the first embodiment, when a new path timing is notified, despreading processing is always performed on a path update slot for one slot using a redundant resource, and the amount corresponding to the one slot is obtained. When the despreading process is completed, the process is restored to the despreading process with individual resources corresponding to each user. Here, the reason for despreading one slot with redundant resources is as follows.

(I) The time width (Tsw) of the path search window is one slot length (667 us) or less (generally several hundred us or less), and the parallel processing time does not exceed one slot length.
(Ii) When a new path timing is notified, regardless of whether the path timing is shifted forward or backward, an operation of always performing parallel despreading processing of slot boundaries using redundant resources is performed. By controlling in this way, it is possible to simplify the control of parallel processing.

  In this case, parallel processing can be completed by occupying redundant resources only in a section of up to (L + 1) slots (3 slots length when L = 2). Conventionally, only one user is redundant in one frame. In some cases, resources were not used, but in the present invention, redundant resources can be used for {15 / (L + 1)} users in one frame, and the circuit scale can be reduced by improving the efficiency of redundant resources. It becomes.

  Further, since the control of the parallel despreading process at the slot boundary can be limited to the resource shift control between the redundant resource and the individual resource, the control circuit can be greatly simplified.

  FIG. 2 shows an example of an operation sequence of the second embodiment of parallel despreading processing using redundant resources. In the second embodiment, for example, as shown in FIG. 2A, when the new path timing is advanced and shifted forward, the individual resource corresponding to the first user, for example, as in the first embodiment, If a new path timing notification is received while the despreading process is being performed for slot 14, the slot number 14 is added with 2 as the number of slots L described above, and the path update process starts. When it is determined that it is a slot boundary, the despreading process with the individual resource for the slot 15 and the despreading process with the redundant resource for the slot 1 are performed in parallel, and when the despreading process for the slot 1 is completed, the slot 2 Thereafter, the despreading process is continuously performed with the individual resource corresponding to the first user.

  In addition, as shown in FIG. 2B, when the new path timing is delayed and shifted backward, the despreading process of, for example, the slot 10 is being performed with the individual resource corresponding to the second user. When the notification of the new path timing is received, there is no overlap between the despreading by the new path timing and the despreading by the old path timing, so the number of slots described above is assigned to the slot number 10 without performing parallel processing using redundant resources. The slot of number 12 with 2 added as L is determined to be the slot boundary for starting the path update process, and after despreading with the individual resource for slot 11, despreading with the individual resource continues for slot 12. Process.

  In addition, as shown in FIG. 2C, when the new path timing does not change and there is no shift, for example, while performing the despreading process of the slot 4 with the individual resource corresponding to the third user, If the notification of the new path timing is received, it is determined that the slot No. 6 which is obtained by adding 2 as the slot number L to the slot number 4 described above is the slot boundary of the path update processing start, After the despreading process, the despreading process is continuously performed on the slot 6 with individual resources.

  In addition, as shown in FIG. 2D, when the new user's new path timing is shifted ahead and shifted forward, the individual resource corresponding to the fourth user, for example, a slot, as in the first embodiment. If the notification of the new path timing is received while the despreading process of 12 is being performed, the slot of number 14 obtained by adding 2 as the slot number L to the slot number 12 is the slot for starting the path update process. When the despreading process with the individual resource for the slot 13 and the despreading process with the redundant resource for the slot 14 are performed in parallel and the despreading process for the slot 14 is completed, The despreading process is continuously performed with the individual resource corresponding to the fourth user.

  FIG. 1E shows the slot number processed by the redundant resource and the occupation state of the redundant resource. As shown in the figure, the redundant resource shifts forward with the new path timing earlier, and the parallel despreading process is used only when the path overlap occurs. And a control circuit for determining whether or not to perform parallel despreading processing using redundant resources based on the detection result, the multiple resource use efficiency of redundant resources can be further improved.

  FIG. 3 shows a configuration example of the multiuser despreading circuit of the present invention. As described above, the searcher unit 3-1 detects the frame head timing of the received signal of each user, and notifies the despreading control unit 3-2 of the path timing to be updated based on the frame head timing. At this time, the searcher unit 3-1 and the despreading processing unit 3-2 are provided with a reference counter that displays the same timing value, and the path timing is notified by the counter value.

  The path timing information of each user notified from the searcher unit 3-1 is temporarily stored in the buffer memory 3-21 of the despreading control unit 3-2. The path timing information held in the despreading control unit 3-2 is timing information obtained by correcting the new path timing at the head of the frame to the timing at the path update slot position. This correction is performed as described above. The configuration performed by the unit 3-1 can also be configured by the despreading control unit 3-2.

  The path timing information of each user held in the buffer memory 3-21 is sequentially read one by one every time a free state of the redundant resource 3-3 occurs, and a reference counter in the despreading control unit 3-2 is read out. When the comparison circuit 3-23 is input to the comparison circuit 3-23 and the coincidence is detected by the comparison circuit 3-23, either the initialization process at the path timing or the parallel processing by the redundant resource is started. However, as in the first embodiment described above, in the embodiment in which parallel processing is always performed in order to simplify control, only parallel processing is activated.

  The initialization process and the parallel process are switched by transferring an identification flag for starting the initialization process as a part of the path timing information from the searcher unit 3-1, and discriminating the identification flag. be able to. Alternatively, it is possible to control the switching of the initialization process or the parallel process according to the path shift direction by monitoring the operation state in the despreading processing unit 3-2.

  In each user-corresponding unit in the despreading processing unit 3-2, when the path timing update is notified by the coincidence detection in the comparison circuit 3-23 for the reception signal being despreaded, the slot counter 3-24 In order to cause the redundant resource 3-3 to perform the despreading processing of the slot (path update slot) having the number obtained by adding the number L of processing slots required for path update preparation to the slot number currently being processed obtained from The initial value of the despread code for the path update slot generated from the initial value generation circuit 3-25 is selected by the first selector 3-26 and the third selector 3-28, and the despread of the redundant resource 3-3 is performed. Set in the code generator 3-31. Thereafter, when the timing of the path update slot is reached, the 1-slot length despreading process is performed with the redundant resource 3-3.

  At this time, in the individual resource 3-4i (i = 1 to M) subject to path update, the despreading process is completed one slot before the path update slot, and the despread code for the slot of (path update slot number + 1) Is selected by the second selector 3-27 from the slot boundary code initial value generation circuit 3-25, and the completion of the despreading processing of the path update slot in the redundant resource 3-3 is awaited. Then, when the path update slot despreading process in the redundant resource 3-3 is completed, the despreading process after the next slot is resumed.

  Note that the first selector 3-26 described above determines the number L of processing slots required for path update preparation from the value of the slot counter 3-24 among the despread codes generated from the slot boundary code initial value generation circuit 3-25. And the second selector 3-27 selects the slot counter 3 among the despread codes generated from the slot boundary code initial value generation circuit 3-25. A despread code corresponding to a slot having a number obtained by adding (the number of processing slots required for path update preparation L + 1) to the value of −24 is selected. The third selector 3-28 selects a user despread code that uses the redundant resource 3-3 from among a plurality of despread codes corresponding to the user.

  The parallel processing control circuit 3-29 includes a reference counter 3-11 for the searcher unit 3-1, a reference counter 3-22 for the despreading control unit 3-2, a buffer memory 3-21 for path timing information, and a comparison circuit 3. −23 and the third selector 3-28, the result of the despreading process by the redundant resource 3-3, and the despreading process by the individual resources 3-41 to 3-4M corresponding to each user It has a function of controlling the selectors 3-51 to 3-5M for selecting one of the results.

  When the notification of the update path timing is received from the comparison circuit 3-23, the despreading process of the path update slot is always performed by the redundant resource 3-3, and the despreading process of the slot after the path update slot is performed for each user. It has the function of a despreading process control means for controlling the corresponding individual resources 3-41 to 3-4M to be executed.

  In addition, the despreading circuit of the redundant resource 3-3 and the individual resource 3-4i (i = 1 to M) is configured by one hard resource by a multiplexing circuit configuration, and the one hard resource is redundant by time division multiplexing. The hardware scale can be further reduced by adopting the configuration used for 3-3 and individual resources 3-4i (i = 1 to M).

  Further, although the configuration of the example corresponding to the second embodiment of the present invention shown in FIG. 2 is not shown, when the update path timing notification is received in the configuration example shown in FIG. A circuit for determining whether or not the path timing is shifted forward is provided. When the path timing is not shifted forward, the initial value of the despread code for the path update slot generated from the slot boundary code initial value generation circuit 3-25 Are input to the individual resource 3-4i (i = 1 to M) via the second selector 3-27, and the despreading result output from the individual resource 3-4i (i = 1 to M) is input to the selector 3 By adopting a configuration in which control is performed by the parallel processing control circuit 3-29 so that selection is made at −51 to 3-5M, when the update path timing is shifted backward or not, the path update slot is set by an individual resource. It is possible to configure the despreading processing control means for controlling to perform despreading processing after.

It is a figure which shows the example of an operation | movement sequence of 1st Embodiment of the parallel despreading process by a redundant resource. It is a figure which shows the example of an operation | movement sequence of 2nd Embodiment of the parallel despreading process by a redundant resource. It is a figure which shows the structural example of the multiuser despreading circuit of this invention. It is a figure which shows the basic composition of a CDMA receiver. It is a figure which shows the basic composition and delay profile of a searcher part. It is a figure which shows the despreading process part of the self-supporting tracking system by a DLL circuit. It is a figure which shows the despreading process part of a redundant hard resource system.

Explanation of symbols

3-1 Searcher Unit 3-11 Reference Counter 3-2 Despreading Control Unit 3-21 Buffer Memory 3-22 Reference Counter 3-23 Comparison Circuit 3-24 Slot Counter 3-25 Slot Boundary Code Initial Value Generation Circuit 3-26 1st selector 3-27 2nd selector 3-28 3rd selector 3-29 parallel processing control circuit 3-3 redundant resource 3-31 despread code generator 3-41-3-4M individual resource 3-51 ~ 3-5M selector

Claims (5)

In a CDMA receiver that performs despreading processing by updating the path timing of each received signal with respect to a CDMA received signal transmitted from a plurality of users' mobile terminals,
When the update path timing notification is received for each user, of the plurality of slots obtained by subdividing the radio frame of the received signal, the slot for which the despreading process is performed in the individual resource that performs the user-specific despreading process A slot-by-slot path update timing calculation means for determining a slot having a number obtained by adding the number of processing slots required for path update preparation to the number as a path update slot and correcting the head timing of the path update slot based on the update path timing When,
Despread code generation means for generating a despread code sequence having an initial value of a despread code corresponding to the path update slot;
Commonly used for despreading of received signals of a plurality of users, the despreading processing of the path update slot is performed at the start timing of the path update slot calculated by the slot unit path update timing calculation means, and , Redundant resources to be performed with the despread code generated by the despread code generating means,
A CDMA receiver characterized by comprising:   When the notification of the update path timing is received, the despreading process of the path update slot is always performed with the redundant resource, and the despreading process of the slot after the path update slot is performed with the individual resource corresponding to each user. 2. The CDMA receiver according to claim 1, further comprising a despreading processing control unit. When receiving the notification of the update path timing, it is determined whether or not the update path timing is shifted forward, and only when the path is shifted forward, the despreading process of the path update slot is performed on the redundant resource, The despreading processing of the slots after the path update slot is performed with individual resources corresponding to each user,
When the update path timing is shifted backward or is not shifted, the despreading process after the path update slot is performed on the dedicated resource by the path update slot calculated by the slot unit path update timing calculation means. 2. The CDMA receiving apparatus according to claim 1, further comprising a despreading processing control unit configured to control the despreading code string generated by the despreading code generation unit at a head timing. In a CDMA receiver path timing update control method for performing despreading processing by updating the path timing of each received signal with respect to CDMA received signals transmitted from mobile terminals of a plurality of users,
When the update path timing notification is received for each user, of the plurality of slots obtained by subdividing the radio frame of the received signal, the slot for which the despreading process is performed in the individual resource that performs the user-specific despreading process A slot-by-slot path update timing calculation step of determining a slot having a number obtained by adding the number of processing required slots for path update preparation to the number as a path update slot and correcting the head timing of the path update slot based on the update path timing When,
A despread code generation step of generating a despread code sequence having an initial value of a despread code corresponding to the path update slot;
When the notification of the update path timing is received, the redundant resource commonly used for the despreading process for a plurality of users, the path update slot start timing calculated in the slot unit path update timing calculation step, and With the despread code generated in the despread code generation step, the despreading process of the path update slot is always performed, and the despread process of the slot after the path update slot is performed with the individual resource corresponding to each user. A despreading control step;
A path timing update control method for a CDMA receiver. In a CDMA receiver path timing update control method for performing despreading processing by updating the path timing of each received signal with respect to CDMA received signals transmitted from mobile terminals of a plurality of users,
When the update path timing notification is received for each user, of the plurality of slots obtained by subdividing the radio frame of the received signal, the slot for which the despreading process is performed in the individual resource that performs the user-specific despreading process A slot-by-slot path update timing calculation step of determining a slot having a number obtained by adding the number of processing required slots for path update preparation to the number as a path update slot and correcting the head timing of the path update slot based on the update path timing When,
A despread code generation step of generating a despread code sequence having an initial value of a despread code corresponding to the path update slot;
When the notification of the update path timing is received, it is determined whether or not the update path timing is shifted forward, and only when it is shifted forward, a redundant resource used in common for a plurality of users, The despreading process of the path update slot is always performed at the start timing of the path update slot calculated in the slot unit path update timing calculation step and the despread code generated in the despread code generation step. The despreading processing of the slots after the path update slot is performed with individual resources corresponding to each user,
When the update path timing is shifted backward or is not shifted, the despreading process after the path update slot is performed on the dedicated resource in the path update slot calculated in the slot unit path update timing calculation step. A despreading process control step for controlling the despreading code sequence generated in the despreading code generation step at the start timing;
A path timing update control method for a CDMA receiver.

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