JP2003298470A - Correlation peak searching method, correlation peak searching apparatus, and program for controlling searching apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a correlation peak searching method, a correlation peak searching apparatus, and a program for controlling searching apparatus for controlling a searching interval of correlation peaks on the basis of reception quality of a received signal so as to be able to reduce power consumed at searching. <P>SOLUTION: A receiver 1 is configured to include: the correlation peak searching apparatus 10; an analog/digital converter 11; an LPF (Low Pass Filter) 12; a correlation unit 13; a replica spread code generating section 14; a synchronization tracing section 15; a demodulation processing section 16; and an error correction section 17, the correlation peak searching apparatus 10 is configured to include: a system clock supply section 10a; a matched filter 10b; a correlation peak detection section 10c; a reception quality discrimination section 10d; and a searching interval control section 10e, and the searching interval control section 10e controls a searching interval of the correlation peaks on the basis of a result of discrimination of the reception quality by the reception quality discrimination section 10d to reduce the power consumption of the receiver. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication using a spread spectrum system, and more particularly to a correlation peak searching apparatus suitable for searching a correlation peak of a plurality of received signals generated by multipath and the like. .

[0002]

2. Description of the Related Art In a radio communication using a spread spectrum system, a direct wave, a reflected wave, a transmitted wave, a diffracted wave are generated in the process in which a radio wave having spread coded information propagates between a transmitting antenna and a receiving antenna. As a result, a multipath (multipath) in which a plurality of transmission paths exist for one signal is generated. In wireless communication, rake reception is important in which correlation peaks of spread codes in a plurality of received signals generated by the multipath are combined to improve quality. In order to perform rake reception, the time timing of the correlation peak is first searched, and after the search is completed, the synchronization tracking circuit follows the fluctuation of the time timing of the correlation peak. However, the existence of multipath is usually
Since it disappears or appears with time, it is necessary to periodically search the correlation peak and update the time timing of the correlation peak. In addition, in the case of mobile phones, not only the multipath correlation peak, but also the signals from the base stations of adjacent cells are regularly searched for the correlation peak to prepare for handover due to inter-cell movement. There must be. Further, normally, a matched filter having a large circuit size and large power consumption is used for the correlation peak search, and a correlator having a small circuit size and low power consumption is used for synchronous tracking of the correlation peak. For the search for the correlation peak, either a continuous search or a search at a certain time interval is used. However, when the communication is stable, the power consumption can be reduced by lowering the frequency of performing the correlation peak search. So far, methods have been proposed in which the search is stopped or the cycle is controlled according to the level of the correlation peak value.

Here, the correlation peak is obtained by performing an exclusive OR operation on bit positions of the same spreading code for one cycle.
Bits that have become "0", that is, bits that have the same compared bits are "+1", bits that have "1" are "-".
This is a state in which the summing operation is performed as "1" and the total becomes maximum, that is, the bit positions of all spreading codes are the same.

Rake reception is a reception system in which correlation peaks generated according to the time axis are added to each incoming received signal due to the respective path delays of a plurality of received signals caused by multipath. It is used to reinforce the weak reception signal of and to perform stable reception.

[0005]

However, in the above-described conventional search method, since the search control is performed only by observing the level of the correlation peak value, fine control is difficult. For example, when receiving while moving at high speed, the correlation peak may fluctuate significantly or a strong correlation peak may suddenly disappear due to the effects of fading and shadowing. If another correlation peak is searched after the correlation peak disappears, communication is interrupted during the search. Further, if it is attempted to minimize the interruption of communication by lowering the threshold value to be compared with the correlation peak value, as a result, the correlation peak search will be performed frequently, resulting in an increase in power consumption.
Further, even if the level of the correlation peak value is strong, it may not always be said that the bit error rate of the received data is low.

Therefore, the present invention has been made by paying attention to the unsolved problem of the conventional technique as described above, and the search interval of the correlation peak is set based on the means for estimating the quality condition of the communication channel. An object of the present invention is to provide a correlation peak search method, a correlation peak search device, and a search device control program that further reduce power consumed during search and stabilize communication by performing fine control.

[0007]

In order to achieve the above object, a correlation peak searching method according to a first aspect of the present invention is a method for detecting a correlation peak from a plurality of received signals in a radio communication using a spread spectrum system. A correlation peak search method for searching time timing, wherein the reception quality of the received signal is judged based on the variance value of the correlation peak of the received signal, and the search execution interval is controlled based on the judgment result. It is characterized by that.

In other words, in order to control the search interval of the correlation peak, the reception quality of the received signal is judged based on the variance value of the correlation peak of the received signal, and the time timing search is executed based on this judgment result. Therefore, it is possible to infer, for example, from the magnitude of the fluctuation of the correlation peak value whether or not fading or shadowing due to high-speed movement is affected. Since it is possible to reduce the frequency of the correlation peak search, it is possible to reduce the power consumed during the search as compared with the case where the search is always executed or the search is executed at regular intervals. .

According to a second aspect of the present invention, in the correlation peak searching method according to the first aspect, the correlation peak is linearly predicted, and the reception quality of the received signal is determined based on the prediction result. It has a feature. That is, when the reception quality is determined, the correlation peak value of the received signal is linearly predicted, and the reception quality is also determined based on the prediction result. Therefore, it is possible to determine the reception quality based on the result of the linear prediction.

According to a third aspect of the present invention, in the correlation peak search method according to the first or second aspect, the reception quality of the received signal is determined based on the error rate of the bit data of the information included in the received signal. It is characterized by making a judgment. That is, when the reception quality is determined, the reception quality is determined also based on the error rate of the information bit data of the received signal. Therefore, when the bit data error rate is high, it is possible to determine that the reception quality has deteriorated.

Further, a correlation peak searching method according to a fourth aspect of the present invention is a correlation peak searching method for searching a time timing of a correlation peak from a plurality of received signals in a radio communication using a spread spectrum system. Therefore, the correlation peak is linearly predicted, the reception quality of the received signal is judged based on the prediction result, and the search execution interval is controlled based on the judgment result.

That is, in order to control the search interval of the correlation peak, the correlation peak value of the received signal is linearly predicted, the reception quality of the received signal is judged based on the prediction result, and the time is judged based on this judgment result. Since the interval for executing the timing search is determined, it is possible to reduce the power consumption during the search as compared to the case where the search is always executed or the search is executed at regular intervals. is there.

According to a fifth aspect of the present invention, in the correlation peak searching method according to the fourth aspect, the reception quality of the received signal is judged based on the error rate of the bit data of the information included in the received signal. It has a feature. That is,
When determining the reception quality, the reception quality is determined also based on the error rate of the information bit data of the received signal. Therefore, when the bit data error rate is high, it is possible to determine that the reception quality has deteriorated.

A correlation peak searching method according to a sixth aspect of the present invention is a correlation peak searching method for searching a correlation peak time timing from a plurality of received signals in a radio communication using a spread spectrum system. Therefore, the reception quality of the received signal is determined based on the error rate of the bit data of the information included in the received signal, and the search execution interval is controlled based on the determination result.

That is, in order to control the search interval of the correlation peak, the reception quality of the received signal is judged based on the error rate of the information bit data of the received signal, and the time timing search is executed based on the judgment result. Since the interval is determined, for example, when the bit data error rate is high, it is determined that the reception quality has deteriorated, and the execution interval is determined by increasing the interval for performing the time timing search. By performing the search, it is possible to reduce the power consumed during the search, as compared with the case where the search is always performed or the search is performed at regular time intervals.

According to a seventh aspect of the present invention, in the correlation peak search method according to any one of the first to sixth aspects, the search execution interval is set based on the determination result. It is characterized in that it is controlled to be changed. That is, for example, instead of immediately stopping the search just because the reception quality is stable,
By controlling the execution interval stepwise with time, such as controlling the execution interval to gradually decrease with time,
It is possible to deal with a sudden situation such as unexpected deterioration of reception quality without delay and to perform stable control.

A correlation peak searching apparatus according to claim 8 of the present invention is a correlation peak searching apparatus for searching a correlation peak time timing from a plurality of received signals in a radio communication using a spread spectrum system. There is a reception quality determination unit that determines the reception quality of the reception signal based on the variance value of the correlation peak of the reception signal, and a search interval control unit that controls the execution interval of the search based on the determination result. It is characterized by having at least.

With such a configuration, the reception quality determination means determines the reception quality of the received signal based on the variance value of the correlation peak of the received signal, and the search interval control means determines the time based on the determination result. Since it is possible to control the interval at which the timing search is executed, it is possible to estimate from the magnitude of fluctuations in the correlation peak value whether or not fading or shadowing due to high-speed movement is affected. Since it is possible to reduce the frequency of the correlation peak search in the state and the state according to it, the power consumed during the search is reduced compared to the case where the search is always executed or the search is executed at regular intervals. It is possible to reduce. .

In the correlation peak searching apparatus according to claim 9 of the present invention, the reception quality judgment means makes a linear prediction of the correlation peak, and judges the reception quality of the received signal based on the prediction result. It is characterized by doing. That is, when the reception quality is determined, the correlation peak value of the received signal is linearly predicted, and the reception quality is also determined based on the prediction result. Therefore, it is possible to determine the reception quality based on the result of the linear prediction.

The invention according to claim 10 is the invention according to claim 8.
Alternatively, in the correlation peak search device according to claim 9, the reception quality determination means determines the reception quality of the received signal based on an error rate of bit data of information included in the received signal. That is, when the reception quality is determined, the reception quality is determined also based on the error rate of the information bit data of the received signal. Therefore,
When the error rate of bit data is large, it is possible to determine that the reception quality has deteriorated.

The correlation peak searching apparatus according to claim 11 of the present invention is a correlation peak searching apparatus for searching the time timing of a correlation peak from a plurality of received signals in a radio communication using a spread spectrum system. Then, a reception quality determination unit that performs linear prediction of the correlation peak and determines the reception quality of the received signal based on the prediction result, and a search interval control unit that controls the execution interval of the search based on the determination result And is provided at least.

With such a configuration, the reception quality judging means makes a linear prediction of the correlation peak value of the received signal, judges the reception quality of the received signal based on the prediction result, and the search interval control means makes it possible. Since it is possible to control the interval for executing the time timing search based on the judgment result, it is consumed at the time of searching as compared with the case where the search is always executed or the search is executed at regular intervals. It is possible to reduce power consumption.

The invention according to claim 12 is the invention according to claim 1.
In the correlation peak search device described in 1, the reception quality determination means determines the reception quality of the received signal based on an error rate of bit data of information included in the received signal. That is, when the reception quality is determined, the reception quality is determined also based on the error rate of the information bit data of the received signal. Therefore, when the bit data error rate is high, it is possible to determine that the reception quality has deteriorated.

A correlation peak searching apparatus according to a thirteenth aspect of the present invention is a correlation peak searching apparatus for searching a correlation peak time timing from a plurality of received signals in a radio communication using a spread spectrum system. Then, reception quality judgment means for judging the reception quality of the reception signal based on the error rate of the bit data of the information included in the reception signal, and search interval control means for controlling the execution interval of the search based on the judgment result. And is provided at least.

With such a configuration, the reception quality judging means judges the reception quality of the received signal based on the error rate of the bit data of the information contained in the received signal, and the search interval control means makes the judgment result. Since it is possible to control the interval for executing the time-timing search based on, the power consumption during the search is reduced compared to the case where the search is always executed or the search is executed at regular intervals. It is possible to

The invention according to claim 14 is the invention according to claim 8.
The correlation peak search device according to any one of claims 13 to 13, wherein the search interval control means performs control to change the search execution interval stepwise based on the reception quality. That is, for example, even if the reception quality is stable, the search is not stopped suddenly, but the execution interval is controlled to be gradually shortened with time based on the reception quality determination result. In addition, by controlling the execution interval stepwise, it is possible to respond to sudden situations such as unexpected quality deterioration without delay.
It is possible to perform stable control.

A search device control program according to a fifteenth aspect of the present invention is a search device control program for controlling a correlation peak search device in a radio communication using a spread spectrum system, A reception quality determination step of determining the reception quality of the received signal based on the variance value of the correlation peak of the signal, and a search interval control step of controlling the execution interval of the search by the time timing search step based on the determination result, Is provided at least.

Here, the present invention is a control program for controlling the correlation peak search device according to claim 8,
Since the effect is duplicated, the description is omitted. The invention according to claim 16 is the search device control program according to claim 15, wherein in the reception quality determination step, linear prediction of the correlation peak is performed, and the reception signal is received based on the prediction result. It is characterized by judging quality.

Here, the present invention is a control program for controlling the correlation peak search device according to claim 9,
Since the effect is duplicated, the description is omitted. The invention according to claim 17 is the program for searching device control according to claim 15 or claim 16, wherein in the reception quality determination step, the error rate of bit data of information included in the received signal is used. The feature is that the reception quality of the received signal is determined.

Here, the present invention is a control program for controlling the correlation peak searching apparatus according to claim 10, and since the effects thereof overlap, the description thereof will be omitted. Also,
The search device control program according to claim 18 according to the present invention is a search device control program for controlling a correlation peak search device in wireless communication using a spread spectrum system, wherein the correlation peak linear prediction is performed. At least a reception quality determination step of determining reception quality of the received signal based on the prediction result, and a search interval control step of controlling an execution interval of the search by the time timing search step based on the determination result. It is characterized by having.

Here, the present invention is a control program for controlling the correlation peak searching apparatus according to claim 11, and since the effects thereof overlap, the description thereof will be omitted. Also,
According to a nineteenth aspect of the invention, in the search device controlling program according to the eighteenth aspect, in the reception quality determination step, the reception quality of the reception signal is determined based on an error rate of bit data of information included in the reception signal. It is characterized by making a judgment.

Here, the present invention is a control program for controlling the correlation peak search device according to claim 12, and since the effects thereof overlap, a description thereof will be omitted. Also,
The search device control program according to claim 20 of the present invention is a search device control program for controlling a correlation peak search device in a wireless communication using a spread spectrum system, wherein At least a reception quality determination step of determining reception quality of the received signal based on an error rate of bit data, and a search interval control step of controlling an execution interval of the search by the time timing search step based on the determination result. It is characterized by having.

Here, the present invention is a control program for controlling the correlation peak search device according to claim 13, and since the effects thereof overlap, the description thereof will be omitted. Also,
According to a twenty-first aspect of the invention, in the search device control program according to any one of the fifteenth to twenty-first aspects, in the search interval control step, the search execution interval is set based on the reception quality. It is characterized in that it is controlled to be changed.

Here, the present invention is a control program for controlling the correlation peak searching apparatus according to claim 14, and since the effects thereof overlap, the description thereof will be omitted.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 are diagrams showing an embodiment of a correlation peak search device according to the present invention. First,
The configuration of the receiving apparatus to which the correlation peak searching apparatus according to the present invention is applied will be described based on FIG. FIG. 1 is a block diagram showing the configuration of a receiving apparatus to which the correlation peak searching apparatus according to the present invention is applied.

The receiving apparatus 1 includes a correlation peak searching apparatus 10
And A / D converter 11 and LPF (Low Pass Filter)
12, a correlator 13, and a replica spreading code generator 14
And a synchronization follow-up unit 15, a demodulation processing unit 16, and an error correction unit 17. The correlation peak search device 10 is configured to include a system clock supply unit 10a, a matched filter 10b, a correlation peak detection unit 10c, a reception quality determination unit 10d, and a search interval control unit 10e.

The system clock supply unit 10a is for supplying an operation clock to the matched filter 10b. The matched filter 10b has a function of separating multipaths by a plurality of delay circuits (for example, flip-flops and the like), and a spread code set for each delay circuit with respect to a received signal input to the delay circuit. And an exclusive OR operation is performed, and the peak value is output when the bit of the spread code and the bit of the spread code of the received signal match. At that time, a value obtained by adding all the peak outputs in the exclusive OR operation unit associated with each delay circuit is output as a peak value.

The correlation peak detector 10c detects the time timing of the correlation peak of the received signal based on the peak output of the matched filter 10b. The reception quality determination unit 10d evaluates and determines the reception quality of the received signal, and in the present embodiment, each of the variance value of the correlation peak value, the linear prediction value of the correlation peak value, and the data error rate of the received signal. The reception quality is evaluated and judged for the item. Here, regarding the variance value of the correlation peak value, when the variance value is large, it is determined that the reception quality has deteriorated because the variation of the correlation peak is large, and the linear prediction of the correlation peak value is performed from the past correlation peak value. The future correlation peak value is linearly predicted, and when the prediction result becomes less than or equal to a predetermined value, it is determined that the reception quality has deteriorated, and the data error rate of the received signal is corrected by the error correction unit. When the error rate calculated by counting the number of data bits of the received signal exceeds a predetermined value, it is determined that the reception quality has deteriorated. In the present embodiment, it is possible to select any of these evaluation contents in any combination, and it is also possible to set a condition for deterioration of reception quality for the selected evaluation contents. It is possible.

The search interval control unit 10e is based on the judgment result of the reception quality judging unit 10d and the system clock supplying unit 10e.
By controlling a and controlling the supply interval of the system clock to the matched filter 10b, the search interval of the correlation peak is controlled. According to the reception quality judgment result, this control controls to lengthen the clock supply time when the reception quality is significantly deteriorated, and lengthens the clock non-supply time when the reception quality is stable. The control is performed to

The A / D converter 11 is for converting a received signal from an analog signal to a digital signal. L
The PF 12 is for removing a noise component contained in the received signal and for shaping the waveform. The correlator 13 performs despreading processing based on the replica spread code supplied from the replica spread code generator 14 at the same timing as the time timing of the correlation peak of the received signal, and extracts the primary modulation signal from the received signal. It is a thing.

The replica spreading code generator 14 generates a replica spreading code for despreading the spreading code of the received signal based on the time timing from the synchronization follower 15, and supplies it to the correlator 13. That is, here, the replica spreading code synchronized with the time timing of the correlation peak detected by the correlation peak detection unit 10c is generated.

The synchronization follow-up unit 15 compares the received signal from the correlator 13 with the time timing of the correlation peak detected by the correlation peak detection unit 10c, and follows the time timing of the correlation peak to obtain the correlation peak. The appropriate time timing is supplied to the replica spreading code generator 14. The demodulation processing unit 16 is for demodulating the primary modulation signal extracted by the correlator 13 into original bit data.

The error correction unit 17 corrects an error that has occurred during communication or the like based on the demodulated bit data. Here, although not shown, the receiving device 1 is a C for executing a control program for controlling the operation of the present device.
PU (Central Processing Unit), ROM (Read Only Memory) in which a control program is stored, and RAM for temporarily storing data necessary for executing the program
(Random Access Memory) and an interface circuit for exchanging data between the above-mentioned units.

The more specific operation of the receiving apparatus 1 will be described below. When receiving the spread-coded signal transmitted from the transmission source, the receiving device 1 first receives the A / D converter 11
In, the received signal which is an analog signal is converted into a digital signal. Next, the LPF 12 removes noise contained in the received signal, shapes the waveform that is distorted due to attenuation during propagation, and outputs the A / D converted received signal to the matched filter 10b and the correlator 13, respectively. To do. The matched filter 10b performs an operation for detecting the correlation peak of the received signal in synchronization with the clock supplied from the system clock supply unit 10a, and based on the result of the operation, the correlation peak detection unit 10c detects the peak of the received signal. Outputs the calculation result of. Correlation peak detector 10c
Then, the time timing of the correlation peak of the received signal is detected based on the peak output from the matched filter 10b, and this timing is transmitted to the synchronization tracking unit 15.
The synchronization tracking unit 15 supplies an appropriate time timing to the replica spreading code generating unit 14 based on the received signal from the correlator 13 and this time timing, and the replica spreading code generating unit 14 determines the time based on this time timing. A replica spread code with the same timing is generated and supplied to the correlator 13. Here, since the received signal is directly input to the correlator 13, the received signal is despread using the replica spreading code synchronized with the time timing of the correlation peak to extract the primary modulation signal, It is transmitted to the demodulation processing unit 16. The demodulation processing unit 16 demodulates the primary modulation signal to extract the original bit data, and transmits it to the error correction unit 17. The error correction unit 17 performs error correction processing such as parity check on the received bit data, transmits the correction content to the reception quality determination unit 10d, and outputs the corrected demodulated signal to the circuit or the like in the next stage. .

On the other hand, the reception quality judgment unit 10d performs the evaluation of the set evaluation items and the reception quality judgment processing based on the evaluation in response to the reception of the signal in the correlator 13, and the judgment result is used as the search interval. It is transmitted to the control unit 10e. When it is determined that the reception quality is deteriorated based on the received determination result, the search interval control unit 10e sets the system clock supply unit 10a to the matched filter 10b so that the number of searches by the matched filter 10b increases.
Control so that the system clock supply time is longer, and when it is determined that the reception quality has not deteriorated,
The system clock supply unit 10a is controlled so that the time for supplying the system clock to the matched filter 10b is shortened so that the number of searches by the matched filter 10b is reduced. That is, when the reception quality deteriorates, the matched filter 10b is searched frequently,
When the reception quality is stable, the matched filter 10
Control is performed to reduce the search by b. Further, when the correlation peak detection unit 10c detects the time timing of the correlation peak, the synchronization tracking unit 15 follows the time timing to perform despreading processing, and the current correlation until the time timing of the next correlation peak is detected. It is designed to maintain peak timing.

Next, the flow of the correlation peak search processing of the received signal in the correlation peak search device 10 will be described with reference to FIG. FIG. 2 is a flowchart showing the processing for searching the correlation peak of the received signal in the correlation peak searching apparatus 10. As shown in FIG. 2, first, the process proceeds to step S200, it is determined whether the clock is supplied to the matched filter 10b, and if it is determined that the clock is supplied (Y
es) moves to step S202, otherwise (No)
Waits for supply.

When the process proceeds to step S202, in the matched filter 10b, the exclusive OR calculation processing is performed on the received signals input to each delay circuit and the correlation peak is searched and found. The sum of the exclusive OR operation results of the delay circuits is output to the correlation peak detection unit 10c, and the process proceeds to step S204.

In step S204, the time timing of the correlation peak is detected based on the peak output from the matched filter 10b, and the process proceeds to step S206. When the process proceeds to step S206, the correlation peak detection unit 10c
Transmits the detected time timing to the synchronization tracking unit 15 and proceeds to step S200. That is, while the clock is being supplied to the matched filter 10b, the processes of steps S200 to S206 are repeated, and the correlation peak search process is performed on the received signal.

Further, the flow of the despreading process of the received signal in the receiving apparatus 1 will be described with reference to FIG. FIG. 3 is a flowchart showing the despreading processing of the received signal in the receiving device 1. As shown in FIG. 3, first, step S300.
When it is determined that the time timing of the correlation peak has been updated based on the output of the received signal from the correlator 13 and the time timing from the correlation peak detection unit 10c, (Yes) is step S3
02, otherwise moves to step S310.

When the process proceeds to step S302, the timing is transmitted to the replica spreading code generator 14 in synchronization with the updated time timing, and the process proceeds to step S304. When the process proceeds to step S304, the replica spreading code generation unit 14 generates a replica spreading code in synchronization with the received time timing, and the replica spreading code is generated by the correlator 1
3, and the process proceeds to step S306.

In step S306, the correlator 13 performs despreading processing on the basis of the replica spreading code and the received signal to extract the primary modulation signal, and the process proceeds to step S308. When the process proceeds to step S308, the extracted primary modulation signal is transmitted to the demodulation processing unit 16 and the process proceeds to step S300. On the other hand, if the time timing is not updated and the process proceeds to step S310, the current time timing is transmitted to the replica spreading code generation unit 14 and then step S30.
Go to 4.

That is, the synchronization follow-up unit 15 follows the time timing of the correlation peak, and the correlator 13
The despreading process is performed at the timing that is followed. Furthermore, the flow of operation processing of the reception quality determination unit 10d will be described with reference to FIG. FIG. 4 is a flowchart showing an operation process of the reception quality judgment unit 10d. As shown in FIG.
First, the process proceeds to step S400, it is determined whether or not to change the evaluation content for evaluating the reception quality, and if it is determined to be done (Yes), the process proceeds to step S402, otherwise (No). Moves to step S404.

When the process proceeds to step S402, the evaluation contents are set and the process proceeds to step S400. Here, in the present embodiment, the evaluation content is any combination of the three items of the correlation value of the correlation peak value, the linear prediction value of the correlation peak value, and the data error rate of the received signal as described above. It is possible to select. In step S400, without changing the evaluation content,
If the process proceeds to step S404, the correlator 13 determines whether or not a signal is received, and it is determined that the signal is received.
(Yes) moves to step S406, otherwise (N
o) waits until it is received.

When the process proceeds to step S406, the setting item evaluation process is performed based on the set item contents, and the process proceeds to step S408. When the process proceeds to step S408, it is determined whether or not the evaluation process is completed. If it is determined that the evaluation process is completed (Yes), the process proceeds to step S410, and if not (No), the process waits until the evaluation is completed.

When the process proceeds to step S410, the reception quality is judged based on the evaluation result, and the process proceeds to step S400. That is, each time the correlator 13 receives a signal, the set evaluation item is evaluated, and the reception quality is evaluated based on the evaluation result. The evaluation result of the reception quality is transmitted to the search interval control unit 10e.

Further, based on FIG. 5, the search interval control unit 10
The flow of the operation process of e will be described. FIG. 5 is a flowchart showing the operation processing of the search interval control unit 10e. Figure 5
As shown in FIG. 11, first, the process proceeds to step S500, it is determined whether or not the determination result is received from the reception quality determination unit 10d, and if it is determined that the determination result is received (Yes), step S50 is performed.
If not (No), the process waits until it is received.

When the process proceeds to step 502, it is judged from the received judgment result whether the reception quality is deteriorated,
If it is determined to be deteriorated (Yes), the process proceeds to step S504, and if not (No), the process proceeds to step S506. When the process proceeds to step S504, the matched filter 10b is supplied to the system clock supply unit 10a.
A control instruction is given to extend the clock supply time to the clock so that the number of searches increases, and the process proceeds to step S500.

On the other hand, when the process proceeds to step S506, the system clock supply unit 10a is given a control command for shortening the clock supply time to the matched filter 10b so as to reduce the number of searches, and then step S5 is performed.
00. That is, each time the reception quality determination result is received, the processing of steps S500 to S506 is performed to control the execution interval of the correlation peak search by the matched filter 10b.

When the reception quality is stable,
A control command may be given to the system clock supply unit 10a so as to gradually increase the execution interval of the search for the correlation peak. As described above, the reception quality determination unit 10d evaluates the reception quality based on the variance value of the correlation peak value, the linear prediction value of the correlation peak value, and the evaluation result of the data error rate of the reception signal, and the search interval control unit 10e receives the reception quality. By controlling the clock supply interval of the system clock supply unit 10a based on the evaluation result of 1., the execution interval of the search for the correlation peak of the received signal by the matched filter 10b is controlled, so that the reception quality is stable. At times, it is possible to prolong the time during which the operation of the matched filter 10b is stopped, and it is possible to reduce power consumption.

Further, when the reception quality is stable, the supply of the clock to the matched filter 10b is not completely stopped but the supply time is gradually shortened so that sudden deterioration of the reception quality is not delayed. It is possible to correspond to. Here, the reception quality judgment unit 10d shown in FIG.
And the search interval control unit 10e corresponds to the search interval control unit according to claims 8, 11, 13, and 14.

In the above embodiment, the reception quality is judged based on the evaluation results of the three items of the variance value of the correlation peak value, the linear prediction value of the correlation peak value, and the data error rate of the received signal. Although the quality is determined, the reception quality may be determined based on other evaluation items without being limited to this. Further, in the above embodiment, when controlling the search interval of the correlation peak, the search interval is controlled by controlling the clock supply time to the system clock supply unit 10a to the matched filter 10b. However, the search interval is not limited to this, and the search interval may be controlled by another method.

[0062]

As described above, according to the correlation peak search method of the first aspect of the present invention, in order to control the search interval of the correlation peak, the correlation peak dispersion value of the received signal is used as the basis. Since the reception quality of the received signal is determined and the interval for executing the time timing search is determined based on this determination result, for example, fading or shadowing due to high-speed movement is determined from the magnitude of the fluctuation of the correlation peak value. It is possible to infer whether or not it is affected, and it is possible to reduce the frequency of correlation peak search in the stationary state and in a similar state, so it is possible to perform a constant search or search at regular intervals. It is possible to reduce the power consumption due to the search, as compared with the case where it is executed.

According to the correlation peak search method of the second aspect, in addition to the effect of the first aspect, when the reception quality is determined, the correlation peak value of the received signal is linearly predicted, and the prediction result is obtained. Since the reception quality is determined based on the above, it is possible to determine the reception quality based on the result of the linear prediction. Further, according to the correlation peak search method of claim 3, in addition to the effect of claim 1 or claim 2, when determining the reception quality, reception is also performed based on the error rate of the information bit data of the received signal. Since the quality is determined, it is possible to determine that the reception quality has deteriorated when the bit data error rate is large.

According to the correlation peak search method of the fourth aspect, in order to control the search interval of the correlation peak, the correlation peak value of the received signal is linearly predicted, and the received signal is calculated based on the prediction result. Since the reception quality of is determined and the interval for executing the search of the time timing is determined based on this determination result, as compared with the case where the constant search is executed or the search is executed at regular time intervals, It is possible to reduce the power consumed during the search.

Further, according to the correlation peak searching method of claim 5, in addition to the effect of claim 4, when determining the reception quality, the reception quality is also based on the error rate of the information bit data of the received signal. Was decided. Therefore, when the bit data error rate is high, it is possible to determine that the reception quality has deteriorated. Further, according to the correlation peak search method of claim 6, in order to control the search interval of the correlation peak, the reception quality of the received signal is judged based on the error rate of the information bit data of the received signal, and this judgment is made. Since the interval for executing the time timing search is determined based on the result, for example, when the error rate of bit data is large, it is determined that the reception quality has deteriorated and the interval for executing the time timing search is set. By deciding the execution interval such as making it longer, it is possible to reduce the power consumed during the search as compared with the case where the search is always executed or the search is executed at regular intervals. .

Further, according to the correlation peak search method of claim 7, in addition to the effect of any one of claims 1 to 6, for example, because the reception quality is stable, Instead of suddenly stopping the search, the execution interval is controlled to be gradually shortened with time, so that the execution interval is controlled stepwise with time. It becomes possible to deal with the situation without delay and to perform stable control.

Here, the correlation peak search device according to any one of claims 8 to 14 is for realizing the peak search method according to any one of claims 1 to 7, and its effects are duplicated. Omit it. Further, the search device control program according to any one of claims 15 to 21 is a program for controlling the correlation peak search device according to any one of claims 8 to 14, and description thereof is omitted because its effects are duplicated. .

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a receiving device to which a correlation peak searching device according to the present invention is applied.

FIG. 2 is a flowchart showing a correlation peak search process of a received signal in the correlation peak search device 10.

FIG. 3 is a flowchart showing a despreading process of a received signal in the receiving device 1.

FIG. 4 is a flowchart showing an operation process of a reception quality judgment unit 10d.

FIG. 5 is a flowchart showing an operation process of a search interval control unit 10e.

[Explanation of symbols]

1 receiver 10 Correlation peak search device 10a System clock supply unit 10b matched filter 10c correlation peak detector 10d reception quality judgment unit 10e Search interval control unit 11 A / D converter 12 LPF 13 Correlator 14 Replica spreading code generator 15 Sync follower 16 Demodulation processing unit 17 Error correction section

Claims (21)

[Claims] 1. A correlation peak search method for searching the time timing of a correlation peak from a plurality of received signals in a wireless communication using a spread spectrum method, which is based on a variance value of the correlation peaks of the received signals. A correlation peak search method, comprising: determining the reception quality of the received signal and controlling the execution interval of the search based on the determination result. 2. The correlation peak searching method according to claim 1, wherein the correlation peak is linearly predicted, and the reception quality of the received signal is determined based on the prediction result. 3. The correlation peak search method according to claim 1, wherein the reception quality of the received signal is determined based on an error rate of bit data of information included in the received signal. 4. A correlation peak search method for searching the time timing of a correlation peak from a plurality of received signals in a wireless communication using a spread spectrum method, wherein the correlation peak is linearly predicted, and the prediction result is obtained. A correlation peak searching method, characterized in that the reception quality of the received signal is judged based on the above, and the search execution interval is controlled based on the judgment result. 5. The correlation peak searching method according to claim 4, wherein the reception quality of the received signal is determined based on an error rate of bit data of information included in the received signal. 6. A correlation peak search method for searching a correlation peak time timing from a plurality of received signals in a wireless communication using a spread spectrum method, wherein an error rate of bit data of information included in the received signals. A correlation peak search method, characterized in that the reception quality of the received signal is determined based on the above, and the execution interval of the search is controlled based on the determination result. 7. The correlation peak search method according to claim 1, wherein control is performed such that the execution interval of the search is changed stepwise based on the determination result. 8. A correlation peak searching device for searching a correlation peak time timing from a plurality of received signals in wireless communication using a spread spectrum method, wherein the correlation peak searching device is based on a variance value of the correlation peaks of the received signals. A correlation peak search device comprising at least a reception quality judgment means for judging the reception quality of the received signal, and a search interval control means for controlling the search execution interval based on the judgment result. 9. The correlation peak search apparatus according to claim 8, wherein the reception quality determination means performs linear prediction of the correlation peak and determines the reception quality of the received signal based on the prediction result. . 10. The reception quality determination means determines the reception quality of the received signal based on an error rate of bit data of information included in the received signal. Correlation peak search device. 11. A correlation peak search device for searching the time timing of a correlation peak from a plurality of received signals in wireless communication using a spread spectrum method, wherein the correlation peak is linearly predicted, and the prediction result is obtained. A correlation peak search apparatus comprising at least a reception quality judgment means for judging the reception quality of the received signal based on the above, and a search interval control means for controlling the execution interval of the search based on the judgment result. 12. The correlation peak search method according to claim 11, wherein the reception quality determination means determines the reception quality of the received signal based on an error rate of bit data of information included in the received signal. . 13. A correlation peak search device for searching the time timing of a correlation peak from a plurality of received signals in a wireless communication using a spread spectrum system, wherein an error rate of bit data of information included in the received signals. A correlation peak search apparatus comprising at least a reception quality judgment means for judging the reception quality of the received signal based on the above, and a search interval control means for controlling the execution interval of the search based on the judgment result. 14. The search interval control means performs control to gradually change the execution interval of the search based on the reception quality. Correlation peak search device. 15. A search device control program for controlling a correlation peak search device in a radio communication using a spread spectrum method, wherein the reception quality of the received signal is based on a variance value of the correlation peak of the received signal. And a search interval control step for controlling the execution interval of the search in the time timing search step based on the determination result. 16. The search device control according to claim 15, wherein in the reception quality determination step, linear prediction of the correlation peak is performed, and the reception quality of the received signal is determined based on the prediction result. For programs. 17. The reception quality of the reception signal is determined based on an error rate of bit data of information included in the reception signal in the reception quality determination step. Search device control program. 18. A search device control program for controlling a correlation peak search device in wireless communication using a spread spectrum method, comprising: linearly predicting the correlation peak; and based on the prediction result, the received signal. And a search interval control step for controlling the execution interval of the search in the time timing search step based on the result of the determination, and a search device control program. . 19. The search device control according to claim 18, wherein, in the reception quality determination step, the reception quality of the reception signal is determined based on an error rate of bit data of information included in the reception signal. For programs. 20. A searching device control program for controlling a correlation peak searching device in a radio communication using a spread spectrum method, wherein the received signal is based on an error rate of bit data of information included in the received signal. And a search interval control step for controlling the execution interval of the search in the time timing search step based on the result of the determination, and a search device control program. . 21. The control according to claim 15, wherein in the search interval control step, control is performed to gradually change the execution interval of the search based on the reception quality. The search device control program described.