JP2001016137A - Cell search method, synchronizing device for communication and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten cell search time corresponding to the receiving state of a signal. SOLUTION: This device is provided with a compactor 14 for comparing an integrated correlation value calculated by an adder 6 with a reference value preset to an integration limit value setting register 11 and a counter 15 for counting the number of integrated correlation values which reach the reference setting value. When the number of paths having the integrated correlation values reaching the reference setting value reaches a path number setting value preset to an integration limit number setting register 12, integration is finished. Thus, the integrated correlation value reaches the reference setting value on the early stage in the stage of satisfactory reception sensitivity of the signal, integration time is shortened by utilizing characteristics a count value reaches the path number setting value on the early stage as well, and cell search operation can be performed at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cell search method and a communication synchronizing device, and further relates to a recording medium storing a program for realizing them by software functions. It is suitable for use in a method and apparatus for synchronizing communication with a station.

[0002]

2. Description of the Related Art Conventionally, an analog FDMA (Frequency Division Multipl.) In which a plurality of mobile stations such as mobile phones are connected to one base station using different frequencies.
In the eAccess) system, one frequency band is occupied by communication of one mobile station, so that the efficiency of use of each divided frequency band is poor, and the number of persons that can be used in the service area (cell) of the base station There was a problem that can not be many.

At present, instead of the FDMA system, digital TDMA (Time Division Multiple Acces) in which a plurality of mobile stations connect one frequency band in a time-division manner.
s) The method is often used. According to this method, 1
Since communication can be performed by allocating a plurality of mobile stations to one frequency band, more users can be accommodated than in the FDMA system.

However, in the TDMA system, a fragmented signal is transmitted and received between a base station and a plurality of mobile stations in a time-division manner, so that the amount of information communicated by one mobile station is reduced. Therefore, in today's digital mobile phones, etc., in order to be able to communicate more information, a signal is compressed and transmitted by encoding, and it is expanded and reproduced on the receiving side. The sound quality of the voice becomes poor.

Therefore, in recent years, as a communication system that can greatly improve the use efficiency of each frequency band and improve the reproduced sound quality, code division using direct spread type spread spectrum (Spread Spectrum) has been proposed. A multiple access, that is, a CDMA (Code Division Multiple Access) system has been receiving attention.

In this CDMA system, a signal to be transmitted from a base station to a plurality of mobile stations is spread using a unique spreading code for each mobile station, and then transmitted using one frequency band. . On the other hand, the receiving mobile station multiplies the received signal by its own spreading code,
By correlating with the spreading code applied on the transmitting side, a peak value of the correlation is detected and only the signal sent to itself is extracted. According to the CDMA system, it is possible to allocate one frequency band to more mobile stations by using different spreading codes. Also, since the amount of information to be sent can be increased, the sound quality of the reproduced sound is also improved.

By the way, when a mobile station such as a mobile phone is turned on, it must receive a predetermined message from a base station in an area (cell). CD
In the MA system, a message from a base station is repeatedly sent in a predetermined slot unit as shown in FIG. 4, but as shown by an arrow in the figure, the power supply of the mobile station is always transmitted to the slot. The message is not always turned on at the first timing, and the message cannot be read correctly as it is.

Therefore, in order to correctly decode a message contained in a slot, it is necessary to detect the timing at the head of the slot (this is called "cell search") and receive the message therefrom. In addition to the above-described initial cell search in which the mobile station first captures a cell connected when the power is turned on, a cell search is performed. That is, even after the power is turned on, for example, when the mobile station moves across cells, the synchronization may be shifted. Therefore, the synchronization is constantly monitored by periodically performing a cell search.

FIG. 5 is a block diagram showing a configuration of a cell search circuit provided in a mobile station according to a conventional wideband CDMA communication system (direct spreading CDMA system). In FIG. 5, a received signal (a transmission path signal as shown in FIG. 4 transmitted from a base station not shown) has the first bit of each slot indicated by hatching in FIG. A common spreading code prepared separately from the code (25 in one bit)
(The number of chips changing six times = 256 spreading codes). Usually, such a transmission path signal for cell search is transmitted using a common channel (perch channel).

[0010] The in-phase component I and the quadrature component Q of the voltage of the received signal are converted into digital signals by the A / D converter 101, and are output from the timing when the power supply of the mobile station is turned on.
Each slot (10 symbols) is sequentially applied to a correlator 102 such as a matched filter or a sliding correlator. The correlator 102 performs despreading by calculating the integral of the digital signal input from the A / D converter 101 and a spreading code generated by the code generator 103 and common to each mobile station.

The in-phase component I and the quadrature component Q of the voltage output from the correlator 102 are supplied to a power conversion unit 104, and are converted into power at each predetermined sampling point in a slot. Then, the power value of each sampling point obtained in this way is sequentially stored in an address corresponding to each sampling point in the memory (RAM) 107 via the adder 106 in the power value integration unit 105.

When a cell search is performed, the number of chips (number of cycles) in one slot in the perch channel is 2
56 × 10 = 2560. Further, in order to improve the accuracy of peak value detection, one chip is divided into four parts and four times oversampling is performed. Therefore, the number of sampling points in one slot is 10240 in total (the chip rate is 4 Mcps). Therefore, the above R
The AM 107 has a capacity of 10240 words.

By performing the above-described processing, a portion having a large correlation with the common spreading code applied by the mobile station within the range of the first one slot after the power of the mobile station is turned on, that is, in the drawing. Only the power values in the hatched portions in FIG. 4 to which a common spreading code has been applied by the base stations that do not appear appear as peaks. Therefore, by detecting this peak portion, the head position of the slot can be confirmed, and the subsequent communication can be performed in accordance with the timing.

However, as shown in FIG. 4, actually,
One mobile station receives transmission path signals from a plurality of base stations near the mobile station with a delay amount. Also, regarding a signal from one base station, not only a direct wave directly received from the base station, but also a reflected wave that is received after being reflected by a building or the ground. Therefore, in the received transmission path signal, there are many portions spread with the common code in one slot, and many peaks of the power value are also detected in one slot. When the mobile station moves during the cell search, a peak may be detected at a position different from the previous position in the next slot.

Under such circumstances, the peak value of the power value is detected not only for the first slot but also for several slots after the power of the mobile station is turned on. That is, the power integrated value from the RAM 107 to the previous slot is read out for each sampling point and given to the adder 106, and the power value at the same sampling point in the current slot is added and stored in the RAM 107 again. By performing such integration of the power value for several slots, it is finally recognized that the portion having the largest peak is the head portion of the transmission path signal transmitted from the nearest base station.

The number of times the power value is integrated (the number of slots) is set in an integration number setting register 108. The counter 109 increments the count value by one each time the integration of one slot is completed, outputs a reaching signal when the number of times set in the integration number setting register 108 is reached, and ends the integration.

[0017]

However, in the cell search using the above-described conventional method, the number of times of integration of the power value is set so that a path having a peak can be extracted even when the signal reception sensitivity is poor. The number is set to a relatively large number (for example, for 32 slots) in accordance with the state of poor reception sensitivity. Therefore, the time required for the cell search is constant irrespective of the reception state of the signal, and even when the reception state is good, more integration than necessary is performed, and the time until the cell search is completed becomes longer. was there.

The present invention has been made to solve such a problem, and has as its object to reduce the time for performing a cell search in accordance with a signal reception state.

[0019]

According to a cell search method of the present invention, a correlation value between a spread code generated in a local station and an input signal is detected for each slot of a predetermined unit, and the process of detecting the correlation value is performed several times. This is a cell search method in which the correlation value obtained in each slot is integrated over a slot and a correlation peak value is detected, and the number of paths where the integrated correlation value reaches a reference set value is set as a path number set value. It is characterized in that the integration is terminated when it reaches.

According to the present invention configured as described above, the integrated correlation value calculated during the integration process performed for each slot is compared with the reference set value, and the number of integrated correlation values that have reached the reference set value is determined. Are sequentially counted, and when the count value reaches the pass number set value in a certain slot, the integration operation is terminated at that point, and the process proceeds to the next phase. Thus, when the signal receiving sensitivity is good, the integral correlation value reaches the reference set value at an early stage, and the count value also reaches the pass number set value at an early stage, so that the integration time is shortened. .

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration example of the cell search circuit according to the present embodiment. The received signal (input signal from the outside) shown in FIG. 1 is a transmission path signal as shown in FIG. 4 transmitted from a base station (not shown), and the first bit of each slot indicated by hatching in FIG. Are spread by a common spreading code (the number of chips = 256) for each mobile station.

The in-phase component I and the quadrature component Q of the voltage of the received signal are applied to the A / D converter 1 after being band-limited to the frequency band of the signal transmitted by the base station by a band-limiting filter (not shown). The A / D converter 1 converts the received signal as described above into a digital signal. The correlator 2 includes, for example, a digital signal input from the A / D converter 1 in units of one slot from the timing when the power of the mobile station is turned on;
Despreading is performed by sequentially calculating the integral of a spreading code common to each mobile station generated by the code generator 3, and the correlation between the own station spreading code and the received signal is detected. The correlator 2 includes, for example, a matched filter, a sliding correlator, and the like.

The power conversion unit 4 calculates the sum of squares of the in-phase component I and the quadrature component Q of the voltage output from the correlator 2 for each of the 10240 sampling points predetermined in the slot, Find the power value of the correlation. Further, the power value integration unit 5 integrates the power value output from the power conversion unit 4 for each sampling point for each sampling point over several slots.

The power value integration section 5 stores the power integration value (integrated correlation value) up to the previous slot in the RAM 7, the power integration value up to the previous slot stored in the RAM 7, and the power conversion section 4. The adder 6 adds the power value in the current slot to the same sampling point at the same sampling point. The adder 6 and the RAM 7 are used to integrate the power value. The RAM 7 of the present embodiment has 1024
A power integrated value is stored for each of the zero sampling points, and a control signal described later is also stored for each of the sampling points.

The number-of-integrations setting register 8 is a register for setting the number of times (the number of slots) in which the power value is integrated in the normal integration mode described later. The first counter 9 counts the number of integrations of the power value, and increments the count value by one each time integration of one slot is completed. Then, when the count value reaches the number of times set in the integration number setting register 8, a reaching signal is output.

The integration limit value setting register 11 is a register for setting a power threshold value (corresponding to the reference setting value of the present invention) for comparison with the power value integrated for each sampling point. This power threshold is set to a value necessary and sufficient to detect a peak from the integrated power value at each sampling point.

The integration limit number setting register 12 sets a pass number threshold value (corresponding to the pass number setting value of the present invention) for comparing the calculated power integrated value with the number of paths having reached the power threshold value. Register. When recognizing the head of the slot, the 1
Since a small value among the power integrated values for 0240 is essentially unnecessary, the pass number threshold is set to a value necessary and sufficient for the recognition process of the slot head.

The mode register 13 is a register for selectively setting one of a normal integration mode similar to the conventional integration and an integration cutoff mode unique to the present embodiment.

The comparator 14 compares the power integrated value output from the adder 6 in the power value integrator 5 with a power threshold value preset in the integration limit value setting register 11 for each sampling point. When the power integrated value is larger than the power threshold, a path detection signal is output. The second counter 15 counts the number of paths for which the power integrated value has reached the power threshold, and counts up by one each time a path detection signal is provided from the comparator 14. Then, when the number of passes set in advance in the integration limit number setting register 12 is reached, a reaching signal is output.

The switch circuit 16 opens and closes in response to a control signal read from the RAM 7 for each sampling point, so that the path once counted by the second counter 15 will not be counted again. belongs to. This switch circuit 16
In the initial state before the start of integration, it is closed, and the output of the adder 6 is given to the comparator 14. As long as the power integrated value calculated for each slot does not reach the power threshold value, the control signal at the position corresponding to each sampling point in the RAM 7 is maintained in the same state as the initial state, and the switch circuit 16 responds accordingly. Closed.

Thereafter, when the power integrated value calculated at a certain sampling point (path) reaches the power threshold in a few slots after the start of the integration, according to the path detection signal output from the comparator 14, The state of the control signal at the position corresponding to the detected path in the RAM 7 is changed. Therefore, even if the power integrated value of the path (which naturally exceeds the power threshold) is output from the adder 6 during the processing of the subsequent slots, the switch circuit 16 is opened according to the corresponding control signal, and The output power integrated value is no longer supplied to the comparator 14. This allows
The same path is prevented from being counted twice by the second counter 15.

The AND circuit 17 calculates the logical product of the integration stop mode setting signal and the arrival signal output from the second counter 15, and outputs the result to the OR circuit 19. The other AND circuit 18 takes the logical product of the normal integration mode setting signal and the arrival signal output from the first counter 9, and outputs the result to the OR circuit 19. The OR circuit 19 calculates the logical sum of the two AND circuits 17 and 18 and outputs the result as an integration end signal.

That is, when the normal integration mode is set, when the arrival signal is output from the first counter 9 as a result of integration performed a preset number of times, the AND circuit 18 and the OR circuit 19 , An integration end signal is output, and the integration operation ends. On the other hand, when the integral abort mode is set, the second counter 15 is set as a result of the number of paths whose power integrated value has reached the power threshold value reaching the preset number of paths.
Outputs a reaching signal. And then AN
An integration end signal is output through the D circuit 17 and the OR circuit 19, and the integration operation is terminated.

Next, the operation of the cell search circuit according to the present embodiment configured as described above will be described below. First, an operation in the case where the integration operation is not terminated halfway will be described. In this case, the normal integration mode is set in the mode register 13.

When the cell search operation is started, the correlator 2
, The correlation between the own-station spreading code and the received signal is detected, and the detected correlation value is converted to power by the power conversion unit 4. The power value output from the power conversion unit 4 is equal to the number of slots preset in the integration count setting register 8 by the power value integration unit 5.
, And as a result, the power integrated value of each sampling point is stored in the RAM 7.

Thereafter, the power integrated value stored in the RAM 7 is output to a DSP (Digital Signal Processor) 20. The DSP 20 selects the one with the larger value from the power integrated value of each sampling point stored in the RAM 7 to determine the position of the corresponding sampling point by the slot of the transmission path signal transmitted from the nearest base station. It can be recognized as the first part.

Next, the operation in the case where the integration operation is terminated halfway will be described. In this case, the integration register mode is set in the mode register 13. When the integration cutoff mode is set, the value set in the integration count setting register 8 is ignored.

When the cell search operation is started, the correlator 2
, The correlation between the own-station spreading code and the received signal is detected, and the detected correlation value is converted to power by the power conversion unit 4. The power value output from the power conversion unit 4 is integrated by the power value integration unit 5 for one slot. The integrated power value of each sampling point is input to the comparator 14 via the switch circuit 16 and compared with the power threshold value set in the integration limit value setting register 11 for each sampling point.

At this time, if there is a sampling point where the power integrated value calculated by the power value integration unit 5 is larger than the power threshold value set in the integration limit value setting register 11, the comparator 14 passes the signal. A detection signal is output, and the count value of the second counter 15 is incremented by one. Then, it is determined whether or not the value of the second counter 15 has reached the number of passes set in the integration limit number setting register 12, and if not, the integration operation is continued.

Thereafter, the integration process is performed one slot at a time. When the count value of the second counter 15 reaches the number of passes set in the integration limit number setting register 12 in a certain slot, the integration process is performed. At this point, the integration operation is stopped. When the integration operation is completed, the DSP 20 selects a power integration value of each sampling point stored in the RAM 7 having a larger value from the power integration value, thereby transmitting the corresponding sampling point position from the nearest base station. It is recognized as the head of the slot of the transmission path signal.

As described above, according to the cell search method of this embodiment, the power threshold and the number-of-paths threshold are set in advance, and during the integration processing of each slot, the power integrated value of the path whose power integrated value has reached the power threshold is set. It is determined whether or not the number has reached the preset pass number threshold value, and if so, the integration operation is stopped at that slot. In this case, when the signal reception sensitivity is good, the power integration value reaches the power threshold value quickly and the required number of paths is secured quickly, so that the integration time can be reduced and the cell search operation can be performed at high speed. Power consumption can be reduced.

The integration limit value setting register 11, the integration limit number setting register 12, and the mode register 1
3 can be set arbitrarily. For example, by rewriting the contents of the setting registers 11 and 12, the user can freely select a desired threshold. Also, by rewriting the contents of the mode register 13, the user can freely select a desired mode.

The integration limit value setting register 1
1 and each threshold in the integration limit number setting register 12 may be automatically changed by firmware such as the DSP 20. For example, it is possible to monitor the reception quality by the DSP 20 and change the setting of each threshold according to the monitored reception quality. In this way, when the reception quality is poor, it is possible to continue the integration until more paths are detected.

For example, in a city where buildings are densely populated, the number of peaks existing in one slot is expected to increase.
By setting the threshold value of the number of paths large, it is possible to execute the cell search with higher accuracy. On the other hand, when using a mobile terminal in a region where reflected waves and interference waves are low,
By setting the threshold value of the number of paths small, it is possible to execute the cell search at a higher speed.

The integration limit value setting register 1
1. The contents of the integration limit number setting register 12 and the mode register 13 may be arbitrarily set via the external terminal 10. For example, by setting various thresholds via the external terminal 10 in a test stage before product shipment, how much the default values of the thresholds set in the integration limit value setting register 11 and the integration limit number setting register 12 should be set. Etc. can be verified.

As described above, the cell search method according to the present embodiment is realized by the circuit configuration as shown in FIG. 1, but the program stored in the RAM or ROM of the computer operates. Can also be realized. FIG. 2 is a block diagram showing a configuration example when the cell search method described in FIG. 1 is realized by software. In FIG. 2, the same blocks as those shown in FIG. 1 are denoted by the same reference numerals.

In FIG. 2, a ROM 21 is a read-only memory that stores a program for executing the cell search operation of the present embodiment and various other necessary data. The RAM 7 is a random access memory for temporarily storing various data obtained in the course of a cell search operation based on the above program, and for storing data finally obtained by the cell search. It is. The above program may be stored in the RAM 7.

The register group 22 includes various registers such as the integration number setting register 8, the integration limit value setting register 11, the integration limit number setting register 12, and the mode register 13 of FIG. The operation unit 23 is used when the user performs a necessary operation when making a call using the portable terminal, or performs a desired setting in the various registers 11 to 13 in FIG. The display unit 24 displays the settings in the registers 11 to 13 and various messages.

The DSP (CPU) 20 mainly executes the operation of the cell search circuit shown in FIG. 1 according to a program stored in the ROM 21 or the RAM 7, and
Processing such as detecting the maximum value from the power integrated values stored in the RAM 7 by cell search and searching for the head of the slot is performed. Further, a process of monitoring the above-described received sound quality and rewriting the contents of the registers 11 and 12 according to the monitoring result is also performed. Although the operation of the correlator 2 and the power conversion unit 4 in FIG. 1 is also performed by the DSP 20 here, the correlator 2 and the power conversion unit 4 are provided separately from the DSP 20 so that they are executed. Is also good.

The I / F unit 25 performs processing such as taking in a signal received by a receiving unit (not shown) or transmitting various signals to a transmitting unit (not shown). This I / F
The unit 25 is also used when reading a program that causes the DSP 20 to perform the cell search function. For example, a program for implementing the cell search method of the present embodiment is recorded on a recording medium such as a CD-ROM, and supplied to the RAM 7 or a hard disk (not shown) via the I / F unit 25. As a recording medium for supplying the program, a floppy disk, a hard disk, a magnetic tape, a magneto-optical disk, a nonvolatile memory card, or the like can be used in addition to the CD-ROM.

FIG. 3 is a flow chart showing the operation in the case where the cell search is executed in the above-mentioned integral cutoff mode by software processing. In FIG. 3, step S1
When the reception of the transmission path signal from the base station is started in step S2, the correlation between the own-station spreading code and the received signal is detected and the correlation value is converted to power for the sampling point currently being processed, and the correlation value is calculated. The power value is added to the power integrated value calculated for the same sampling point up to the previous slot.

Next, in step S3, it is determined whether or not the sampling point currently being processed has already been counted assuming that the calculated power integrated value has reached a preset power threshold. If the sampling point has already been counted, the process proceeds to step S7 in order to proceed to the next sampling point. Then, after the sampling point is advanced by one in step S7, the process returns to step S2, and the same processing is performed for the next sampling point.

On the other hand, if the sampling point to be processed is not already counted, the process proceeds to step S4, and it is determined whether or not the power integrated value calculated in step S2 has reached a preset power threshold. to decide. Here, if the power integrated value is smaller than the power threshold, the process proceeds to step S7 in order to proceed to the next sampling point. Then, after the sampling point is advanced by one in step S7, step S2
And the same processing is performed for the next sampling point.

If the power integrated value has reached the power threshold, the process proceeds to step S5, where the value of the counter for counting the number of sampling points (paths) at which the power integrated value has reached the power threshold is set to one. Count up. Then, in a step S6, it is determined whether or not the count value at that time has reached a preset pass number threshold value.

Here, if the counted number of passes is smaller than the pass number threshold, the process proceeds to step S7 in order to proceed to the next sampling point. Then, after the sampling point is advanced by one in step S7, the process returns to step S2, and the same processing is performed for the next sampling point. On the other hand, if the counted number of passes has reached the number-of-passes threshold, the integration operation ends at that point.

With the above processing, when the signal receiving sensitivity is good, the integration time can be shortened, the cell search operation can be performed at high speed, and the power consumption can be reduced accordingly. .

In the above embodiment, two types of voltage information of the in-phase component I and the quadrature component Q of the voltage obtained by the correlator 2 are converted into electric power, and an integrating operation is performed on the correlated correlation value. However, the integration operation may be performed on each of the two types of correlation values of the in-phase component I and the quadrature component Q. In this case, two types of voltage thresholds for comparison with the integral correlation value based on the voltage are prepared for the in-phase component I and the quadrature component Q.

In the above embodiment, the adder 6 shown in FIG.
Is supplied to the comparator 14, but the power integrated value read from the RAM 7 is
You may make it supply to. Further, the power value output from the power conversion unit 4 may be supplied to the comparator 14. In the latter example, when the transmission path signal from the base station is transmitted with higher power, the power value itself calculated for each slot is used as the power threshold value without performing integration over several slots. This is an example in which such a case can be dealt with.

In the above embodiment, the control signal is stored in the RAM 7 together with the power integrated value for each sampling point, and the switch circuit 16 is opened and closed according to the control signal read from the RAM 7. However, the configuration for preventing the counting operation from being repeated for the same sampling point is not limited to this example. For example, an AND circuit is provided in place of the switch circuit 16, one of the input terminals receives the power integrated value from the comparator 14 or the RAM 7, and the other input terminal outputs “0” with respect to the counted sampling points.
It is possible to input a mask signal as follows.

In the above embodiment, the initial cell search when the power of the portable terminal is turned on has been particularly described. However, the present invention is similarly applied to the cell search performed during the standby state. Is possible. Also,
The cell search system according to the present invention can be applied to digital television and the like in addition to mobile communication such as a mobile phone and satellite communication.

Further, the configurations and connection relations of the respective parts in the circuit shown in the above embodiment are merely examples of the embodiment for carrying out the present invention, and the technical scope of the present invention is not limited thereto. Should not be construed as limiting. That is, the present invention can be embodied in various forms without departing from the spirit or main features thereof.

Various forms of the present invention are summarized as follows. (1) A correlation value between a spread code generated in the own station and an input signal is detected for each predetermined unit of slot, the above-described correlation value detection process is performed over several slots, and a correlation value obtained in each slot is obtained. A cell search method for detecting a correlation peak value by integrating the number of paths, wherein the integration is terminated when the number of paths for which the integrated correlation value has reached the reference set value has reached the set number of paths. Characteristic cell search method. (2) The cell search method according to (1), wherein the comparison as to whether the integrated correlation value has reached the reference set value is performed based on the power value. (3) The cell search method according to (1), wherein the comparison as to whether the integral correlation value has reached the reference set value is performed based on the voltage value. (4) The cell search method according to (1), wherein the reference set value can be set arbitrarily. (5) The cell search method according to (1), wherein the set value of the number of paths can be arbitrarily set.

(6) The correlation value between the spread code generated in the own station and the input signal is detected for each predetermined unit of slot, and the correlation value is detected over several slots. A cell search method for integrating a correlation peak value and detecting a correlation peak value, wherein the integration is terminated when the number of paths whose integral correlation value has reached a reference set value has reached a pass number set value. Mode and a second time for integrating a predetermined number of times
A cell search method comprising: (7) The cell search method according to (6), wherein the first mode and the second mode can be arbitrarily selected and set.

(8) The correlation value between the spread code generated in the local station and the input signal is detected for each predetermined unit of slot, and the process of detecting the correlation value is performed over several slots. A communication synchronization device for detecting a synchronization point of the input signal by integrating the calculated correlation value and detecting a correlation peak value, comprising a comparing means for comparing the calculated integrated correlation value with a reference set value. A communication synchronization device. (9) The communication synchronization device according to (8), further including a counting unit that counts the number of paths in which the integrated correlation value has reached the reference set value as a result of the comparison by the comparing unit. . (10) The communication synchronization apparatus according to (9), further comprising means for terminating the integration when the count number of the counting means reaches the pass number set value.

(11) The communication synchronizer according to (8), further comprising register means for arbitrarily setting the reference set value. (12) The communication synchronization device according to (8), further including an external terminal for arbitrarily setting the reference set value. (13) The communication synchronization device according to (8), wherein the comparison by the comparing means is performed based on the power value. (14) The communication synchronization device according to (8), wherein the comparison by the comparison means is performed based on a voltage value.

(15) The communication synchronization device according to (8), wherein the comparing means compares the integrated correlation value output from the adder for performing the integration with a reference set value. (16) The communication synchronization device according to (8), wherein the comparing means compares the integrated correlation value output from the memory storing the calculated integrated correlation value with a reference set value. . (17) The communication synchronization device according to (10), further comprising a register unit for arbitrarily setting the path number setting value. (18) The communication synchronization device according to (10), further including an external terminal for arbitrarily setting the path number setting value.

(19) The correlation value between the spread code generated in the own station and the input signal is detected for each predetermined unit of slot, and the process of detecting the correlation value is performed over several slots. A communication synchronization device for detecting the synchronization point of the input signal by integrating the detected correlation value and detecting a correlation peak value, wherein the detected correlation value is output from a power converter for powering the detected correlation value. A communication synchronization device, comprising: comparison means for comparing a value with a reference set value.

(20) The correlation value between the spread code generated in the own station and the input signal is detected for each predetermined unit of slot, and the detection process of the correlation value is performed over several slots. A communication synchronization device for detecting a synchronization point of the input signal by integrating the correlation value and detecting a correlation peak value, wherein the number of paths for which the integrated correlation value has reached a reference setting value is a path number setting value. A first mode for terminating the integration when the number of times reaches
And a communication synchronization device. (21) The communication synchronization device according to (20), further comprising register means for arbitrarily selecting and setting the first mode and the second mode. (22) The communication synchronization device according to (20), further including an external terminal for arbitrarily selecting and setting the first mode and the second mode.

(23) The correlation value between the spread code generated in the own station and the input signal is detected for each predetermined unit of slot, and the process of detecting the correlation value is performed over several slots. When performing a cell search to detect the correlation peak value by integrating the correlation values obtained, the function of terminating the integration when the number of paths for which the integrated correlation value has reached the reference set value has reached the set number of paths. A computer-readable recording medium on which a program for causing a computer to execute is recorded.

[0070]

As described above, according to the present invention, the integration operation is terminated when the number of paths for which the integral correlation value has reached the reference set value has reached the pass number set value. In a good condition, the integration time can be shortened by utilizing the characteristic that the integral correlation value reaches the reference set value at an early stage, and the number of paths also reaches the set value at an early stage. The operation can be performed at high speed, and the power consumption can be reduced accordingly. As a result, for example, in a wideband CDMA mobile phone, it is possible to increase the speed of cell search and reduce its power consumption.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a cell search circuit according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration example when the cell search method according to the present embodiment is implemented by software.

FIG. 3 is a flowchart illustrating a cell search method according to the present embodiment implemented in an integral truncation mode.

FIG. 4 is a diagram for explaining a cell search operation.

FIG. 5 is a block diagram showing a configuration of a conventional cell search circuit.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 A / D converter 2 Correlator 3 Code generator 4 Power conversion unit 5 Power value integration unit 6 Adder 7 RAM 8 Integration count setting register 9 First counter 10 External terminal 11 Integration limit value setting register 12 Integration limit number Setting register 13 mode register 14 comparator 15 second counter 16 switch circuit 17, 18 AND circuit 19 OR circuit 20 DSP (CPU) 21 ROM 22 register group 23 operation unit 24 display unit 25 I / F unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masami Kanasugi 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Masahiro Hikita 4-chome Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture No. 1 No. 1 Fujitsu Limited F term (reference) 5K022 EE02 EE36 5K047 AA02 BB01 CC01 GG34 GG37 HH01 HH03 HH15 MM35 MM62 5K067 AA15 AA43 BB04 CC10 DD25 DD34 EE02 EE10 EE24 HH15 KK03 JJ03 KK03

Claims (6)

[Claims] 1. A method for detecting a correlation value between a spreading code generated in a local station and an input signal for each predetermined unit slot, performing the correlation value detection processing over several slots, and obtaining the correlation value in each slot. A cell search method for integrating a correlation value to detect a correlation peak value, wherein the integration is terminated when the number of paths for which the integrated correlation value has reached a reference set value has reached the set number of paths. A cell search method, characterized in that: 2. A correlation value between a spread code generated in the own station and an input signal is detected for each slot of a predetermined unit, and the correlation value detection processing is performed over several slots, and the correlation value is obtained in each slot. A cell search method for integrating a correlation value and detecting a correlation peak value, wherein the integration is terminated when the number of paths whose integrated correlation value has reached a reference set value has reached the set number of paths. A cell search method comprising: a mode; and a second mode in which integration is performed a predetermined number of times. 3. A correlation value between a spread code generated by the own station and an input signal is detected for each predetermined unit of slot, and the correlation value is detected over several slots. A communication synchronizer for detecting a synchronization point of the input signal by integrating a correlation value and detecting a correlation peak value, comprising a comparing means for comparing the calculated integrated correlation value with a reference set value. A communication synchronization device, characterized in that: 4. A correlation value between a spread code generated in the own station and an input signal is detected for each predetermined unit of slot, and the correlation value detection processing is performed over several slots, and the correlation value is obtained in each slot. A communication synchronizer for detecting a synchronization point of the input signal by integrating a correlation value and detecting a correlation peak value, wherein the detected correlation value or a value output from a power converter for powering the detected correlation value. A communication synchronization device, comprising: comparison means for comparing a reference value with a reference value. 5. A correlation value between a spreading code generated in the own station and an input signal is detected for each predetermined unit of slot, and the correlation value is detected over several slots. A communication synchronizer for detecting a synchronization point of the input signal by integrating a correlation value and detecting a correlation peak value, wherein the number of paths whose integral correlation value has reached a reference set value is equal to the number of paths set value. A communication synchronization device, comprising: a first mode for terminating the integration when it reaches the first mode; and a second mode for performing a predetermined number of integrations. 6. A correlation value between a spread code generated in the own station and an input signal is detected for each predetermined unit of slot, and the process of detecting the correlation value is performed over several slots. When performing a cell search for integrating a correlation value and detecting a correlation peak value, a computer has a function of terminating the integration when the number of paths whose integrated correlation value has reached a reference set value has reached the set number of paths. A computer-readable recording medium having recorded thereon a program for realizing the program.