JP3701447B2 - Initial synchronization acquisition circuit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an initial synchronization acquisition method, and more particularly, to an initial synchronization acquisition method and an initial synchronization acquisition circuit capable of shortening a long code synchronization acquisition time in a CDMA communication system.
[0002]
[Prior art]
The long code synchronization acquisition method in the prior art will be described with reference to FIGS. 4 to 6 by taking the synchronization acquisition of the synchronization channel of the base station as an example. FIG. 4 is a block diagram showing the configuration of a conventional initial synchronization acquisition circuit, FIG. 5 is an explanatory diagram showing mapping of a synchronization channel in a conventional base station, and FIG. 6 shows an output of a matched filter (MF). It is explanatory drawing which shows an example.
[0003]
As shown in FIG. 5, in the base station synchronization channel, the portion (x) spread by the short sync channel short code in the system and the long code unique to the base station are multiplied by the short sync channel short code in the system. And a portion (y) spread by the spread code.
[0004]
The part (x) spread with a short code for the only synchronization channel in the system is called a mask symbol, and usually uses a code obtained by multiplying a long code unique to the base station by a unique short code in the system as a spreading code. However, by masking a long code having a symbol length of one spread code period, a portion (mask symbol) that is spread only by a short code is inserted.
The mobile station first receives a synchronization channel in order to acquire synchronization.
[0005]
The configuration of a conventional initial synchronization acquisition circuit will be described with reference to FIG.
As shown in FIG. 4, the conventional initial synchronization acquisition circuit includes a short code generator 31, a matched filter (MF) 32, a peak detector 33, a synchronization channel spreading code generator 34, and a correlator 35. And a threshold value determination unit 36, a synchronization control unit 37, and a demodulation unit 38.
[0006]
Next, each part of the conventional initial synchronization acquisition circuit will be specifically described with reference to FIG.
The short code generation unit 31 generates a short code for the synchronization channel.
The matched filter (MF) 32 receives a reception spread signal, despreads the reception spread signal input with the short code generated by the short code generation unit 31, and outputs a correlation.
[0007]
The peak detector 33 detects the position where the peak stands from the correlation output of the MF 32, and outputs a long code activation timing (spread code activation timing signal) to the synchronization channel spread code generator 34 at that timing.
[0008]
The synchronization channel spreading code generation unit 34 uses the long code unique to the base station designated from the outside at the long code activation timing (spreading code activation timing signal) from the peak detection unit 33 to generate the synchronization channel spreading code. A candidate is generated.
[0009]
The correlator 35 despreads the input received spread signal with the synchronization channel spreading code from the synchronization channel spreading code generator 34 and outputs the correlation.
The threshold value determination unit 36 determines whether or not the correlation output of the correlator 35 has exceeded the threshold value, and outputs the result to the synchronization control unit 37.
[0010]
When the result that the correlation output exceeds the threshold value is input from the threshold value determination unit 36, the synchronization control unit 37 sets the synchronization acquisition flag and outputs the synchronization acquisition flag to the demodulation unit 38, assuming that the synchronization acquisition is completed. At the same time, a signal specifying a candidate for a long code unique to the base station is output to the synchronization channel spreading code generator 34.
[0011]
In addition, the synchronization control unit 37 monitors the input from the threshold value determination unit 36, that is, it monitors the correlation time of the correlator 35, and synchronizes even if the specific time (specified correlation time) has passed. When the acquisition flag is not raised, a peak detection restart signal is output to instruct the peak detection unit 33 to redo peak detection.
[0012]
The demodulator 38 demodulates and decodes the correlation output (received signal) from the correlator 35 while the synchronization acquisition flag is input from the synchronization controller 37, and outputs synchronization channel decoded data.
[0013]
Next, the operation of the conventional initial synchronization acquisition circuit will be described with reference to FIG.
First, the short code generation unit 31 generates a short code for a synchronization channel. The MF 32 performs despreading by correlating the short code with the received spread code. An output example of the MF 32 is as shown in FIG. This example is an output example corresponding to the mask symbol arrangement shown in FIG.
[0014]
The peak detection unit 33 receives an MF output as shown in FIG. 6 and averages the input to remove a noise component and generate a delay profile. Then, the base station to which the path having the maximum power is to be connected is determined from the delay profile, and the reception timing at this time is output as a spreading code activation timing signal.
[0015]
The synchronization channel spreading code generation unit 34 receives the spreading code activation timing signal and outputs a synchronization channel spreading code candidate using the base station-specific long code specified by the synchronization control unit 37. . The correlator 35 obtains a correlation between the spread code from the synchronization channel spread code generator 34 and the received spread signal, and performs despreading.
[0016]
Here, if the synchronization channel spreading code candidate matches that of the base station to be connected, the correlation output exceeds the threshold value of the threshold value judgment unit 36. The threshold will not be exceeded.
[0017]
Therefore, when the synchronization control unit 37 cannot obtain information that the threshold value is exceeded from the threshold value determination unit 36 even after taking a correlation for a certain period of time, the synchronization control unit 37 sends the following information to the synchronization channel spreading code generation unit 34. Outputs a signal specifying a long code candidate.
[0018]
Further, if the synchronization acquisition flag does not stand even after standing for a certain period of time, the synchronization control unit 37 determines that the peak detection unit 33 has detected a peak detection error as the long code timing of the base station to which the peak detection unit 33 should be connected. A peak detection restart signal is output to order redo.
[0019]
The above processing is continued until the synchronization control unit 37 sets the synchronization acquisition flag. When the synchronization flag is set, the demodulator 38 is activated in response thereto, and the synchronization channel is demodulated and decoded to output the synchronization channel decoded data, so that broadcast information transmitted on the synchronization channel can be obtained. It is.
[0020]
[Problems to be solved by the invention]
However, in the above-described conventional initial synchronization acquisition method, when the long code timing is detected, the type and phase of the long code of the base station to be connected are not known, and when the number of long codes used in the system increases, Accordingly, the number of long code candidates that correlate with the received spread signal by the correlator increases, and there is a problem in that the long code acquisition time becomes long.
[0021]
The present invention has been made in view of the above circumstances, and an object thereof is to provide an initial synchronization acquisition method and an initial synchronization acquisition circuit that can shorten the synchronization acquisition time of a long code.
[0024]
[Means for Solving the Problems]
  Claims for solving the problems of the conventional example1In the described invention, a sequence obtained by multiplying a plurality of transmission symbol sections by a unique long code for each transmitting station and a unique short code for each multiplexed channel in the transmitting station is used as a spread code for spread spectrum. In the initial synchronization acquisition circuit at the receiving station in the CDMA communication system to be used, the initial synchronization acquisition circuit of the receiving station receives a long code unique to each transmitting station from the transmitting station to the long code of the transmitting station at a constant period. Is set, and a mask block that is spread only by a unique short code is set for each channel in the transmitting station, and information symbols spread by the mask block are used at an arbitrary timing after the mask block. Receives a spread signal in which information on the type and / or phase of the long code unique to the transmitting station is transmitted The initial synchronization acquisition circuit includes a channel short code generation unit that generates a unique short code for each multiplexed channel, and a spread obtained by multiplying the channel short code or the channel short code and a long code. Receive spread signal using codeMask block part or part other than mask block inDespreadingprocessingDetecting a peak exceeding a predetermined threshold from the output of the despreading unit, and outputting a demodulation unit start timing signal in synchronization with the detected peak position, The type of long code unique to the transmitting station at an arbitrary timing after the mask block, which is received and demodulated in accordance with a demodulation unit activation timing signal, demodulated, and included in the reception demodulation result of the mask block Alternatively, a demodulator that outputs phase or phase information as long code information, outputs the timing as a long code activation timing signal, receives and demodulates the long code according to the demodulation unit activation timing signal, and outputs demodulated data And a long code based on the long code information by the long code activation timing signal. A long code generator for generating a de, from the long code generatorLong codeAnd from the channel short code generatorChannel short codeA multiplier that performs multiplication of the long code activation timing signal from the demodulatorNot inTime is the aboveChannel short code generationFrom the departmentChannel short codeIs output to the despreading unit, and the long code activation timing signal is input.RuTime is the aboveMultiplicationFrom the departmentMultiplication result of channel short code and long codeWhen the long code activation timing signal is input from the demodulator, the selector outputs the demodulated data from the demodulator to the despreader.As connection transmitting station decoding dataAnd a switch that outputs the long code information from the demodulator to the long code generator when the long code activation timing signal is not input, and is included in the mask block. The long code synchronization acquisition for the channel to be connected immediately can be performed by the connection transmitting station long code information and the long code activation timing, so the long code synchronization acquisition time can be shortened, and a single despreading unit, Since the demodulator is switched by a switch and used in a time-sharing manner, the circuit can be reduced in size.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
In the initial synchronization acquisition method according to the embodiment of the present invention, a transmitting station receives a mask block including information on the type and / or phase of a long code unique to the transmitting station at an arbitrary timing after the mask block. Transmits to the station, demodulates the mask block at the receiving station, acquires the type and / or phase information and arbitrary timing of the long code for the channel to be connected, and acquires the synchronization of the subsequent long code Yes, it is possible to immediately acquire the synchronization of the long code for the connected channel from the type and / or phase information and timing of the transmitting station specific long code included in the mask block, and to shorten the long code synchronization acquisition time. is there.
[0026]
First, the concept of the initial synchronization acquisition method according to the embodiment of the present invention will be described with reference to FIG. FIG. 3 is an explanatory diagram showing mapping of multiplexed channels in the transmitting station according to the embodiment of the present invention.
[0027]
Long code specific to the transmitting station used in each channelTheA part that is spread only with a short cord (a)TheScobrotWithEach transmitting station controls so that the mask blocks do not overlap.
[0028]
The mask block includes information on the long code type and / or phase of the unmasked portion (b) at an arbitrary timing after the mask block. Then, the receiving station side can receive the mask block, demodulate it, and immediately obtain information on the long code type and / or phase for the channel to be connected. As a result, the synchronization acquisition of the long code for the connected channel can be performed in a short time.
[0029]
Next, an initial synchronization acquisition circuit according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a configuration block diagram of a first initial synchronization acquisition circuit according to an embodiment of the present invention.
As shown in FIG. 1, a first initial synchronization acquisition circuit (first initial acquisition circuit) according to the present embodiment includes a channel short code generation unit 11, a first despreading unit 12, and peak detection. The unit 13 includes a first demodulator 14, a long code generator 15, a multiplier 16, a second despreader 17, and a second demodulator 18.
[0030]
Furthermore, each part of the first initial synchronization acquisition circuit will be specifically described with reference to FIG.
The channel short code generator 11 generates a short code for the connection channel.
The first despreading unit 12 despreads the received reception spread signal with the short code from the channel short code generation unit 11.
[0031]
The peak detection unit 13 detects the position where the peak stands from the output of the first despreading unit 12, and determines that the mask block has been received if the detected peak is a correlation peak exceeding a predetermined threshold value. The first demodulator 14 and the second demodulator 18 output a demodulator activation timing signal indicating the activation timing of the demodulator.
[0032]
The first demodulator 14 is activated and demodulates the despread received signal output from the first despreader 12 at the timing of the demodulator activation timing signal from the peak detector 13. As a result, the despread mask block portion is demodulated. Since the demodulation result includes the long code type and / or phase information and timing information at an arbitrary timing after the mask block, the long code type and / or phase information is connected and transmitted. The long code timing information is output to the long code generation unit 15 as station long code information, and the long code timing information is output to the long code generation unit 15 as a long code activation timing signal.
[0033]
The long code generation unit 15 sets a long code based on the long code type and / or phase information from the first demodulation unit 14 in the long code activation timing signal from the first demodulation unit 14, A long code unique to the transmitting station is generated. This completes the capture of the long code.
[0034]
The multiplier 16 multiplies the long code for the connected transmitting station from the long code generator 15 and the channel short code from the channel short code generator 11 and outputs the result as a spread code.
[0035]
The second despreading unit 17 despreads the received spread signal with the spread code from the multiplication unit 16.
The second demodulator 18 demodulates the despread signal output from the second despreader 17, and thereby demodulates the received signal in a portion other than the mask block. .
[0036]
Next, the operation of the first initial synchronization acquisition circuit will be described with reference to FIG.
First, the channel short code generation unit 11 generates a short code for a channel to be connected. Then, the first despreading unit 12 performs despreading by correlating the short code with the received spread code.
[0037]
When the peak detection unit 13 detects a correlation peak exceeding a predetermined threshold value, it determines that a mask block has been received, outputs a demodulation unit activation timing signal, and activates the first demodulation unit 14 It is activated by the timing signal.
[0038]
The first demodulator 14 receives the demodulator activation timing signal and demodulates the signal despread by the first despreader 12. Demodulating the received signal that has been despread at the timing of the demodulator activation timing signal means that the mask block portion is demodulated because it is correlated with the short code.
[0039]
Since the demodulation result in the first demodulator 14 includes information on the long code type and / or phase at any timing after the mask block and the timing information thereof, the first demodulator 14 The long code generation unit 15 outputs the long code timing as a long code activation timing signal, and simultaneously outputs the long code type and / or phase information obtained from the demodulation result.
[0040]
Then, the long code generation unit 15 outputs a long code having the long code type and / or phase information output from the first demodulation unit 14 as a long code unique to the transmission station to the multiplication unit 16. The output start timing is given from the first demodulator 14 as a long code activation timing signal. At this point, long code synchronization acquisition is completed.
[0041]
Then, the multiplication unit 16 multiplies the channel short code from the channel short code generation unit 11 by the long code from the long code generation unit 15 and outputs the result as a spreading code.
[0042]
The second despreading unit 17 obtains a correlation between the spread code from the multiplication unit 16 and the received spread signal and performs despreading. The despread signal is demodulated by the second demodulator 18.
In this way, it is possible to perform synchronization supplementation of the long code for the channel to be connected, and obtain information from the transmitting station transmitted on the channel of the connected transmitting station.
[0043]
Next, a second initial synchronization acquisition circuit according to the embodiment of the present invention will be described with reference to FIG. FIG. 2 is a block diagram showing the configuration of the second initial synchronization acquisition circuit according to the embodiment of the present invention.
As shown in FIG. 2, the second initial synchronization acquisition circuit (second initial synchronization acquisition circuit) according to the embodiment of the present invention includes a channel short code generation unit 21, a despreading unit 22, and a peak detection unit. 23, a demodulator 24, a long code generator 25, a multiplier 26, a selector 27, and a switch 28.
[0044]
Each part of the second initial synchronization acquisition circuit will be specifically described with reference to FIG.
The channel short code generation unit 21 generates a short code for the connection channel and outputs it to the multiplication unit 26 and the selector 27.
The long code generation unit 25 sets a long code based on the long code information (long code type and / or phase information) from the demodulator 24 based on the long code activation timing signal from the demodulator 24. Then, a long code for the connected transmitting station is generated and output to the multiplication unit 26.
[0045]
The multiplier 26 multiplies the long code from the long code generator 25 and the channel short code from the channel short code generator 21 and outputs the result to the selector 27 as a spread code.
[0046]
The selector 27 switches the channel short code output from the channel short code generation unit 21 and the spreading code from the multiplication unit 26 with the long code activation timing signal from the demodulation unit 24 and outputs it to the despreading unit 22. is there. Specifically, when there is no input of the long code activation timing signal, the connection channel short code from the channel short code generation unit 21 is output to the despreading unit 22, and when the long code activation timing signal is input. The spreading code from the multiplication unit 26 is output to the despreading unit 22.
[0047]
The despreading unit 22 despreads the input received spread signal with the code that is the output of the selector 27 and outputs it to the peak detection unit 23 and the demodulation unit 24.
The peak detection unit 23 detects the position where the peak stands from the output of the despreading unit 22, and when a correlation peak exceeding a predetermined threshold is detected, the peak detection unit 23 determines that the mask block has been received before synchronization is established. After the establishment, it is determined that a long code portion other than the mask block has been received, and a demodulation unit activation timing signal is output to the demodulation unit 24.
[0048]
The demodulator 24 is activated and demodulated at the timing of the demodulator activation timing signal from the peak detector 23 before the long code synchronization is acquired. is there. As a result, the despread mask block portion is demodulated. Since the demodulation result includes the long code type and / or phase information and timing information at an arbitrary timing after the mask block, the long code type and / or phase information is connected and transmitted. The long code information is output to the long code generation unit 25 via the switch 28 as station long code information, and further, the long code timing information is output to the long code generation unit 25, the selector 27 and the switch 28 as a long code activation timing signal. is there.
[0049]
The demodulator 24 is used for demodulating channel transmission information after long code synchronization acquisition is completed. Here, the demodulated connection transmission station decoded data is output to the outside via the switch 28.
[0050]
  The switch 28 switches the output destination by a long code activation timing signal from the demodulator 24. Specifically, the switch 28 controls to output the data demodulated by the demodulator 24 to the long code generator 25 when the long code activation timing signal is not input from the demodulator 24. Long code activation tie from demodulator 24MiWhen a ringing signal is input, the data demodulated by the demodulator 24 is output to the outside as connected transmitting station decoded data.
[0051]
Next, the operation of the second initial synchronization acquisition circuit according to the embodiment of the present invention will be described with reference to FIG.
First, the short code of the channel to which the channel short code generating unit 21 is connected is generated. The generated short code is input to the selector 27 and the multiplication unit 26.
[0052]
The selector 27 selects and outputs a short code as an output until the synchronization of the long code to be connected is made, that is, until a long code activation timing signal is input from the demodulator 24.
The despreading unit 22 performs despreading by correlating the code output from the selector 27 and the received spread signal. Until the synchronization of the long code for the channel to be connected is acquired, the output from the selector 27 is a channel short code, and the correlation peak after despreading appears when the receiving station receives the mask block.
[0053]
  The correlation detection peak when the mask block is received is determined as a threshold by the peak detector 23, and when the threshold is exceeded, a demodulator activation timing signal is output at that timing.
  The demodulator 24 receives the demodulator activation timing signal from the peak detector 23 and demodulates the received mask block until the long channel code to be connected is captured. Since the demodulation result includes the long code type and / or phase information at any timing after the mask block and the timing information thereof, the demodulation unit 24IsOutputs long chord type and / or phase information obtained from adjustment resultsAt that timing, a long code activation timing signal is output.To do.
[0054]
The switch 28 is connected so that the output destination is the long code generation unit 25 until the long code for the channel to be connected is captured.
Then, the long code generation unit 25 outputs a long code having the long code type and / or phase information (connected transmission station long code information) output from the demodulation unit 24 as a long code unique to the transmission station. The output start timing is given as a long code activation timing signal from the demodulator 24. At this point, long code synchronization acquisition is completed.
[0055]
On the other hand, the multiplication unit 26 outputs a result obtained by multiplying the channel short code from the channel short code by the long code from the long code generation unit 25 as a spread code, and inputs the result to the selector 27. After the synchronization is established, the selector 27 switches the output of the selector 27 from the channel short code to the spreading code from the multiplication unit 26 by the long code activation timing signal from the demodulation unit 24.
[0056]
Thus, the despreading unit 22 shifts from the despreading of the mask block part to the despreading process of the part other than the mask block. Then, since the despread output has a peak at a portion other than the mask block this time, the peak value is determined by the peak detector 23 as a threshold value. The peak detection unit 23 outputs a demodulation unit activation timing signal to the demodulation unit 24 at a timing exceeding the threshold value.
[0057]
Receiving the demodulator activation timing signal, the demodulator 24 demodulates parts other than the mask block. Further, the switch 28 receives the long code activation timing signal and switches the connection destination so that the transmission station decoded data is output. In this way, long code synchronization supplementation can be performed, and information from the transmitting station transmitted on the channel of the connected transmitting station can be obtained.
[0058]
According to the initial synchronization acquisition method of the embodiment of the present invention, the long code type and / or phase information and the timing information thereof are transmitted by the mask block of the transmission channel, and the mask block is demodulated to obtain the long code. Since it is possible to obtain information on the type and / or phase of the code and timing information thereof, and based on this information, it is possible to realize synchronization acquisition of a long code for a channel to be connected immediately, so that the correlation is higher than that of a conventional correlator. The number of processes can be greatly reduced, and high-speed synchronization acquisition can be performed.
[0059]
According to the first initial synchronization acquisition circuit of the embodiment of the present invention, before the long code synchronization acquisition, the channel short code generation unit 11, the first despreading unit 12, the peak detection unit 13, and the first demodulation unit. 14 is used to demodulate the mask block from the received spread signal to obtain the connection transmitting station long code information (long code type and / or phase information) and the long code activation timing, and to connect the long code for the channel to be connected. Synchronization acquisition is performed, and after acquisition of the long code synchronization, the long code generation unit 15, the multiplication unit 16, the second despreading unit 17, and the second demodulation unit 18 are used to obtain the acquired connection transmitting station long code information and long code. Since the connection transmission station decoded data is obtained from the received spread signal at the code activation timing, the connection transmission station long code included in the mask block is obtained. The de information and long code start timing, because the immediate can perform synchronization acquisition of the long code for the channel to be connected, which reduces the acquisition time of the long code.
[0060]
According to the second initial synchronization acquisition circuit of the embodiment of the present invention, the channel short code generation unit 21, the despreading unit 22, the peak detection unit 23, the demodulation unit 24, and the switch 28 are set before the long code synchronization acquisition. To acquire the long code synchronization for the channel to be connected by acquiring the connection transmitting station long code information and the long code activation timing, and after acquiring the long code synchronization, in addition to the above configuration, the long code generation unit 25, Since the connection transmission station decoded data is obtained from the received spread signal based on the acquired connection transmission station long code information and the long code activation timing using the multiplication unit 26 and the selector 27, the connection transmission included in the mask block is used. The long code for the channel to be connected immediately depends on the station long code information and the long code activation timing. It is possible to perform the acquisition, which reduces the acquisition time of the long code.
[0061]
Unlike the first initial synchronization acquisition circuit, the second initial synchronization acquisition circuit includes one despreading unit and one demodulation unit, and these despreading unit and demodulation unit are used in a time-sharing manner using the switch 28. Therefore, there is an effect that the initial synchronization acquisition circuit can be reduced in size.
[0064]
【The invention's effect】
  Claim1According to the described invention, before acquiring the long code synchronization, the long code information and the long code activation timing of the connected transmitting station are acquired using the channel short code generation unit, the despreading unit, the peak detection unit, the demodulation unit, and the switch After acquiring the long code synchronization for the connected channel, in addition to the above configuration, using the long code generation unit, the multiplication unit, and the selector, the acquired connection transmission station long code information and Since the initial synchronization acquisition circuit obtains the connected transmitting station decoded data from the received spread signal by the long code activation timing, the long for the channel to be connected immediately by the connected transmitting station long code information and the long code activation timing included in the mask block. Since code synchronization can be acquired, long code synchronization acquisition There is an effect that can be shortened. In addition, a single despreader, because you have to use a time division demodulation unit switches the switch, there is an effect that can be miniaturized circuit.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a first initial synchronization acquisition circuit according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a second initial synchronization acquisition circuit according to the embodiment of the present invention.
FIG. 3 is an explanatory diagram showing mapping of multiplexed channels in the transmission station according to the embodiment of the present invention.
FIG. 4 is a configuration block diagram of a conventional initial synchronization acquisition circuit.
FIG. 5 is an explanatory diagram showing synchronization channel mapping in a conventional base station.
FIG. 6 is an explanatory diagram illustrating an output example of a matched filter (MF).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Channel short code production | generation part, 12 ... 1st despreading part, 13 ... Peak detection part, 14 ... 1st demodulation part, 15 ... Long code production | generation part, 16 ... Multiplication part, 17 ... 2nd despreading , 18 ... second demodulator, 21 ... channel short code generator, 22 ... despreader, 23 ... peak detector, 24 ... demodulator, 25 ... long code generator, 26 ... multiplier, 27 ... selector 28 ... Switch, 31 ... Channel short code generation unit, 32 ... MF (matched filter), 33 ... Peak detection unit, 34 ... Spread code generation unit for synchronization channel, 35 ... Correlator, 36 ... Threshold determination unit 37 ... Synchronization control unit 38 ... Demodulation unit

Claims (1)

In a CDMA communication system using, as a spreading code for spread spectrum, a sequence obtained by multiplying a unique long code for each transmitting station and a unique short code for each multiplexed channel in the transmitting station over a plurality of transmission symbol periods In the initial synchronization acquisition circuit at the receiving station,
The initial synchronization acquisition circuit of the receiving station masks a long code unique to each transmitting station from the transmitting station to the long code of the transmitting station at a constant cycle, and is unique to each channel in the transmitting station. A mask block that is spread only by a short code is set, and the type and / or phase of the long code unique to the transmitting station at an arbitrary timing after the mask block using an information symbol spread by the mask block Receiving a spread signal with information transmitted,
The initial synchronization acquisition circuit includes
A channel short code generator for generating a unique short code for each multiplexed channel;
A despreading unit that performs a despreading process on a mask block portion or a portion other than the mask block in a received spread signal using the channel short code or a spread code obtained by multiplying the channel short code and a long code;
A peak detection unit that detects a peak exceeding a predetermined threshold value from the output of the despreading unit, and outputs a demodulation unit start timing signal in synchronization with the detected peak position;
The mask block consisting of a plurality of symbols is received and demodulated according to the demodulator activation timing signal, and the long code unique to the transmitting station at an arbitrary timing after the mask block is included in the reception demodulation result of the mask block. Demodulation that outputs type and / or phase information as long code information, outputs the timing as a long code activation timing signal, receives and demodulates the long code according to the demodulation unit activation timing signal, and outputs demodulated data And
A long code generation unit that generates a long code by the long code activation timing signal based on the long code information;
A multiplier for multiplying the long code from the long code generator by the channel short code from the channel short code generator;
When the long code start timing signal from said demodulating unit is not input to output channel short code from said channel short code generator to said despreading unit, wherein when the long code start timing signal that has been input the A selector that outputs a multiplication result of the channel short code and the long code from the multiplication unit to the despreading unit;
When a long code activation timing signal is input from the demodulator, the demodulated data from the demodulator is output to the outside as connected transmission station decoded data, and when the long code activation timing signal is not input, the demodulation is performed. An initial synchronization acquisition circuit, comprising: a switch that outputs long code information from the unit to the long code generation unit.

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