JP3273435B2 - Spreading code initial synchronization method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system for performing multiple access using spread spectrum.
In the DMA system, it relates to initial synchronization in correlation detection of a radio receiver.

[0002]

2. Description of the Related Art Direct sequence multiple access (DS-
In CDMA (transmission) transmission, a conventional information data modulation signal is subjected to secondary modulation for spreading with a high-speed rate spreading code and transmitted. On the receiving side, first, a wideband received signal is restored to an original narrowband signal in the process of despreading, and then conventional demodulation processing is performed. The despreading on the receiving side detects the correlation between the received signal and the spread code replica synchronized with the spread code phase of the estimated received signal. Therefore, in order to reproduce the signal, it is necessary to synchronize the spread code of the received signal with the spread code replica.

This synchronization can be classified into a process called initial synchronization (Acquisition) and a process called synchronization holding (Tracking).
Orthogonal codes used for spreading can normally obtain autocorrelation only within a range of ± 1 chip. For this reason, first, in the process of initial synchronization, capture is performed so that the phase difference between the spread code of the received signal and the spread code replica on the receiving side is within a range sufficiently smaller than ± 1 chip. In the next tracking processing, the mutual signs are held in this range.

[0004] The present invention relates to this initial synchronization method. In general, the initial synchronization of a spread code is performed by multiplying a received signal by a spread code replica on the receiving side and integrating over one spread code period to obtain a correlation between the two signals. The correlation output is subjected to amplitude square detection, and it is determined whether or not synchronization has been established based on the magnitude of the output value. This is DS-CDMA
Since the auto-correlation characteristic of the spread code in the above is impulse-like, a large correlation value amplitude is detected only when the phase difference between the spread code of the received signal and the spread code replica is ± 1 chip. Utilizes the characteristic of being substantially zero. For this determination, the correlation value obtained by changing the phase of the spread replica code generated on the receiving side with respect to the received signal is individually determined by a threshold value, or the maximum correlation value is obtained after obtaining the correlation value for all phase differences. The spread code replica phase from which the value has been obtained can be roughly divided into two types with the synchronization phase as the synchronization phase.

By the way, in the DS-CDMA transmission system, the communication speed and capacity can be increased by distributing the information signal of one communication party to a plurality of channels that are spread with different spreading codes and transmitting the information. At this time, the receiving side receives a signal spread by a plurality of spreading codes.

[0006]

As described above, when one communicator performs communication using a plurality of spreading codes, a special channel (such as a pilot channel) in a received signal is used when initial synchronization is performed on the receiving side. When the correlation detection is performed using only the spread code of the spread code as a spread code replica, the cross-correlation between the spread codes is small, but the spread code replica of another spread code
Interference. Therefore, there is no mutual
For correlation of a plurality accumulation peak of the correlation characteristics appearing only in the original synchronization point appears in asynchronous point, the detection of the sync phase is considered you to increase the synchronization difficult-than erroneous.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to increase the speed of initial synchronization in an environment where one communicator performs communication using a plurality of spreading codes.
An object of the present invention is to provide an initial synchronization of a spreading code which realizes high accuracy.

[0008]

In order to achieve the above object, the invention according to claim 1 is directed to direct spread transmission for performing multiple access transmission by spreading a wideband signal with a spreading code having a rate higher than the information transmission rate. Accordingly, Shin of feed is distributed to a plurality of channels for performing spread the information signals for one correspondent with different spreading codes
In the spread code initial synchronization method of performing initial synchronization for reproducing the reproduced signal , a plurality of spread codes generated on the receiving side are provided.
The correlation between the spreading code replica and the received signal is detected for each spreading code, obtains the sum of correlation detection values of the spreading code number of obtained by the detection of the correlation for each spreading code, which the threshold determination Thus, it is characterized by determining whether or not the spread code of the received signal and the spread code replica are synchronized.

According to a second aspect of the present invention, an information signal of one communicator is spread with a different spreading code by direct spreading transmission in which multiple access transmission is performed by spreading a wideband signal with a spreading code higher in speed than the information transmission rate. Spread over multiple channels to spread
The signal signal sent Te, the expansion <br/> dispersion code initial synchronization method for performing initial synchronization to play, each spreading the correlation between the plurality of spreading code replica generated at the receiving side and the spread code of the received signal was detected for each code, the number exceeding the threshold of correlation detection values of the spreading code number of which is obtained by detecting the correlation of each of said spreading codes, or spreading codes with spreading code replica of the received signal is synchronized not Is determined.

According to a third aspect of the present invention, an information signal of one communicator is spread by a different spreading code by direct spread transmission in which multiple access transmission is performed by spreading a wideband signal with a spreading code higher in speed than the information transmission rate. Spread over multiple channels to spread
The signal signal sent Te, the expansion <br/> dispersion code initial synchronization method for performing initial synchronization to play, each spreading the correlation between the plurality of spreading code replica generated at the receiving side and the spread code of the received signal was detected for each code, the detection of the correlation of each spreading code
The more correlation integral detection value of the spreading code number of the resulting detected in the phase difference of the spreading code and the spreading code replica of all received signals, before Symbol position total retardation spreading code number × more obtained detection in retardation It is characterized by determining the sum of the correlation values for the number of spreading codes at each phase difference from the correlation values for several phases, and determining the initial synchronization of the spreading code with the phase of the spreading code replica that obtained the maximum value of the sum. And

According to a fourth aspect of the present invention, an information signal of one communicator is spread by a different spread code by direct spread transmission in which a spread code having a higher speed than the information transmission rate is spread over a wide band signal to perform multiple access transmission. Spread over multiple channels to spread
The signal signal sent Te, the expansion <br/> dispersion code initial synchronization method for performing initial synchronization to play, each spreading the correlation between the plurality of spreading code replica generated at the receiving side and the spread code of the received signal was detected for each code, the detection of the correlation of each spreading code
The more correlation integral detection value of the spreading code number of the resulting detected in the phase difference of the spreading code and the spreading code replica of all received signals, before Symbol position total retardation spreading code number × more obtained detection in retardation Of the correlation integral values for the number of spread codes in each phase difference from the correlation integral values for several, the number exceeding the threshold value is calculated for the phase difference between the spread codes of all received signals and the spread code replica, and the maximum number of It is characterized by determining the initial synchronization of the spreading code using the phase of the spreading code replica from which the value was obtained.

According to a fifth aspect of the present invention, an information signal of one communicator is spread by a different spread code by direct spread transmission in which a spread code having a higher speed than the information transmission rate is spread over a wideband signal to perform multiple access transmission. Spread over multiple channels to spread
The signal signal sent Te, the expansion <br/> dispersion code initial synchronization apparatus for initial synchronization to play, each spreading the correlation between the plurality of spreading code replica generated at the receiving side and the spread code of the received signal A spread code correlation detecting means for detecting each code, and a sum of correlation detection values for the number of spread codes obtained by the spread code correlation detection means is obtained, and a threshold value of the sum is used to determine the spread code and spread of the received signal. And a spreading code initial synchronization determining means for determining whether or not the code replicas are synchronized.

According to a sixth aspect of the present invention, an information signal of one communicator is spread by a different spread code by direct spread transmission in which multiple access transmission is performed by spreading a wideband signal with a spread code having a higher speed than the information transmission rate. Spread over multiple channels to spread
The signal signal sent Te, the expansion <br/> dispersion code initial synchronization apparatus for initial synchronization to play, each spreading the correlation between the plurality of spreading code replica generated at the receiving side and the spread code of the received signal The spread code of the received signal and the spread code replica are synchronized by the spread code correlation detection means for detecting each code and the number exceeding the threshold value of the correlation detection value for the number of spread codes obtained by the spread code correlation detection means. And spreading code initial synchronization determining means for determining whether or not the synchronization has been performed.

According to a seventh aspect of the present invention, an information signal of one communicator is spread with a different spreading code by direct spreading transmission in which a spread code having a higher speed than the information transmission rate is spread over a wideband signal to perform multiple access transmission. Spread over multiple channels to spread
The signal signal sent Te, the expansion <br/> dispersion code initial synchronization apparatus for initial synchronization to play, each spreading the correlation between the plurality of spreading code replica generated at the receiving side and the spread code of the received signal A spreading code correlation detecting means for detecting each code, and a correlation integration detection value for the number of spreading codes obtained by the spreading code correlation detecting means for detecting a phase difference between a spreading code and a spreading code replica of all received signals. A phase difference correlation detecting means and a sum of correlation values for the number of spreading codes in each phase difference are obtained from the correlation values for the number of spreading codes × the total number of phase differences obtained from the total phase difference correlation detecting means, and the maximum value of this sum And spreading code initial synchronization determining means for determining the initial synchronization of the spreading code using the phase of the obtained spreading code replica.

According to an eighth aspect of the present invention, an information signal of one communicator is spread by different spreading codes by direct spreading transmission in which multiple access transmission is performed by spreading a wideband signal with a spreading code higher in speed than the information transmission rate. Spread over multiple channels to spread
The signal signal sent Te, the expansion <br/> dispersion code initial synchronization apparatus for initial synchronization to play, each spreading the correlation between the plurality of spreading code replica generated at the receiving side and the spread code of the received signal A spreading code correlation detecting means for detecting each code, and a correlation integration detection value for the number of spreading codes obtained by the spreading code correlation detecting means for detecting a phase difference between a spreading code and a spreading code replica of all received signals. The phase difference correlation detecting means and the correlation integral value for the number of spreading codes at each phase difference from the correlation integral value for the number of spreading codes × the total number of phase differences obtained by the total phase difference correlation detecting means, exceed the threshold value. The number is calculated based on the phase difference between the spread code and the spread code replica of all the received signals, and the phase of the spread code replica from which the maximum value of the number is obtained is determined to be spread code initial synchronization. And setting means.

The ninth aspect of the present invention is the seventh aspect of the present invention.
In the spread code initial synchronization apparatus described above, each output of the full phase difference correlation detection means is output in series.

According to a tenth aspect of the present invention, in the spread code initial synchronizer according to the seventh or eighth aspect, each output of the full phase difference correlation detecting means is output in parallel.

The invention according to claim 11 is the invention according to claims 5-1.
0, the spread code correlation detecting means generates the spread code replica.
A spreading code generator for, a multiplier for multiplying the spreading code with the received the <br/> spreading code replica from said spreading code generator, an integrator for integrating the output of said multiplier, said integrator And a detector for squaring the output to the amplitude squared.

According to the twelfth aspect of the present invention,
In the spread code initial synchronization apparatus according to any one of the above, after detecting the synchronization, the synchronization is confirmed again.

In the present invention, when performing initial synchronization in a multi-code environment in which one communicator simultaneously communicates using a plurality of spreading codes, each of the plurality of received spreading codes is used as a spreading code replica on the receiving side. By calculating the correlation with the number of spread codes and making the overall synchronization determination, the increase in false synchronization due to accumulation of cross-correlation between spreading codes in a multi-code environment is reduced, and high-speed and high-speed Accurate initial synchronization can be realized.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a basic configuration of a square amplitude value detection section of a correlation integral value in multicode initial synchronization according to the present invention. The square amplitude value detection unit is configured to calculate the correlator 1
To n. Each squared amplitude value detection unit includes a spreading code replica generator 11, a multiplier 12, an integrator 13, and an amplitude squared detector 14.

On the receiving side, the square amplitude value detector detects the number of spreading codes (n) contained in a signal to be received from now on.
Are prepared, and the spread code replica from the replica generator of the received spread code is set in each correlator. The phase of the spreading code replica and the correlation integration start time are the same. Each of the correlators 1 to n first multiplies the received signal by the spreading code replica, and integrates this value for a certain period of time. The obtained correlation integral value is squared, and this amplitude is output.

[Embodiment 1] FIG. 2 shows a basic configuration of an initial synchronization apparatus according to Embodiment 1 of the present invention. In the initial synchronization according to the first embodiment, the initial synchronization is detected by determining the threshold value of the square amplitude value of the correlation integral value between the received signal and the spread code replica.

In FIG. 2, reference numeral 21 denotes the correlation 2 shown in FIG.
Reference numeral 22 denotes an accumulator, and reference numeral 23 denotes a threshold value determination circuit. An operation 24 receives the signal when the output of the threshold value judgment circuit 23 is not equal to or larger than the threshold value, updates the phase of the spread code replica generator of the correlation square amplitude value detection section 21, and obtains the correlation again. Is a circuit that outputs a signal to start the operation.

In the initial synchronization apparatus according to the first embodiment shown in FIG. 2, the correlation square amplitude values for the number of spread codes, which are the outputs of the square amplitude values of the correlation integral values of the received signal and the spread code replica, are output. Is obtained by the accumulation unit 22. And
The threshold value determination circuit 23 determines whether or not the sum of the correlation square amplitude values is larger than a predetermined threshold value. If the threshold value is exceeded, it is assumed that the initial synchronization has been detected and the mode is shifted to the tracking mode, or
The correlation is detected again at the same spreading code replica phase to confirm the initial synchronization detection. If the sum of the correlation square amplitude values does not exceed the threshold value, it is determined that the phases of the received spreading code and the spreading code replica are not in phase, and the phase of the spreading code replica is updated by a signal from the circuit 24 to update the correlation. Ask for. Such an operation is repeated until the threshold value is exceeded. The overall control is performed by a control unit (not shown).

[Second Embodiment] FIG. 3 shows a basic configuration of an initial synchronization device according to a second embodiment of the present invention. Also in the initial synchronization in the second embodiment, the initial synchronization is detected by determining the threshold value of the square amplitude value of the correlation integral value between the received signal and the spread code replica.

In FIG. 3, reference numeral 31 denotes the correlation 2 shown in FIG.
A squared amplitude value detection unit 32 is a circuit for generating the number of squared amplitude values larger than the first threshold value, and 33 is a second threshold value determination circuit. . Numeral 34 is an operation for receiving a signal when the output of the threshold value judging circuit 33 is not equal to or larger than the threshold value, updating the phase of the spread code replica generator of the correlation square amplitude value detecting section 31, and obtaining the correlation again. Is a circuit that outputs a signal to start the operation.

The operation of FIG. 3 will be described. The circuit 32 compares each of the correlation square amplitude values for the number of spread codes, which is the output of the detection unit 31 of the square integration value of the correlation integral value between the received signal and the spread code replica, with a first threshold value. . And
Generate a number of correlated squared amplitude values that exceed a first threshold. The determination of the establishment of the initial synchronization is made based on whether or not the number exceeds the second threshold value. The operation after the second threshold determination is as follows.
This is the same as the initial synchronization of the first embodiment. The overall control is performed by a control unit (not shown).

Third Embodiment FIG. 4 shows a third embodiment of the present invention.
1 shows the basic configuration of the initial synchronization device. The initial synchronization of the third embodiment is based on the correlation integral value of the received signal and the spread code replica being 2
The power amplitude value is detected in the total phase difference between the received signal and the spread code replica, and the maximum likelihood determination of the spread code replica phase for obtaining the initial synchronization is performed based on the detected value.

In order to detect correlation samples in all phase differences between the received signal and the spread code replica, a correlator for the number of spread codes shown in FIG. 1 is further prepared in parallel, and a parallel detection is performed. There is a configuration in which the correlation samples in the phase difference are serially detected with a time lag, but in Embodiment 3, the initial synchronization can be realized by either configuration.

In FIG. 4, reference numeral 41 denotes the number of spread codes n.times.all obtained by sequentially shifting the phase of the spread code replica of the detector for detecting the squared amplitude value of the correlation integral value between the received signal and the spread code replica shown in FIG. Correlation square amplitude value R (q) for q number of phase differences
This is a circuit that outputs n. The circuit 41 may have a configuration in which correlators for the number of spreading codes shown in FIG. 1 are provided in parallel, the correlation is detected in parallel, and the output is output in parallel.
Further, the circuit 41 may serially output the correlation samples at the respective phase differences of the correlators corresponding to the number of spreading codes shown in FIG. 42-1 to 42-q are
This accumulator calculates the sum of the correlation square amplitude values for the number of spreading codes for each phase difference. The accumulator 42 has two types, a configuration for obtaining an accumulated value of a parallel output according to the output of the circuit 41 and a configuration for obtaining an accumulated value of a serial output. 43
Is a maximum phase difference detection circuit for detecting the phase difference of the maximum value of the sum.

The operation of the third embodiment shown in FIG. 4 will be described.
In the initial synchronizer according to the third embodiment, the circuit 41 calculates the correlation square amplitude value R for each spread code replica of the received signal.
(Q) First detect _n . Next, the accumulator 42 calculates the sum of the correlation square amplitude values for the number of spreading codes for each phase difference.
The maximum phase difference detection circuit 43 compares the sum value for each phase difference, and determines the spread code replica phase having detected the maximum value as the initial synchronization phase. After the determination, the mode shifts to the confirmation mode or the tracking mode. The overall control is performed by a control unit (not shown).

[Embodiment 4] FIG. 5 shows Embodiment 4 of the present invention.
1 shows the basic configuration of the initial synchronization device. In the initial synchronization of the fourth embodiment, as in the third embodiment, the square amplitude value of the correlation integral value between the received signal and the spread code replica is detected in the total phase difference between the received signal and the spread code replica. The maximum likelihood determination of the spreading code replica phase for obtaining synchronization is performed.

As in the third embodiment, in order to detect correlation samples in the total phase difference between the received signal and the spread code replica, correlators for the number of spread codes shown in FIG. 1 are further prepared in parallel and detected in parallel. There is a configuration in which the correlation sample in each phase difference is detected serially with a time lag, and in the fourth embodiment, the initial synchronization can be realized by either configuration.

FIG. 5 is similar to the circuit 41 of FIG. The circuit 51 may be such that correlators for the number of spreading codes shown in FIG. 1 are prepared in parallel, the correlation is detected in parallel, and the output is output in parallel. Also, the circuit 51
May output serially the correlation samples at the respective phase differences of the correlators corresponding to the number of spreading codes shown in FIG. 52-1 to 52-q are the correlation square amplitude values R larger than the third threshold value for each phase difference x.
(X) ₁ ... R (x) A circuit for determining the number N (x) of _n . The circuit 52 has two types, a configuration for obtaining an accumulated value of a parallel output according to the output of the circuit 51 and a configuration for obtaining an accumulated value of a serial output. 53 is the number N
This is a maximum phase difference detection circuit that detects the phase difference between the maximum values of (1) to N (q).

In the initial synchronizer of the fourth embodiment, the circuit 51
In step (1), a correlation code amplitude value R (q) _n of n × q total phase differences obtained by sequentially shifting the phase of the spread code replica of the correlation amplitude value squared value detection unit is detected.
Next, the circuits 52-1 to 51-q count, for each phase difference, the number of correlation square amplitude values corresponding to the number of spread codes exceeding a certain threshold value. The spreading code replica phase having the maximum count is determined by the circuit 53 as the initial synchronization phase. After the determination, the mode shifts to the confirmation mode or the tracking mode. The overall control is performed by a control unit (not shown).

[0038]

As described above, according to the present invention,
Upon performing an initial synchronization under multicode environment, the correlation of each using the reception signals a plurality of spreading codes for receiving and spreading code replica calculated by using the synchronization determination, diffusion
Reduce the increase of false synchronization due to accumulation of cross-correlation between codes,
Higher speed and higher accuracy of initial synchronization can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a squared amplitude value detection unit of a correlation integral value according to the present invention.

FIG. 2 is a diagram illustrating a configuration of an initial synchronization device according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a configuration of an initial synchronization device according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating a configuration of an initial synchronization device according to a third embodiment of the present invention.

FIG. 5 is a diagram illustrating a configuration of an initial synchronization device according to a fourth embodiment of the present invention.

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04B 1/69-1/713 H04J 13/00-13/06

Claims (12)

(57) [Claims] In 1. A data transmission rate than the high rate of the spreading code by the spreading transmission directly performing spread to multiple access transmission to wideband signals, the plurality of channels for performing spread the information signals for one correspondent with different spreading codes the signal signal sent by distributing, again
In the spreading code initial synchronization method for performing initial synchronization to live, and detects a correlation between the plurality of spreading code replica generated at the receiving side and the spread code of a received signal for each spreading code, correlation of each of said spreading code The sum of the correlation detection values for the number of spreading codes obtained by the detection is determined, and a determination is made as to the threshold value to determine whether the spreading code of the received signal and the spreading code replica are synchronized or not. A spreading code initial synchronization method. In wherein information transmission rate than high rate spreading code by spreading transmission directly performing spread to multiple access transmission to wideband signals, the plurality of channels for performing spread the information signals for one correspondent with different spreading codes the signal signal sent by distributing, again
In the spreading code initial synchronization method for performing initial synchronization to live, and detects a correlation between the plurality of spreading code replica generated at the receiving side and the spread code of a received signal for each spreading code, correlation of each of said spreading code Determining whether or not the spread code of the received signal and the spread code replica are synchronized by the number exceeding the threshold value of the correlation detection value for the number of spread codes obtained by the detection of Spreading code initial synchronization method. 3. A direct spread transmission in which a wideband signal is spread with a spreading code having a higher speed than the information transmission rate to perform multiple access transmission, whereby an information signal of one communicator is spread to a plurality of channels which are spread with different spreading codes. the signal signal sent by distributing, again
In the spreading code initial synchronization method for performing initial synchronization to live, and detects a correlation between the plurality of spreading code replica generated at the receiving side and the spread code of a received signal for each spreading code, correlation of each of said spreading code of more correlation integral detection value of the spreading code number of obtained detector detects the phase difference of the spreading code and the spreading code replica of all received signals, before Symbol position total spreading code number × more obtained detection in retardation Determining the sum of the correlation values for the number of spreading codes at each phase difference from the correlation values for the number of phase differences, and determining the spreading code initial synchronization using the phase of the spreading code replica that obtained the maximum value of the sum. A spreading code initial synchronization method, characterized in that: In 4. Information transmission rate than high rate spreading code by spreading transmission directly performing spread to multiple access transmission to wideband signals, the plurality of channels for performing spread the information signals for one correspondent with different spreading codes the signal signal sent by distributing, again
In the spreading code initial synchronization method for performing initial synchronization to live, and detects a correlation between the plurality of spreading code replica generated at the receiving side and the spread code of a received signal for each spreading code, correlation of each of said spreading code of more correlation integral detection value of the spreading code number of obtained detector detects the phase difference of the spreading code and the spreading code replica of all received signals, before Symbol position total spreading code number × more obtained detection in retardation Of the correlation integral values for the number of spread codes in each phase difference from the correlation integral values for the number of phase differences, the number exceeding the threshold value is calculated for the phase difference between the spread codes and the spread code replicas of all the received signals, and the number is calculated. And determining the initial synchronization of the spreading code by using the phase of the spreading code replica that has obtained the maximum value of the spreading code. In 5. Information transmission rate than high rate spreading code by spreading transmission directly to spread over a wide band signal performs multiple access transmission, the plurality of channels for performing spread the information signals for one correspondent with different spreading codes the signal signal sent by distributing, again
In a spread code initial synchronization device that performs initial synchronization to generate a spread code, a spread code correlation detection unit that detects a correlation between a plurality of spread code replicas generated on the receiving side and a spread code of a received signal for each spread code, The sum of the correlation detection values for the number of spreading codes obtained by the spreading code correlation detection means is determined, and the threshold value is determined to determine whether the spreading code of the received signal is synchronized with the spreading code replica. A spreading code initial synchronization device comprising: code initial synchronization determining means. In 6. Information transmission rate than high rate spreading code by spreading transmission directly to spread over a wide band signal performs multiple access transmission, the plurality of channels for performing spread the information signals for one correspondent with different spreading codes the signal signal sent by distributing, again
In a spread code initial synchronization device that performs initial synchronization to generate a spread code, a spread code correlation detection unit that detects a correlation between a plurality of spread code replicas generated on the receiving side and a spread code of a received signal for each spread code, Spreading code initial synchronization determining means for determining whether or not the spreading code of the received signal and the spreading code replica are synchronized by the number exceeding the threshold value of the correlation detection value for the number of spreading codes obtained by the spreading code correlation detecting means. And a spread code initial synchronization device. In 7. Information transmission rate than high rate spreading code by spreading transmission directly to spread over a wide band signal performs multiple access transmission, the plurality of channels for performing spread the information signals for one correspondent with different spreading codes the signal signal sent by distributing, again
In a spread code initial synchronization device that performs initial synchronization to generate a spread code, a spread code correlation detection unit that detects a correlation between a plurality of spread code replicas generated on the receiving side and a spread code of a received signal for each spread code, An all-phase-difference correlation detecting means for detecting a correlation-integral detection value for the number of spreading codes obtained by the spreading-code correlation detecting means in a phase difference between a spread code and a spread code replica of all received signals; The sum of the correlation values for the number of spreading codes at each phase difference is obtained from the correlation values for the number of spreading codes obtained by the means × the total number of phase differences, and the initial phase of the spreading code is calculated using the phase of the spreading code replica that obtained the maximum value of the sum. And a spread code initial synchronization determining means for determining the spread code initial synchronization. 8. A direct spread transmission in which a wideband signal is spread with a spreading code having a higher speed than an information transmission rate to perform multiple access transmission, whereby an information signal of one communicator is spread to a plurality of channels which are spread with different spreading codes. the signal signal sent by distributing, again
In a spread code initial synchronization device that performs initial synchronization to generate a spread code, a spread code correlation detection unit that detects a correlation between a plurality of spread code replicas generated on the receiving side and a spread code of a received signal for each spread code, An all-phase-difference correlation detecting means for detecting a correlation-integral detection value for the number of spreading codes obtained by the spreading-code correlation detecting means in a phase difference between a spread code and a spread code replica of all received signals; Of the correlation integral values for the number of spread codes at each phase difference from the correlation integral values for the number of spread codes obtained by the means × the total number of phase differences, the number of spread codes and spread code replicas of all received signals that exceed the threshold. And a spreading code initial synchronization determining means for determining the spreading code initial synchronization using the phase of the spreading code replica which obtained the maximum value of the number. DOO spread code initial synchronization apparatus according to claim. 9. The spread code initial synchronizing apparatus according to claim 7, wherein each output of said total phase difference correlation detecting means is output in series. 10. The spread code initial synchronizing apparatus according to claim 7, wherein each output of said total phase difference correlation detecting means is output in parallel. 11. The spread code initial synchronization apparatus according to claim 5, wherein the spread code correlation detecting means sets the spread code replica
A spread code generator for generating, from the spread code generator
Diffusion, characterized in that it comprises a multiplier for multiplying the spreading code received with the spreading code replica, and an integrator for integrating the output of said multiplier, and a detector for squaring amplitude of the output of the integrator Sign initial synchronizer. 12. The spread code initial synchronization apparatus according to claim 5, wherein after detecting the synchronization, the synchronization is confirmed again.