JP2001186054A - Spread spectrum communication system, its transmitter- receiver, communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems that many spread codes are consumed while an initial synchronization acquisition time is made the same degree as the case with no multiplexing in the case of providing a different spread code to multiplex channels, and spread code generators whose number is equal to the number of multiplexed channels are required for a transmitter and a receiver respectively. SOLUTION: The same spread code sequence is assigned to each of multiplexed channels while only the phase of the sequence is changed differently at a transmitter side. A memory 4 at a receiver side stores a correlation calculated by a digital correlator 3 and a CPU 5 reads this correlation to control the phase of the spread code generated from a spread code generator 2. Thus, the time required to acquire initial synchronization is decreased at the same speed as the case with assignment of different spread codes to each channel. Since one kind of the spread code generator is enough to save the spread codes and the size of the transmitter and the receiver can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spread spectrum communication system, a transmission / reception apparatus thereof, and a spread spectrum communication method, and more particularly to allocation of a spread code and high-speed initial synchronization acquisition in a communication system using a spread spectrum communication system.

[0002]

2. Description of the Related Art Generally, in a spread spectrum communication system,
This is a communication system that performs code spreading on the transmission side and despreading on the reception side using a PN (Pseudorandom Noise) code. In this case, multiple access is realized by changing the spreading code for each line. A method of performing communication by assigning different spreading codes to a plurality of lines as described above is described in Japanese Patent Application Laid-Open No. H11-252444.

The reasons for using different spreading codes are as follows. That is, if the same spreading code is used in a plurality of lines, the lines may have the same code phase,
The lines interfere with each other, and communication becomes impossible. Further, if the same spreading code is used for a plurality of lines, the desired line cannot be selected on the receiving side by the spreading code. Since these problems occur, a general spread spectrum communication system or CDMA (Code Division Multip
le Access) In a communication system, a different spreading code is assigned to each line.

FIG. 9 shows a transmitter in a general spread spectrum communication system, and FIG. 10 shows a receiver in a general spread spectrum communication system. Referring to FIG. 9, in the transmitting apparatus, a spreading code 220 such as a known gold code is generated by a spreading code generator 22. Then, the spreading code 220 is multiplied by the baseband signal 23 in the multiplier 20 to perform a code spreading process. Further, the multiplier 21
, The modulated signal 26
To perform conversion to IF (Intermediate Frequency) and conversion to RF (Radio Frequency). Then, the output signal of the multiplier 21 is transmitted as a transmission signal from an antenna (not shown). Note that the multiplier 21 is generally provided for each of IF conversion and RF conversion.

On the other hand, a transmission signal transmitted from a transmission device is received by a reception device shown in FIG. A received signal 6 input via an antenna (not shown) provided in the receiving device is multiplied by a demodulated signal 7 in a multiplier 10 and then converted into a digital signal by an A / D converter (not shown) and received. This becomes the input signal 1. Note that the multiplier 10 is generally provided for each of RF conversion and IF conversion.

[0006] This receiving apparatus is also provided with a local spreading code generator 2 similar to the transmitting apparatus. The spread code 200 output from the spread code generator 2 is input to the digital correlator 3 together with the received input signal 1, and the correlation value 30 between them is calculated. Then, the phase of the spread code 200 output from the spread code generator 2 is controlled according to the peak value of the correlation value.

FIG. 11 shows a configuration for controlling the phase of the spreading code. Referring to the figure, in the digital correlator 3, the calculated correlation value 30 is:
It is stored in the correlation value memory 4. That is, the correlation curve 400 is stored in the memory space of the correlation value memory 4. Then, the CPU 5 reads out the stored correlation value (correlation curve) and searches for a peak value. The CPU 5 controls the phase of the spread code 200 output from the spread code generator 2 according to the phase position of the peak value.

The correlation value 30 in the digital correlator 3
Will be described with reference to FIG. In the figure,
A digital signal having a value of “1” or “0” is shown. In the figure, one cycle of the code is assumed to be 6 chips for convenience of explanation.

Consider a case where a correlation value with a received input signal as shown in FIG. 2B is calculated using the spreading code shown in FIG. In this case, since the two data completely match for six chips, the correlation value is “6”.

[0010] Also, consider a case where a correlation value with a received input signal as shown in FIG. 1C is calculated using the spreading code shown in FIG. 1A. In this case, since the two data only match for three chips, the correlation value is “3”.

As described above, when the correlation value is calculated, the correlation value shows a peak value (correlation peak) at a certain phase.
In other phases, the correlation value is ideally zero. Actually, it does not become zero due to noise or the like, but the difference from the peak value is clear, so that an appropriate phase value for the spreading code can be detected.

An example of the internal configuration of the digital correlator 3 for calculating the correlation value will be described with reference to FIG. Referring to FIG. 1, the digital correlator includes a reception input signal buffer 31 for storing the reception input signal 1, a spreading code buffer 32 for storing the spreading code 200, and a value corresponding to the coincidence and non-coincidence of the two. Accumulator 33 to increase or decrease
It is comprised including. The received input signal stored in the buffer 31 and the spread code stored in the buffer 32 are compared one bit at a time, and “+1” is assigned to a bit that matches both bits and “−” to a bit that does not match. 1 "
, And “+1” and “−1” for all bits are added by the accumulator 33. By doing so, the correlation value 30 is sent from the accumulator. This correlation value 30
Is stored in the correlation value memory 4.

The correlation value memory 4 has a capacity to store the correlation value calculated by the digital correlator 3 by an amount corresponding to one cycle of the spread code. FIG.
As shown in FIG. 4, the correlation value memory 4 stores a correlation curve 400 in which only one peak P appears in one cycle of the spreading code. The phase of the spreading code 200 is controlled according to the phase position of the peak P.

[0014]

As described above, in the conventional spread spectrum communication system, different spread codes are assigned to multiple lines for communication. However, this is a waste of spreading codes in a sense. in this case,
It is necessary to provide a spreading code generator corresponding to each spreading code, and there is a disadvantage that the hardware scale of the transmitting device and the receiving device is increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the prior art, and has as its object to reduce the scale of hardware of a transmitting device and a receiving device without wasting a spreading code. An object of the present invention is to provide a spread communication system, a transmission / reception device thereof, and a spread spectrum communication method.

[0016]

SUMMARY OF THE INVENTION A spread spectrum communication system according to the present invention is a spread spectrum communication system for multiplexing a plurality of lines by using a spreading code and transmitting / receiving the multiplexed signals. A transmission device that allocates and transmits the same spreading code, which is changed by a different amount, and measures a phase distance between peak values of correlation values between the received signal transmitted from the transmission device and the reception signal and the spreading code. A receiving device for identifying each of the plurality of lines. Further, the transmitting apparatus performs transmission by spreading the plurality of lines using the spreading code. The receiving apparatus includes a spreading code generator for generating the spreading code, and a correlator for calculating a correlation value between the spreading code and the received signal, and a peak value for a correlation value obtained by the correlator. The phase of the spread code generated by the spread code generator is controlled according to the phase distance between the spread code and a peak value adjacent thereto.

Further, the receiving device includes a memory for storing the correlation value obtained by the correlator, a peak value detected from the correlation value stored in the memory to obtain the phase distance, and the obtained phase distance And a controller for controlling the phase of the spreading code in accordance with Then, when the phase distance between a certain peak value and a peak value adjacent to the certain peak value among the correlation values stored in the memory is k × m chips (k and m are natural numbers, the same applies hereinafter), The two peak values are respectively the k-th line and (k +
1) Treat them as corresponding to the first line.

A transmitting apparatus according to the present invention is a transmitting apparatus used in a spread spectrum communication system in which a plurality of lines are multiplexed using a spreading code and transmitted and received. It is characterized in that the same changed spreading code is allocated and transmitted. Then, transmission is performed by spreading the plurality of lines using the spreading code.

A receiving apparatus according to the present invention is a receiving apparatus used in a spread spectrum communication system for multiplexing and transmitting a plurality of lines by using a spreading code and transmitting and receiving a signal transmitted from a transmitting side and receiving the received signal. Each of the plurality of lines is identified by measuring a phase distance between peak values of a correlation value with a code. And a spread code generator for generating the spread code, and a correlator for calculating a correlation value between the spread code and the received signal, and a peak value adjacent to a certain peak value for the correlation value obtained by the correlator. The phase of the spread code generated from the spread code generator is controlled in accordance with the phase distance from the peak value.

A memory for storing the correlation value obtained by the correlator; a peak value being detected from the correlation value stored in the memory to obtain the phase distance; And a control unit for controlling the phase of the code. Then, the control unit, when a phase distance between a certain peak value and a peak value adjacent to the certain peak value among the correlation values stored in the memory is k × m chips,
The two peak values are handled as corresponding to the k-th line and the (k + 1) -th line, respectively.

A spread spectrum communication method according to the present invention is a spread spectrum communication method for multiplexing and transmitting a plurality of lines by using a spreading code, and comprising:
The same spreading code whose phase is changed by a different amount is assigned to a plurality of lines provided for multiplexing and transmitted, and on the receiving side, a correlation value between a received signal transmitted from the transmitting side and receiving it and the spreading code is transmitted. And measuring the phase distance between the peak values of the plurality of lines to identify each of the plurality of lines. Then, on the transmitting side, the plurality of lines are spread and transmitted using the spreading code.

On the receiving side, a spread code is generated, a correlation value between the generated spread code and the received signal is obtained, and a certain peak value and a peak value adjacent thereto are determined for the obtained correlation value. And controlling the phase of the spreading code according to the phase distance between Further, on the receiving side, the obtained correlation value is stored, a peak value is detected from the stored correlation value to obtain the phase distance, and the phase of the spreading code is calculated according to the obtained phase distance. It is characterized by controlling. When controlling the phase, when the phase distance between a certain peak value and a peak value adjacent to the certain peak value among the stored correlation values is k × m chips, both of the peak values are k-th. It is characterized in that it is treated as corresponding to the line and the (k + 1) th line, respectively.

[0023]

Next, an embodiment of the present invention will be described with reference to the drawings. In the drawings referred to in the following description, the same parts as those in the other drawings are denoted by the same reference numerals.

According to the present invention, in a spread spectrum communication system for realizing a line having one high information rate by multiplexing a plurality of lines, the same spreading code is used for a plurality of lines provided for multiplexing. For example, when the number of lines is 10, if different spreading codes are used, as shown in FIG. 2, ten types of spreading codes of A, B, C,... Required. This means that the spreading code is wasted.

Therefore, as shown in FIG. 3, if the same spreading code A1, A2, A3,..., A10 is used for a plurality of lines, the spreading code is not wasted. in this way,
By using the same spreading code for a plurality of lines provided for multiplexing, interference between lines can be avoided, and high-speed initial synchronization acquisition can be performed.

As described above, in a spread spectrum communication system, a different spreading code is generally assigned to each line. However, in a system that realizes one high-speed line by multiplexing a plurality of lines, it is possible to use the same spreading code only for a plurality of lines to be multiplexed. This is because, in this case, since a plurality of lines can be considered as one lump, the phase can be controlled in the lump so that the phases of the spreading codes of the respective lines do not overlap. If the phases of the spreading codes are shifted, interference between lines does not occur.

However, even in this case, the lack of line selectivity remains a problem. That is, in this method, since all the lines in the block are spread with the same spreading code, the receiving side cannot identify which line is currently being received. If the line cannot be identified correctly, subsequent multiplexing cannot be performed.Therefore, it is necessary to identify the line by some method.However, when the spreading code is the same, the line is identified by the data of the line or the position of the spreading code. A method of changing the phase difference for each line can be considered.

In the case of identification by line data, a certain line is despread, and after demodulating the data, frame synchronization or the like is performed to find out what number the line is in the block. Thereafter, control is performed so as to receive a line having a phase different from that of the spread code of the line. This method is not suitable because it has problems such as crushing a data transmission area with line information and requiring a very long time to receive a plurality of lines.

In order to deal with this problem, in the present system, the transmitting side changes the phase of the spreading code for each line in the line in the block. That is, the same spreading code whose phase is changed by a different amount is assigned to a plurality of lines provided for multiplexing, and the plurality of lines are spread and transmitted using this spreading code. This is shown in FIG.
In the figure, L is one cycle of the spreading code.

In the figure, for example, the phase of the spreading code is shifted by m chips (shifted in phase) between the first line (first line) and the second line (second line), and the second line (2nd line) and 3rd line (3rd line)
Shift by m chips. Similarly, in the case of the n-th line and the (n + 1) -th line, n × m chips are shifted.

That is, one cycle of the second line is delayed by a phase of m chips relatively to one cycle of the spread code of the first line. In addition, one cycle of the third line is delayed by a phase of 2 m chips relatively to one cycle of the spread code of the second line. Similarly, in the same way, 1
One cycle of the spread code of the (n + 1) th line is delayed by n × m chips relative to the cycle. Thus, the transmission is performed with the phase changed.

On the other hand, on the receiving side, after receiving a certain line,
The spreading code is shifted in units of m chips, and it is checked how many times the spreading code should be shifted until the next correlation appears. If the next correlation is obtained after shifting k times, the line caught first is (k−
1) Since it is known that the line is the first line, the phases of all the lines are immediately known.

The basic configuration of the present system is not different from that of a commonly used initial synchronization acquisition circuit. However, the number of stages of the digital correlator is a unit for shifting the phase of the spreading code,
That is, it is longer than m.

FIG. 1 is a block diagram showing an embodiment of a receiving apparatus in a spread spectrum communication system according to the present invention. FIG. 1 shows an initial synchronization acquisition circuit which is a main part of a receiving device in the present system. The circuit configuration itself shown in the figure is basically the same as the circuit configuration of FIG. 11 described above.

The operation of each unit in FIG. 1 will be described below. A received signal received from an antenna or the like (not shown) passes through an RF unit or IF unit (not shown), is converted into a baseband signal, and is then converted into a digital signal by an A / D converter (not shown). The received input signal 1 in the figure is an A / D converted baseband signal. The digital correlator 3 is a device for calculating a cross-correlation between two code sequences. In the figure, the digital correlator 3 calculates a cross-correlation between the received input signal 1 and a spread code output from the local spread code generator 2.

The correlation value output from the correlator 3 is stored in the correlation value memory 4. In the present system, a plurality of correlation peaks appear on the correlation curve stored in the correlation value memory 4. Then, the CPU 5 searches for the peak value of the correlation value. The CPU 5 controls the phase of the spread code 200 output from the spread code generator 2 according to the phase position of the peak value.

Here, when a signal spread with a spreading code different for each line is received, only one line at a maximum is spread with a code matching the local spreading code.
When a correlation is obtained for one cycle, only one correlation peak appears. This is as described with reference to FIG.

On the other hand, in the present system, the same spreading code is used for a plurality of lines while changing the phase. Then, in this case, a plurality of correlation peaks appear on the correlation value memory 4. This is shown in FIG. FIG. 5 shows a correlation curve 401 stored in the correlation value memory in FIG.

When the number of multiplexes is N (N is an integer of 2 or more, the same applies hereinafter), N peaks appear in one cycle. For example, if N = 5, five peaks P1 to P5 appear as shown in FIG. Therefore, when reading the contents stored in the correlation value memory 4 by the CPU 5, by measuring the phase distance between these peaks, it is possible to instantaneously know what line is the peak of interest.

For example, if attention is paid to the peak P4 in the figure, the phase d34 between the adjacent peak P3 is 3
In the case of a chip, the peak P4 can be recognized as the fourth line. Similarly, if attention is focused on the peak P4, the phase d between the adjacent peak P5
If 45 is 4 chips, the peak P4 can be recognized as the fourth line.

That is, in the present system, a spreading code in which a phase difference increasing by m is used for spreading the N lines is used, so that the phase distance between two peaks is k ×
For m chips, the two peaks indicate the k-th line and the (k + 1) -th line, respectively. Therefore, if at least one position is found among the N peaks,
The remaining peaks are at positions where the phase is plus or minus by a multiple of m from there, and can be calculated mechanically.
In addition, verification using actual measurement values stored in the correlation value memory 4 can be easily performed.

That is, in the prior art (FIG. 11), the maximum peak in the correlation value memory 4 is used as the correlation phase. In this system, however, attention is paid to a plurality of peaks, and the distance between the peaks is measured to determine the correlation phase. Is determined. By doing so, even in the case of line multiplexing using the same spreading code, individual lines can be identified at the same speed as when the spreading code is changed for each line. Once the N lines have been identified at the time of the initial synchronization acquisition, the N lines can be demodulated by individually despreading the N lines using a well-known integral-dump type filter. .

Next, the processing of the CPU 5 for reading a correlation value from the correlation value memory 4 in FIG. 1 and searching for a correlation peak will be described. First, FIG. 6 shows the correlation value memory 4 in FIG.
, Ie, an example of stored correlation value data. Referring to the figure, memory address # 1
The correlation values for one cycle of the spreading code are stored in # 1000. As described above, the correlation value shows a peak value in a certain phase. In this example, the location where the correlation value is "1000" is the peak value. In other phases, the correlation value is ideally zero, but in practice it does not become zero due to noise or the like but becomes a value of about "9" to "20". Therefore, the difference between the peak value and other portions is clear.

In the figure, for convenience of explanation, the address #
Although there are several peak values (locations where the correlation value is "1000") from 1 to # 12, the interval between addresses where the correlation values corresponding to the correlation peaks are stored is several tens to Hundreds of addresses are free.

Here, the correlation value “100” is assigned to address # 3.
0 ”is stored, and the correlation value“ 100 ”is stored in the address # 5.
"0" and the correlation value "1000" at address # 8. Therefore, focusing on the correlation peak corresponding to the address # 5, the other correlation peak adjacent to the correlation peak is the correlation peak corresponding to the address # 3 or the address # 8. Address # 5 and address # 3
Since one address is vacant between and, it can be recognized that the correlation peak corresponding to address # 3 corresponds to the first line and the correlation peak corresponding to address # 5 corresponds to the second line. is there.

Similarly, there are two addresses between address # 5 and address # 8, so that address # 5
Correspond to the second line and have an address #
It can be recognized that the correlation peak corresponding to 8 corresponds to the third line. This makes it possible to detect an appropriate phase value for the spread code.

The correlation value itself corresponding to the correlation peak does not become the same value (such as “1000” described above). Therefore, a threshold value may be determined in advance, and a value exceeding the threshold value may be treated as a correlation peak.

FIG. 7 is a flowchart showing the processing performed by the CPU 5 in FIG. 1 on the correlation value memory 4. As shown in the drawing, the CPU first checks the contents of the correlation value memory, that is, all stored correlation values (step S101). Next, two peak values to be focused on are searched for (step S102), and a chip difference between them is calculated (step S103). By checking the chip difference, it is possible to recognize which line the peak value of interest is, as described above. Then, the phase of the spreading code generator is controlled according to the recognition result (step S104).

If a difference occurs in the correlation value on the receiving side at the transmitting side, it is possible to identify which line by itself. For example, if the correlation values are “2000”, “1000”, “5”
If there is a difference in the correlation values stored in the correlation value memory, such as "00", the line of interest can be recognized only by shifting the same chip amount. That is, in the above example, the amount of chips shifted for each correlation peak is changed, but the amount of chips shifted for each correlation peak is made constant, and the correlation value of the correlation peak is made different. In this way, the line of interest can be recognized by detecting the difference between the correlation value and the adjacent peak value.

The operating frequency of a spread code is generally as high as several tens of MHz, and the code cycle is as long as several thousand chips. For this reason, it is difficult to make the length (storage capacity) of the digital correlator 3 in FIG. 1 equal to the length of one cycle of the spread code, and is usually about several times shorter.

Therefore, in order to obtain a correlation for one cycle, a partial correlation is obtained by using a technique called partial correlation, and the part for which the correlation is obtained is shifted little by little, and finally, the whole is obtained. Obtain cross-correlation properties. Digital correlator 3
Is a quarter (1/4) of one cycle of the spreading code, partial correlation is performed four times. As shown in FIG. 8, the cross-correlation values are partially integrated, such as T1 for the first partial correlation, T2 for the second partial correlation, T3 for the third partial correlation, and T4 for the fourth partial correlation. And 1
A correlation characteristic of 1/4 of the period is obtained. Therefore, by performing this operation four times, a correlation peak for one entire cycle is finally obtained.

As described above, when the technique called partial correlation is used, the length (storage capacity) of the digital correlator 3 can be reduced, and the size of the receiver housing can be further reduced.

By the way, the spread spectrum system described above is a spread spectrum communication method in which a plurality of lines are multiplexed using a spreading code and transmitted and received. Allocate and transmit the same spreading code with the phase changed by different amounts,
On the receiving side, a spread-spectrum communication method for identifying each of a plurality of lines by measuring a phase distance between peak values of correlation values between a received signal transmitted from the transmitting side and receiving the received signal and a spreading code, and realizing the method. become. Then, on the transmitting side, a plurality of lines are spread and transmitted using a spreading code, and on the receiving side, a spreading code is generated, and a correlation value between the generated spreading code and a received signal is obtained. The phase of the spread code is controlled according to the phase distance between a certain peak value and a peak value adjacent to the peak value.

On the receiving side, the obtained correlation value is stored, the peak value is detected from the stored correlation value to determine the phase distance, and the phase of the spreading code is controlled in accordance with the determined phase distance. It is doing. Then, when controlling the phase, when the phase distance between a certain peak value and the adjacent peak value among the stored correlation values is k × m chips, the two peak values are respectively set to the k-th line. (K +
1) Treat them as corresponding to the first line.

As described above, the same spreading code sequence in which only the phase is changed by a different amount is assigned to each of the multiplexed lines and transmitted, and the receiving side recognizes the line by measuring the phase distance between the peaks of the autocorrelation. By doing so, only one type of spreading code generator needs to be used, so that the size of the transmitting / receiving apparatus can be further reduced. Therefore, if the present invention is applied to a mobile phone terminal, its housing can be reduced in size and weight. Further, the present invention is not limited to a mobile phone terminal,
Obviously, the present invention can be applied to a telephone for a car, a communication device for a ship, and the like. A repeater such as a communication satellite may be provided between the transmitting device and the receiving device.

[0056]

As described above, according to the present invention, the same spreading code sequence in which only the phase is changed by a different amount is assigned to each of the multiplex lines and transmitted. By measuring, there is an effect that the initial synchronization can be captured at high speed. In addition, the time required for initial synchronization acquisition can be suppressed to substantially the same as the case where a different spreading code is used for each line, so that there is an effect that it can be used for burst communication. Since only one kind of spreading code generator may be used, there is an effect that the spreading code can be saved and the size of the transmitting / receiving apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a main part of a receiving apparatus according to an embodiment of a spread spectrum communication system according to the present invention.

FIG. 2 is a diagram illustrating a case where spread spectrum communication is realized using different spreading codes.

FIG. 3 is a diagram showing a case where spread spectrum communication is realized using the same spreading code.

FIG. 4 is a diagram showing allocation of spread codes to a plurality of lines in the spread spectrum communication method according to the present invention.

FIG. 5 is a diagram showing a peak of a correlation value in a correlation curve in FIG. 1;

FIG. 6 is a diagram showing an example of storage contents of a correlation value memory in FIG. 1;

FIG. 7 is a flowchart illustrating a process performed by a CPU in FIG. 1;

FIG. 8 is a diagram showing a correlation peak (1/4 of one cycle) when a correlation value is calculated by a partial correlation method.

FIG. 9 is a diagram illustrating a general configuration of a receiving device in a spread spectrum communication system.

FIG. 10 is a diagram illustrating a general configuration of a transmission device in a spread spectrum communication system.

FIG. 11 is a diagram showing a correlation characteristic when a different spreading code is used for each line.

FIG. 12 is a diagram illustrating a method of calculating a correlation value using a digital correlator.

FIG. 13 is a block diagram illustrating an example of an internal configuration of a digital correlator.

FIG. 14 is a diagram showing a peak of a correlation value in a correlation curve in FIG. 11;

[Explanation of symbols]

 Reference Signs List 1 received input signal 2 local spreading code generator 3 digital correlator 4 correlation value memory 5 CPU

Claims (16)

[Claims] 1. A spread spectrum communication system for multiplexing and transmitting a plurality of lines by using a spread code and transmitting and receiving the same spread code having different phases by different amounts to a plurality of lines provided for multiplexing. And a receiving device for identifying each of the plurality of lines by measuring a phase distance between peak values of correlation values between the received signal transmitted from the transmitting device and the received signal and the spreading code. A spread spectrum communication system characterized by including: 2. The spread spectrum communication system according to claim 1, wherein the transmitting apparatus spreads the plurality of lines by using the spreading code to perform transmission. 3. The receiving apparatus includes a spreading code generator for generating the spreading code, and a correlator for calculating a correlation value between the spreading code and the received signal. 3. The spread spectrum communication system according to claim 1, wherein a phase of the spread code generated from the spread code generator is controlled according to a phase distance between a certain peak value and a peak value adjacent thereto. 4. The receiving apparatus according to claim 1, wherein the memory stores a correlation value obtained by the correlator, and detects a peak value from the correlation value stored in the memory to obtain the phase distance.
4. The spread spectrum communication system according to claim 3, further comprising: a control unit that controls a phase of the spreading code according to the obtained phase distance. 5. The controller according to claim 1, wherein a phase distance between a certain peak value and a peak value adjacent to the peak value among the correlation values stored in the memory is k × m chips (k and m are natural numbers, and the same hereinafter). 5. The spread spectrum communication system according to claim 4, wherein said peak values are treated as corresponding to the k-th line and the (k + 1) -th line, respectively. 6. A transmitting apparatus used in a spread spectrum communication system for transmitting and receiving a plurality of lines by multiplexing using a spreading code and transmitting and receiving the same by changing the phases of the plurality of lines to be multiplexed by different amounts. A transmitting device, which allocates and transmits a spreading code. 7. The transmitting apparatus according to claim 6, wherein the transmission is performed by spreading the plurality of lines using the spreading code. 8. A receiving apparatus for use in a spread spectrum communication system for multiplexing and transmitting a plurality of lines by using a spreading code, and a correlation value between a received signal transmitted from a transmitting side and receiving the received signal and the spreading code. A phase distance between peak values of the plurality of lines, and identifying each of the plurality of lines. 9. A spread code generator for generating the spread code, and a correlator for obtaining a correlation value between the spread code and the received signal, wherein a peak value and a correlation value for a correlation value obtained by the correlator are calculated. The receiving apparatus according to claim 8, wherein a phase of the spread code generated from the spread code generator is controlled according to a phase distance from a peak value adjacent to the spread code. 10. A memory for storing a correlation value obtained by the correlator, and a peak value is detected from the correlation value stored in the memory to obtain the phase distance, and the diffusion is performed in accordance with the obtained phase distance. The receiving device according to claim 9, further comprising a control unit that controls a phase of the code. 11. The controller, when a phase distance between a certain peak value and a peak value adjacent to the certain peak value among the correlation values stored in the memory is k × m chips, the two peak values are respectively k 11. The receiving apparatus according to claim 10, wherein the receiving apparatus is handled as respectively corresponding to the (k) -th line and the (k + 1) -th line. 12. A spread-spectrum communication method for multiplexing and transmitting a plurality of lines by using a spreading code, wherein the transmitting side changes the phases of the plurality of lines to be multiplexed by different amounts by the same amount. A spreading code is allocated and transmitted. On the receiving side, each of the plurality of lines is identified by measuring a phase distance between peak values of correlation values between the received signal transmitted from the transmitting side and receiving the received signal and the spreading code. A spread spectrum communication method characterized by the above-mentioned. 13. The spread spectrum communication method according to claim 12, wherein said transmitting side performs transmission by spreading said plurality of lines using said spreading code. 14. The receiving side generates a spread code, obtains a correlation value between the generated spread code and the received signal, and calculates a certain peak value and a peak value adjacent thereto for the obtained correlation value. 14. The spread spectrum communication method according to claim 12, wherein a phase of said spread code is controlled according to a phase distance between the spread code and the spread code. 15. The receiving side stores the calculated correlation value, detects a peak value from the stored correlation value to determine the phase distance, and sets the spread code in accordance with the determined phase distance. 15. The spread spectrum communication method according to claim 14, wherein the phase of the signal is controlled. 16. When controlling the phase, when a phase distance between a certain peak value and a peak value adjacent thereto in the stored correlation values is k × m chips, the two peak values are respectively 16. The spread spectrum communication method according to claim 15, wherein the k-th line and the (k + 1) -th line are dealt with respectively.