WO2018133262A1 - Method and system for constructing two-dimensional bipolar code with time/frequency domain zero-correlation zone - Google Patents

Abstract

The present invention provides a method and a system for constructing a two-dimensional bipolar code with a time/frequency domain zero-correlation zone. The construction method comprises: A. constructing a time domain zero-correlation zone spreading sequence LA having a zero-correlation zone; B. constructing a single-coincidence sequence in a frequency domain; C. constructing a Walsh sequence; D. combining the time domain zero-correlation zone spreading sequence having the zero-correlation zone with the single-coincidence sequence in the frequency domain to form a two-dimensional optical orthogonal code with a time/frequency domain zero-correlation zone; and E. combining the two-dimensional optical orthogonal code with the time/frequency domain zero-correlation zone with the Walsh sequence to form a two-dimensional bipolar code with a time/frequency domain zero-correlation zone. The present invention is beneficial in that the present invention completely eliminates multiple access interference and beat noise of a two-dimensional coherent OCDMA system, and can also eliminate the near-far effect of the two-dimensional coherent OCDMA system. Therefore, the present invention can realize a large-capacity two-dimensional coherent OCDMA system for application to an optical access network, an optical local area network, an optical code label switching network, a fiber optic sensor network, and the like.

Description

Method and system for constructing time/frequency domain zero correlation zone two-dimensional bipolar code Technical field

The present invention relates to the field of communication technologies, and in particular, to a method and system for constructing a two-dimensional bipolar code in a zero-correlation region in time/frequency domain.

Background technique

Optical code division multiple access (OCDMA) has the characteristics of broadband, security and random instant access, and is one of the best solutions for high-speed local area networks and access networks in the future. According to the degree of freedom, it can be divided into one-dimensional OCDMA system and two-dimensional OCDMA system. The address code of the two-dimensional OCDMA system not only expands in the time domain, but also expands in wavelength, which is called two-dimensional optical orthogonal code.

At present, many scholars at home and abroad have constructed many types of two-dimensional OCDMA address codes. Based on Prime code, Tancevski.L and other PC/PC and EQC/PC are constructed. The autocorrelation limit of PC/PC code is 0, the cross-correlation limit is 1, and the autocorrelation limit of EQC/PC is 0. The relevant limit is 2. Wan Shengpeng and others based on prime digital and optical orthogonal codes, constructed a PC/OOC code with an autocorrelation limit of 0 and a cross correlation limit of 1. Based on the RS code, Zhou Xiuli et al. constructed a multi-length long multi-wavelength RS code with an autocorrelation limit of 0 and a cross-correlation limit of 1. Yin Hongjun et al. constructed a two-dimensional OCFHC/OOC code and a two-dimensional variable weight code with a cross-correlation limit of 1. Li Chuanqi et al. constructed a two-dimensional QPC code with a cross-correlation limit of 1. Lee and Seo use two different one-dimensional OOCs to spread in the time domain and the frequency domain respectively. The constructed two-dimensional optical orthogonal code has a code weight of 3 and a cross-correlation limit of 1. Kwong and Yang use the prime hopping code to control the time domain and the frequency domain. The code length of the constructed two-dimensional optical orthogonal code is prime, and the cross-correlation limit is equal to 1. Kwong et al. use prime numbers and their cyclic sequences as frequency domain spreading sequences. One-dimensional OOC is a time-domain spreading sequence, and the number of wavelengths is the product of prime numbers. The cross-correlation limit of two-dimensional optical orthogonal codes is equal to 1. E.S. Shivaleela et al. directly constructed a two-dimensional optical orthogonal code using a finite field, and the cross-correlation limit is equal to one. Jen-Hao Tien and Yang et al. constructed a two-dimensional code with cross-correlation limit of 2, which increased the codeword capacity, but increased the multiple access interference between users. S.Kim and K.Yu construct three-dimensional optical orthogonal codes, which are extended in the time domain/frequency domain/space domain (or polarization domain) respectively, and the codeword capacity is greatly increased, but the system implementation is difficult, and related subsequent researches are more less.

On the other hand, with the development of optical codec technology, the traditional two-dimensional non-coherent OCDMA system has evolved to a two-dimensional coherent OCDMA system. The so-called two-dimensional coherent OCDMA refers to the use of bipolar two-dimensional address codes for spread spectrum coding and optical correlation decoding in a coherent OCDMA system, which has the advantage that the code word capacity is greatly increased. Ye Zhang uses a bipolar m hopping sequence to implement a phase-encoded two-dimensional SSFBG encoder/decoder, a two-dimensional coherent OCDMA system. In two dimensions In a coherent OCDMA system, the codewords between different users are not completely orthogonal, which will lead to multiple access interference. When the target signal and the interference signal pass through the photodetector, the beat noise will be caused, and the beat noise is much larger than the multiple access interference. The most important noise of two-dimensional coherent OCDMA systems. Ji Jianhua et al. constructed a collision-free bipolar hopping code, which can eliminate multiple access interference and beat noise, but the codeword capacity is small (the code weight is equal to the code length), which makes the capacity of the two-dimensional coherent OCDMA system limited. A large-capacity two-dimensional coherent OCDMA system is realized. Ji Jianhua et al. constructed a method and device for forming a two-dimensional optical orthogonal code with zero correlation window, but only suitable for two-dimensional non-coherent OCDMA systems, and the codeword capacity is limited (equal to the effective wavelength of the system).

In the two-dimensional coherent OCDMA system, the noise that affects the performance of the entire system mainly includes multiple access interference and beat noise. Multiple access interference is caused by the non-orthogonality of the codewords, which are caused by the squared nature of the photodetector, again depending on the orthogonality of the codewords. At present, the two-dimensional coherent OCDMA system adopts bipolar m hopping sequence, the address code can not be completely orthogonal (the minimum cross-correlation limit is 1), and the cross-correlation property is not ideal, so the system has multiple access interference and beat noise. Especially when the number of concurrent users is large, the multiple access interference and the beat noise become the most important noise, which causes the bit error rate of the two-dimensional coherent OCDMA system to rise sharply, which results in the limitation of the number of access users of the two-dimensional coherent OCDMA. At the same time, since the address codes cannot be completely orthogonal, the two-dimensional coherent OCDMA system has a near-far effect, which requires complicated power control. Therefore, the current two-dimensional coherent OCDMA system is difficult to put into practical use.

Ji Jianhua et al. constructed a non-collision zone bipolar hopping code, which can eliminate multiple access interference and beat noise, but the codeword capacity is small (equal to the effective wavelength of the system), making the capacity of the two-dimensional coherent OCDMA system limited. A large-capacity two-dimensional coherent OCDMA system cannot be realized.

Summary of the invention

The invention provides a method for constructing a time/frequency domain zero correlation zone two-dimensional bipolar code, comprising the following steps:

A. Constructing a time domain zero correlation zone spreading sequence LA with a zero correlation zone;

B. Constructing a single coincidence sequence of the frequency domain;

C. constructing a Walsh sequence;

D. combining the time domain zero correlation zone spreading sequence of the zero correlation zone with the single coincidence sequence of the frequency domain to form a time/frequency domain zero correlation zone two-dimensional optical orthogonal code;

E. Combining the time/frequency domain zero correlation zone two-dimensional optical orthogonal code with the Walsh sequence, constitutes a time/frequency domain zero correlation zone two-dimensional bipolar code.

As a further improvement of the present invention, in the step A, let m and ZCZ be positive integers, where m represents the number of basic pulses, ZCZ represents the length of the zero correlation zone, and the number of basic pulses is m. And the zero correlation region length ZCZ constructs the base sequence of the LA code, and sets the length of the base sequence to N, and uses s={s1, s2, ..., sN} to represent the base sequence, using {δi, i=1, 2, ..., m} denotes the corresponding basic pulse interval in the base sequence, assuming that the distribution positions of the m basic pulses are x1, x2, ..., xm, respectively, and it is assumed that 0 ≤ x1 ≤ x2 ≤ ... ≤ xm ≤ N-1.

其中i＝1，2，…，q。As a further improvement of the present invention, in the step B, the single coincidence sequence is a frequency hopping pseudo random sequence designed for a wireless frequency hopping CDMA system. For a given parameter, the number of wavelengths q is an odd integer, defined. The length of the hopping sequence is L=m=q-2d-1. If q is an even integer, then L=q-2d-2 is defined, where m is the same as in step A, and d is any two adjacent The minimum interval of the "chip" wavelength can constitute q single-coincidence sequence sets of length L, and the sequence set is represented by A={a1, a2, ..., aq}, wherein

Where i=1, 2,...,q.

As a further improvement of the present invention, in the step D, the base sequence s of the LA code is a time-spreading pseudo-random sequence, and the single-coherence sequence is a wavelength hopping pseudo-random sequence, and the time/frequency domain zero correlation region is formed. Dimensional optical orthogonal code.

As a further improvement of the present invention, in the step E, according to the polarity of the corresponding chip of the Walsh sequence, the phase of the corresponding chip of the two-dimensional optical orthogonal code of the zero-correlation region in the time/frequency domain is controlled, thereby forming a time/frequency domain. Zero-correlation zone two-dimensional bipolar code.

The invention also provides a construction system of a time/frequency domain zero correlation zone two-dimensional bipolar code, comprising:

a first constructing module, configured to construct a time domain zero correlation zone spreading sequence LA having a zero correlation zone;

a second construction module for constructing a single coincidence sequence in the frequency domain;

a third building block for constructing a Walsh sequence;

a first processing module, configured to combine a time domain zero correlation zone spreading sequence of a zero correlation zone with a single coincidence sequence of a frequency domain to form a time/frequency domain zero correlation zone two-dimensional optical orthogonal code;

The second processing module is configured to combine the two-dimensional optical orthogonal code of the time/frequency domain zero correlation zone with the Walsh sequence to form a time/frequency domain zero correlation zone two-dimensional bipolar code.

As a further improvement of the present invention, in the first configuration module, let m and ZCZ be positive integers, where m represents the number of basic pulses, ZCZ represents the length of the zero correlation zone, and the basic pulse number m and the zero correlation zone The length ZCZ constructs the base sequence of the LA code, and sets the length of the base sequence to N. The base sequence is represented by s={s1, s2, ..., sN}, using {δi, i=1, 2,...,m} Representing the corresponding basic pulse interval in the base sequence, assuming that the distribution positions of the m basic pulses are x1, x2, ..., xm, respectively, and assuming that 0 ≤ x1 ≤ x2 ≤ ... ≤ xm ≤ N-1.

其中i＝1，2，…，q。As a further improvement of the present invention, in the second configuration module, the single coincidence sequence is a frequency hopping pseudo-random sequence designed for a wireless frequency hopping CDMA system, and for a given parameter, the number of wavelengths q is an odd integer. Define the length of the hopping sequence as L=m=q-2d-1. If q is an even integer, define L=q-2d-2, where m is the same as the meaning in the first building block, and d is arbitrary. The minimum interval between two adjacent "chip" wavelengths may constitute q single-coincidence sequence sets of length L, and the sequence set is represented by A={a1, a2, ..., aq}, wherein

Where i=1, 2,...,q.

As a further improvement of the present invention, in the first processing module, the base sequence s of the LA code is a time-spreading pseudo-random sequence, and the single-coherence sequence is a wavelength hopping pseudo-random sequence, forming a time/frequency domain zero correlation. Area two-dimensional optical orthogonal code.

As a further improvement of the present invention, in the second processing module, according to the polarity of the corresponding chip of the Walsh sequence, the phase of the corresponding chip of the two-dimensional optical orthogonal code of the time-correlation region/time domain is controlled, thereby forming a/ Two-dimensional bipolar code in the frequency domain zero correlation zone.

The invention has the beneficial effects that: as long as the delay between users is within the zero correlation zone, all codewords are completely orthogonal, which completely eliminates the multiple access interference and beat noise of the two-dimensional coherent OCDMA system, and can also eliminate the second The near-far effect of the dimensional coherent OCDMA system. Therefore, the time/frequency domain zero correlation zone two-dimensional bipolar code constructed by the invention can realize a large-capacity two-dimensional coherent OCDMA system, and is applied to an optical access network, an optical local area network, an optical code label switching network, and an optical fiber sensor network. Wait.

DRAWINGS

Figure 1 is a flow chart of the method of the present invention.

detailed description

As shown in FIG. 1 , the present invention discloses a method for constructing a two-dimensional bipolar code in a time/frequency domain zero correlation zone, which includes the following steps:

Step S1. Constructing a time domain zero correlation zone spreading sequence LA having a zero correlation zone;

Step S2. Constructing a single coincidence sequence of the frequency domain;

Step S3. Constructing a Walsh sequence;

Step S4. Combining the time domain zero correlation zone spreading sequence of the zero correlation zone with the single coincidence sequence of the frequency domain to form a time/frequency domain zero correlation zone two-dimensional optical orthogonal code;

Step S5. Combining the time/frequency domain zero correlation zone two-dimensional optical orthogonal code with the Walsh sequence, the time/frequency domain zero correlation zone two-dimensional bipolar code is formed.

In step S1, let m and ZCZ be positive integers, where m represents the number of basic pulses, ZCZ represents the length of the zero correlation zone, and the base sequence of the LA code can be constructed from the basic pulse number m and the zero correlation zone length ZCZ. (Also can be searched by an algorithm), and the length of the base sequence is N, the base sequence is represented by s={s1, s2, ..., sN}, and the base is represented by {δi, i=1, 2, ..., m} In the sequence For the corresponding basic pulse interval, it is assumed that the distribution positions of the m basic pulses are x1, x2, ..., xm, respectively, and it is assumed that 0 ≤ x1 ≤ x2 ≤ ... ≤ xm ≤ N-1.

其中i＝1，2，…，q。In step S2, the single coincidence sequence is a frequency hopping pseudo-random sequence designed for a wireless frequency hopping CDMA system. The sequence is characterized by an autocorrelation limit of zero and a cross correlation limit of one. Construction method: For a given parameter, let the number of wavelengths q be an odd integer, and define the length of the hopping sequence as L=m=q-2d-1 (if q is an even integer, then define L=q-2d- 2), where m is the same as in step S1, and d is the minimum interval of any two adjacent "chip" wavelengths, so that q single coincidence sequence sets of length L can be constructed, using A = {a1, a2, ..., aq} represents the sequence set, where

Where i=1, 2,...,q.

In step S3, the second-order Hadamard matrix H2 is:

The 2N-order Hadamard matrix H _2N is:

In step S4, the base sequence s of the LA code is a time-spreading pseudo-random sequence, and the single-coincidence sequence is a wavelength hopping pseudo-random sequence, and the time/frequency domain zero correlation zone two-dimensional optical orthogonal code is constructed. For the single coincidence sequence set A extension, a sequence set H = {h1, h2, ..., hq} of length N (so that the sequence is the same length as the LA base sequence) is generated, wherein

其中i＝1，2，…，q，序列集C就是具有零相关区的时/频域零相关区二维光正交码，码长为N，零相关区长度为ZCZ，波长数为q，码重为m＝L，码字容量为q，自相关限为0，互相关限为1，用参数表示为(N，ZCZ，m，0，1)。The base sequence s is multiplied by each of the sequence sets H={h1, h2, ..., hq}, and the resulting sequence set C={c1, c2, ..., cq}, wherein

Where i=1, 2,...,q, the sequence set C is a two-dimensional optical orthogonal code of the time-frequency domain zero correlation zone with zero correlation zone, the code length is N, the length of the zero correlation zone is ZCZ, and the number of wavelengths is q. The code weight is m=L, the codeword capacity is q, the autocorrelation limit is 0, and the cross-correlation limit is 1, which is represented by parameters (N, ZCZ, m, 0, 1).

In step S5, according to the polarity of the corresponding chip of the Walsh sequence (ie +1 or -1), the phase of the corresponding chip of the two-dimensional optical orthogonal code of the time-correlation region/time domain is controlled, thereby forming a time/frequency domain zero. Correlated 2D bipolar code. Codeword capacity is q*m, code length is N, zero correlation zone length is ZCZ, wavelength The number is q, the code weight is m=L, the autocorrelation limit is 0, and the cross correlation limit is 1.

The specific structure is as follows:

In step S1, it is assumed that the basic pulse number of the LA-based sequence is m=8, and the length of the zero-correlation zone is ZCZ=16, and the corresponding basic pulse interval {δi, i=1, 2, ... in the base sequence can be obtained. m}={16,17,18,20,19,22,23,21}, the base sequence with a total length of N=156 is:

In step S2, it is assumed that the number of wavelengths (that is, the number of effective wavelengths) q=13 of the single-coincidence sequence is constructed, and the minimum interval of any two adjacent wavelengths is d=2, so that the sequence length can be L=q-2d- The single coincidence sequence of 1=8 is (3,5,6,4,10,8,7,9), and the generated sequence is obtained by a computer search method, and the single coincidence sequence constructed by the generated sequence is as follows: Shown as follows:

Sequence 1 3,8,1,5,2,10,4,0 Sequence 2 4,9,2,6,3,11,5,1 Sequence 3 5,10,3,7,4,12,6,2 Sequence 4 6,11,4,8,5,0,7,3 Sequence 5 7,12,5,9,6,1,8,4 Sequence 6 8,0,6,10,7,2,9,5 Sequence 7 9,1,7,11,8,3,10,6 Sequence 8 10,2,8,12,9,4,11,7 Sequence 9 11,3,9,0,10,5,12,8 Sequence 10 12,4,10,1,11,6,0,9 Sequence 11 0,5,11,2,12,7,1,10 Sequence 12 1,6,12,3,0,8,2,11

Sequence 13 2,7,0,4,1,9,3,12

In step S3, a Walsh sequence of length 8 is constructed with a codeword capacity of 8, i.e., each row of the matrix represents a Walsh code.

In step S4, a two-dimensional optical orthogonal code of the time/frequency domain zero correlation region is constructed from the above LA base sequence s and the single coincidence sequence in Table 1, as shown in Table 2, the code length of the two-dimensional code is 156, The length of the zero correlation zone is 16, the code weight is 8, the effective wavelength is 13, the codeword capacity is 13, the autocorrelation limit is 0, and the cross correlation limit is 1, which can be expressed as (156,16,8,0). ,1).

Table 2

In step S5, according to the polarity of the corresponding chip of the Walsh sequence (ie +1 or -1), the phase of the corresponding chip of the two-dimensional optical orthogonal code of the time-correlation region/time domain is controlled, thereby forming a time/frequency domain zero. Correlated 2D bipolar code. Taking C13 as an example, each Walsh code is combined with C13 (controls the phase of the corresponding chip) to form two time/frequency domain zero correlation zone two-dimensional bipolar codes, ie

Similarly, any one of the time/frequency domain zero correlation zone two-dimensional optical orthogonal codes in Table 2 can be combined with each Walsh code (control the phase of the corresponding chip), which can constitute 104 time/frequency domain zeros in total. The two-dimensional bipolar code of the relevant area (the codeword capacity of the non-collision zone bipolar hopping code is only 13, and the codeword capacity of the two-dimensional optical orthogonal code of the zero correlation window is only 13). therefore. The large-capacity time/frequency domain zero correlation zone two-dimensional bipolar code constructed by the invention can realize a large-capacity two-dimensional coherent OCDMA system, and is applied to an optical access network, an optical local area network, an optical code label switching network, and a fiber sensor network. Wait.

The invention also discloses a construction system of a time/frequency domain zero correlation zone two-dimensional bipolar code, comprising:

a first constructing module, configured to construct a time domain zero correlation zone spreading sequence LA having a zero correlation zone;

a second construction module for constructing a single coincidence sequence in the frequency domain;

a third building block for constructing a Walsh sequence;

a first processing module, configured to combine a time domain zero correlation zone spreading sequence of a zero correlation zone with a single coincidence sequence of a frequency domain to form a time/frequency domain zero correlation zone two-dimensional optical orthogonal code;

The second processing module is configured to combine the two-dimensional optical orthogonal code of the time/frequency domain zero correlation zone with the Walsh sequence to form a time/frequency domain zero correlation zone two-dimensional bipolar code.

In the first configuration module, let m and ZCZ be positive integers, where m represents the number of basic pulses, ZCZ represents the length of the zero correlation zone, and the LA code is constructed from the basic pulse number m and the zero correlation zone length ZCZ. The base sequence, and the length of the base sequence is N, the base sequence is represented by s={s1, s2, ..., sN}, and the corresponding basic base sequence is represented by {δi, i=1, 2, ..., m} The pulse interval assumes that the distribution positions of the m basic pulses are x1, x2, ..., xm, respectively, and it is assumed that 0 ≤ x1 ≤ x2 ≤ ... ≤ xm ≤ N-1.

其中i＝1，2，…，q。In the second configuration module, the single coincidence sequence is a frequency hopping pseudo-random sequence designed for a wireless frequency hopping CDMA system. For a given parameter, the number of wavelengths q is an odd integer, and the length of the hopping sequence is defined. L=m=q-2d-1, if q is an even integer, then define L=q-2d-2, where m is the same as in the first building block, and d is any two adjacent “chips” The minimum interval of wavelengths can constitute q single-coincidence sequence sets of length L, and the sequence set is represented by A={a1, a2, ..., aq}, wherein

Where i=1, 2,...,q.

In the first processing module, the base sequence s of the LA code is a time-spreading pseudo-random sequence, and the single-coincidence sequence is a wavelength hopping pseudo-random sequence, and the two-dimensional optical orthogonal code of the zero-correlation region in the time/frequency domain is formed. .

In the second processing module, according to the polarity of the corresponding chip of the Walsh sequence, the phase of the corresponding chip of the two-dimensional optical orthogonal code in the zero-correlation region of the time/frequency domain is controlled, thereby forming a time/frequency domain zero correlation region two-dimensionally. Bipolar code.

The method and system for constructing a time/frequency domain zero correlation region two-dimensional bipolar code according to the present invention is different from the traditional two-dimensional optical orthogonal code and different from the traditional one-dimensional time domain zero correlation region spreading sequence. Moreover, the code word capacity is much larger than the existing collision-free area bipolar hopping code. In the present invention, as long as the delay between users is within the zero correlation region, all codewords are completely orthogonal, which will completely eliminate the multiple access interference and beat noise of the two-dimensional coherent OCDMA system, and can also eliminate the near-far effect of the two-dimensional coherent OCDMA system. . Therefore, the time/frequency domain zero correlation zone two-dimensional bipolar code constructed by the invention can realize a large-capacity two-dimensional coherent OCDMA system, and is applied to an optical access network, an optical local area network, an optical code label switching network, and an optical fiber sensor network. Wait.

The above is a further detailed description of the present invention in connection with the specific preferred embodiments, and the specific embodiments of the present invention are not limited to the description. It will be apparent to those skilled in the art that the present invention may be made without departing from the spirit and scope of the invention.

Claims (10)

A method for constructing a time/frequency domain zero correlation zone two-dimensional bipolar code, comprising the steps of: A. Constructing a time domain zero correlation zone spreading sequence LA with a zero correlation zone; B. Constructing a single coincidence sequence of the frequency domain; C. constructing a Walsh sequence; D. combining the time domain zero correlation zone spreading sequence of the zero correlation zone with the single coincidence sequence of the frequency domain to form a time/frequency domain zero correlation zone two-dimensional optical orthogonal code; E. Combining the time/frequency domain zero correlation zone two-dimensional optical orthogonal code with the Walsh sequence, constitutes a time/frequency domain zero correlation zone two-dimensional bipolar code. The construction method according to claim 1, wherein in the step A, m and ZCZ are positive integers, wherein m represents the number of basic pulses, and ZCZ represents the length of the zero correlation region, and the number of basic pulses m and the zero correlation zone length ZCZ construct the base sequence of the LA code, and set the length of the base sequence to N, and use s={s1, s2,..., sN} to represent the base sequence, using {δi, i=1, 2 , ..., m} denotes the corresponding basic pulse interval in the base sequence, assuming that the distribution positions of the m basic pulses are x1, x2, ..., xm, respectively, and it is assumed that 0 ≤ x1 ≤ x2 ≤ ... ≤ xm ≤ N-1. The construction method according to claim 2, wherein in the step B, the single coincidence sequence is a frequency hopping pseudo random sequence designed for a wireless frequency hopping CDMA system, and the number of wavelengths is set for a given parameter. q is an odd integer, and the length of the hopping sequence is defined as L=m=q-2d-1. If q is an even integer, then L=q-2d-2 is defined, where m has the same meaning as in step A. d is the minimum interval of any two adjacent "chip" wavelengths, and may constitute q single coincidence sequence sets of length L, and the sequence set is represented by A={a1, a2, ..., aq}, wherein

Where i=1, 2,...,q. The construction method according to claim 3, wherein in the step D, the base sequence s of the LA code is a time-spreading pseudo-random sequence, and the single-coherence sequence is a wavelength hopping pseudo-random sequence. / Frequency domain zero correlation zone two-dimensional optical orthogonal code. The method according to claim 4, wherein in the step E, the phase of the corresponding chip of the two-dimensional optical orthogonal code in the zero-correlation region of the time/frequency domain is controlled according to the polarity of the corresponding chip of the Walsh sequence. Thus, a two-dimensional bipolar code of time-frequency domain zero correlation region is constructed. A time/frequency domain zero correlation zone two-dimensional bipolar code construction system, characterized in that: a first constructing module, configured to construct a time domain zero correlation zone spreading sequence LA having a zero correlation zone; a second construction module for constructing a single coincidence sequence in the frequency domain; a third building block for constructing a Walsh sequence; a first processing module, configured to combine a time domain zero correlation zone spreading sequence of a zero correlation zone with a single coincidence sequence of a frequency domain to form a time/frequency domain zero correlation zone two-dimensional optical orthogonal code; The second processing module is configured to combine the two-dimensional optical orthogonal code of the time/frequency domain zero correlation zone with the Walsh sequence to form a time/frequency domain zero correlation zone two-dimensional bipolar code. The construction system according to claim 6, wherein in the first configuration module, m and ZCZ are positive integers, wherein m represents the number of basic pulses, and ZCZ represents the length of the zero correlation zone, The pulse number m and the zero correlation region length ZCZ construct the base sequence of the LA code, and set the length of the base sequence to N, and use s={s1, s2, ..., sN} to represent the base sequence, using {δi, i=1 , 2, ..., m} represents the corresponding basic pulse interval in the base sequence, assuming that the distribution positions of the m basic pulses are x1, x2, ..., xm, respectively, and assuming that 0 ≤ x1 ≤ x2 ≤ ... ≤ xm ≤ N-1 . The construction system according to claim 7, wherein in the second configuration module, the single coincidence sequence is a frequency hopping pseudo-random sequence designed for a wireless frequency hopping CDMA system, and for a given parameter, The number of wavelengths q is an odd integer, and the length of the hopping sequence is defined as L=m=q-2d-1. If q is an even integer, then L=q-2d-2 is defined, where m is in the first construction module. The meaning is the same, d is the minimum interval of any two adjacent "chip" wavelengths, then it can form q single coincidence sequence sets of length L, and the sequence set is represented by A={a1, a2, ..., aq}. among them

Where i=1, 2,...,q. The construction system according to claim 8, wherein in the first processing module, the base sequence s of the LA code is a time-spreading pseudo-random sequence, and the single-coherence sequence is a wavelength hopping pseudo-random sequence. A two-dimensional optical orthogonal code constituting a time/frequency domain zero correlation region. The construction system according to claim 9, wherein in the second processing module, the corresponding chip of the two-dimensional optical orthogonal code of the zero-correlation region in the time/frequency domain is controlled according to the polarity of the corresponding chip of the Walsh sequence. The phase, which constitutes a time/frequency domain zero correlation zone two-dimensional bipolar code.

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