CN103117981A - Vector accumulation based direct spread communication method - Google Patents

Abstract

The purpose of the invention is to provide a vector accumulation based direct spread communication method. The vector accumulation based direct spread communication method comprises the following steps: selecting r sequences from a PN code sequence family; selecting (r-1) transmission sequences correspondingly capable of transmitting information data of [log2C<r-1>M-1] bits, wherein (r-1) spread spectrum sequences totally have q phase selections and are correspondingly capable of transmitting information data of (r-1)[log2q] bits, and (r-1) sequences totally have information transmission of (r-1)*[log2L] bits; putting the states and the information data in one-to-one correspondence; and accumulating vectors of (r-1) PN code transmission sequences, sequence displacement and phase states and one fixed localizer sequence together for transmission so as to form an efficient direct spread signal. The vector accumulation based direct spread communication method improves an efficient spread spectrum communication method, increases the spread spectrum communication transmission efficiency and effectiveness of whole communication, fully utilizes the superiority of the vector accumulation, and achieves higher transmission efficiency than a transmission and reception method of a fixed PN code displacement modulation based efficient direct spread system under the same condition.

Description

A kind of based on vector superposed direct-sequence spread-spectrum communication method

Technical field

What the present invention relates to is a kind of communication means.

Background technology

Modern communications increases day by day to the requirement of communication high efficiency.Efficient direct-sequence spread-spectrum communication is a kind of spread spectrum communication mode with higher communication efficiency, and has inherited the advantages such as conventional spread spectrum communication is anti-interference.The parallel combined spread spectrum communication mode that efficiency of transmission is higher obtains the favorable comment of Chinese scholars, and is introduced on scholarly journal by Chinese scholars.Efficient direct-sequence spread-spectrum communication also has room for promotion on efficiency of transmission.

Summary of the invention

The object of the present invention is to provide to take full advantage of vector superposed further increase and once send data volume, thereby solved a kind of based on vector superposed direct-sequence spread-spectrum communication method on the problem that affects of system transmissions efficient of higher spreading gain.

The object of the present invention is achieved like this:

The present invention is a kind of based on vector superposed direct-sequence spread-spectrum communication method, it is characterized in that:

(1) the K Bit data that sends is designated as d ₁, d ₂, d ₃..., d _K, each information data cycle is T _d, KT wherein _d=LT _c, L is the code element number of each PN sequence, T _cBe chip period; K bit transmission information is sent into serial/parallel transducer, obtains K road signal;

(2) the K road signal that step (1) is obtained is divided into three parts, corresponds to respectively

Bit, (r-1) [log ₂Q] bit and (r-1) [log ₂L] bit; Choose the sequence of (r-1) individual transmission from PN sequence family according to the data-mapping algorithm, total Plant and send the selection of frequency expansion sequence situation, to transmitting

The information data of bit, [x] represent x round numbers part, It is the combination of getting r in M; (r-1) individual frequency expansion sequence has q kind phase place S=[S ₁(t), S ₂(t) ...., S _r-1(t)] select to send, wherein S _j(t)=exp[j{2 π (m _j-1)/q}], m _j=1,2 ..., q, q 〉=2; (r-1) individual frequency expansion sequence is chosen certain phase state transmission from q kind phase place, to transmitting (r-1) [log ₂Q] information data of bit; (r-1) in individual sequence, each sequence has L position can select to send, total (r-1) [log ₂L] the bit information transmission; Corresponding one by one with information data these states, corresponding information data K is:

$K=(r-1)\left[{\log }_{2}q\right]+\left[{\log }_2{C}_{M-1}^{r-1}\right]+(r-1)\left[{\log }_{2}L\right]$

Selecting (r-1) individual transmission PN code sequence, sequence displacement and phase state etc. and 1 stationary positioned mark sequence, in the vector space transmission that is superimposed, form direct sequence signal displacement Rankine-Hugoniot relations

$A^{\&prime;}=\{{\mathrm{PN}}_1\left(0\right),{\mathrm{<figure-callout\; id="1"\; label="S\; j"\; filenames="HDA00002835748300011.png"\; state="\{\{state\}\}">S</figure-callout>}}_{j_{}}{\mathrm{PN}}_{j_1}\left(p_{j_1}\right),....,S_{j_2}{\mathrm{PN}}_{j_2}\left(p_{j_2}\right),....,S_{j_{(r-1)}}{\mathrm{PN}}_{j_{(r-1)}}\left(p_{j_{(r-1)}}\right)\}$

In formula, { S _j∈ exp[j{2 π (m _j-1)/q}], j=1,2 ..r _p, m _j=1,2 ..., q}; R sequence superposes at vector space, forms the combination multi-valued signal:

$\mathrm{MD}(r,t)={\mathrm{PN}}_1\left(0\right)+\underset{i=1}{\overset{r-1}{\mathrm{\&Sigma;}}}{S}_{j_i}{\mathrm{PN}}_{j_i}\left(p_{j_i}\right)$

MD is many-valued transmitted signal, and t is time variable,

Be that i transmission sequence of j order moves to left with respect to fixed bit mark sequence

Individual position;

(3) multi-valued signal of vector superposed generation after carrier modulation, is mapped as the MQAM carrier modulation and sends, transmitted signal s (t)

In formula, P is carrier power;

(4) under Gaussian white noise channel, the reception signal is

r(t)＝s(t-τ)+n(t)+J(t)

In formula, τ is the communication transmission time delay; N (t) is white Gaussian noise, and its double-side band power spectral density is N ₀/ 2; J (t) is interference signal; If the frequency of transmitting terminal and receiving terminal carrier wave, symbol phases Complete Synchronization according to the sequence signal that is superimposed after carrier wave demodulation, remove known PN ₁(0) information, then be real number or pure imaginary number according to the data of this moment, or plural number, demodulate the phase information of modulation, remove the phase information of modulation, revert to whole real data and carry out again despreading; Receiving terminal has M frequency multiplier, uses respectively PN after carrier wave demodulation _i(t) (i=1,2 ... M) do despreading and process, the i except the 1st demodulator in M demodulator (2≤i≤M) individual extended frequency demodulator is output as:

$Z_i\left(t\right)=P\underset{j=1}{\overset{r-1}{\mathrm{\&Sigma;}}}{S}_{i_j}\underset{\mathrm{\&tau;}}{\overset{T+\mathrm{\&tau;}}{\&Integral;}}{\mathrm{PN}}_{i_j}(t-\mathrm{\&tau;}){\mathrm{PN}}_i(t-\mathrm{\&tau;})\mathrm{dt}+N_i\left(t\right)+J_i$

In formula, i=i _jIntegration be the auto-correlation of frequency expansion sequence, i ≠ i _jIt is cross-correlation; Demodulator is output as

$Z_i\left(t\right)=\left\{\begin{array}{cc}{S}_{\mathrm{ij}}\mathrm{PT}+N_i+J_i& i=i_j\\ N_i+J_i& i\&NotEqual;i_j\end{array}\right.$

Two groups of PN sequence row that use are accurate quadrature each other;

(5) (M-1) the individual demodulator output valve that step (4) is obtained with and corresponding PN code sequence number input data-sequence selection inverse mapping device, in some phase place output valves from (M-1) individual despreader, choose the corresponding frequency expansion sequence sequence number of (r-1) individual output valve, phase polarity and the displacement relation of absolute value maximum as the composite sequence that sends, send into data-displacement inverse mapping device, draw the K circuit-switched data information of reception;

The K circuit-switched data information that (6) will draw reception obtains K bit prime information through parallel/serial conversion.

Advantage of the present invention is: the low problem of efficiency of transmission that the invention solves existing efficient straight spread spectrum, utilize vector superposed further increase once to send data volume, simultaneously also preferably resolve higher spreading gain to the problem that affects of system transmissions efficient, preferably resolve the contradiction of high-speed transfer and bandwidth, can increase substantially band efficiency.The efficient spread spectrum communication of existing direct sequence is chosen r sequence the parallel combined spread spectrum mode and is transmitted from M PN code sequence, once can only transmit

$K=r+\left[{\log }_2\left(C_M^r\right)\right]$

Bit data, and a kind ofly once can transmit under the same conditions based on vector superposed efficient direct-sequence spread-spectrum communication method

$K=(r-1)\left[{\log }_{2}q\right]+\left[{\log }_2{C}_{M-1}^{r-1}\right]+(r-1)\left[{\log }_{2}L\right]$

Bit information; General q=4 or 8 or ..., once can multiplely send (r-1) [log ₂Q] Bit data, efficiency of transmission is further promoted.

Description of drawings

Fig. 1 is process of transmitting structure chart of the present invention;

Fig. 2 is receiving course structure chart of the present invention.

Embodiment

For example the present invention is described in more detail below in conjunction with accompanying drawing:

In conjunction with Fig. 1～2, step 1: the K Bit data of transmission is designated as d ₁, d ₂, d ₄..., d _K, each information data cycle is T _d, KT wherein _d=LT _c, L is the code element number of each PN sequence, T _cBe chip period; K bit transmission information is sent into serial/parallel transducer, obtains K road signal;

Step 2: the K road signal that step 1 is obtained is divided into three parts, corresponds to respectively

Bit, (r-1) [log ₂Q] bit and (r-1) [log ₂L] bit; Choose the sequence of (r-1) individual transmission from PN sequence family (M-1 PN code sequence except fixed bit mark sequence) according to the data-mapping algorithm, total total

Plant and send the selection of frequency expansion sequence situation, to transmitting

The information data of bit, [x] represent x round numbers part,

It is the combination of getting r in M; Then consider that (r-1) individual frequency expansion sequence can have multiple phase place S=[S ₁(t), S ₂(t) ...., S _r-1(t)] select to send total q kind (q 〉=2) Selecting phasing, wherein S _j(t)=exp[j{2 π (m _j-1)/q}], m _j=1,2 ..., q, general q=4 or 8 or If (r-1) individual frequency expansion sequence is chosen certain phase state transmission from q kind phase place, to transmitting (r-1) [log ₂Q] information data of bit; Consider that again in (r-1) individual sequence (the sequence code length is all L), each sequence has L position, and (position is from p ₀To p _L-1) can select to send (according to fixed bit mark sequence location), have (r-1) [log ₂L] the bit information transmission; Corresponding one by one with information data these states, corresponding information data K is:

$K=(r-1)\left[{\log }_{2}q\right]+\left[{\log }_2{C}_{M-1}^{r-1}\right]+(r-1)\left[{\log }_{2}L\right]$

Selecting (r-1) individual transmission PN code sequence, sequence displacement and phase state etc. and 1 stationary positioned mark sequence, in the vector space transmission that is superimposed, form efficient direct sequence signal displacement Rankine-Hugoniot relations

$A^{\&prime;}=\{{\mathrm{PN}}_1\left(0\right),{\mathrm{<figure-callout\; id="1"\; label="S\; j"\; filenames="HDA00002835748300011.png"\; state="\{\{state\}\}">S</figure-callout>}}_{j_{}}{\mathrm{PN}}_{j_1}\left(p_{j_1}\right),....,S_{j_2}{\mathrm{PN}}_{j_2}\left(p_{j_2}\right),....,S_{j_{(r-1)}}{\mathrm{PN}}_{j_{(r-1)}}\left(p_{j_{(r-1)}}\right)\}$

In formula, { S _j∈ exp[j{2 π (m _j-1)/q}], j=1,2 ..r _p, m _j=1,2 ..., q}; R sequence is at vector space stack ((a _j+ b _jI) value addition), form the combination multi-valued signal:

$\mathrm{MD}(r,t)={\mathrm{PN}}_1\left(0\right)+\underset{i=1}{\overset{r-1}{\mathrm{\&Sigma;}}}{S}_{j_i}{\mathrm{PN}}_{j_i}\left(p_{j_i}\right)$

Step 3: the multi-valued signal of vector superposed generation after carrier modulation, can be mapped as the MQAM carrier modulation and send, transmitted signal s (t)

In formula, P is carrier power, with signal s (t) emission that obtains;

The receiving terminal process:

Step 4: under Gaussian white noise channel, the reception signal is

r(t)＝s(t-τ)+n(t)+J(t)

In formula, τ is the communication transmission time delay; N (t) is white Gaussian noise, and its double-side band power spectral density is N ₀/ 2; J (t) is interference signal; If the frequency of transmitting terminal and receiving terminal carrier wave, symbol phases Complete Synchronization according to the sequence signal that is superimposed after carrier wave demodulation, remove known PN ₁(0) information (PN ₁(0) do not carry out phase-modulation), then be real number or pure imaginary number according to the data of this moment, or plural number, demodulate the phase information of modulation, remove the phase information of modulation, need to revert to whole real data and carry out again despreading; Receiving terminal has M frequency multiplier, uses respectively PN after carrier wave demodulation _i(t) (i=1,2 ... M) do despreading and process, in M demodulator except the 1st demodulator the i(2≤i≤M) individual extended frequency demodulator is output as:

$Z_i\left(t\right)=P\underset{j=1}{\overset{r-1}{\mathrm{\&Sigma;}}}{S}_{i_j}\underset{\mathrm{\&tau;}}{\overset{T+\mathrm{\&tau;}}{\&Integral;}}{\mathrm{PN}}_{i_j}(t-\mathrm{\&tau;}){\mathrm{PN}}_i(t-\mathrm{\&tau;})\mathrm{dt}+N_i\left(t\right)+J_i$

In formula, τ is the communication transmission time delay; I=i _jIntegration be the auto-correlation of frequency expansion sequence; I ≠ i _jIt is cross-correlation; Demodulator is output as

$Z_i\left(t\right)=\left\{\begin{array}{cc}{S}_{\mathrm{ij}}\mathrm{PT}+N_i+J_i& i=i_j\\ N_i+J_i& i\&NotEqual;i_j\end{array}\right.$

Two groups of PN sequence row that use are accurate quadrature each other, meets the demands;

Step 5: (M-1) individual demodulator output valve that step 4 is obtained with and corresponding PN code sequence number input data-sequence selection inverse mapping device, in L phase place output valve from (M-1) individual despreader, choose the corresponding frequency expansion sequence sequence number of (r-1) individual output valve, phase polarity and the displacement relation of absolute value maximum as the composite sequence that sends, send into data-displacement inverse mapping device, draw the K circuit-switched data information of reception;

Step 6: through parallel/serial conversion, obtain K bit prime information.

The below illustrates:

In conjunction with Fig. 1, a kind of based on the vector superposed efficient direct-sequence spread-spectrum communication method employing system parameters identical system parameters identical with conventional the parallel combined spectrum spreading method, choose r=3 sequence the parallel combined and send from M=16 PN code sequence, PN code length L=512, q=4;

Step 1: in emission process, the K Bit data of transmission is designated as d ₁, d ₂, d ₃..., d ₂₈, $K=(3-1)\left[{\log }_{2}4\right]+\left[{\log }_2{C}_{16-1}^{3-1}\right]+(3-1)\&CenterDot;\left[{\log }_{2}512\right]=28;$ 28 bit transmission information are sent into serial/parallel transducer, obtain 28 road parallel signals; These parallel signals are divided into three parts, are respectively information 6 bits, 4 bits and 18 bits;

Step 2: the parallel data that will correspond to 6 bits, 4 bits and 18 bits, choose the sequence of 2 transmissions from PN sequence family (comprising altogether 15 PN code sequences) according to data-mapping algorithm, always have 105 kinds and send the selection of frequency expansion sequence situation, to transmitting the information data of 6 bits; Consider that 2 frequency expansion sequences can have q=4 kind phase place S=[S ₁(t), S ₂(t)] select to send total q=4 kind Selecting phasing, wherein S _j(t)=exp[j{2 π (m _j-1)/4}], m _j=1,2,3,4; If 2 frequency expansion sequences are chosen certain phase state and are sent from 4 kinds of phase places, to transmitting the information data of 4 bits; Consider that again in 2 sequences (the sequence code length is all 512), each sequence has 512 positions, and (position is from p ₀To p _L-1) can select to send (according to fixed bit mark sequence location), have 18 bit information transmission; Send PN code sequence, sequence displacement and phase states etc. and 1 stationary positioned mark sequence selecting 2, in the vector space transmission that is superimposed, form efficient direct sequence signal displacement Rankine-Hugoniot relations

$A^{\&prime;}=\{{\mathrm{PN}}_1\left(0\right),{\mathrm{<figure-callout\; id="1"\; label="S\; j"\; filenames="HDA00002835748300011.png"\; state="\{\{state\}\}">S</figure-callout>}}_{j_{}}{\mathrm{PN}}_{j_1}\left(p_{j_1}\right),S_{j_2}{\mathrm{PN}}_{j_2}\left(p_{j_2}\right)\}$

In formula, { S _j∈ exp[j{2 π (m _j-1)/q}], j=1,2,, m _j=1,2,3,4}; 3 sequences at vector space stack concrete grammar are, total q=4 kind phase place, so that+1 ,-1, and+i ,-i} when having 3 sequences to send, has 3 ⁴=27 kinds of situations, but some situations merge, and can produce 16 kinds of phase places according to the vector planisphere;

(a) superpose when 3 sequences all are the real number phase place, according to the combination law, have 4 kinds of situations: 1,1,1}, 1 ,-1,1}, 1,1 ,-1}, and 1 ,-1 ,-1}; These 4 kinds of situations altogether can produce 4 kinds of new phases 3 ,-1,1,3};

(b) when 3 sequences all are the pure imaginary number Phase Stacking, according to the combination law, also have 4 kinds of situations: { i, i, i}, { i ,-i, i}, { i, i ,-i}, { i ,-i ,-i}.These 4 kinds of situations can produce 4 kinds of new phases { 3i ,-i, i, 3i} altogether;

(c) superpose when 3 sequences are all real number imaginary number mixed-phase, according to the combination law, have 12 kinds of situations, { 1,1, i}, { 1,1 ,-i}, 1 ,-1, i}, { 1 ,-1,-i}, and 1 ,-1, i}, 1 ,-1 ,-i}, { i, i, 1}, { i, i ,-1}, { i ,-i, 1}, { i ,-i ,-1}, { i ,-i, 1}, { i ,-i ,-1}; These 12 kinds of situations can produce 8 kinds of new phases { 2+i, 2-i ,-2+i ,-2-i, 1+2i, 1-2i ,-1+2i ,-1-2i} altogether.

Step 3: the multi-valued signal of vector superposed generation, produce altogether 16 kinds of phase places, after carrier modulation, can be mapped as the 16QAM carrier modulation and send, transmitted signal s (t)

In formula, P is carrier power, with signal s (t) emission that obtains;

Step 4: under the receiving terminal Gaussian white noise channel, the reception signal is

r(t)＝s(t-τ)+n(t)+J(t)

In formula, τ is the communication transmission time delay; N (t) is white Gaussian noise, and its double-side band power spectral density is N ₀/ 2; J (t) is interference signal; If the frequency of transmitting terminal and receiving terminal carrier wave, symbol phases Complete Synchronization according to the sequence signal that is superimposed after carrier wave demodulation, remove known PN ₁(0) information (PN ₁(0) do not carry out phase-modulation), then be real number or pure imaginary number according to the data of this moment, or plural number, demodulate the phase information of modulation, remove the phase information of modulation, need to revert to whole real data and carry out again despreading; Receiving terminal has 16 frequency multipliers, uses respectively PN after carrier wave demodulation _i(t) (i=1,2 ... 16) do despreading and process, the i(2 except the 1st demodulator≤i≤16 in 16 demodulators) individual extended frequency demodulator is output as:

$Z_i\left(t\right)=P\underset{j=1}{\overset{2}{\mathrm{\&Sigma;}}}{S}_{i_j}\underset{\mathrm{\&tau;}}{\overset{T+\mathrm{\&tau;}}{\&Integral;}}{\mathrm{PN}}_{i_j}(t-\mathrm{\&tau;}){\mathrm{PN}}_i(t-\mathrm{\&tau;})\mathrm{dt}+N_i\left(t\right)+J_i$

In formula, τ is the communication transmission time delay; I=i _jIntegration be the auto-correlation of frequency expansion sequence; I ≠ i _jIt is cross-correlation; Demodulator is output as

$Z_i\left(t\right)=\left\{\begin{array}{cc}{S}_{\mathrm{ij}}\mathrm{PT}+N_i+J_i& i=i_j\\ N_i+J_i& i\&NotEqual;i_j\end{array}\right.$

Two groups of PN sequence row that use are accurate quadrature each other, meets the demands;

Step 5:

15 demodulator output valves that step 4 is obtained with and corresponding PN code sequence number input data-sequence selection inverse mapping device, in 512 phase place output valves from 15 despreaders, choose the corresponding frequency expansion sequence sequence number of 2 output valves, phase polarity and the displacement relation of absolute value maximum as the composite sequence that sends, send into data-displacement inverse mapping device, draw 28 circuit-switched data information of reception;

Step 6: through parallel/serial conversion, obtain 28 bit prime informations.

Choose 3 sequences and carry out the parallel combined spread spectrum mode and transmit from 16 PN code sequences of the same terms, once can only transmit $K=r+\left[{\log }_2\left(C_M^r\right)\right]=12$ Bit data, and a kind ofly can once transmit under the same conditions based on vector superposed efficient direct-sequence spread-spectrum communication method $K=(3-1)\left[{\log }_{2}4\right]+\left[{\log }_2{C}_{16-1}^{3-1}\right]+(3-1)\&CenterDot;\left[{\log }_{2}512\right]=28$ Bit information, general q=4 or 8 or ..., once can multiplely send 4 Bit datas, efficiency of transmission is further promoted.The present invention has improved efficient spectrum spread communication method, improve the validity of spread spectrum communication efficiency of transmission and integrated communication, take full advantage of vector superposed advantage, higher with the method for reseptance efficiency of transmission than a kind of efficient directly-enlarging system emission based on fixed PN code displacive modulation under the same conditions; Also can solve preferably simultaneously higher spreading gain to the problem that affects of system transmissions efficient, preferably resolve the contradiction of high-speed transfer and bandwidth, can increase substantially band efficiency.When vector space q was more, efficiency of transmission was higher.

Claims (1)

1. one kind based on vector superposed direct-sequence spread-spectrum communication method, it is characterized in that:

(1) the K Bit data that sends is designated as d ₁, d ₂, d ₃..., d _K, each information data cycle is T _d, KT wherein _d=LT _c, L is the code element number of each PN sequence, T _cBe chip period; K bit transmission information is sent into serial/parallel transducer, obtains K road signal;

(2) the K road signal that step (1) is obtained is divided into three parts, corresponds to respectively

Bit, (r-1) [log ₂Q] bit and (r-1) [log ₂L] bit; Choose the sequence of (r-1) individual transmission from PN sequence family according to the data-mapping algorithm, total

Plant and send the selection of frequency expansion sequence situation, to transmitting

The information data of bit, [x] represent x round numbers part,

It is the combination of getting r in M; (r-1) individual frequency expansion sequence has q kind phase place S=[S ₁(t), S ₂(t) ...., S _r-1(t)] select to send, wherein S _j(t)=exp[j{2 π (m _j-1)/q}], m _j=1,2 ..., q, q 〉=2; (r-1) individual frequency expansion sequence is chosen certain phase state transmission from q kind phase place, to transmitting (r-1) [log ₂Q] information data of bit; (r-1) in individual sequence, each sequence has L position can select to send, total (r-1) [log ₂L] the bit information transmission; Corresponding one by one with information data these states, corresponding information data K is:

$K=(r-1)\left[{\log }_{2}q\right]+\left[{\log }_2{C}_{M-1}^{r-1}\right]+(r-1)\left[{\log }_{2}L\right]$

Selecting (r-1) individual transmission PN code sequence, sequence displacement and phase state etc. and 1 stationary positioned mark sequence, in the vector space transmission that is superimposed, form direct sequence signal displacement Rankine-Hugoniot relations

$A^{\&prime;}=\{{\mathrm{PN}}_1\left(0\right),S_{j_1}{\mathrm{PN}}_{j_1}\left(p_{j_1}\right),....,S_{j_2}{\mathrm{PN}}_{j_2}\left(p_{j_2}\right),....,S_{j_{(r-1)}}{\mathrm{PN}}_{j_{(r-1)}}\left(p_{j_{(r-1)}}\right)\}$

In formula, { S _j∈ exp[j{2 π (m _j-1)/q}], j=1,2 ..r _p, m _j=1,2 ..., q}; R sequence superposes at vector space, forms the combination multi-valued signal:

$\mathrm{MD}(r,t)={\mathrm{PN}}_1\left(0\right)+\underset{i=1}{\overset{r-1}{\mathrm{\&Sigma;}}}{S}_{j_i}{\mathrm{PN}}_{j_i}\left(p_{j_i}\right)$

MD is many-valued transmitted signal, and t is time variable,

Be that i transmission sequence of j order moves to left with respect to fixed bit mark sequence

Individual position;

(3) multi-valued signal of vector superposed generation after carrier modulation, is mapped as the MQAM carrier modulation and sends, transmitted signal s (t)

In formula, P is carrier power;

(4) under Gaussian white noise channel, the reception signal is

r(t)＝s(t-τ)+n(t)+J(t)

In formula, τ is the communication transmission time delay; N (t) is white Gaussian noise, and its double-side band power spectral density is N ₀/ 2; J (t) is interference signal; If the frequency of transmitting terminal and receiving terminal carrier wave, symbol phases Complete Synchronization according to the sequence signal that is superimposed after carrier wave demodulation, remove known PN ₁(0) information, then be real number or pure imaginary number according to the data of this moment, or plural number, demodulate the phase information of modulation, remove the phase information of modulation, revert to whole real data and carry out again despreading; Receiving terminal has M frequency multiplier, uses respectively PN after carrier wave demodulation _i(t) (i=1,2 ... M) do despreading and process, in M demodulator except the 1st demodulator the i(2≤i≤M) individual extended frequency demodulator is output as:

$Z_i\left(t\right)=P\underset{j=1}{\overset{r-1}{\mathrm{\&Sigma;}}}{S}_{i_j}\underset{\mathrm{\&tau;}}{\overset{T+\mathrm{\&tau;}}{\&Integral;}}{\mathrm{PN}}_{i_j}(t-\mathrm{\&tau;}){\mathrm{PN}}_i(t-\mathrm{\&tau;})\mathrm{dt}+N_i\left(t\right)+J_i$

In formula, i=i _jIntegration be the auto-correlation of frequency expansion sequence, i ≠ i _jIt is cross-correlation; Demodulator is output as

$Z_i\left(t\right)=\left\{\begin{array}{cc}{S}_{\mathrm{ij}}\mathrm{PT}+N_i+J_i& i=i_j\\ N_i+J_i& i\&NotEqual;i_j\end{array}\right.$

Two groups of PN sequence row that use are accurate quadrature each other;

(5) (M-1) the individual demodulator output valve that step (4) is obtained with and corresponding PN code sequence number input data-sequence selection inverse mapping device, in some phase place output valves from (M-1) individual despreader, choose the corresponding frequency expansion sequence sequence number of (r-1) individual output valve, phase polarity and the displacement relation of absolute value maximum as the composite sequence that sends, send into data-displacement inverse mapping device, draw the K circuit-switched data information of reception;

The K circuit-switched data information that (6) will draw reception obtains K bit prime information through parallel/serial conversion.

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