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

Abstract

The purpose of the present invention is to provide a direct spread communication method based on vector superposition, which includes the following steps: select r sequences from a PN code sequence family, and select (r-1) sequences to be sent according to the data-sequence selection mapping algorithm , corresponding to the transmission

Bit information data, (r-1) spread spectrum sequences have q kinds of phase selections, corresponding to the information data that can transmit (r-1)[log ₂ q] bits; (r-1) sequences have (r-1 )·[log ₂ L] bit information transmission, corresponding these states with information data one by one, and select (r-1) transmitted PN code sequences, sequence displacement and phase states, etc. and a fixed positioning sequence, vector They are superimposed and sent together to form an efficient direct spread signal. The invention improves the high-efficiency spread spectrum communication method, improves the transmission efficiency of spread spectrum communication and the effectiveness of overall communication, fully utilizes the advantages of vector superposition, and transmits more efficiently than a high-efficiency direct spread system based on fixed PN code displacement modulation under the same conditions The transfer efficiency is somewhat higher with the receive method.

Description

A Direct Spread Communication Method Based on Vector Superposition

technical field

The invention relates to a communication method. the

Background technique

Modern communication has increasingly high requirements for communication efficiency. High-efficiency direct spread communication is a spread spectrum communication method with high communication efficiency, and it inherits the advantages of conventional spread spectrum communication such as anti-interference. The parallel combined spread spectrum communication method with higher transmission efficiency has been well received by scholars at home and abroad, and has been introduced in academic journals by domestic and foreign scholars. Efficient direct spread communication still has room for improvement in transmission efficiency. the

Contents of the invention

The purpose of the present invention is to provide a direct spread communication method based on vector superposition, which fully utilizes vector superposition to further increase the amount of data sent at one time, thereby solving the problem of the influence of higher spread spectrum gain on system transmission efficiency. the

The purpose of the present invention is achieved like this:

A kind of direct spread communication method based on vector superposition of the present invention is characterized in that:

(1) The sent K-bit data is denoted as d ₁ , d ₂ , d ₃ ,…,d _K , and each information data period is T _d , where KT _d = LT _c , and L is the number of symbols in each PN sequence Number, T _c is the chip cycle; K bit transmission information is sent to the serial/parallel converter to obtain K channel signals;

比特、(r-1)[log₂q]比特和(r-1)·[log₂L]比特；根据数据映射算法从PN序列族中选取(r-1)个发送的序列，共有种发送扩频序列情况选择，对应能传输 

比特的信息数据，[x]表示对x取整数部分，是M中取r的组合；(r-1)个扩频序列有q种相位S＝[S₁(t),S₂(t),....,S_r-1(t)]选择发送，其中S_j(t)＝exp[j{2π(m_j-1)/q}]，m_j＝1,2,...,q，q≥2；(r-1)个扩频序列从q种相位中选取某种相位状态发送，对应能传输(r-1)[log₂q]比特的信息数据；(r-1)个 序列中，每个序列都有L个位置可以选择进行发送，则共有(r-1)·[log₂L]比特信息传输；把这些状态与信息数据一一对应，则对应的信息数据K是：  (2) Divide the K-channel signal obtained in step (1) into three parts, corresponding to

bits, (r-1)[log ₂ q] bits and (r-1)[log ₂ L] bits; select (r-1) transmitted sequences from the PN sequence family according to the data mapping algorithm, and have a total of A selection of the transmission spread spectrum sequence, corresponding to the transmission

Bit information data, [x] represents the integer part of x, It is a combination of r in M; (r-1) spread spectrum sequences have q kinds of phases S=[S ₁ (t), S ₂ (t),...,S _r-1 (t)] selection Send, where S _j (t)=exp[j{2π(m _j -1)/q}], m _j =1,2,...,q, q≥2; (r-1) spread spectrum The sequence selects a certain phase state from q phases to send, corresponding to the information data that can transmit (r-1)[log ₂ q] bits; among (r-1) sequences, each sequence has L positions to choose from Sending, then there are (r-1)·[log ₂ L] bit information transmission; if these states and information data are corresponding one by one, then the corresponding information data K is:

$\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; q</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; ]</span>$

The selected (r-1) transmitted PN code sequences, sequence displacements and phase states, etc. and a fixed positioning sequence are superimposed and sent together in the vector space to form a direct spread signal displacement arrangement relationship.

${\mathrm{<span\; class="notranslate">\; A</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; PN</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="S\; j"\; filenames="HDA00002835748300011.png"\; state="\{\{state\}\}">S</figure-callout></span><figure-callout\; id="1"\; label="S\; j"\; filenames="HDA00002835748300011.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{{\mathrm{<span\; class="notranslate">\; </span>}}_{}}{\mathrm{<span\; class="notranslate">\; PN</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; PN</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}}{\mathrm{<span\; class="notranslate">\; PN</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \}</span>$

In the formula, {S _j ∈ exp[j{2π(m _j -1)/q}], j=1,2,..r _p ,m _j =1,2,...,q}; r Sequences are superimposed in vector space to form combined multivalued signals:

$\mathrm{<span\; class="notranslate">\; MD</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; PN</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; S</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\mathrm{<span\; class="notranslate">\; PN</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; )</span>$

为第j次第i个发送序列相对于固定位标序列左移

个位置；  MD is a multi-valued sending signal, t is a time variable,

Shift the i-th transmission sequence to the left relative to the fixed index sequence for the j-th time

location;

(3) The multi-valued signal generated by vector superposition, after carrier modulation, is mapped to MQAM carrier modulation and sent out, sending signal s(t)

In the formula, P is the carrier power;

(4) Under the Gaussian white noise channel, the received signal is

r(t)=s(t-τ)+n(t)+J(t)

In the formula, τ is the communication propagation delay; n(t) is Gaussian white noise, and its double sideband power spectral density is N ₀ /2; J(t) is the interference signal; set the carrier frequency, code The element phases are completely synchronized, and the known PN ₁ (0) information is removed according to the superimposed sequence signals after carrier demodulation, and then demodulated according to whether the data at this time are real numbers, pure imaginary numbers, or complex numbers. Phase information, remove the modulated phase information, restore it to all real data and then despread; there are M spreaders at the receiving end, and use PN _i (t) (i=1,2,...M ) for despreading processing, then the i-th (2≤i≤M) spread spectrum demodulator output of the M demodulators except the first demodulator is:

${\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; P</span>}\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; S</span>}}_{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}}\underset{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}{\overset{\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&tau;</span>}}{<span\; class="notranslate">\; \&Integral;</span>}}{\mathrm{<span\; class="notranslate">\; PN</span>}}_{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&tau;</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; PN</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&tau;</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; dt</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}$

In the formula, the integral of i=i _j is the autocorrelation of the spread spectrum sequence, and i≠i _j is the cross correlation; the demodulator output is

${\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; ij</span>}}\mathrm{<span\; class="notranslate">\; PT</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}& \mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}\\ {\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}& \mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&NotEqual;</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}\end{array}\right.$

The two sets of PN sequence rows used are quasi-orthogonal to each other;

(5) Input the (M-1) demodulator output values obtained in step (4) and their corresponding PN code serial numbers into the data-sequence selection inverse mapper, and select from one of the (M-1) despreaders Among the phase output values, the spread spectrum sequence number, phase polarity and displacement relationship corresponding to the (r-1) output values with the largest absolute value are selected as the combined sequence sent, and sent to the data-displacement inverse mapper, and the obtained Received K-way data information;

(6) Parallel/serial conversion is performed on the received K-channel data information to obtain K-bit original information. the

The advantages of the present invention are: the present invention solves the problem of low transmission efficiency of the existing high-efficiency direct spread spectrum, uses vector superposition to further increase the amount of data sent at one time, and also better solves the impact of higher spread spectrum gain on system transmission efficiency The impact of the problem, a better solution to the contradiction between high-speed transmission and bandwidth, can greatly improve the frequency band utilization. In the existing direct sequence high-efficiency spread spectrum communication, r sequences are selected from M PN code sequences and combined in parallel for spread spectrum transmission, which can only be transmitted at a time

$\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>$

Bit data, and a high-efficiency direct spread communication method based on vector superposition can transmit at one time under the same conditions

$\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; q</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; ]</span>$

Bit information; generally q=4 or 8 or..., more (r-1)[log ₂ q] bit data can be sent at one time, so that the transmission efficiency can be further improved.

Description of drawings

Fig. 1 is a sending process structural diagram of the present invention;

Fig. 2 is a structural diagram of the receiving process of the present invention. the

Detailed ways

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

Combining with Figures 1 and 2, Step 1: The sent K-bit data is denoted as d ₁ , d ₂ , d ₄ ,...,d _K , and each information data period is T _d , where KT _d = LT _c , and L is each The number of code elements of the PN sequence, _Tc is the chip period; the K-bit transmission information is sent to the serial/parallel converter to obtain the K-channel signal;

比特、(r-1)[log₂q]比特和(r-1)·[log₂L]比特；根据数据映射算法从PN序列族（除固定位标序列外的M-1个PN码序列）中选取(r-1)个发送的序列，总共有

种发送扩频序列情况选择，对应能传输

比特的信息数据，[x]表示对x取整数部分，

是M中取r的组合；然后考虑(r-1)个扩频序列可以有多种相位S＝[S₁(t),S₂(t),....,S_r-1(t)]选择发送，共有q种（q≥2）相位选择，其中S_j(t)＝exp[j{2π(m_j-1)/q}]，m_j＝1,2,...,q，一般q＝4或者8或者…；如果(r-1)个扩频序列从q种相位中选取某种相位状态发送，对应能传输(r-1)[log₂q]比特的信息数据；再考虑到(r-1)个序列（序列码长都为L）中，每个序列都有L个位置（位置从p₀到p_L-1）可以选择进行发送（根据固定位标序列位置），则共有(r-1)·[log₂L]比特信息传输；把这些状态与信息数据一一对应，则对应的信息数据K是：  Step 2: Divide the K-channel signal obtained in Step 1 into three parts, corresponding to

bits, (r-1)[log ₂ q] bits and (r-1)[log ₂ L] bits; according to the data mapping algorithm, from the PN sequence family (M-1 PN code sequences except the fixed index sequence ) to select (r-1) sent sequences, a total of

A selection of the transmission spread spectrum sequence, corresponding to the transmission

Bit information data, [x] represents the integer part of x,

is the combination of taking r in M; then consider that (r-1) spreading sequences can have multiple phases S=[S ₁ (t), S ₂ (t),....,S _r-1 (t )] to choose to send, there are q kinds of (q≥2) phase selections, where S _j (t) = exp[j{2π(m _j -1)/q}], m _j =1,2,..., q, generally q=4 or 8 or...; if (r-1) spread spectrum sequences are selected from q phases to send in a certain phase state, corresponding to the information data that can transmit (r-1)[log ₂ q] bits ; Considering (r-1) sequences (sequence code lengths are all L), each sequence has L positions (positions from p ₀ to p _L-1 ) that can be selected for transmission (according to the fixed index sequence position), then there are (r-1)·[log ₂ L] bits of information transmission; if these states and information data are one-to-one, the corresponding information data K is:

$\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; q</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; ]</span>$

The selected (r-1) transmitted PN code sequences, sequence displacements and phase states, etc. and a fixed positioning mark sequence are superimposed and sent together in the vector space to form a high-efficiency direct spread signal displacement arrangement relationship.

${\mathrm{<span\; class="notranslate">\; A</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; PN</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="S\; j"\; filenames="HDA00002835748300011.png"\; state="\{\{state\}\}">S</figure-callout></span><figure-callout\; id="1"\; label="S\; j"\; filenames="HDA00002835748300011.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{{\mathrm{<span\; class="notranslate">\; </span>}}_{}}{\mathrm{<span\; class="notranslate">\; PN</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; PN</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}}{\mathrm{<span\; class="notranslate">\; PN</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \}</span>$

In the formula, {S _j ∈ exp[j{2π(m _j -1)/q}], j=1,2,..r _p ,m _j =1,2,...,q}; r Sequences are superimposed in vector space (addition of (a _j + b _j i) values) to form a combined multivalued signal:

$\mathrm{<span\; class="notranslate">\; MD</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; PN</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; S</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\mathrm{<span\; class="notranslate">\; PN</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; )</span>$

Step 3: The multi-valued signal generated by vector superposition, after carrier modulation, can be mapped to MQAM carrier modulation and sent out, sending signal s(t)

In the formula, P is the carrier power, and the obtained signal s(t) is transmitted;

Receiver process:

Step 4: Under the Gaussian white noise channel, the received signal is

r(t)=s(t-τ)+n(t)+J(t)

In the formula, τ is the communication propagation delay; n(t) is Gaussian white noise, and its double sideband power spectral density is N ₀ /2; J(t) is the interference signal; set the carrier frequency, code The element phase is completely synchronized. According to the sequence signal superimposed after carrier demodulation, the known information of PN ₁ (0) is removed (PN ₁ (0) has no phase modulation), and then according to whether the data at this time is real or pure The imaginary number, or complex number, demodulates the modulated phase information, removes the modulated phase information, needs to be restored to all real data and then despreads; there are M spreaders at the receiving end, and PN _i is used after carrier demodulation (t)(i=1,2,...M) is despreading, then the i-th (2≤i≤M) spread-spectrum demodulator except the first demodulator among the M demodulators outputs for:

${\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; P</span>}\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; S</span>}}_{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}}\underset{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}{\overset{\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&tau;</span>}}{<span\; class="notranslate">\; \&Integral;</span>}}{\mathrm{<span\; class="notranslate">\; PN</span>}}_{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&tau;</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; PN</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&tau;</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; dt</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}$

In the formula, τ is the communication propagation delay; the integral of i=i _j is the autocorrelation of the spreading sequence; i≠i _j is the cross-correlation; the demodulator output is

${\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; ij</span>}}\mathrm{<span\; class="notranslate">\; PT</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}& \mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}\\ {\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}& \mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&NotEqual;</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}\end{array}\right.$

The two sets of PN sequence lines used are quasi-orthogonal to each other and meet the requirements;

Step 5: Input the (M-1) demodulator output values obtained in step 4 and their corresponding PN code serial numbers into the data-sequence selection inverse mapper, and output from the L phases in the (M-1) despreaders Among the values, the spread spectrum sequence number, phase polarity and displacement relationship corresponding to the (r-1) output values with the largest absolute value are selected as the combined sequence sent, and sent to the data-displacement inverse mapper to obtain the received K channel data information;

Step 6: Obtain K-bit original information through parallel/serial conversion. the

The following example illustrates:

In conjunction with Figure 1, a high-efficiency direct spread communication method based on vector superposition adopts the same system parameters as the conventional parallel combined spread spectrum method, and selects r=3 sequences from M=16 PN code sequences to be combined and sent in parallel , PN code length L=512, q=4;

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

Step 2: For the parallel data corresponding to 6 bits, 4 bits and 18 bits, select 2 transmission sequences from the PN sequence family (including 15 PN code sequences) according to the data-mapping algorithm, and there are 105 transmission extensions in total. The selection of the frequency sequence corresponds to the information data that can transmit 6 bits; considering that 2 spread spectrum sequences can have q=4 kinds of phase S=[S ₁ (t), S ₂ (t)] to choose to send, there are q=4 kinds Phase selection, where S _j (t)=exp[j{2π(m _j -1)/4}], m _j =1, 2, 3, 4; if two spreading sequences select a certain phase from 4 phases The phase state is sent, which corresponds to the information data that can transmit 4 bits; and considering the two sequences (the sequence code length is 512), each sequence has 512 positions (positions from p ₀ to p _L-1 ) can be If you choose to send (according to the position of the fixed marker sequence), there will be a total of 18 bits of information transmission; select 2 transmission PN code sequences, sequence displacement and phase status, etc. and 1 fixed marker sequence, and send them together in the vector space , forming a high-efficiency direct-spread signal displacement arrangement relationship

${\mathrm{<span\; class="notranslate">\; A</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; PN</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="S\; j"\; filenames="HDA00002835748300011.png"\; state="\{\{state\}\}">S</figure-callout></span><figure-callout\; id="1"\; label="S\; j"\; filenames="HDA00002835748300011.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{{\mathrm{<span\; class="notranslate">\; </span>}}_{}}{\mathrm{<span\; class="notranslate">\; PN</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; PN</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \}</span>$

In the formula, {S _j ∈ exp[j{2π(m _j -1)/q}], j=1,2,, m _j =1,2,3,4}; three sequences superimposed in the vector space specifically The method is that there are q=4 kinds of phases in total, which are {+1,-1,+i,-i}, when there are 3 sequences to send, there are 3 ⁴ =27 situations in total, but some situations are combined, according to the vector constellation The graph can generate 16 phases;

(a) When the three sequences are all real number phases, according to the combination law, there are four situations: {1,1,1}, {1,-1,1}, {-1,1,-1}, {-1,-1,-1}; These 4 situations can generate 4 new phases {-3,-1,1,3} in total; 

(b) When the three sequences are pure imaginary phase superposition, according to the combination law, there are also four cases: {i,i,i}, {i,-i,i}, {-i,i,-i }, {-i,-i,-i}. These 4 situations can generate 4 new phases {-3i,-i,i,3i} in total;

(c) When the three sequences are all real and imaginary mixed phases, according to the combination law, there are 12 cases in total, {1,1,i}, {1,1,-i}, {1,-1,i} , {1,-1,-i}, {-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 cases can generate a total of 8 new phases {2+i, 2-i, -2+i, -2-i, 1+2i, 1-2i, -1+2i, -1-2i}. the

Step 3: The multi-valued signal generated by vector superposition generates a total of 16 phases. After carrier modulation, it can be mapped to 16QAM carrier modulation and sent out. Send signal s(t)

In the formula, P is the carrier power, and the obtained signal s(t) is transmitted;

Step 4: Under the Gaussian white noise channel at the receiving end, the received signal is

r(t)=s(t-τ)+n(t)+J(t)

In the formula, τ is the communication propagation delay; n(t) is Gaussian white noise, and its double sideband power spectral density is N ₀ /2; J(t) is the interference signal; set the carrier frequency, code The element phase is completely synchronized. According to the sequence signal superimposed after carrier demodulation, the known information of PN ₁ (0) is removed (PN ₁ (0) has no phase modulation), and then according to whether the data at this time is real or pure The imaginary number, or complex number, demodulates the modulated phase information, removes the modulated phase information, needs to be restored to all real data and then despreads; there are 16 spreaders at the receiving end, and the PN _i (t)(i=1,2,...16) is despreading, and the i-th (2≤i≤16) spread spectrum demodulator except the first demodulator among the 16 demodulators outputs for:

${\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; P</span>}\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; S</span>}}_{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}}\underset{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}{\overset{\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&tau;</span>}}{<span\; class="notranslate">\; \&Integral;</span>}}{\mathrm{<span\; class="notranslate">\; PN</span>}}_{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&tau;</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; PN</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&tau;</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; dt</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}$

In the formula, τ is the communication propagation delay; the integral of i=i _j is the autocorrelation of the spreading sequence; i≠i _j is the cross-correlation; the demodulator output is

${\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; ij</span>}}\mathrm{<span\; class="notranslate">\; PT</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}& \mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}\\ {\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}& \mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&NotEqual;</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}\end{array}\right.$

The two sets of PN sequence rows used are quasi-orthogonal to each other and meet the requirements;

Step five:

Input the 15 demodulator output values obtained in step 4 and their corresponding PN code numbers into the data-sequence selection inverse mapper, and select the 2 outputs with the largest absolute value from the 512 phase output values in the 15 despreaders The spread spectrum sequence number, phase polarity and displacement relationship corresponding to the value are used as the combined sequence sent, and sent to the data-displacement inverse mapper to obtain the received 28-channel data information;

Step 6: Obtain 28-bit original information through parallel/serial conversion. the

Select 3 sequences from 16 PN code sequences with the same conditions for parallel combined spread spectrum transmission, and only one time can be transmitted $K=r+\left[{\log }_2\left(C_m^r\right)\right]=12$ bit data, while an efficient direct spread communication method based on vector superposition can transmit at one time under the same conditions $K=(3-1)\left[{\log }_{2}4\right]+\left[{\log }_2{C}_{16-1}^{3-1}\right]+(3-1)\&Center\; Dot;\left[{\log }_{2}512\right]=28$ For bit information, generally q=4 or 8 or..., 4 more bits of data can be sent at a time, which further improves the transmission efficiency. The invention improves the high-efficiency spread spectrum communication method, improves the transmission efficiency of spread spectrum communication and the effectiveness of the overall communication, fully utilizes the advantages of vector superposition, and transmits more efficiently than a high-efficiency direct spread system based on fixed PN code displacement modulation under the same conditions The transmission efficiency of the receiving method is higher; at the same time, it can also better solve the problem of the influence of higher spreading gain on the transmission efficiency of the system, better solve the contradiction between high-speed transmission and bandwidth, and greatly improve the frequency band utilization. When the vector space q is more, the transmission efficiency is 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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