阅读说明：本技术 一种用于实现低杂度高频谱效率的多址序列构造方法 (Multi-address sequence construction method for realizing low-complexity high-spectrum efficiency ) 是由 齐婷 周亮 吕斌 于 2019-11-08 设计创作，主要内容包括：本发明公开了一种用于实现低杂度高频谱效率的多址序列构造方法,求得的多址序列能够在最大化系统频谱效率的同时,最优化各用户多址序列构成的多址矩阵的稀疏度,从而使得在低复杂度的MPA多用户检测时,达到高频谱效率。(The invention discloses a multi-address sequence construction method for realizing low-complexity high-frequency spectrum efficiency, and the obtained multi-address sequence can optimize the sparsity of a multi-address matrix formed by multi-address sequences of all users while maximizing the system spectrum efficiency, so that the high-frequency spectrum efficiency is achieved during MPA multi-user detection with low complexity.)

1. A method for constructing a multiple access sequence for achieving low-complexity high spectral efficiency, comprising the steps of:

step S1, each user multiplies its own transmission data symbol by

step S2, let S ═ S₁,…,s_k](K ═ 1.. K), the S representing an N × K multiple access matrix of K multiple access sequences, each column vector of the multiple access matrix corresponding to one multiple access sequence and having a normalized energy M that is equal in value to N, i.e., | S_k‖²＝M＝N,

Wherein P is the respective transmission power P of all users_kForm a diagonal matrix, and P ═ diag { P₁,…,p_kWhere, S is 1^HRepresenting the conjugate transpose of S, det () representing determinant, log () representing logarithmic function, N₀Which is indicative of the power of the noise,I_Na unit array representing NxN;

step S3, let spa (S) denote the sparsity of S, defined as the number of all non-zero elements of the multiple access matrix S, and the expression is as follows:

wherein, | s_k||₀Representing a vector s_kL of₀A norm;

step S4, judging the respective transmitting power p of all users_kWhether equal, if equal, and K is greater than or equal to 2N or

step S5, constructing a multiple access matrix S, wherein S is a diagonal matrix diag { B } composed of α block matrixes₁,...,B_aWhere the block matrix B_jJ 1.. α is

step S6, constructing a multiple access sequence

2. The method as claimed in claim 1, wherein in step S1, the resource blocks refer to orthogonally divided wireless resources, and adopt sub-carriers, frequency bands or time slots.

3. The method as claimed in claim 1, wherein in step S2, AWGN channel is used, and the received signal vectors on N resource blocks are

Wherein the content of the first and second substances,

4. The method for constructing multiple access sequences with low complexity and high spectral efficiency according to claim 1, wherein the step S5 specifically comprises:

step a) initializes the multiple access matrix S of step S4, let k be 1, S be 0, let N be 1, …, N, let

Step b) sequentially executing N from 1 to N;

step c) if λ_n< 1, order

Wherein the parameter theta₁,θ₂,θ₃∈[0,2π]，e_nIs an identity matrix I_NThe nth column vector of (1);

column count k ═ k +2, row n +1 modulo square λ to be assigned_n+1＝λ_n+1-(2-λ_n) The nth row structure completes the order of lambda_n＝0；

If λ_nGreater than or equal to 1, order

Step d) determining if lambda is present_nIf yes, returning to the step b), and if not, returning to the step c).

Step e) letting α be gcd (K, N) representing the greatest common divisor of K and N, the spa (S) constructed in steps a) to d) has the optimal value K +2(N- α), and when K and N are not mutually prime, the multiple access matrix S is a diagonal matrix diag { B { consisting of α block matrices₁,...,B_α}。

5. The method for constructing multiple access sequences with low complexity and high spectral efficiency according to claim 1, wherein the step S6 specifically comprises:

step 1) defining transformation matrix of SThe modulus squared of the K column vectors of V is

Step 2) initializing the transformation matrix of step 1), column count k being 1, V being 0, modulo square λ of n-th row_n＝1,

Step 3) sequentially executing N from 1 to N;

step 4) if λ_n＜b_kAnd 2 λ_n＝b_k+b_k+1Order to

Column k

step 5) if λ_n＜b_kAnd 2 λ_n≠b_k+b_k+1Let the k column

Step 6) column count k ═ k +2, row n +1 modulo square λ to be assigned_n+1＝λ_n+1-(b_k+b_k+1-λ_n) The nth row structure completes the order of lambda_n＝0；

Step 7) if λ_n≥b_kLet the k column

step 8) if λ_nReturning to the step 2) if the value is 0, otherwise returning to the step 3);

step 9) obtaining a multiple access sequence

6. The method for constructing multiple access sequences with low complexity and high spectral efficiency as claimed in claim 1, wherein in step S1, the receiving end is a receiving end using a smart phone.

Technical Field

The invention relates to the field of wireless communication, in particular to a multiple access sequence construction method for realizing low-complexity high-spectrum efficiency.

Background

Wireless communication is developing towards the beauty vision of the interconnection of everything, and various new business and application scenes are emerging continuously, so that the future wireless communication is required to realize intelligent interconnection of people and things and between things and things. With the deployment of a large number of internet of things devices and the access network of a large number of machine devices, the access of a large number of users becomes one of the key challenges for the development of wireless communication.

Non-Orthogonal Multiple Access (NOMA) is receiving much attention as a new generation of wireless communication technology. NOMA breaks the orthogonality of the signals of each user, and the users do not monopolize the resources any more, but realize the resource sharing, thereby improving the access number of the users. Specifically, NOMA allows different user signals to be transmitted by overlapping on the same resource in some way, and advanced signal processing means including multi-user detection and decoding are used at the receiving end to process interference and decode each user signal. According to different resource sharing modes, the NOMA schemes can be divided into two types: in power domain NOMA, each user signal is directly superimposed on one resource block for transmission, and the early research is called Superposition Coding (SC); and in the code domain NOMA, user information is mapped to one code word, and the code words of all users are mutually overlapped and expanded to a plurality of resource blocks for transmission. Usually, the number of users is larger than the number of resources, the system works in an overload state, and the codewords are not orthogonal. The code word generation mode can be divided into two types, one type is a design codebook, and information bits are directly mapped into code words; one is to design a multiple access sequence, and map the information bits into constellation symbols first, and then multiply the constellation symbols with the multiple access sequence to obtain code words.

The existing code word design usually cannot give good consideration to performance and complexity, the NOMA system sum capacity and sum capacity reachable method has been sufficiently researched, in the aspect of dealing with the complexity problem, the existing research considers designing sparse codes to realize resource sharing, and reduces the interference among users through the sparse characteristic, so that the users can be distinguished by using a low-complexity and high-efficiency information transfer Algorithm (Message Passing Algorithm, MPA) for multi-user detection. However, the problem of how to achieve as high a spectral efficiency of the system as possible with as low complexity as possible has not been solved.

Disclosure of Invention

The invention provides a multi-address sequence construction method for realizing low-complexity high-spectrum efficiency, which can optimize the sparsity of a multi-address matrix formed by multi-address sequences of all users while maximizing the spectrum efficiency of a system, and reduce the realization complexity of the system by applying an MPA multi-user detection method with low complexity.

The invention is realized by the following technical scheme:

a method of multiple access sequence construction for achieving low-complexity high spectral efficiency, comprising the steps of:

step S1, each user multiplies its own transmission data symbol by

Multiple access sequences of fields s_kThen, each symbol in the obtained N-dimensional symbol vector is sequentially and respectively corresponding to N resource blocks for transmission, and if the number of the users is K, the receiving end receives superposed signals of the K users on the N resources;

step S2, let S ═ S₁,…,s_k](K1.. K), said S representing an N × K multiple access matrix of K multiple access sequences, each column vector of said multiple access matrix corresponding to a multiple access sequence and having a normalized energy M which is numerically equal to N, i.e. K

The sum rate of all said users is

Wherein P is the respective transmission power P of all users_kForm a diagonal matrix, and P ═ diag { P₁,…,p_kWhere, S is 1^HRepresenting the conjugate transpose of S, det () representing determinant, log () representing logarithmic function, N₀Representing the noise power, I_NA unit array representing NxN;

step S3, let spa (S) denote the sparsity of S, defined as the number of all non-zero elements of the multiple access matrix S, and the expression is as follows:

wherein, | s_k||₀Representing a vector s_kL of₀A norm;

step S4, judging the respective transmitting power p of all users_kWhether equal, if equal, and K32N or

If yes, go to step S5, otherwise, go to step S6;

step S5A multiple access matrix S is created, and S is a diagonal matrix diag { B } consisting of α block matrices₁,...,B_αWherein, a block matrix

A dimensional multiple access matrix;

step S6, constructing a multiple access sequence

Wherein the content of the first and second substances,

is the sum of the transmit powers of the devices.

Further, in step S1, the resource block refers to an orthogonally divided radio resource, and adopts a subcarrier, a frequency band, or a time slot.

Further, in step S2, the AWGN channel is adopted, and the vectors of the received signals on the N resource blocks are

Wherein the content of the first and second substances,

representing a gaussian white noise vector.

Further, in step S5, specifically, the step includes:

step a) initializes the multiple access matrix S of step S4, let k be 1, S be 0, let N be 1, …, N, let

Step b) sequentially executing N from 1 to N;

step c) if λ_n< 1, order

Wherein the parameter theta₁,θ₂,θ₃∈[0,2π]，e_nIs an identity matrix I_NThe nth column vector of (1);

column count k ═ k +2, row n +1 modulo square λ to be assigned_n+1＝λ_n+1-(2-λ_n) The nth row structure completes the order of lambda_n＝0；

If λ_nGreater than or equal to 1, order

θ∈[0,2π]Column count k ═ k +1, row n to be assigned modulo square λ_n＝λ_n-1；

Step d) determining if lambda is present_nIf yes, returning to the step b), and if not, returning to the step c).

Step e) letting α be gcd (K, N) representing the greatest common divisor of K and N, the spa (S) constructed in steps a) to d) has the optimal value K +2(N- α), and when K and N are not mutually prime, the multiple access matrix S is a diagonal matrix diag { B { consisting of α block matrices₁,...,B_α}。

Further, in step S6, specifically, the step includes:

step 1) defining transformation matrix of S

The modulus squared of the K column vectors of V is

Step 2) initializing the transformation matrix of step 1), column count k being 1, V being 0, modulo square of n-th row

Modulus squared of the k column

Step 3) sequentially executing N from 1 to N;

step 4) if λ_n＜b_kAnd 2 λ_n＝b_k+b_k+1Order to

Column k

Column k +1

Wherein the parameter theta₁,θ₂,θ₃∈[0,2π]，e_nIs an identity matrix I_NThe nth column vector of (1);

step 5) if λ_n＜b_kAnd 2 λ_n≠b_k+b_k+1Let the k column

Column k +1

Wherein the parameter theta₁,θ₂,θ₃∈[0,2π]；

Step 6) column count k ═ k +2, row n +1 modulo square λ to be assigned_n+1＝λ_n+1-(b_k+b_k+1-λ_n) The nth row structure completes the order of lambda_n＝0；

Step 7) if λ_n≥b_kLet the k column

Wherein the parameter theta_k∈[0,2π]N-th row of squares λ to be assigned_n＝λ_n-1, column count k ═ k + 1;

step 8) if λ_nReturning to the step 2) if the value is 0, otherwise returning to the step 3);

step 9) obtaining a multiple access sequence

Further, in step S1, the receiving end is a smartphone receiving end.

Compared with the prior art, the invention has the beneficial effects that:

the method for constructing the non-orthogonal multiple access sequence optimizes the sparsity of a multiple access matrix formed by multiple access sequences of each user on the basis of maximizing the system and the rate, and can effectively reduce the complexity of MPA multi-user detection while maximizing the system frequency spectrum efficiency.

Drawings

FIG. 1 is a schematic diagram of a system model for use in an embodiment;

FIG. 2 is a sparsity simulation contrast curve;

FIG. 3 is a graph of achievable and rate comparison for different multiple access schemes at equal power;

fig. 4 is a graph of the achievable and rate comparison for different multiple access schemes where the users are not all equally powerful.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.