阅读说明：本技术 一种基于蜂群算法的毫米波大规模mimo混合预编码设计方法 (Millimeter wave large-scale MIMO hybrid precoding design method based on bee colony algorithm ) 是由 谭方青 肖晴 崔子健 徐旭 于 2021-06-03 设计创作，主要内容包括：本发明公开了一种基于蜂群算法的毫米波大规模MIMO混合预编码设计方法,属于编码技术领域,该方法首先在基带部分采用迫零预编码来设计数字预编码矩阵,在模拟预编码部分单独设计模拟预编码矩阵,将模拟移相器的相位作为目标变量,将使系统可达和速率最大的条件作为目标函数,使用ABC算法对此问题进行寻优,得到尽可能好的预编码矩阵。该方法大大提高了收敛速度,降低了运算量,本发明采用人工蜂群(Artificial Bee Colony)算法来设计混合预编码,借助群智能算法的思想将混合预编码设计等效为随机寻优问题,不涉及矩阵求逆等复杂运算,运算量较低,取得了较好的性能。(The invention discloses a millimeter wave large-scale MIMO mixed precoding design method based on a swarm algorithm, which belongs to the technical field of coding. The method greatly improves the convergence rate and reduces the operation amount, the invention adopts an Artificial Bee Colony (Artificial Bee Colony) algorithm to design the mixed precoding, the mixed precoding design is equivalent to the random optimization problem by means of the thought of a swarm intelligence algorithm, the complex operations such as matrix inversion are not involved, the operation amount is lower, and better performance is obtained.)

1. A millimeter wave large-scale MIMO hybrid precoding design method based on a bee colony algorithm is characterized by comprising the following steps:

step 1, firstly, a simulation pre-coding matrix and a millimeter wave large-scale MIMO system model are manufactured;

step 2, inputting, NP: the number of populations; maximum: maximum number of iterations; h: a channel matrix; n is a radical of_t: the dimension of the vector θ; k: receiving the number of antennas;

step 3, initializing relevant parameters, wherein the current iteration time t is 0, and randomly generating NP dimensions N_tIs given as the theta vector ofCalculating the objective function value corresponding to each thetaNamely, it is

Step 4, using xi_iCalculating the fitness values of NP individuals, wherein half of the NP individuals in the population with better fitness values form a leading bee population, and the other half of the NP individuals form a following bee population;

step 5, sequentially searching and generating new leading bee populations and following bee populations by leading bees and following bees;

step 6, evaluating NP functional values to obtain functional values according to the objective functional values, reserving a theta vector with better performance, and recording the theta vector as theta_elite. When t is less than maximum,if it is notThenIf the iteration time t is t +1, when the iteration time is less than the maximum iteration time, returning to the step 5, otherwise, entering the step 7;

step 7, after the maximum iteration times are reached, using theta_eliteGenerating an analog precoding matrix, i.e.Output F_RF＝diag{f₁,f₂,...,f_N}。

2. The millimeter wave massive MIMO hybrid precoding design method based on the bee colony algorithm as claimed in claim 1, wherein the step 1 is specifically: firstly, designing a digital precoding matrix by adopting zero-forcing precoding in a base band part, independently designing an analog precoding matrix in an analog precoding part, taking the phase of an analog phase shifter as a target variable, taking the condition of enabling the system to reach the maximum speed as a target function, and optimizing the problem by using an ABC algorithm to obtain the best possible precoding matrix.

3. The millimeter wave massive MIMO hybrid precoding design method based on bee colony algorithm as claimed in claim 1, wherein in the millimeter wave massive MIMO system model, first, N is pairs of N through digital precoders_sThe lane data streams are digitally pre-encoded. After each data stream passes through a corresponding radio frequency link, analog precoding is carried out on the data stream by an analog precoder formed by L phase shifters. After analog pre-coding, each data stream is transmitted through a sub-antenna array which is connected with a corresponding radio frequency link and only has L antennas. Total number of transmit antennas N_tWhen the number of the receiving end users is equal to LN, the number of the receiving end users is K, the users are single antennas, and then the receiving signal y of the user end belongs to C^K×1Can be expressed as:

y＝HF_RFF_BBs+n＝HFs+n (1)

wherein H ═ H₁,h₂,...,h_K]^T∈C^K×LNIs a channel matrix, F_RF＝diag{f₁,f₂,...,f_N}∈C^LN×NAn analog pre-coding matrix is represented,representing a digital precoding matrix, F ═ F_RFF_BBA hybrid pre-coding matrix is represented,is a transmission signal, n ∈ C^K×1Representing additive white Gaussian noise, i.e. n-CN (0, sigma)²I_K)，σ²The variance is indicated. F_RFAnd F_BBSatisfy a total transmit power constraint, i.e.

The system reach and rate are expressed as:

wherein the content of the first and second substances,

the optimized objective function of the ABC algorithm is as follows:

4. the millimeter wave massive MIMO hybrid precoding design method based on bee colony algorithm as claimed in claim 1, wherein leading bee search: target individual in current t-th generation leading bee populationRandom selection of individuals r₁E {1, 2., NP/2} carries out cross search by dimension, and generates new individuals according to formula (6)

For newly-generated individualsAnd target individualAnd evaluating the fitness, comparing the fitness values of the two, and selecting the individuals with better fitness values to enter the leading bee population.

5. The millimeter wave massive MIMO hybrid precoding design method based on the bee colony algorithm as claimed in claim 4, wherein following bee search: by roulette following the bee (i.e. by betting on the wheel)) Selecting better order in new leading bee colonySubject matterSearching with randomly selected individuals j according to formula (6) to generate new individualsForming a follower bee population.

6. The millimeter wave large-scale MIMO hybrid precoding design method based on the bee colony algorithm as claimed in claim 5, characterized in that after the leading bee search and the following bee search are completed, the two bee colonies are combined to generate an iterative population, whether a scout bee behavior occurs is judged, if so, scout bee search is performed according to formula (6) to generate a new individual, and after one-to-one comparison with the original individual, the individual with a better fitness value is selected to enter the iterative population.

Technical Field

The invention relates to the technical field of coding, in particular to a millimeter wave large-scale MIMO mixed precoding design method based on a swarm algorithm.

Background

The millimeter wave has a short wavelength, so that a large number of antennas can be packaged in a small aperture, and meanwhile, the huge antenna array provides remarkable beam forming gain, so that the path loss of the millimeter wave can be compensated. Therefore, the combination of millimeter wave and massive MIMO technology is one of the key technologies of 5G. The conventional digital precoding method requires the number of RF chains equal to the number of antennas, but causes a drastic increase in hardware cost and power consumption. The conventional analog precoding method replaces the RF chain with a phase shifter, but results in a loss of system performance. Therefore, a hybrid precoding combining digital precoding and analog precoding is proposed, and the core idea of the hybrid precoding is to decompose a conventional digital precoder into a low-dimensional digital precoder consisting of a small number of RF chains and an analog precoder consisting of a large number of phase shifters, thereby reducing hardware cost and performance loss. At present, precoding modes such as OMP, SVD, SIC and the like are mostly adopted in large-scale MIMO, and the operation complexity is increased along with the increase of the number of days of a base station and users in a cell.

Disclosure of Invention

The invention aims to provide a millimeter wave large-scale MIMO hybrid precoding design method based on a swarm algorithm, so as to solve the problems in the background art.

In order to achieve the purpose, the invention provides the following technical scheme:

a millimeter wave large-scale MIMO hybrid precoding design method based on a bee colony algorithm comprises the following steps:

step 1, firstly, a simulation pre-coding matrix and a millimeter wave large-scale MIMO system model are manufactured;

step 2, inputting, NP: the number of populations; maximum: maximum number of iterations; h: a channel matrix; n is a radical of_t: the dimension of the vector θ; k: receiving the number of antennas;

step 3, initializing relevant parameters, wherein the current iteration time t is 0, and randomly generating NP dimensions N_tIs given as the theta vector ofCalculating the objective function value corresponding to each thetaNamely, it is

Step 4, using xi_iCalculating the fitness values of NP individuals, wherein half of the NP individuals in the population with better fitness values form a leading bee population, and the other half of the NP individuals form a following bee population;

step 5, sequentially searching and generating new leading bee populations and following bee populations by leading bees and following bees;

step 6, evaluating NP functional values to obtain functional values according to the objective functional values, reserving a theta vector with better performance, and recording the theta vector as theta_elite. When t is less than maximum,if it is notThenIf the iteration time t is t +1, when the iteration time is less than the maximum iteration time, returning to the step 5, otherwise, entering the step 7;

step 7, after the maximum iteration times are reached, using theta_eliteGenerating an analog precoding matrix, i.e.Output F_RF＝diag{f₁,f₂,...,f_N}。

As a further technical solution of the present invention, the step 1 specifically comprises: firstly, designing a digital precoding matrix by adopting zero-forcing precoding in a base band part, independently designing an analog precoding matrix in an analog precoding part, taking the phase of an analog phase shifter as a target variable, taking the condition of enabling the system to reach the maximum speed as a target function, and optimizing the problem by using an ABC algorithm to obtain the best possible precoding matrix.

As a further technique of the present inventionAccording to the scheme, in the millimeter wave large-scale MIMO system model, firstly, N is subjected to digital precoder_sThe lane data streams are digitally pre-encoded. After each data stream passes through a corresponding radio frequency link, analog precoding is carried out on the data stream by an analog precoder formed by L phase shifters. After analog pre-coding, each data stream is transmitted through a sub-antenna array which is connected with a corresponding radio frequency link and only has L antennas. Total number of transmit antennas N_tWhen the number of the receiving end users is equal to LN, the number of the receiving end users is K, the users are single antennas, and then the receiving signal y of the user end belongs to C^K×1Can be expressed as:

y＝HF_RFF_BBs+n＝HFs+n (1)

wherein H ═ H₁,h₂,...,h_K]^T∈C^K×LNIs a channel matrix, F_RF＝diag{f₁,f₂,...,f_N}∈C^LN×NAn analog pre-coding matrix is represented,representing a digital precoding matrix, F ═ F_RFF_BBA hybrid pre-coding matrix is represented,is a transmission signal, n ∈ C^K×1Representing additive white Gaussian noise, i.e. n-CN (0, sigma)²I_K)，σ²The variance is indicated. F_RFAnd F_BBSatisfy a total transmit power constraint, i.e.

The system reach and rate are expressed as:

wherein the content of the first and second substances,

the optimized objective function of the ABC algorithm is as follows:

as a further technical solution of the present invention, the search of bees is led: target individual in current t-th generation leading bee populationRandom selection of individuals r₁E {1, 2., NP/2} carries out cross search by dimension, and generates new individuals according to formula (6)

For newly-generated individualsAnd target individualAnd evaluating the fitness, comparing the fitness values of the two, and selecting the individuals with better fitness values to enter the leading bee population.

As a further technical scheme of the invention, following bee search: by roulette following the bee (i.e. by betting on the wheel)) Selecting better target individuals in new leading bee coloniesSearching with randomly selected individuals j according to formula (6) to generate new individualsForming a follower bee population.

As a further technical scheme of the invention, after the leading bee search and the following bee search are finished, the two bee colonies are combined to generate an iterative population, whether reconnaissance bee behaviors occur or not is judged, if yes, reconnaissance bee search is carried out according to a formula (6) to generate a new individual, and after one-to-one comparison with the original individual is carried out, the individual with a better fitness value is selected to enter the iterative population.

Compared with the prior art, the invention has the beneficial effects that: the invention adopts an Artificial Bee Colony (Artificial Bee Colony) algorithm to design the mixed precoding, and the mixed precoding design is equivalent to the random optimization problem by means of the thought of a swarm intelligence algorithm, so that the complex operations such as matrix inversion are not involved, the operation amount is lower, and the better performance is obtained.

Drawings

Fig. 1 is a millimeter wave massive MIMO system model.

Detailed Description

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 only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, embodiment 1: a millimeter wave large-scale MIMO hybrid precoding design method based on a bee colony algorithm comprises the following steps:

step 1, firstly, designing a digital precoding matrix by adopting zero-forcing precoding at a base band part, independently designing an analog precoding matrix at an analog precoding part, taking the phase of an analog phase shifter as a target variable, taking a condition that the system can reach and the speed is maximum as a target function, and optimizing the problem by using an ABC algorithm to obtain a precoding matrix as good as possible. The method greatly improves the convergence rate and reduces the operation amount;

step 2, inputting, NP: the number of populations; maximum: maximum number of iterations; h: a channel matrix; n is a radical of_t: the dimension of the vector θ; k: receiving the number of antennas;

step 3, initializing relevant parameters, wherein the current iteration time t is 0, and randomly generating NP dimensions N_tTheta vector ofIs marked asCalculating the objective function value corresponding to each thetaNamely, it is

Step 4, using xi_iCalculating the fitness values of NP individuals, wherein half of the NP individuals in the population with better fitness values form a leading bee population, and the other half of the NP individuals form a following bee population;

step 5, sequentially searching and generating new leading bee populations and following bee populations by leading bees and following bees;

leading bee search: target individual in current t-th generation leading bee populationRandom selection of individuals r₁E {1, 2., NP/2} carries out cross search by dimension, and generates new individuals according to formula (6)

For newly-generated individualsAnd target individualAnd evaluating the fitness, comparing the fitness values of the two, and selecting the individuals with better fitness values to enter the leading bee population.

Searching following bees: by roulette following the bee (i.e. by betting on the wheel)) Selecting better target individuals in new leading bee coloniesSearching with randomly selected individuals j according to formula (6) to generate new individualsForming a follower bee population;

after the leading bee search and the following bee search are finished, combining the two bee swarms to generate an iterative population, judging whether scout bee behaviors occur or not, if so, performing scout bee search according to a formula (6) to generate a new individual, comparing the new individual with the original individual one by one, and selecting an individual with a better fitness value to enter the iterative population.

Step 6, evaluating NP functional values to obtain functional values according to the objective functional values, reserving a theta vector with better performance, and recording the theta vector as theta_elite. When t is less than maximum,if it is notThenIf the iteration time t is t +1, when the iteration time is less than the maximum iteration time, returning to the step 5, otherwise, entering the step 7;

step 7, after the maximum iteration times are reached, using theta_eliteGenerating an analog precoding matrix, i.e.Output F_RF＝diag{f₁,f₂,...,f_N}。

Embodiment 2, on the basis of embodiment 1, in the millimeter wave massive MIMO system model, N is first paired by a digital precoder_sThe lane data streams are digitally pre-encoded. After each data stream passes through a corresponding radio frequency link, analog precoding is carried out on the data stream by an analog precoder formed by L phase shifters. After analog pre-coding, each data stream passes through and pairAnd transmitting the sub-antenna array which is only provided with L antennas and connected with the radio frequency link. Total number of transmit antennas N_tWhen the number of the receiving end users is equal to LN, the number of the receiving end users is K, the users are single antennas, and then the receiving signal y of the user end belongs to C^K×1Can be expressed as:

y＝HF_RFF_BBs+n＝HFs+n (1)

wherein H ═ H₁,h₂,...,h_K]^T∈C^K×LNIs a channel matrix, F_RF＝diag{f₁,f₂,...,f_N}∈C^LN×NAn analog pre-coding matrix is represented,representing a digital precoding matrix, F ═ F_RFF_BBA hybrid pre-coding matrix is represented,is a transmission signal, n ∈ C^K×1Representing additive white Gaussian noise, i.e. n-CN (0, sigma)²I_K)，σ²The variance is indicated. F_RFAnd F_BBSatisfy a total transmit power constraint, i.e.

The system reach and rate are expressed as:

wherein the content of the first and second substances,

the optimized objective function of the ABC algorithm is as follows:

it will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.