Research On Peak-to-Average Ratio Suppression Technology And Algorithms Based On Symbol-Level Precoding

Orthogonal Frequency Division Multiplexing(OFDM)is an effective method to address frequency selective fading in broadband wireless communication systems,and is also one of the key technologies in the fourth generation(4G)and fifth generation(5G)mobile communication systems.However,due to the independent phase of each subcarrier in OFDM,it is susceptible to the influence of Peak to Average Power Ratio(PAPR).Excessive PAPR may cause linear RF components(such as power amplifiers)to operate in the nonlinear amplification range.This not only leads to signal distortion and out of band radiation,but also leads to excessive system energy consumption,which has become an important issue restricting the development of the communication industry.This paper utilizes Symbol Level Precoding(SLP)to convert harmful Multi User Interference(MUI)into the required signal gain,and proposes a peak to average ratio suppression scheme based on SLP.Study the transmission theory and efficient design mechanism based on SLP,and seek more ways and methods to reduce the PAPR of signals.The specific research content is as follows:(1)This article focuses on multi input multi output orthogonal frequency division multiplexing(MIMO OFDM)systems.By constructing a joint design optimization problem of SLP and low PAPR under the constraints of transmission power and symbol level precoding scheme,the system PAPR is suppressed and the signal to interference noise ratio(SINR)of users is maximized.Firstly,establish the signal model of MIMO-OFDM system and SLP,and establish the joint design optimization problem of SLP and low PAPR under the constraints of transmission power and symbol level precoding scheme.Due to its non convex nature,it is difficult to efficiently solve the problem.We propose a dual iteration optimization algorithm based on the dichotomy Fast Iterative Truncation Algorithm(FITRA),which suppresses PAPR through the inner layer FITRA algorithm and maximizes the SINR of the received signal through the outer layer dichotomy to achieve good communication performance.Finally,the effectiveness and related performance indicators of the proposed algorithm are analyzed and evaluated through simulation.(2)In practical application scenarios,due to the difficulty in obtaining the upper limit of SINR in advance when solving problems using the binary FITRA dual iteration optimization algorithm,this paper proposes an adaptive design for SLP and low PAPR under the constraints of transmission power and symbol level precoding scheme.Firstly,formalize and equivalently transform the established optimization problem,and use Log Sum Exp to approximate the unsmooth infinite norm for subsequent solving of the optimization problem.Then,an efficient SLP-PAPR algorithm based on the Dinkelbach framework is used to solve the optimization problem.Due to the complex form of its objective function and the large number of constraints,directly using a universal convex solver would result in low computational efficiency.Therefore,this article presents a customized Penalty Dual Decomposition(PDD)algorithm and efficiently solves it using the Monotone Accelerated Projection Gradient(MAPG)algorithm.By iteratively converging to the global optimal solution,the adaptive adjustment of the communication system is achieved.Finally,the effectiveness of the algorithm and related performance indicators are analyzed and evaluated through simulation results.