Research On Polar Coded Cooperation System Based On SWIPT

Polar code is a new type of channel coding proposed by Professor Arikan.Its core idea lies in the channel polarization theory,that is,the polarized noiseless channel is used to transmit useful information,and the full noise channel is used to transmit frozen information or no information.Polar code has been proved theoretically to be able to achieve the channel capacity of binary discrete memoryless channel.At the same time,its recursive encoding and decoding structure reduces the complexity of hardware resources.Coded cooperation combines channel coding and cooperative communication,which can gain both coding and cooperation.Simultaneous Wireless Information and Power Transfer(SWIPT)technology is widely used to solve the problems of relay energy limitation and system lifetime constraints by obtaining energy from radio frequency(Radio Frequency,RF)signals to transmit simultaneous interpreting information and energy.This paper focuses on the polar coded cooperation based on SWIPTt.The main work includes the following:1.We studied the basic knowledge of polar code,collaboration technology and SWIPT technology.In the aspect of polar code,we explain the channel splitting and combination,and introduce the construction method of polar code and the encoding and decoding method of polar code in detail;In terms of cooperation,we introduce three different cooperation modes under half duplex and full duplex conditions,and deduce the expression of mutual information under each cooperation mode;For SWIPT technology,we describe four different receiver structures in detail and illustrate the cutting-edge and advantages of SWIPT technology.2.We established a polar coded cooperation model based on SWIPT.Since the Plotkin construction method of polar code splits a long code into two short codes,which is very suitable for coded cooperation scenarios,we use the Plotkin construction method to jointly design the polar codes of the source node and the relay node,and decode them at the destination node.Theoretical analysis and simulation results show that compared with the traditional point-to-point system,the polar coded cooperation system based on SWIPT greatly reduces the system outage probability;Compared with the coded cooperation scheme using random low density parity check(LDPC)code,the proposed scheme has better bit error performance when the number of decoding iterations is low.3.In order to reduce the decoding delay of the system,we construct and decode the polar code through the product code,establish the product polar coded cooperation model based on SWIPT,take the polar code as the component code of the product code,construct the product polar code,encode its row and column at the source node and relay node respectively,and propose a two-step decoding algorithm with low decoding delay at the destination node,In the first step,the codeword matrix of the received product polar code is subjected to serial SC decoding and column SC decoding respectively.If the first step decoding fails,the second step decoding is performed,that is,the codeword matrix of the product polar code is transformed into a single line polar code,and then SC decoding.Theoretical analysis and simulation show that compared with point-to-point system,the product polar coded cooperation based on SWIPT greatly reduces the decoding delay;Compared with the product LDPC coded cooperation using belief propagation(BP)decoding algorithm,the proposed scheme has better bit error performance.