Research On LDPC Decoding Technology In 5G Communication System

The fifth generation mobile communication technology has finally met with the world after years of gestation and development,thanks to the ardent expectation and unremitting efforts of the public.5G NR standard puts forward higher requirements in terms of information transmission rate and delay.Channel Coding is indispensable for effective and reliable transmission of digital signals.For 5G communication system,there are two most important channel coding: LDPC code and Polar code.Therefore,with the rapid development of 5G,it is particularly significant to study efficient LDPC decoding technology in 5G communication system.This paper firstly analyzed five kinds of basic decoding algorithms and two common message passing schedules,and then put forward a kind of algorithm which based on the belief propagation decoding algorithm,the simulation shows that this algorithm possess a great compromise between belief propagation decoding algorithm and minimum decoding algorithm.It shows both favorable decoding performance and low complexity.Then,a scheduling optimization scheme in hierarchical decoding is proposed.By adjusting the layer structure order of the check matrix,iterative decoding can prioritize the node information with high confidence.Simulation shows that this scheme can accelerate the convergence speed of decoding algorithm and improve its error performance.Finally,two new schemes are combined to obtain the improved decoding algorithm with hierarchical scheduling optimization,which has excellent decoding performance,less iteration times and good compatibility.In terms of hardware implementation,this paper first introduced the design of FPGA process and the alternative implementation structure of 5G LDPC decoder.Subsequently,when the implementation of LDPC decoder is determined,the Normalized min-sum decoding algorithm is used to integrate the scheduling optimization scheme in hierarchical decoding,and the software platform simulation is used to determine the necessary parameters of the decoder.After that,the storage structure,working principle and flow mode of control signal and data signal of each key module in hardware decoder are explained in detail.Finally,plate-level verification is carried out,and the output results are compared with the software simulation results to verify the implementation of the decoder.The LDPC decoder can support all 102 kinds of check matrices in 5G standard for decoding,which greatly improved the throughput without increasing resources,and has the advantages of high resource reusing rate,low control complexity and high throughput.