Research On NR Sidelink Link Simulation And Related Technology

With the gradual improvement and commercialization of 5G NR standards,a variety of business and application scenarios based on 5G NR have been extensively studied.Among them,Vehicle to Everything(V2X)is one of the key research topics.According to the Release 16 agreement,the Third Generation Partnerships Project(3GPP)has put forward higher requirements for 5G V2 X from the aspects of reliability,delay,and flexible scheduling.Currently,the standardization research of 5G V2 X is mainly focused on the physical layer technology of the sidelink(SL),including resource mapping schemes,signal processing procedures,and resource allocation.In the standardization process,a simulation evaluation is performed for each new technology,and the corresponding performance analysis and evaluation results are given.This thesis mainly investigate the signal transmission technology scheme of NR sidelink link level.The main contributions of this work are as follows.First,based on the existing 3GPP 5G physical layer related standards and the NR sidelink standard proposal,a link-level simulation platform for NR sidelink physical layer technology simulation is established.The link simulation platform includes a physical sidelink sharing channel and a physical sidelink control channel.Its main goal is to evaluate the performance of different NR sidelink technology solutions.Second,for the sidelink using DFT-S-OFDM transmission and the DMRS sequence length less than 30,the generated DMRS symbol has a high PAPR problem.A new CGS sequence generation method for generating DMRS signals is provided.The search uses the auto-correlation,PAPR value,cross-correlation,and demodulation performance of the sequence as search conditions to obtain a new set with better-performing CGS sequences.This method not only optimizes the CGS sequence in the existing protocol,but also provides a new length CGS sequence to meet different DMRS frequency domain mapping schemes.Compared with the existing CGS sequence,the DMRS generated by the new CGS sequence reduces the PAPR value by 49.2% and the autocorrelation value by 75%,and the cross-correlation value and demodulation performance are also improved accordingly.Third,to deal with the problem of increasing the complexity when the receiver blindly detect the SCI caused by the different sizes of the SCI transmitted by the sender in different scenarios in NR sidelink,a two-step transmission SCI scheme is proposed.Among them,the 1st SCI in the first part is a fixed-size broadcast SCI.The second part 2nd SCI is a variable size multicast or unicast SCI.In the transmission process,the demodulation instruction information of the 2nd SCI is placed in the 1st SCI.So the receiving end only needs to blindly decode the fixed-size 1st SCI,thereby reducing the complexity of blindly interpreting the SCI.In addition,in order to reduce the increased signaling overhead,the 2nd SCI is transmitted on the PSSCH channel,and the increased signaling overhead is offset by multiplexing the DMRS signal of the PSSCH.Finally,a resource mapping scheme for the 2nd SCI on the PSSCH channel is presented.In terms of demodulation performance,it is proved by simulation that when PSSCH layer 1 is transmitted,its performance is only reduced by about 1.5d B,which can be ignored,while when PSSCH layer 2 is transmitted,its performance is reduced by about 6d B.In the actual signal processing process,the demodulation performance can be improved by increasing the transmission power of 2nd SCI.