Research On Downlink Signal Detection In LTE System

With the development of society,the requirement for telecommunication increase a lot.So,LTE(term evolution long)was put forward by 3 GPP.LTE take use of MIMO and OFDM technology,which its system performance has greatly improved in the transmission speed,reliability,throughput,etc.LTE has become a hot-button issue,so it is very necessary to research the detection of LTE system,because the results of signal detection directly affect the performance of the whole system.This paper first deeply analyzes the existing classical detection algorithms,including maximum likelihood algorithm,zero forcing algorithm,minimum mean square error algorithm,interference cancellation algorithm,QR decomposition detection algorithm and sphere decoding.In order to calculate the radius of sphere decoding,a novel way to calculate the radius is proposed which based on the log likelihood ratio of signal.In this paper,we focus on the ordering of the SIC algorithm,including consider two methods based on SNR and LLR.And then a partial search algorithm(PS-OSIC)based on OSIC is proposed to solve error propagation problem in OSIC.More candidate results are retained rather than retaining one output when at the detection of every previous symbol in OSIC,and the number of the output decrease with the detect signal order.Through simulation analysis,it shows that the PS-OSIC algorithm has better performance than the traditional OSIC algorithm.