Research On LTE Synchronization Technology And Implement On FPGA

LTE,as Chinese pre-4G, evolves from 3G technical standard. Therefore, ISI caused by timing offset and ICI caused by carrier frequency offset will weaken the OFDM system. So frequency synchronization is in charge of OFDM. A good frequency synchronization makes a good OFDM system.This paper introduces the research background and research status quo of LTE synchronization technology and some algorithms for synchronization firstly. Then analyzes the existing OFDM synchronization method, simulates them with LTE protocol, gets the best method. Our work focus on the process of downlink synchronization through physical layer's synchronization channel. Then we can get the appropriate method to meet the LTE downlink OFDM system.At last,the method will be improved and implemented on the FPGA,and we will analyze the data.The paper's work is as follows.First, the paper introduces the physical layer including LTE data frame, resource grid,synchronization channel and reference sequence,which provide theoretical basis for the study of LTE synchronization technology.Second,show how the synchronization offset, such as timing offset and frequency offset, influence the OFDM system. Then analyze the OFDM synchronization plans,such as blind synchronization and the method based on trained sequence.Compare them by the simulation result and computational complexity.Third, get the synchronization method adjust to LTE downlink OFDM system with the emerge way of physical signal and time-frequency location characteristics.The paper gets coarse timing synchronization point by PSS sequence and local PSS sequence cross-correlation method, estimates fractional and integer frequency offset by PSS.Fourth,design module of LTE downlink synchronization technology.Including coarse timing module, frequency offset estimation module and deviation correction module. And then simulation every module by matlab,put forward a complete synchronization method. The simulation result shows the method presented meet the requirement of LTE system downlink synchronization.At last,based on the above chapters,the paper modules the OFDM system on the FPGA.Comparing with DSP, FPGA has the following advantages.First, flexible architecture and logic unit.Second, high level of integration. Third, apply a wide range.Lastly, Speed is fast.Lastly,summarizes the main work and the results obtained in this paper,and analyze the performance of the whole system,point out the place where need to improve and Improvement measures.