Research On Timing Synchronization Technology For Mimo SC-FDMA System In LTE-Advanced Uplink

With the development of broadband mobile communication systems, mobile Internet multimedia applications become more and more popular. LTE project was proposed by the3GPP in2004,and formally applied to commercial use in2009.To further meet user demand for broadband mobile communications, broadband adapt to the rapid development of mobile communications.3GPP proposed the R10version of the LTE technology in2009, which is the LTE-Advanced technology.LTE-Advanced downlink peak rate is1Gbit/s and uplink peak rate is500Mbit/s.LTE-Advanced technology has been formally established as one of4G technology standard.LTE-Advanced uplink is using a single carrier frequency division multiple access techniques.SC-FDMA combines orthogonal frequency division multiplexing and single carrier transmission technology, which has the advantage of low PAPR. MIMO technology which has the advantage of spatial diversity is used in LTE-Advanced uplink.By increasing the utilization of the physical space, the transmission performance of system is improved effectively.This paper studies the timing synchronization algorithm in LTE-Advanced uplink MIMO SC-FDMA system.The development process of mobile communication technology is described at the beginning of this paper. And then an overview of LTE-Advanced related content is given. Then this paper introduces the principle, the model of SC-FDMA system, signal structure and MIMO technology, which raises the descriptions of MIMO SC-FDMA system.Expounded on maximum likelihood detection algorithm,linear and nonlinear detection algorithms for MIMO detection algorithm. After the cause of MIMO SC-FDMA system timing offset, and its influence on the system are discussed in this paper.Finally this paper proposes a parallel interference elimination algorithm to reduce the effects of timing offset.The traditional timing synchronization algorithm generally through the study of the coarse estimation of signal, then fine estimates method to find the starting position of the FFT window. In this paper the parallel interference elimination technique is applied in MIMO SC-FDMA system, in order to achieve the purpose of eliminating interference brought by timing offset.In this paper, the algorithm is not estimating timing offset, but assuming that timing offset already exists and has interferenced on the system. The interference which is generated by timing offset which is eliminated from the received signal by using the method of interference cancellation.Therefore a timing synchronization algorithm combining QR decomposition with parallel interference cancellation is proposed. The problems caused by timing deviation in LTE-Advanced uplink MIMO SC-FDMA system is solved.The preliminary information estimate is obtained by QR decomposition algorithm,the interference which is generated by timing offset which is eliminated from the received signal by this method.Theoretical analysis and simulation results show that the QR-PIC and multistage iterative PIC algorithm can significantly improve system performance.