SC-FDMA System Key Technology

Long Term Evolution (LTE), As an emerging communication technology of the Third Generation Partnership Project (3GPP), is an attractive alternative for the 4rd Generation (4G) mobile communication system. LTE can achieve a data rate of 100Mbps in downlink and 50Mbps in uplink under the bandwidth of 20MHz with a broad market prospects and high application value.This paper has four parts, including the principle of Single Carrier Frequency Division Multiple Access (SC-FDMA) in LTE uplink, the impact of different modulation schemes and subcarrier interval to peak to average power ratio (PAPR) of SC-FDMA system, the theory of frequency domain equalization and the relationship between the equalization algorithm and the Bit Error Rate (BER) of system, as well as the implement of Multiple Input Multiple Output (MIMO) SC-FDMA system and the corresponding block diagram combining with space-time coding is given.The content of this thesis is as follows:firstly, we introduce the principle and implement of SC-FDMA system, describe the working principle and method of each part of the block diagram, then analyze the two channel resources allocation scheme:Localized-FDMA (L-FDMA) and Interleaved-FDMA (I-FDMA), as well as the subcarrier mapping schemes impact on the system performance of PAPR. We compare the PAPR performance of SC-FDMA system with different modulation schemes and subcarrier interval and the Orthogonal Frequency Division Multiple Access (OFDMA) system. The block diagram of MIMO SC-FDMA combining with space-time coding is researched, we modify the existing implement scheme to reduce the complexity of the system. From the perspective of matrix, we describe the workflow of two-transmitter two-receiver system in detail and analyze the channel relativity. Finally, The technology of frequency domain equalization can improve the transmission performance of SC-FDMA system. We introduce the working principle of the common frequency domain equalization technology of SC-FDMA, including Zero Forcing equalization, Minimum Mean Square Error equalization, decision directed feedback equalization. We analyze the equalization technology impact on performance of BER by simulation.This paper primary study the major physical layer technique of SC-FDMA system, analyze the PAPR, frequency domain equalization algorithm and MIMO impact to system performance and we also present the corresponding solutions to reduce the BER.