cp不足的ofdm系统中数据检测的分析word格式论文.docxVIP

AbstractWith rapid development of wireless communication, and more popular the wireless applications are, utilization of wireless spectrum are unsatisfactory. In OFDM and SC-FDMA system, the traditional method is using the cyclic prefix to eliminate the interference, but in fact the multi-path delay is unpredictable in different environments and different application scenarios. Because of the urgency of improving spectrum efficiency, OFDM systems with insufficient CP are studied, namely how to ensure the full use of spectrum efficiency, and also eliminate the interference addressed by this insufficient CP.The traditional residual inter-symbol interference cancellation (RISIC) algorithm and cyclic prefix reconstruction (CPR) algorithm, is used as a classic method confronting ISI and ICI introduced by lack of CP, but because of its hard decision methods, the errors would be propagated to next symbol duration. In fact many OFDM systems are coded systems, then soft decoding method especially Turbo equalization combined with traditional RISIC algorithms are being paid attention and much more and more attentionIn this paper a detailed analysis of ISI and ICI due to lack of CP in a variety of scenarios, such as short-CP, no CP and full CP systems, together with fast-varying channel conditions, are discussed. And because of the uniqueness of its channel estimation (CE), we firstly propose several CE methods applied in insufficient CP systems. If the channel is too long, designers also can do channel shortening (CS) firstly to compress the channel impulse response to a certain length, and then, do the data detection more conveniently. CEs and CS techniques are a base for signal detection and later Turbo equalizationIn this paper an improved Turbo equalization is proposed, the initial iteration with the weighted CP reconstruction method, and frequency-domain equalization using MMSE with SIC based FDE, the two different methods’ complexity in iterations are discussed. In this