基于并行干扰抵消的OFDM/OQAM系统中的信号检测方法

在多径衰落信道中,基于交错正交幅度调制的正交频分复用(OFDM with Offset QAM,OFDM/OQAM)系统使用迫零均衡器进行信号检测时,不能完全消除信道复数特性和滤波器实数正交特性引入的时域符号间干扰和频域子载波间干扰,及信道估计误差导致的误码率性能损失。该文利用对数据初始判决并重构相邻载波及符号间干扰的思想,通过分析采用迫零均衡信号检测时的残余干扰与信道估计误差干扰,提出了一种基于并行干扰抵消和迫零均衡器结合的OFDM/OQAM信号检测方法,并在IEEE 802.22技术标准的两种典型多径衰落信道中进行了计算机仿真与比较研究。仿真结果表明,与基于迫零均衡的检测方法相比,基于并行干扰抵消的迭代信号检测方法在误码率为1%时,可获得1 dB至2 dB的性能提升。

Parallel Interference Cancellation Based Signal Detection for OFDM/OQAM Systems

Because of the usage of practical windowed pulse shaping filter and limitation of real field orthogonality of OFDM with Offset QAM (OFDM/OQAM) systems, the zero-forcing equalization as signal detector can not completely remove the Inter-Symbol Interference (ISI) and Inter-Carrier Interference (ICI) introduced by multipath fading channels. The ISI and ICI lead to severe degradation of BER performance of OFDM/OQAM system. Moreover, the imperfect channel estimation by using preamble also results in the further BER performance degradation. In this paper, one Parallel-Interference-Cancellation (PIC) signal detection method based on zero-forcing equalization for OFDM/OQAM systems is proposed by reconstruction of ISI and ICI with aid of initial data detection. And analytical results on residual interference by Zero-Forcing (ZF) and imperfect channel estimator are given. Finally, simulation results demonstrate that OFDM/OQAM system with PIC signal detector can achieve better BER performance by 1 dB to 2 dB while BER equal to 1% than conventional signal detector.