Orthogonal frequency division multiplexing-interleave division multiple access (OFDM-IDMA) systems may suffer from serious inter-carrier interference (ICI) in time-and frequency-selective (doubly selective) channels. ...Orthogonal frequency division multiplexing-interleave division multiple access (OFDM-IDMA) systems may suffer from serious inter-carrier interference (ICI) in time-and frequency-selective (doubly selective) channels. In such case, the conventional OFDM-IDMA detection algorithm for quasi-static channels will result in significantly performance degradation. In this paper, signal detection is investigated for OFDM-IDMA uplink over doubly selective channels. Firstly, the impact of time-varying channels for OFDM-IDMA uplink is analyzed, which leads to the failure of the conventional algorithm. Secondly, a novel iterative detection algorithm is developed based on an integrated interference canceller, which can iteratively estimate and mitigate the ICI as well as multiple access interference (MAI) simultaneously. In addition, an improved detection algorithm is derived for reducing the complexity using an approximation to the mean and variance of the interference. Simulation results indicate that the proposed algorithm can significantly enhance the system performance to the conventional case, and the improved algorithm can strike a balance between performance and complexity.展开更多
雷达通信一体化系统(Integrated Radar and Communication System,IRCS)可提升设备的可用性、可靠性和电磁兼容性,已成为雷达和通信交叉领域的研究热点。正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)具有高信息传输...雷达通信一体化系统(Integrated Radar and Communication System,IRCS)可提升设备的可用性、可靠性和电磁兼容性,已成为雷达和通信交叉领域的研究热点。正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)具有高信息传输性能,且其模糊函数具有低旁瓣特性,在IRCS中得到广泛关注。在OFDM-IRCS中,组网时同频干扰严重影响雷达探测性能。针对这一问题,从信干比(Signal to Interference Ratio,SIR)分析了IRCS同频干扰特性,推导了回波信号SIR的表达式。然后,结合OFDM中交织多址(Interleave Division Multiple Access,IDMA)和干扰重构的思想,提出了基于OFDM-IDMA的IRCS同频干扰抑制算法。所提算法通过不同的交织方式区分不同IRCS节点的信号,同时利用基于干扰重构的干扰消除算法实现干扰抑制。仿真结果表明,所提算法有效地抑制了IRCS同频干扰,实现了同频干扰环境下雷达目标探测性能提升。展开更多
文摘Orthogonal frequency division multiplexing-interleave division multiple access (OFDM-IDMA) systems may suffer from serious inter-carrier interference (ICI) in time-and frequency-selective (doubly selective) channels. In such case, the conventional OFDM-IDMA detection algorithm for quasi-static channels will result in significantly performance degradation. In this paper, signal detection is investigated for OFDM-IDMA uplink over doubly selective channels. Firstly, the impact of time-varying channels for OFDM-IDMA uplink is analyzed, which leads to the failure of the conventional algorithm. Secondly, a novel iterative detection algorithm is developed based on an integrated interference canceller, which can iteratively estimate and mitigate the ICI as well as multiple access interference (MAI) simultaneously. In addition, an improved detection algorithm is derived for reducing the complexity using an approximation to the mean and variance of the interference. Simulation results indicate that the proposed algorithm can significantly enhance the system performance to the conventional case, and the improved algorithm can strike a balance between performance and complexity.
文摘雷达通信一体化系统(Integrated Radar and Communication System,IRCS)可提升设备的可用性、可靠性和电磁兼容性,已成为雷达和通信交叉领域的研究热点。正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)具有高信息传输性能,且其模糊函数具有低旁瓣特性,在IRCS中得到广泛关注。在OFDM-IRCS中,组网时同频干扰严重影响雷达探测性能。针对这一问题,从信干比(Signal to Interference Ratio,SIR)分析了IRCS同频干扰特性,推导了回波信号SIR的表达式。然后,结合OFDM中交织多址(Interleave Division Multiple Access,IDMA)和干扰重构的思想,提出了基于OFDM-IDMA的IRCS同频干扰抑制算法。所提算法通过不同的交织方式区分不同IRCS节点的信号,同时利用基于干扰重构的干扰消除算法实现干扰抑制。仿真结果表明,所提算法有效地抑制了IRCS同频干扰,实现了同频干扰环境下雷达目标探测性能提升。
