广义空频索引调制(generalized space and frequency index modulation,GSFIM)技术的提出显示了其相比传统多输入多输出正交频分复用技术更优的系统性能。然而,GSFIM有着较复杂的系统结构以及高复杂度的检测器。讨论一种特殊形式的空频...广义空频索引调制(generalized space and frequency index modulation,GSFIM)技术的提出显示了其相比传统多输入多输出正交频分复用技术更优的系统性能。然而,GSFIM有着较复杂的系统结构以及高复杂度的检测器。讨论一种特殊形式的空频索引调制技术,即基于频率正交幅度调制(frequency and quadrature amplitude modulation,FQAM)/频相移键控(frequency and phase shift keying,FPSK)的空间调制(spatial modulation,SM)技术,其大大简化了系统结构。为了进一步提升该系统的频谱效率,提出了结合非正交子载波的FQAM/FPSK-SM。仿真结果表明,在不同的参数配置下,通过调整压缩系数,非正交FQAM/FPSK-SM系统不仅能够带来频谱效率的提升,而且能够在发送速率相同的前提下达到与正交系统基本相同的性能,提高了系统的单位带宽吞吐量。展开更多
Unlike wired networks, random packet loss due to bit errors may cause significant performance degradation of Transmission Control Protocol (TCP). We propose and study a novel end-to-end congestion control mechanism ca...Unlike wired networks, random packet loss due to bit errors may cause significant performance degradation of Transmission Control Protocol (TCP). We propose and study a novel end-to-end congestion control mechanism called TCP-LD (Loss Detection) that is simple and effective for dealing with random packet loss. We also give its steady state throughput model. Both the ns2 and numerical simulation results show that our scheme can achieve significant throughput improvements without adversely affecting other concurrent TCP connections, including other concurrent Reno connections both in wired and wireless environment.展开更多
文摘广义空频索引调制(generalized space and frequency index modulation,GSFIM)技术的提出显示了其相比传统多输入多输出正交频分复用技术更优的系统性能。然而,GSFIM有着较复杂的系统结构以及高复杂度的检测器。讨论一种特殊形式的空频索引调制技术,即基于频率正交幅度调制(frequency and quadrature amplitude modulation,FQAM)/频相移键控(frequency and phase shift keying,FPSK)的空间调制(spatial modulation,SM)技术,其大大简化了系统结构。为了进一步提升该系统的频谱效率,提出了结合非正交子载波的FQAM/FPSK-SM。仿真结果表明,在不同的参数配置下,通过调整压缩系数,非正交FQAM/FPSK-SM系统不仅能够带来频谱效率的提升,而且能够在发送速率相同的前提下达到与正交系统基本相同的性能,提高了系统的单位带宽吞吐量。
文摘Unlike wired networks, random packet loss due to bit errors may cause significant performance degradation of Transmission Control Protocol (TCP). We propose and study a novel end-to-end congestion control mechanism called TCP-LD (Loss Detection) that is simple and effective for dealing with random packet loss. We also give its steady state throughput model. Both the ns2 and numerical simulation results show that our scheme can achieve significant throughput improvements without adversely affecting other concurrent TCP connections, including other concurrent Reno connections both in wired and wireless environment.
