Minimum Error Transmissions with Imperfect Channel Information in High Mobility Systems
Minimum Error Transmissions with Imperfect Channel Information in High Mobility Systems
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DOI：
10.1109/milcom.2013.160
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发表时间：
2013-11
期刊：
影响因子：
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通讯作者：
Ning Sun;Jingxian Wu
中科院分区：
文献类型：
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作者：
Ning Sun;Jingxian Wu
高机动性系统（如无人机（UAV））中的通信所面临的主要挑战之一是快速时变衰落。本文研究了在不完全信道状态信息（CSI）的情况下，使高移动性无线通信系统的差错概率最小的最优系统设计问题。我们考虑一个系统，采用导频辅助最小均方误差（MMSE）信道估计。在高移动性系统中，信道估计误差通常是不可忽略的，并且可能对系统性能产生重大影响。通过渐近分析，将信道估计均方误差（MSE）表示为导频符号在发送符号中所占百分比的封闭表达式。然后，通过分析信道估计误差的统计特性，得到了不理想信道状态信息系统的最佳接收机和相应的误符号率。将误码率表示为导频百分比、最大多普勒扩展和信噪比等参数的显式函数，分析确定了使误码率最小的最佳导频百分比，并通过理论分析和仿真研究了信道状态信息不完善对系统性能的影响。
One of the main challenges faced by communications in high mobility systems, such as unmanned aerial vehicle (UAV), is the fast time-varying fading. This paper studies the optimum system design that can minimize the error probability of a high mobility wireless communication system with imperfect channel state information (CSI). We consider a system that employs pilot-assisted minimum mean square error (MMSE) channel estimation. The channel estimation error is usually non-negligible in high mobility systems and might have significant impacts on system performance. With asymptotic analysis, the channel estimation mean square error (MSE) is expressed as a closed-form expression of the percentage of pilot symbols in the transmitted symbols. An optimum receiver for systems with imperfect CSI and the corresponding symbol error rate (SER) are then derived by analyzing the statistical properties of the channel estimation error. The SER is expressed as an explicit function of a number of parameters, such as pilot percentage, maximum Doppler spread, and the signal-to-noise ratio (SNR), etc. The optimum pilot percentage that can minimize the SER is analytically identified, and the impacts of the imperfects CSI on the system performance are studied through both theoretical analysis and simulations.