Adaptive robust Max-SLNR precoder for MU-MIMO-OFDM systems with imperfect CSI  

作　　者：Feng SHU Juanjuan TONG Xiaohu YOU Chen GU Jiajun WU 

机构地区：[1]School of Electronic and Optical Engineering, Nanjing University of Science and Technology [2]National Mobile Communications Research Laboratory, Southeast University [3]Ministerial Key Laboratory of JGMT, Nanjing University of Science and Technology

出　　处：《Science China(Information Sciences)》2016年第6期126-139,共14页中国科学（信息科学）（英文版）

基　　金：supported in part by the open research fund of National Mobile Communications Research Laboratory, Southeast University (Grant No. 2013D02);the Fundamental Research Funds for the Central Universities (Grant No. 30920130122004);the National Natural Science Foundation of China (Grant Nos. 61271230, 61472190)

摘　　要：The accuracy of channel state information（CSI） available at a base station（BS） has a direct impact on the performance of precoding in wideband multi-user multiple input, multiple output-orthogonal frequency division multiplexing（MIMO-OFDM） systems and depends on many factors, including： the delay between estimation and beamforming at the BS（also called the CSI delay）, Doppler spread, the channel estimation method used, the average transmit power of pilot symbols, and the average number of pilot symbols that must be estimated per channel parameter. In this paper, the coefficient of CSI error needed to adapt to fading channels is modeled as a function of Doppler spread, CSI delay, and signal-to-noise ratio（SNR）. In terms of the Gaussian-Markov CSI error model, an adaptive robust maximum signal-to-leakage-and-noise ratio（MaxSLNR） precoder is designed to track the statistical parameters of CSI error. The Doppler spread and SNR can be obtained through real-time estimation based on orthogonal pilot patterns. Simulation results show that,compared to non-adaptive robust and non-robust precoders of Max-SLNR, the proposed adaptive robust MaxSLNR precoder performs much better in terms of bit error rate（BER）. Moreover, as either the average number of training symbols per channel parameter or the average transmit power increases, the BER performance of the proposed precoder approaches that of a precoder with ideal CSI.The accuracy of channel state information（CSI） available at a base station（BS） has a direct impact on the performance of precoding in wideband multi-user multiple input, multiple output-orthogonal frequency division multiplexing（MIMO-OFDM） systems and depends on many factors, including： the delay between estimation and beamforming at the BS（also called the CSI delay）, Doppler spread, the channel estimation method used, the average transmit power of pilot symbols, and the average number of pilot symbols that must be estimated per channel parameter. In this paper, the coefficient of CSI error needed to adapt to fading channels is modeled as a function of Doppler spread, CSI delay, and signal-to-noise ratio（SNR）. In terms of the Gaussian-Markov CSI error model, an adaptive robust maximum signal-to-leakage-and-noise ratio（MaxSLNR） precoder is designed to track the statistical parameters of CSI error. The Doppler spread and SNR can be obtained through real-time estimation based on orthogonal pilot patterns. Simulation results show that,compared to non-adaptive robust and non-robust precoders of Max-SLNR, the proposed adaptive robust MaxSLNR precoder performs much better in terms of bit error rate（BER）. Moreover, as either the average number of training symbols per channel parameter or the average transmit power increases, the BER performance of the proposed precoder approaches that of a precoder with ideal CSI.

关 键 词：multiuser MIMO OFDM Max-SLNR adaptive robust precoder beamforming 

分 类 号：TN929.5[电子电信—通信与信息系统] F273.2[电子电信—信息与通信工程]