Study on optimal transmission and reception schemes for mobile communications

移动通信最优发射接收方案研究

基本信息

批准号：
15560318
负责人：
FUKAWA Kazuhiko
金额：
$ 2.24万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2006
项目状态：
已结题

项目摘要

This study aims to realize the optimum signal transmission in mobile radio OFDM systems, and focuses upon (i) minimum bit error rate (BER) precoding, (ii) the optimal receiver under co-channel interference conditions, and (iii) multiuser detection for the random access protocol. The details are described below.(1)When a receiver performs the maximum likelihood detection (MLD), a MIMO-OFDM precoder that can minimize BER of MLD is proposed. The proposed precoder controls linear processing of transmitted signals so that the upper bound of BER based on the pairwise error can be minimized. Thus it can improve BER of MLD more drastically than the conventional MMSE precoder.Furthermore, a precoder for a base station is also derived. It utilizes feedback information on a covariance matrix of interference plus noise from mobile stations, besides channel impulse responses of desired signals which are estimated by the base station. It is superior in BER performance to the conventional one that us … More es information on only the estimated channel impulse responses.(2)A receiver based on the maximum likelihood criterion is proposed to cope with co-channel interference in MIMO-OFDM systems. The proposed receiver suppresses co-channel interference by prewhitening signals received by multiple antennas, and performs signal detection by using an error between a whitening filter output and its replica. Both coefficients of the whitening filters and channel impulse responses for the replica are estimated by the eigenvalue decomposition. Computer simulations show that the proposed receiver can drastically compensate for degradation caused by the interference.(3)To improve packet throughput, a combination of the multiuser detection that can separate collided packets and the auto repeat request (ARQ) that performs metric combining is proposed. The proposed scheme identifies users whose packets collide by detecting user IDs, and then separates collided packets by nonlinear multiuser detection. When packet errors occur, it can reduce the number of retransmissions of ARQ by the metric combining. It is demonstrated that the proposed scheme can achieve about twice as much throughput as that of a conventional one. Less

本研究旨在实现移动无线电 OFDM 系统中的最佳信号传输，重点关注 (i) 最小误码率 (BER) 预编码、(ii) 同信道干扰条件下的最佳接收器，以及 (iii) 多用户检测(1)当接收器执行最大似然检测(MLD)时，提出了一种能够最小化MLD的BER的MIMO-OFDM预编码器，该预编码器控制发送信号的线性处理。认为基于成对误差的BER上限可以被最小化，因此它可以比传统的MMSE预编码器更显着地提高MLD的BER。此外，还导出了一种用于基站的预编码器，它利用了干扰协方差矩阵的反馈信息。加上来自移动站的噪声，除了由基站估计的所需信号的信道脉冲响应之外，它的 BER 性能优于仅使用估计的信道脉冲响应信息的传统方法。(2)A。提出了一种基于最大似然准则的接收器来应对MIMO-OFDM系统中的同信道干扰。所提出的接收器通过对多个天线接收的信号进行预白化来抑制同信道干扰，并利用白化滤波器之间的误差来执行信号检测。输出及其副本。白化滤波器的系数和副本的信道脉冲响应都是通过特征值分解来估计的。计算机模拟表明，所提出的接收器可以显着补偿由干扰引起的退化。（3）改进数据包。为了提高吞吐量，提出了将可分离冲突数据包的多用户检测与执行度量组合的自动重复请求（ARQ）相结合的方案，该方案通过检测用户ID来识别数据包发生冲突的用户，然后通过非线性多用户检测来分离冲突数据包。当发生分组错误时，通过度量组合可以减少ARQ的重传次数，结果表明该方案可以实现大约是传统方案的两倍的吞吐量。