Sampling-based soft equalization for frequency-selective MIMO channels
Sampling-based soft equalization for frequency-selective MIMO channels
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DOI：
10.1109/tcomm.2004.841996
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发表时间：
2005-03
影响因子：
8.3
通讯作者：
B. Dong;Xiaodong Wang
中科院分区：
文献类型：
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作者：
B. Dong;Xiaodong Wang
研究了宽带无线多输入多输出（MIMO）系统在频率选择衰落信道上的信道均衡问题，该问题基于贝叶斯推理的时序蒙特卡罗（SMC）采样技术。随机采样器在重要性采样技术的基础上，生成加权随机MIMO符号样本，并利用重采样来恢复样本流；而确定性采样器是随机采样器的启发式修改，在空间和时间域以贪婪的方式递归地执行探索和选择步骤。这种空时采样方案可以很好地抑制码间干扰和同信道干扰。所提出的基于采样的MIMO均衡器在计算复杂度相当的情况下显著优于决策反馈MIMO均衡器。更重要的是，这些基于采样的MIMO均衡器本质上是软输入软输出，可以用作编码宽带MIMO系统turbo接收机的第一级软解调器。这种turbo接收机通过迭代均衡、信道重估计、信道解码等步骤，不断提高接收机的性能。最后，给出了计算机仿真结果，以证明所提出的基于采样的软MIMO均衡器在非编码和涡轮编码系统中的性能。
We consider the problem of channel equalization in broadband wireless multiple-input multiple-output (MIMO) systems over frequency-selective fading channels, based on the sequential Monte Carlo (SMC) sampling techniques for Bayesian inference. Built on the technique of importance sampling, the stochastic sampler generates weighted random MIMO symbol samples and uses resampling to rejuvenate the sample streams; whereas the deterministic sampler, a heuristic modification of the stochastic counterpart, recursively performs exploration and selection steps in a greedy manner in both space and time domains. Such a space-time sampling scheme is very effective in combating both intersymbol interference and cochannel interference caused by frequency-selective channel and multiple transmit and receiver antennas. The proposed sampling-based MIMO equalizers significantly outperform the decision-feedback MIMO equalizers with comparable computational complexity. More importantly, being soft-input soft-output in nature, these sampling-based MIMO equalizers can be employed as the first-stage soft demodulator in a turbo receiver for coded broadband MIMO systems. Such a turbo receiver successively improves the receiver performance through iterative equalization, channel re-estimation, and channel decoding. Finally, computer simulation results are provided to demonstrate the performance of the proposed sampling-based soft MIMO equalizers in both uncoded and turbo coded systems.