Abstract: Previous studies have shown that multi-user interference can be eliminated by means of pre-coding for four-user Multiple Input Multiple Output Multi-Access Channel（MIMO-MAC）. However, a large amount of feedback information is required. For this problem, a non-feedback interference cancellation method is proposed for this scene. Perfect space-time block code is used at each user, and the transmission of each code is properly designed so that multi-user interference can be eliminated by linear processing received signals at the receiver. The proposed scheme greatly reduces feedback amount while the transmission efficiency, the average transmission power of each symbol and diversity gain of the proposed scheme are the same as that of the existing scheme. Simulation results demonstrate the validity of the proposed scheme.

Key words: Multiple Input Multiple Output（MIMO）, multi-access channel, interference cancellation, perfect space-time block code, transmission efficiency, feedback amount

摘要： 已有的研究表明，预编码可以消除4用户的多输入多输出多址接入信道（MIMO-MAC）中的多用户干扰，然而，该方法需要大量的反馈信息。针对该问题，提出了该场景中一种无反馈的干扰消除方法。每个用户采用完美空时分组编码，通过合理地设计每个编码的发送方式，使得接收端对接收信号进行线性处理后消除了多用户干扰。与已有方案相比，所提方案在不改变传输效率、每个符号平均发送功率以及分集增益的同时，极大地降低了反馈量。仿真结果验证了所提方案的有效性。

关键词: 多输入多输出, 多址接入信道, 干扰消除, 完美空时分组编码, 传输效率, 反馈量