MIMO 系统分集复用折中及自适应链路实现

多输入多输出技术可以增加分集阶数或系统自由度，以往研究多侧重于最大化其中一种增益，不能充 分利用多天线系统的性能．针对上述问题，本文提出了一种新的基于链路自适应技术的分集复用折中方法．该方法 以误比特率为判决准则，依据实时信道状态信息进行自适应码率、功率分配，并通过少量比特信息反馈到发送端来 确定系统的工作方式．同时，为降低计算量，通过对不同工作方式下接收端信噪比边界值的近似，给出了低复杂度 的次优判决准则．本文所提算法可充分利用分集、复用增益，提高系统可靠性的同时保证了较高的传输速率，具有 较小的计算量，抗扰动性强．仿真结果表明，与传统方法相比本文提出的折中方法具有较好的性能，满足了无线通 信系统实时性、快速性的要求．

Diversity-Multiplexing Switched MIMO System with Link Adaptive

Multiple-input multiple-output(MIMO) technology can be used to increase the amount of diversity or the number of degrees of freedom.Previous works focus much on maximizing one of the gains,and this makes it difficult to make full USe of the performance of multiple antennas system.Aiming at these problems,a novel diversity and multiplexing decision algorithm is proposed based on adaptive link technique.Taking bit error rate(BER)as decision criterion,the proposed algorithm achieves adaptive bit and power allocation according to real-time channel state information(CSI),and the system mode is dynamically adjusted based on limited feedback bits from receiver.To reduce the computational complexity,the proposed algorithm gives out the sub-optimal decision criterion utilizing the approximate bound of received signal-to-noise ratio(SNR)based on CSI.The proposed algorithm can obtain the diversity and multiplexing gains simultaneously,improves the system reliability and transmission rate,has lower computational complexity,and provides excellent robustness against channel fading.Simulation results show that comparing with the traditional algorithms the proposed algorithm has a better performance and meets the real-time and rapidity requirements of the practical communication system.