【作者】 崔晋；

【导师】 焦永昌；

【作者基本信息】 西安电子科技大学 ， 系统工程， 2009， 硕士

【摘要】 多输入多输出(MIMO)是下一代移动通信的重要技术之一,它不仅能使系统容量成倍提高,还能显著提高无线通信系统的频谱利用率。但过高的硬件成本限制了它的应用。天线选择是MIMO系统中一项重要技术,它能从MIMO系统的多个发射天线和多个接收天线中选择出性能最好的一个或多个天线,从而以较小的性能损失换取成本的大幅降低,极大地提高MIMO系统的性能价格比。论文首先介绍和分析了一些经典的天线选择算法,最优算法虽然能获得最高的系统容量,但因其复杂度太高不具有实用价值。本文从香农公式出发,并结合前人的算法,通过数学推导,提出了一种新的快速天线选择算法,其所获得的系统容量与最优算法非常接近。仿真结果表明,在发射端与接收端分别有4根和8根天线并且接收端选择4根天线接收信号的情况下,新算法获得了与最优算法相近的系统容量,并且使复数加和复数乘的计算量分别减少了36.4%和40.8%。因此,新算法收敛更快。论文采用空时分组码与新算法相结合的方法分析了新算法的误比特率。在发送端使用空时分组码编码方案,在接收端先用新算法进行天线选择,再使用空时分组码最大似然译码方案进行译码。仿真结果表明,在接收端进行天线选择,使用新算法后系统误码性能与使用最优算法时的误码性能基本一致。因此,新算法具有更好的性能。更多还原

【Abstract】 Multi-Input and Multi-Output (MIMO) is one of the most important techniques for next generation mobile communications. MIMO can increase capacity of the communication system, and improve the spectral utilization. However, the hardware of the MIMO system is very expensive, which greatly limits its applications. As an important technique in the MIMO system, antenna selection can choose properly one or several best antennas from multiple transmitting and receiving antennas, and reduce the expense with less performance loss. Therefore, the performance-cost-ratio of the MIMO system is improved greatly.In this thesis, the classic algorithms are introduced and analyzed first. Although the optimal algorithm can achieve the highest channel capacity, it is not of practical value because it has a very high complexity. Starting from the Shannon formula and the existing algorithms, a new antenna selection algorithm is proposed through the derivation of mathematical formulas, and its channel capacity is close to that obtained by the optimal algorithm. Simulation results indicate that in the case of 4 transmitting and 8 receiving antennas, choosing 4 antennas to receive signals, the algorithm has a channel capacity close to the capacity obtained by the optimal algorithm. Meanwhile the calculating amount for the addition and multiplication of complex numbers decreases 36.4% and 40.8% respectively. Thus the proposed algorithm converges very fast.The proposed algorithm and Alamouti’s Space-Time Block Code (STBC) scheme are used together to analyze its Bit Error Rate (BER). In fact, Alamouti’s coding scheme is used at the transmitting end. Meanwhile, at the receiving end, the antenna selection algorithm is used first, and then Alamouti’s maximum likelihood decoding scheme is used. Simulation results show that with antenna selection at the receiving end the BER of the proposed algorithm is almost identical with that of the optimal algorithm. Therefore, the proposed algorithm has a better performance.更多还原