基于MIMO天线多载波系统的最大容量及最优信道选择算法

Maximum Capacity and Optimal Channel Selection Algorithm Based on Multicarrier System with MIMO Antennae

为了实现多输入多输出(MIMO)系统的最优传输,在加性高斯白噪声信道下分析了MIMO天线的信道容量增益,进而提出在MIMO多载波系统中,对信道进行时-频-空三维划分的理论,并给出了时-频-空三维能量密度谱的概念,从而对能量和时-频资源进行约束.在此基础上推导并得出了MIMO多载波系统在加性噪声下的最优能量分配准则和MIMO多载波系统的容量上限.在最优能量注水解的指导下,对基于MIMO天线的正交频分复用(OFDM)系统进行最优信道选择,并与未经信道选择算法的系统在相同资源约束和信道环境下进行性能比较.仿真结果表明,经过信道选择的系统能更有效地保证符号可靠传输,并且系统容量逼近提出的容量上限.

In order to achieve optimal transmission in multiple-input multiple-output （MIMO）system,channel capacity gain with MIMO antennae was analyzed under additive Gaussian white noise channel. Then the theory that the channel can be partitioned in three dimensions--time,frequency and space in MIMO multicarrier system was proposed and the timefrequency-space energy density spectrum was brought forward as a constraint of energy and time-frequency resources. Based on this,optimal energy distribution guideline in MIMO multicarrier system under additive noise and the capacity upper limit of the system were deduced. Under the guidance of optimal water-filling resolution ,optimal channel selection was done in orthogonal frequency division multiplexing （OFDM） system based on MIMO antennae. The performance of the system with optimal channel selection and that without channel selection were compared under the same resource constraints and channel condition. The simulation results show that the system with optimal channel selection can ensure more effective and reliable symbol transmission and the system capacity approaches the capacity upper limit proposed previously.