OFDM闭环发射分集结合自适应功率分配

将自适应功率分配技术应用于多发送多接收天线正交频分复用(MIMO-OFDM)系统，如何在载波和天线间分配能量是个关键问题。该文提出:对不同发射天线的各个子载波采用闭环发射分集方案；接着再进行载波间的功率分配，该算法的目标是使误码率最小。文中用数学方法证明了此方案是使总误码率最小的最佳方案。仿真结果显示:在误码率取0.1%时，对于两根发射天线一根接收天线4个子载波的OFDM系统，与传统的将开环发射分集与OFDM相结合的算法相比，此算法能带来6.5dB的增益。

OFDM Closed-Loop Transmit Diversity Combined with Adaptive Power Allocation

How to allocate power to antennas and carriers is a key problem when adaptive power allocation method is used to multi-antenna and multi-carriers Orthogonal Frequency Division Multiplexing (MIMO-OFDM) system. In this paper, a novel algorithm for allocation of power is proposed. The algorithm firstly combines OFDM with closed-loop transmit diversity technique, then allocates the power to carriers to minimize the Bit Error Rate (BER). This algorithm has the optimum performance which has been proved by mathematical method. To the two transmitted antennas and one received antenna system when the number of OFDM subcarriers are equal to 4, simulation results show that there is 6.5dB gain by comparing with the traditional OFDM-STBC method at the BER of 0.1%.