MIMO-OFDM两跳再生中继系统下的迭代功率分配

Iterative power allocation scheme for two-hop regenerative MIMO-OFDM relay system

分析了发射端与中继端和功率受限条件下MIMO-OFDM两跳再生中继系统发射功率优化问题.为最大化系统容量,提出一种迭代功率分配算法,该算法根据两跳信道条件,不断调节其发射功率,直到两跳容量相差达到设定的门限值,天线上功率分配考虑在各子载波上每跳各天线之间等功率分配和利用注水原理进行功率分配;其次,分析迭代功率分配时迭代精度的选择问题,最后,研究在功率分配之前考虑子载波配对.仿真结果表明,利用迭代功率分配系统容量得到有效优化,迭代精度的选取是权衡算法复杂度与系统容量的结果,考虑子载波配对系统容量亦有进一步提高.

This paper considers a two-hop regenerative multiple-input and multiple-out- put （MIMO） orthogonal frequency division multiplexing （OFDM） relay communication system model. In this model, the overall transmission power of the source and relay is limited; the power allocated to the source and relay over one subcarrier is equally distributed to each antenna, or utilizing water filling algorithm to allocate power to each antenna at the source and relay. To maximize the system capacity, first, an iterative power allocation algorithm that jointly optimizes the transmission power between the source and relay is proposed with the condition that not considering subcarrier pairing. This algorithm is concentrating on constantly adjusting the transmission power between the source and relay according to two-hop channel conditions, until the capacity margin between the two hops achieves a specified threshold value. Next, the iterative precision choice problem in the process of iterative power allocation is analyzed. Then, subcarrier paring is taken into account before carrying out iterative power allocation. Simulation results show that the proposed power allocation algorithm can achieves significant improvement on system capacity. The iterative selection of precision is the result of weighing the algorithm complexity and system performance. And then when subcarrier is involved, more improvement can be obtained.