中文摘要：

在MIMO—OFDM无线通信系统中，采用基于子载波线性预编码设计和变步长加载算法得到一种优化的自适应加载算法，在完全已知信道状态前提下，能在满足固定速率和给定误比特率约束下使系统总发射功率达到最小。仿真结果表明，该算法复杂度比Capello算法低，并且性能与之近似，都远远优于非自适应MIMIO系统的性能。

英文摘要：

An adaptive modulation scheme is proposed in order to minimize the total transmission power subject to given BER and transmit data rate in MIMO - OFDM wireless communication systems. It is derived from a linear precoding design and various-step adaptive loading algorithm. The simulation results show that the presented algorithm has a similar system performance to Capello algorithm,but less complexity than it, and both performances are much better than non- adaptive MIMO system.