低复杂度的MIMO-OFDM系统自适应调制方案

Adaptive Modulation Scheme with Low Complexity for MIMO-OFDM Systems

以最小化发射总功率为目标,提出了一种低复杂度的MIMO-OFDM无线通信系统的自适应调制方案.在发射端,基于已知信道状态信息,应用奇异值分解将空分复用信道转化为并行的子信道,并将表征信道增益的信道矩阵特征值用于子信道自适应调制优化设计中.针对MQAM调制,采用变步长的贪婪算法得到优化的子信道比特加载及功率分配方案.仿真结果表明,所提出的简化算法与一种近似最优的自适应调制算法性能接近,但复杂度降低了30%以上.

A low complexity adaptive modulation scheme was proposed in order to minimize the total transmission power of the transmitter in MIMO-OFDM wireless communication systems. At the transmitter end, singular value decomposition （SVD） method was utilized to transform the spatial multiplexing channel into parallel subchannels based on the known channel state information. The eigenvalues of channel matrix representing the subchannel gains were employed in the optimization design of sub-channel＇s adaptive modulation scheme. For MQAM modulation, the optimized bit loading and power allocation were derived from a various-step greedy algorithm. The simulation results show that the presented scheme has a performance close to the sub-optimal algorithm, saving computation complexity by 30% and more.