中文摘要：

提出了一种适用于多输入多输出系统的自适应调制算法，在满足总发送功率和误比特率限制条件下利用不精确的信道状态信息使系统信息传输速率最大化。该算法首先利用拉格朗日方法得到最优化问题在实数域的闭合最优解，然后将其调整为符合多进制正交幅度调制要求的离散比特数，从而获得最终的比特和功率分配结果。仿真结果表明，与传统算法相比，该算法不仅呈现对不精确信道状态信息更加鲁棒的误比特率特性，而且在相同误比特率条件下可以提供更高的频谱效率。

英文摘要：

An adaptive modulation algorithm is proposed for multiple-input multiple-output （MIMO） systems to maximize transmission rate satisfying transmit power and bit error rate （BER） requirements with imperfect channel state information （CSI）. By Lagrange method, the solution of optimization problem in the real field is derived and then adjusted into discrete bits suitable for M-ary quardrature amplitude modulation. Simulation results show this algorithm can provide not only the more robust BER performance to CSI imperfection, but also higher spectral efficiency than the conventional adaptive modulation algorithms based on perfect CSI assumption.