一种多径衰落水声MIMO信道自适应均衡仿真研究

Simulation of MIMO Adaptive Equalization for Multipath Underwater Acoustic Channels

水声通信信道带宽十分有限,为了提高信道容量和传输速率,将M IMO技术应用于水声通信。针对多径衰落引起的码间干扰(ISI)和多个发射信号间的信道间干扰(CC I),采用多组判决反馈均衡器结构,能够同时消除ISI和CC I的影响,分别提取各个发射机上的不同数据。给出了M IMO均衡器的结构、最小均方误差解和LMS均衡算法。通过计算机仿真,证明了该方法的有效性,并将单发单收(SISO)均衡与两发两收情况下的M IMO均衡进行了性能对比。结果显示,尽管M IMO均衡的误码率略高,但却可以获得两倍于SISO系统的数据传输速率,有很好的应用前景。

The available bandwidth of underwater acoustic channel is inherently narrow that impedes high transmission rate. In this paper, a MIMO adaptive equalization system is employed to increase the effective underwater acoustic channel bandwidth. To cope with intersymbol interference caused by multipath propagation,and cochannel interference of the channel, a MIMO decision - feedback - equalizer（DIRE） is used to get different data from multiple transmitters. The structure of the equalizer is given, together with a least mean square error solution and a LMS algorithm. Effectiveness of this method is proved by simulations and the performance of MIMO equalization with two transmitters and two receivers is compared with SISO equalization. Simulation results show that although bit error rate is a little higher, MIMO system can achieve two times data transmission rate than SISO, which is very channing for severely bandlimitted underwater channels.