Selective time reversal receiver for shallow water acoustic MIMO communications

MIMO systems is capable of achieving two to three spatially parallel communication channels in very shallow water to improve communication performance as well as capacity. For MIMO communications, simultaneous presence of multipath and co-channel interference poses substantial difficulties for the design of receiver. While the classic space-time multi-channel DFE receiver consisting of multiple DFE equalizers is limited by high computational complexity when multipath time delay is large, the low complexity time reversal receiver needs a large number of receivers (>10) to achieve satisfactory performance. This paper presents the design of a selective time reversal underwater acoustic MIMO communication receiver to accommodate the small receiver number of space-time DFE and the multipath focusing capability of time reversal by coupling the time reversal with multi-channel DFE. Sea trial experiments are carried out to demonstrate the superior performance of the proposed method.