Adaptive spatial and temporal diversity combining in spread spectrum, multi-access, sub-sea acoustic communication receivers

In this paper we propose a spread spectrum-based adaptive array receiver structure for reliable low data-rate multi-access communication in the shallow-water acoustic channel. The performance of the proposed receiver algorithms is evaluated by employing offline processing of received data from experiments in the North Sea. Results indicate that multi-access error-free reception is attainable in network scenarios where transmission is multipath impaired, and in which user data is overlapping and unsynchronized. In addition, the receiver architecture is also employed in a RAKE structure to achieve adaptive temporal combining, and it is shown that spatial or temporal combining can be used interchangeably to achieve improved signal to interference noise ratio.