Distance-alignment based adaptive MAC protocol for underwater acoustic networks

Interference channel (IC) can achieve significant spectrum benefit due to interference alignment (IA). In this paper, we consider the application of IC to underwater acoustic networks (UANs), which have narrow bandwidth and low channel capacity. Based on the underwater acoustic propagation model, a new IA-based distance-alignment structure (DAS) is studied for UANs with the following contributions. Firstly, the feasibility of proposed DAS in a three-dimension water space has been validated and demonstrated up to 4 pairs of transmit-receive nodes. Then a delay-aware adaptive multiple access (MAC) protocol, which can automatically switches between two basic modes according to interference distance, is investigated, and the performance study shows that the proposed protocol along with the DAS can asymptotically achieve the theoretic result of IC.