Interference-Avoidance and Low-Latency Cross-Layer Multipath Routing for Underwater Acoustic Communication Networks

Due to the specific characteristics of underwater channels and the hostile ocean environment, it is challenging to provide reliable data transmissions in underwater acoustic communication networks (UACNs). Multipath routing (MR) has emerged as a promising solution to enhance transmission reliability by leveraging redundant paths to transmit data concurrently. However, MR is prone to cross-path interference, which will degrade transmission latency performance. To this end, this paper proposes an interference-avoidance and low-latency cross-layer multipath routing (ILMR) protocol to address the tradeoff between reliability and latency in MR. Specifically, ILMR considers the transmission latency as the optimization objective and formulates a constrained optimization problem that jointly optimizes path selection at the network layer and transmission scheduling at the medium access control layer. By cross-layer joint design, ILMR can reduce cross-path interference and achieve reliable MR with lower latency in UACNs. Furthermore, unlike most previous works on routing for UACNs that are only verified through simulations, we have also carried out field experiments, including an experiment in Minghui Lake, and a sea trial near Dongju Island in the Zhoushan Archipelago. Experimental results show that the proposed cross-layer MR scheme can improve network performance. Specifically, the transmission latency performance is reduced by about 30% and the packet delivery ratio performance is increased by about 5%.