Coverage Guaranteed Cooperative MIMO Formation for Underwater MI-Assisted Acoustic WSNs

Underwater magnetic induction (MI)-assisted acoustic cooperative multiple-input-multiple-output (MIMO) technology enables reliable communication with high throughput over long transmission distances. The combination of such as technology and underwater wireless sensor networks (UWSNs) is initiating a novel underwater Internet of Things (IoT paradigm): underwater MI-assisted acoustic cooperative MIMO WSNs. The MIMO UWSNs meets the requirements of reliable communication networks connecting underwater sensor nodes and remote surface base station (BS) for the next generation of smart ocean applications. The objective of the paper is to obtain the cooperative MIMO formation scheme in these networks for minimizing the nodes' energy consumption, simultaneously ensuring the connectivity of nodes and surface BS, and improving the coverage of networks. This paper proposes a scaly cooperative MIMO formation (SCMF) scheme based on the greedy algorithm to solve the constrained optimization problem, which is a two-phase method. In the first phase, the members of the cooperative MIMO are preliminarily determined while ensuring that there is only a single coverage hole in each iteration. In the second phase, a new master node (MN) is selected and the transmission power is determined to reduce energy consumption. Simulation results show that our proposed scheme not only fills the gap that the existing algorithm does not consider the network coverage, but also confirms that it can achieve significant energy saving and prolongs the network lifetime considerably.