An On-Demand Scheduling-Based MAC Protocol for UW-WiFi Networks

Underwater Internet-of-Things (UIoT) is an extension of technology in underwater. The underwater acoustic network with WiFi architecture (UW-WiFi), as a specific deployment UIoT, has been proved to be promising technique for wide-ranging marine applications. However, due the unique features channel, such long and variable propagation delay, low available bandwidth high bit error rate, conventional medium access control (MAC) protocols designed terrestrial networks need overhaul work efficiently UW-WiFi networks. In consideration aforementioned channel features, different demands nodes occupy resources reliability data transmission, time sequence-based dynamic on-demand assignment (SDDA) MAC protocol proposed this paper. SDDA, collision-free scheduling integrated reservation mechanism, aiming address issue various requirements diverse task on system. employs delays amount sent by terminal achieve non-conflict transmissions packets packets. Additionally, scheme does not require extra overhead synchronization. Comparison simulations demonstrate that SDDA provides considerable benefits terms utilization, end-to-end delay packet delivery ratio. At last, implemented system set up environment. ocean field experiment results agree well simulated ones also verify conflict-free scheduling, fairness among at ranges practicability actual environments.