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

Abstract

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

uw-WiFi: Small-Scale Data Collection Network-Based Underwater Internet of Things

“…In this network, we designed a protocol called SDDA [44]. The main principle behind it is to achieve a slotted packet reception at the base station node.…”

An AUV-Assisted Data Gathering Scheme Based on Deep Reinforcement Learning for IoUT

“…The concept of the underwater internet of things (IoUT) was mentioned for the first time in 2010 and identified as an extension and new category of IoT [1]. IoUT is expected to establish the interconnection of underwater objects [2,3] and realize smart oceans [4,5]. Due to the special characteristics of the marine environment, terrestrial IoT technologies cannot be used in the underwater environment directly.…”