Design of EM Wave Based MAC Protocols for Underwater Sensor Networks with TDMA based Control Channel

Abstract

Underwater communication is the major tool for exploring vast underwater space, which is extremely critical for the progress of human race. To perform communication in underwater, sensors are deployed to form underwater networks, which in return provides an efficient robust communication system. For the past few decades, almost inevitably, underwater communication systems have grown deploying acoustic based signal propagation. However in recent times, the demand of low latency and high throughput applications, and the emergence of short-range underwater communications has drawn notable attention of many academia and industries for developing electromagnetic (EM) wave based underwater sensor networks (UWSNs). In light of this, this thesis work proposes novel multiple access control (MAC) protocols by integrating EM based communications in single-hop communications based UWSNs. Proposed protocols use a separate TDMA based control channel and single or multiple data channel(s) for data packet transmission. EM wave is proposed for the control channel, whereas EM or acoustic wave can be used in the data channel(s).

Performance of the proposed MAC protocols is investigated considering both protocol interference model and physical interference model. A MATLAB based simulation platform is developed for thoroughly investigating the performance of the proposed MAC protocols. Performance is evaluated in terms of throughput, packet collision rate, waiting time, energy requirement, network coverage, etc. Impact of system parameters, such as offered load, network size, data packet size, control packet power, water conductivity and channel bandwidth are analyzed thoroughly. A comparison and feasibility study of the proposed protocols is also presented demonstrating better performance compared to CSMA, ALOHA-CS and ALOHA-AN MAC protocols. Our investigation using physical interference model also identifies that EM-EM based scenario can be used for short distance communication achieving improved network performance. This also suggests that EM-EM based multi-hop communications might be a better choice for long-range UWSNs, which will be considered in our future works.