An Adaptive OFDMA-Based MAC Protocol for Underwater Acoustic Wireless Sensor Networks

Sensors

Issa M. Khalil²  Yasser Gadallah¹  Mohammad Hayajneh² 

[1] Department of Electronics and Communications Engineering, Misr International University, Cairo 11311, Egypt; E-Mail:;College of Information Technology, United Arab Emirates University, Al Ain 17555, United Arab Emirates; E-Mail:

关键词: MAC protocols;    sensor networks;    OFDMA;    CDMA;    channel access/reservation;   

DOI  :  10.3390/s120708782

来源: mdpi

【 摘 要 】

Underwater acoustic wireless sensor networks (UAWSNs) have many applications across various civilian and military domains. However, they suffer from the limited available bandwidth of acoustic signals and harsh underwater conditions. In this work, we present an Orthogonal Frequency Division Multiple Access (OFDMA)-based Media Access Control (MAC) protocol that is configurable to suit the operating requirements of the underwater sensor network. The protocol has three modes of operation, namely random, equal opportunity and energy-conscious modes of operation. Our MAC design approach exploits the multi-path characteristics of a fading acoustic channel to convert it into parallel independent acoustic sub-channels that undergo flat fading. Communication between node pairs within the network is done using subsets of these sub-channels, depending on the configurations of the active mode of operation. Thus, the available limited bandwidth gets fully utilized while completely avoiding interference. We derive the mathematical model for optimal power loading and subcarrier selection, which is used as basis for all modes of operation of the protocol. We also conduct many simulation experiments to evaluate and compare our protocol with other Code Division Multiple Access (CDMA)-based MAC protocols.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.