UW‐MAC: An underwater sensor network MAC protocol

Abstract

Abstract-As over 70 percent of the earth's surface is covered by water, it is desirable to deploy underwater sensor networks to support oceanic research. Under Water Sensor Networks (UWSNs) use acoustic waves and are characterized by long and variable propagation delays, intermittent connectivity, limited bandwidth and low bit rates. Energy savings have always been the primary concern in wireless sensor network protocols; however there are applications where latency and throughput are prioritized over energy efficiency and are so significant that the application would not be able to satisfy its requirements without them. Although existing duty-cycle MAC protocols are power efficient, they introduce significant end-to-end delivery latency, provide poor throughput and are not suitable for the challenging environment of an UWSN. In this paper, we utilize CDMA as the underlying multiple access technique, due to its resilience to multi-path and Doppler's effects prevalent in underwater environments. We propose UW-MAC, a CDMA-based power controlled medium access protocol that uses both transmitter based and receiver based CDMA inside a formed cluster, and uses a TDMA schedule to make the cluster heads communicate with the base station. Our MAC algorithm targets latency and throughput needs in addition to its ability to increase the overall network lifetime. We discuss the design of UW-MAC, and provide a head-to-head comparison with other protocols through extensive simulations focusing on the performance in terms of latency, throughput and energy consumption.

A Multichannel MAC Protocol for Underwater Acoustic Sensor Networks

“…For the limited available bandwidth in underwater acoustic channels, FDMA was not suitable for UWSN [2]. The second type of code-division protocol, usually used in inner-cluster UWSN for communications, includes HRMAC [3] and UW-MAC [4]. The last type, time based protocol, is the most developed.…”

Signaling game approach to improve the MAC protocol in the underwater wireless sensor networks

“…For the first type, there are protocols based on three multiple access techniques such as FDMA, 11 TDMA, [12][13][14] and CDMA. 15,16 The second protocols type are classified into random access and handshaking protocols that have the advantage of using the full bandwidth of the communication channel. Carrier sense multiple access (CSMA) 17 and ALOHA 18 represent the same type of those protocols.…”

Asymmetric Propagation Delay-Aware TDMA MAC Protocol for Mobile Underwater Acoustic Sensor Networks

“…In high traffic scenarios, packet collisions of MUASNs not only severely degrade network throughput, but also cause intolerably long latency due to uncertain number of retransmissions. On the other hand, contention-free MAC protocols [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] are significantly superior to contention-based ones in high traffic scenarios because the medium is orthogonalized in a certain domain.…”