TDMA-based MAC Protocol For Small-scale Underwater Acoustic Sensor Networks

Under-Water Acoustic Sensor Networks (UW-ASNs) consist of a variable number of sensors and vehicles that are deployed to perform collaborative monitoring tasks over a given area. A mac protocol allows the nodes in network to share the common broadcast channel. The main task of MAC protocol is to resolve data packet collision and to prevent simultaneous transmissions while providing energy efficiency, low channel access delays and fairness among competing nodes. MAC layer in underwater sensor networks has much importance on the network utilization in the presence of harsh underwater acoustic channel. Recently, many new MAC protocols for underwater sensor networks have been proposed. Selection of a suitable MAC protocol has a great impact on the system efficiency and is especially importance for channels with low quality and high latency.The research in this paper focuses on some shortcoming aspects of the MAC protocol of underwater sensor networks. Then we propose new MAC protocols for UW-ASNs. Based on computer simulations, the effectiveness and perform of these protocols are verified. The main contents of this thesis are as follows:We propose a TDMA-based MAC Protocol for Single-hop underwater acoustic sensor networks (TMP-S). TMP-S dynamically determines each node’s sending time according to the variable offered load, and assigns the time slot to each node based on the minimum waiting time rule. In addition, the protocol combines the sending and acknowledgement to overcome low throughput and the long end-to-end delay problems.We propose a TDMA-based MAC Protocol for Multiple-hops underwater acoustic sensor networks (TMP-M). TMP-M models transmission scheduling in multiple-hops UW-ASNs as a vertex coloring problem and improves the channel utilization by allowing exposed senders to transmit simultaneously.