A battery aware high-throughput MAC layer protocol in sensor networks

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. The communication unit and the antenna operation consume most of the battery-powered energy of the node. Thus, the access to the medium must be controlled in a very strict manner in order to avoid collisions which result in lost transmissions and have a dramatic impact on the lifetime of the network. Although existing duty cycle MAC protocols are power efficient, they introduce significant end-to-end delivery latency and provide poor throughput. In this paper, we propose SN-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 algorithm targets latency and throughput needs in addition to its ability to increase the overall network lifetime. We provide a head-to-head comparison with other protocols through extensive simulations focusing on the performance in terms of latency, throughput, and energy consumption

Energy efficient medium access protocol for DS-CDMA based wireless sesor networks.

Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.Wireless Sensor Networks (WSN), a new class of devices, has the potential to revolutionize the capturing, processing, and communication of critical data at low cost. Sensor networks consist of small, low-power, and low-cost devices with limited computational and wireless communication capabilities. These sensor nodes can only transmit a finite number of messages before they run out of energy. Thus, reducing the energy consumption per node for end-to-end data transmission is an important design consideration for WSNs. The Medium Access Control (MAC) protocols aim at providing collision-free access to the wireless medium. MAC protocols also provide the most direct control over the utilization of the transceiver, which consumes most of the energy of the sensor nodes. The major part of this thesis is based on a proposed MAC protocol called Distributed Receiver-oriented MAC (DRMACSN) protocol for code division multiple access (CDMA) based WSNs. The proposed MAC protocol employs the channel load blocking scheme to reduce energy consumption in the network. The performance of the proposed MAC protocol is verified through simulations for average packet throughput, average delay and energy consumption. The performance of the proposed MAC protocol is also compared to the IEEE 802.15.4 MAC and the MAC without the channel load sensing scheme via simulations. An analytical model is derived to analyse the average packet throughput and average energy consumption performance for the DRMACSN MAC protocol. The packet success probability, the message success and blocking probabilities are derived for the DRMACSN MAC protocol. The discrete-time multiple vacation queuing models are used to model the delay behaviour of the DRMACSN MAC protocol. The Probability Generating Functions (PGF) of the arrivals of new messages in sleep, back-off and transmit states are derived. The PGF of arrivals of retransmitted packets of a new message are also derived. The queue length and delay expressions for both the Bernoulli and Poisson message arrival models are derived. Comparison between the analytical and simulation results shows that the analytical model is accurate. The proposed MAC protocol is aimed at having an improved average packet throughput, a reduced packet delay, reduced energy consumption performance for WSN