CLUSTERED DATA DIFFUSION ROUTING PROTOCOL FOR LARGE-SCALE WIRELESS SENSOR NETWORKS

One of the major challenges in the implementation of WSNs is to prolong the lifetime of the energy source in the sensor nodes. This can be achieved through designing energy-efficient routing protocol. Energy-efficient routing protocol enables WSNs to stay in operation for a long time by managing communication between the sensor nodes and the sink. In addition the routing protocol can handle a large number of sensor nodes in energy-efficient manner utilizing multihop communications among the sensors. Four existing routing protocols performance were analyzed using J-Sim simulator. Results obtained from the performance analysis show that the Directed Diffusion (DD), creates a large amount of overhead when broadcasting a query message to the whole network. This causes huge amount of energy consumption, which reduces WSNs lifetime. Low Energy Adaptive Clustering Hierarchy (LEACH) routing protocol, which assumes one-hop communication range from the sink node is not scalable for large-scale WSNs. To enhance the way the data can be gathered in query-driven data reporting method, a cluster-based data diffusion routing protocol for large-scale wireless sensor networks has been proposed. In the proposed method, the sink node sends the interest message unicastly, only to the cluster heads. In addition, multihop communication between the cluster heads for sending the interest, and receiving the data packets back from the source node has been used. The results obtained have been analyzed and compared with DD and PCDD protocols as well as with other works, in which some enhancements over DD were made using different approaches. The overall results using different metrics have shown that, the proposed protocol outperforms DD and PCDD in saving the energy . The improvement of CDD in saving the energy is between 50% and 63.64% while comparing it to DD and, 8% and 42.8% compared to PCDD, for the fixed density scenario. For the fixed area scenario the improvement is up to 29.4% and at least 15% while comparing CDD to PCDD and up to 63.1% and at least 26.1% while comparing it to DD. The proposed clustering data diffusion method also was extended to handle a combination of mobile and static nodes, and user’s (sink’s) mobility as well. It improved the coverage of the sensor network and for applications which need some movements of the sink node in order to gather data by sending the query message to the sensor field. A performance analysis for the extended protocol was conducted, and a significant energy saving was achieved especially in denser networks

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