Modeling and Prolonging Techniques on Operational Lifetime of Wireless Sensor Networks

• Main Authors: Fuu-Cheng Jiang, 江輔政
• Other Authors: Der-Chen Huang
• Format: Others
• Language: en_US
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/48918523071877887453

博士 === 國立中興大學 === 資訊科學與工程學系所 === 99 === Power consumption is an essentially important issue and an interesting challenge to prolong the operational lifetime of wireless sensor network (WSN). To prolong the lifetime of sensor nodes, most research works have focused on how to tune the duty cycling schemes among nodes to save the communication cost using multifarious wake-up strategies. To this aim, we propose a novel design strategy for mitigating average power consumption of sensor node using the Min(N, T) policy M/G/1 queuing theory. There is a heavy overhead for packet collisions and channel contention resulting from restarting the process of medium contention. The basic point of our approach is that Min(N, T) dyadic policy would mitigate the total average times of medium contention by having both a counter (N) and a timer (T) for the control of triggering on a radio server to transmit queued packets, and then power consumption of communication can be alleviated. We show how the improvement level on power consumption can be achieved through analytical and simulated results. To meet the mission requirements in sensor networks, the proposed add-on power saving technique can also provide a design framework for the sensor network manager to optimize relevant system parameters including power consumption and latency delay. Sensors closer to a sink node have a larger forwarding traffic burden and consume more energy than nodes further away from the sink. The whole operational lifetime of WSN is deteriorated because of such an uneven node power consumption patterns, leading to what is known as an energy hole problem (EHP) around the sink node. Basically the innermost shell nodes have a larger forwarding burden and consume more energy than nodes further away from the sink node. In this dissertation, the proposed queue-based power-saving technique can be expanded and applied to alleviate the EHP as well. With little management cost, the proposed queue-based power-saving technique can be applied to prolong the lifetime of sensor network economically and effectively. For the proposed queue-based model, mathematical framework on performance measures have been formulated. And also we will analyze the average traffic load per node for concentric sensor network. Focusing on the nodes located in the innermost shell of WSN, numerical and NS-2 network simulation results validate that the proposed approach indeed provides a feasibly cost-effective approach for lifetime elongation of sensor networks.