Performance Analysis Of Delay Tolerant Sensor Networks With Mobile Sinks

Wireless sensor networks and Ad Hoc networks which represent newly arisen wireless communication networks are first applied to the challenging special environment of the emergency communications field, because they have some advantages such as easy to setup and flexible to communicate with each other. These characters are lacked by traditional cellular networks. Communication in special environment has complicated channels and many difficulties. Delay tolerant networks (DTN) is exactly under this kind of background to emerge with the tide of the times. From Interplanetary network (IPN) by satellite to various wireless special environment communication, the system dynamics of DTN, such as time-varying and error-prone wireless links, dynamic and limited bandwidth, time-varying traffic pattern and energy constraints, pose new challenges that do not exist in wired networks.At the same time, wireless sensor networks (WSN), consisting of a large number of small sensor nodes with sensing, computing, and communication capabilities, recently received tremendous attention from both academia and industry because of its promise of a wide range of potential applications in both civil and military areas. It is declared as one of the most important technologies for the 21st century.This paper tries to introduce the delay tolerant applications into wireless sensor networks. The research of network performance is developed through three aspects. First, the paper has studied the impact of mobility on network performance and the design principles of Sink's mobile trajectory. Then we consider the tradeoff between resources and design space and through reasonable adjustment parameters to achieve the overall performance optimization. Finally through analysis of the current routing protocols using in mobile sensor networks and DTN, we propose a new routing scheme which is applied to delay tolerant sensor networks with mobile Sinks.The contributions of this thesis include:(1) We prove the mobility can improve the network performance through theoretical analysis and simulation. From the trajectory design methods of circle and rectangle, we give the design principles of Sink's mobile trajectory. (2) Through the theoretical modeling of delay tolerant sensor networks, we evaluate the network performance and parameters and propose the analysis model of average packet delivery delay.(3) Performance analysis of delay tolerant sensor networks with the random movement of Sinks. Through the analysis of the characters in random mobility models, we propose the mathematics method to calculate the average packet delivery delay, number of copies and energy consumption in single-hop and multihop networks and verify the results by simulation. The analytical results that are in high agreement with simulations results.(4) Performance analysis of delay tolerant sensor networks with the fixed trajectory of the mobile Sinks. We propose the mathematics method of average packet delivery delay in single-hop networks and verify the results by simulation. While analysis the performance of multihop networks, we consider four typical network routings of DTN networks and propose the mathematics method to calculate the average packet delivery delay, number of copies and energy consumption. We analyze the tradeoff between delay and energy and study the impact of parameters on network performance.(5) We propose a new routing scheme which is applied to delay tolerant sensor networks with mobile Sinks and compare our routing algorithm with mainy existing routing methods. From the simulation results, our routing scheme DSOT is a considerably energy efficient, robust protocol with low delay in delay tolerant sensor networks.The entire works of this dissertation are exploring forefront in constructing delay tolerant networking with mobile sensor networks. Proposals and results are expected to optimize the design of network protocols and improve the network performance.