Shortest path routing with reliability requirement in delay tolerant networks
ABSTRACT The topology of a delay tolerant network (DTN) over time has been modeled by a space-time graph. However, the mobility of nodes, such as buses, may not be completely predictable due to factors such as traffic load, road condition, the number of passengers getting on and off the buses, and the operations of traffic lights. In this paper, we adapt the space-time graph by augmenting each horizontal edge with a direct contact probability to model the uncertainty of connectivity. With such an augmented space-time graph, our goal is to compute a shortest routing path satisfying a given end-to-end delivery reliability in a DTN. To facilitate such computation, we adapt the Floyd-Warshall algorithm to compute the maximum contact probability matrix at each time interval. By using an iterative matrix multiplication scheme on a maximum contact matrix, we can compute the shortest path satisfying the reliability constraint. Simulation results validate the performance of our solution which achieves a good balance between delay and reliability.
Article: Look-Ahead Strategies Based on Store-Carry and Forward Relaying for Energy Efficient Cellular Communications[show abstract] [hide abstract]
ABSTRACT: With the increasing availability of Internet type services on mobile devices and the attractive flat rate all-you-can-eat billing system, cellular telecommunication networks are experiencing a tremendous growth in data usage demand. However, there are increasing concerns that current network deployment trends (including more efficient radio access techniques and increased spectrum allocation strategies), will be unable to support the increased Internet traffic in a sustainable way. The delay tolerant nature of mobile Internet traffic allows for a large degree of flexibility in optimizing network performance to meet different design objectives and it’s a feature that has mostly gone unexplored by the research community. In this paper, we introduce a novel message forwarding mechanism in cellular networks that benefits from the inherent delay tolerance of Internet type services to provide flexible and adjustable forwarding strategies for efficient network operation while guaranteeing timely deliveries. By capitalizing on the elasticity of message delivery deadlines and the actual mobility of nodes inside the cell, considerable performance gains can be achieved by physically propagating information messages within the network.Future Internet. 01/2010;