Energy and Time Trade-Offs in Duplicate Packet Transmission
Erol Gelenbe, Avgoustinos Filippoupolitis and Imad Eid
International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS 2007)
San Diego, California (USA), July 16-18, 2007
SPECTS_Summary
Sensor and ad hoc networks are designed to function in uncertain environments. The transmission medium, the possible mobility and unreliability of nodes, and possible malicious interventions by adversaries, create significant uncertainty and increase the effective transmission delays, which in turn may be mitigated by appropriate protocols. One obvious approach to mitigating uncertainty is to forward information over multiple independent paths, but this means of reducing overall unreliability comes at the cost of increased energy consumption as well as the creating of congestion and possible conflicts and packet collisions. In recent papers theoretical models have been developed for packet travel times in a wireless network whose nodes are distributed over a volume of space, and in which packets have to travel over a random number of multiple relay hops before they reach their destination. In this paper we present detailed simulation studies in a variety of wireless topologies to investigate the trade-off between reliable packet delivery, the effective packet delivery time, and the energy cost per packet in wireless networks. Our simulations include unfavourable conditions, such as when the packet is provided with wrong information about the direction that it should follow, and include the effect of time-outs and packet retransmission when it is assumed that the packet has been lost. We observe that under specific conditions, the simultaneous transmission of duplicate packets can lead to improved overall performance, in significantly reducing travel effective delay without significantly increasing energy expenditure.