Routing Algorithms for Energy-Efficient Reliable Packet Delivery in Multihop Wireless Networks

• Main Authors: BANERJEE, Suman, MISRA, Archan
• Format: text
• Language: English
• Published: Institutional Knowledge at Singapore Management University 2006
• Subjects: Software Engineering
• Online Access: https://ink.library.smu.edu.sg/sis_research/723; https://doi.org/10.1002/0471755591.ch5
• Institution: Singapore Management University

Algorithms for minimum‐energy routing in wireless networks typically select minimum cost multihop paths. In scenarios where the transmission power is fixed, each link has the same cost and the minimum hop path is selected. In situations where the transmission power can be varied with the distance of the link, the link cost is higher for longer hops; the energy aware routing algorithms select a path with a large number of small distance hops. In this chapter, we argue that such a formulation based solely on the energy spent in a single transmission is not able to find minimum energy paths for end to end reliable packet transmissions. The proper metric should include the total energy (including that expended for any retransmissions necessary) spent in reliably delivering the packet to its final destination. We first examine how link error rates affect this retransmission aware metric, and how it leads to an efficient choice between a path with a large number of short distance hops and another with a smaller number of large distance hops. Such studies motivate the definition of a link cost that is a function of both the energy required for a single transmission attempt across the link and the link error rate. This cost function captures the cumulative energy expended in reliable data transfer, for both reliable and unreliable link layers. Through detailed simulations, we show that such schemes can lead to up to 30–70% energy savings over best known current schemes, under realistic environments. We next describe how these techniques can be applied to work with on demand routing protocols. In particular, we focus on one specific on demand routing protocol, namely Ad hoc On Demand routing protocol (AODV), and show how it should be adapted to compute energy efficient reliable paths. We perform a detailed study of the AODV protocol and our energy efficient variants, under various noise and node mobility conditions. Our results show that even in low noise environments there are specific scenarios where an unmodified on demand protocol will achieve significantly lower throughput in comparison to our modified variants. Our results show that our proposed variants of on demand routing protocols can achieve between 10% to orders of magnitude improvement in energy efficiency of reliable data paths.