Energy Efficient Packet Size Optimization for Wireless Ad Hoc Networks

Abstract

Energy efficiency is crucial for ad hoc networks because of limited energy stored in the battery. Recharging the nodes frequently is sometimes not possible. Therefore, proper energy utilization is paramount. One possible solution of increasing energy efficiency is to optimize the transmitted packet size. But, we claim that only optimal packet size can not boost the energy efficiency in the noisy channel due to high packet loss rate and overhead. Hence, to reduce the overhead size and packet loss, compression and Forward Error Correction (FEC) code are used as remedy. However, every method has its own cost. For compression and FEC, the costs are computation energy cost and extra processing time. Therefore, to estimate the energy-optimize packet size with FEC or compression, processing energy cost and delay need to be considered for precise estimation. Otherwise, for delay sensitive real time applications (such as: VoIP, multimedia) over ad hoc network, energy efficient optimal packet size can be overestimated. We will investigate without degrading the Quality of Service (QoS) with these two different techniques FEC and compression, how much energy efficiency can be achieved by using the energy efficient optimal packet size for different scenarios such as: single hop, multi-hop, multiple source congested network etc. This thesis also shows the impact of time variable channel, packet fragmentation, packet collision on the optimal packet size and energy efficiency. Our results show that, for larger packets, error correction improves the energy efficiency in multi-hop networks only for delay tolerant applications. Whereas for smaller packets, compression is more energy efficient most of the cases. For real-time application like VoIP the scope of increasing the energy efficiency by optimizing packet after maintaining all the constraints is very limited. However, it is shown that, in many cases, optimal packet size improves energy efficiency significantly and also reduces the overall packet loss.