Prolong the Lifetime of Wireless Sensor Networks Through Mobility: A General Optimization Framework

Though mobility is rarely considered in traditional wireless sensor networks (WSNs), actively exploiting mobility to improve the performance of WSNs has been increasingly recognized as an important aspect of designing WSNs. This chapter focuses on exploiting mobility to improve the network lifetime of a WSN. We present a general optimization framework that is able to capture several aspects of maximizing network lifetime (MNL) involving mobile entities. Based on this framework, we conduct an in-depth analysis on each of these aspects and also describe algorithms that can be used to solve the resulting optimization problems. We also present certain numerical results where engineering insights can be acquired. 18.1 Mobile Elements in Wireless Sensor Networks: Stir Up the Pond Traditionally, mainstream research envisioned wireless sensor networks (WSNs) as an avatar of static multi-hop wireless networks [1]. Although the mobility issues were present even from the early stage of theWSN-related investigations (e.g., [27]), those issues failed to attract a lot of attention until very recently. The reason is twofold. On one hand, it is much more difficult, from both theoretical and practical point of views, to deal with networks with mobile entities. On the other hand, we only recently realized that we could actively utilize mobility rather than having to passively accept its inevitable presence. In this chapter, we will focus on one of the active applications of mobility to improve an important aspect of network Luo Jun School of Computer Engineering, Nanyang Technological University (NTU), Singapore, e-mail: