Detours Save Energy in Mobile Wireless Networks Chia Ching Ooi and Christian Schindelhauer Chia Ching Ooi Christian Schindelhauer Albert-Ludwigs-Universit¨ at Freiburg, Computer Networks and Telematics, Georges-K¨ ohler- Allee 51, 79110 Freiburg, Germany, e-mail: ooi, schindel @informatik.uni-freiburg.de Abstract Autonomous robotic systems have been gaining the attention of research community in mobile ad hoc network since the past few years. While motion cost and communications cost constitute the primary energy consumers, each of them is investigated independently. By taking into account the power consumption of both entities, the overall energy efficiency of a system can be further improved. In this paper, the energy optimization problem of radio communication and motion is examined. We consider a hybrid wireless network that consists of a single au- tonomous mobile node and multiple relay nodes. The mobile node interacts with the relays within its vicinity by continuously communicating high-bandwidth data, e.g. triggered by a multimedia application like video surveillance. The goal is to find the best path such that the energy consumption for both mobility and communica- tions is minimized. We introduce the Radio-Energy-Aware (REA) path computation strategy by utilizing node mobility. Given the starting point, the target point and the position of the relays, our simulation results show that the proposed strategy im- proves the energy efficiency of mobile node compared to the Motion-Energy-Aware (MEA) path constructed based only on the mobility cost. 1 Introduction With the unprecedented growth of wireless communication technologies witnessed over the past two decades, intensive researches [1] have been conducted to improve the performance of communications in mobile wireless network. Among them, a number of improvements were achieved [2, 3] through the extensive investigation of node mobility. However, most of the existing literature assumes that mobility cannot be controlled. A mobile node in a wireless network can be a mobile handheld device, a manned or unmanned vehicle, a mobile robot, or a combination of them. Among them, the artificial mobile nodes are capable of controlling their own movement but the natural mobile nodes are not. Recently, networked robotics has been gaining increasing interest among robotic and mobile networking research community. Many modern mobile robots are al- ready equipped with networking capabilities [4, 5], using either radio frequency, or infra-red communications. Multi-robot systems (MRS) [6, 7, 8, 9] take the ad- Please use the following format when citing this chapter: Ooi, C.C. and Schindelhauer, C., 2008, in IFIP International Federation for Information Processing, Volume 284; Wireless and Mobile Networking; Zoubir Mammeri; (Boston: Springer), pp. 69–82.