Node Positioning in a Limited Resource Wireless Network

By using a non-standard limited resource technique in wireless networks it is possible to reach features, which are more suitable for sensor networks and personal embedded applications than using standard protocols. Using new heavily integrated controller chips and RF-modems, it is possible to implement new features, for example, low-power routing, positioning and dynamic flat topology in limited resource wireless network (LRWN). We are researching the features of light wireless networks at Seinäjoki University of Applied Sciences. The main focuses of our research projects are size minimization, low-power routing, positioning and interactive features between devices, users and environment. The aim of this paper is to introduce the positioning methods usable in LRWN. The main problem is: how satisfactory positioning is possible in LRWN. The important feature for positioning is distance measuring between nodes. The RF-modem chip that we use gives some possibilities to measure distances. Another possible data source for distance measuring is routing tables i.e. number of multi-hops between nodes. We have simulated positioning methods and we have obtained better results than expected. The simplest method was the mean value calculation of neighbour coordinates. It gives quite acceptable results for some applications. The best results come with more complex methods while distances were measured as four multi-hops. As a result of our simulation we have seen that very simple positioning can be acceptable. Positioning methods provide more accurate results when moving the nodes slowly and randomly. Through randomizing, the static lock configurations are released, which normally gives positioning errors. We will test simulated methods in a real wireless network later this year. In the real world the distance measurement is more random, but expected results should be near simulation values. IWES 2007 6th International Workshop on Ambient Intelligence & Embedded Systems 6-7 September, 2007, Vaasa, Finland 2 Introduction The research of wireless systems is currently based on the transfer of voice and/or video data.