Location-based Mechanism for Positioning of a Mobile Relay

Abstract

Leveraging a relay for communication is a promising approach for improving throughput, coverage, and energy efficiency in wireless networks. A mobile relay that is capable of positioning itself at different locations opens the possibility for dynamic optimization of the path quality between the source and the nomadic destination. How to optimally position the mobile relay in order to maximize the path quality, however, remains a challenging task. Under the assumption that the physical location information of the devices are either known or can be estimated, we propose a mechanism for positioning of the mobile relay with the aim of maximizing the SNR between the source and the destination. The proposed mechanism takes into account the practically unavoidable inaccuracies of estimated locations, as well as the propagation characteristics of a served environment. Using WiFi as an example technology, we experimentally evaluate the proposed mechanism in a complex indoor environment with the support of a specifically designed testbed infrastructure. For relatively small localization errors, our results show less than 4 dB difference between the measured SNR at optimal locations and the SNR at locations yielded by the proposed mechanism. Our results also illustrate how the quality of the paths created by the proposed positioning mechanism degrades in the face of increasing localization errors.