Time of arrival-based location estimation for cooperativerelay networks

Abstract

Cooperative communications is a technique to create a virtual antenna array using several distributed single antenna nodes in the system. It helps in increasing the area of coverage without the need of increased transmission power. As the destination receives multiple copies of the source's signal, it also improves the diversity order. The performance of cooperative networks has been thoroughly investigated in the past for various system models, protocols, forwarding techniques and fading environments. Location estimation is another crucial process in cooperative relay networks, as it is for the other types of wireless communications networks. For instance, the range and location information can be used for network authentication, localization or cluster forming in cooperative networks. However, to the best of our knowledge, there is no study in the literature that addresses the location estimation problem in cooperative relay networks. In this study, we investigate the performance of a cooperative relay network performing location estimation through time of arrival (TOA). We derive Cramer-Rao lower bound (CRLB) for the location estimates made using the relay network. The analysis is extended to obtain average CRLB considering the signal fluctuations in both relay and direct links. The effects of the channel fading of both relay and direct links and amplification factor and location of the relay node on average CRLB are investigated. Simulation results show that the channel fading of both relay and direct links and amplification factor and location of relay node affect the accuracy of TOA-based location estimation.