Direct Location Estimation for MIMO Systems in Multipath Environments

Location estimation in multipath environments (ME) can lead to significantly higher accuracy if the information contained in the Non-Line-of-Sight (NLOS) signal components is exploited thoroughly with the use of multiple antennas at both sides of a communication system and with the aid of appropriate channel modeling. In this contribution, this information is exploited and a Maximum-Likelihood (ML) estimator for the location of the Mobile Terminal is proposed, which is based on the reception of the signal in only one Base Station (BS). The method described herein can be characterized as direct location estimation since, in contrast to the traditional two-step approaches, the solution is formulated in terms of the received signal and not some channel-dependent parameters whose values have been estimated a-priori. The high accuracy of the method is validated using the Cramer-Rao Bound (CRB). Intuitive conclusions are reached through the comparison of different systems and for different propagation environments, which is performed by simulations.