Geometrical transformations as an efficient mean for reducing impact of multipath propagation on positioning accuracy

The major challenge in time-based mobile positioning techniques is derivation of reliable time of arrival or range measurements. Multipath propagation error corrupts the accuracy of positioning, and therefore adequate techniques need to be deployed. This paper proposes an algorithm for decreasing the contribution of multipath propagation on positioning in networks, typical for macrocellular urban deployment in UMTS. Since the whole procedure is based on geometrical transformations, the impact on system performance as well as the implementation complexity is kept at the minimum level. The algorithm constitutes an enhancement to an inexpensive cell ID+RTT location method, thus the functionality together with performance analysis is presented in the context of this technique. However, it can easily be applied on the top of alternative time-biased cellular positioning methods. Accuracy of enhanced cell ID+RTT in the multipath environment has been simulated with very promising results. Outcomes have shown that nearly 90% of users can be located within 170 m, and correspondingly 67% with the accuracy of 120 m, in the scenario with the highest considered multipath errors and without presence of LOS.