LTE Ranging Measurement Using Uplink Opportunistic Signals and the SAGE algorithm

With the increase of services that need accurate location of the user, new techniques that cooperate with the Global Navigation Satellite System (GNSS) are necessary. GNSS suffers poor performance in indoor and dense urban environments, due to high signal attenuation and severe multipath propagation. The current release of the 3rd Generation Partnership Project(3GPP) LTE specification, supports the Uplink Time Difference Of Arrival (UTDOA) localization technique, which uses as reference the Sounding Reference Signal (SRS). Local Measurement Units (LMUs) devices use knowledge of the SRS to perform time difference measures. This paper studies the possibility of performing radio localization using a new UTDOA technique that exploits the uplink Demodulation Reference Signal (DM-RS) in 4G Long Term Evolution (LTE) cellular networks. We point out the advantages of our proposal and evaluate its feasibility by measuring the distance between two antennas using real DM-RS signals generated by an LTE module.