On mobile positioning via Cellular Synchronization Assisted Refinement (CeSAR) in LTE and GSM networks

Inferring user equipment (UE) location in cellular networks via uplink timing management presents attractive possibilities in an increasingly mobile-connected world. Power constrained mobile devices with ever more common applications that rely on location-based services demand an alternate solution to positioning than a Global Navigation Satellite System (GNSS) and its derivatives. In this paper we provide analysis of mobile positioning via timing advance (TA), an LTE parameter also accounted for in legacy network deployments. Specifically, we provide analysis for a TA-based method Cellular Synchronization Assisted Refinement (CeSAR). We demonstrate through analysis and simulation how CeSAR can increase accuracy in timing advance-based positioning by several hundreds of meters with no impact to radio link level traffic. CeSAR is shown to be robust to situations where unassisted TA-based positioning can provide poor positioning accuracy.