Symbol Timing Offset Mitigation in OFDMA-Based CoMP Utilizing Position Aware Transmission

Orthogonal frequency division multiple access and coordinated multipoint transmission/reception are two key techniques employed in LTE-Advanced to provide high-speed connectivity to mobile users regardless of their locations within the cells. The combination of the two techniques in a cellular network with large cells however, results in timing asynchronization. This leads to symbol timing offset (STO) and, thus, degrades users´ performance. In this paper, we propose a novel user position aware (UPA) algorithm to tackle the timing offset problem by partitioning the coverage area into different zones based on users´ received power requirements. Serving base stations in each zone are assigned such that their distances to a user within the zone are bounded. Hence, the time difference of signals arrived at the user is controlled and, therefore, the effect of STO is mitigated. We analyze the performance of the proposed method by deriving bounds on the STO, and signal-to-interference-plus-noise ratio (SINR) in different zones. Simulation results confirm that the proposed UPA algorithm significantly reduces the STO and improves users´ SINR.