An Efficient ToA Estimation Technique Based on Phase Correction for 5G mMTC system

In 5G mMTC system, massive user equipment (UE) access network simultaneously by contending a common RACH resource. It is thus of significant importance for network to estimate the time-of-arrival (ToA) of each UE efficiently based on preamble allocated for Physical Random Access Channel(PRACH) so that UE can achieve uplink synchronization with network reliably. In this paper, we focus on improving the accuracy and performance of ToA estimation. Considering the phase ambiguity problem due to varied propagation delay defined as ToA during detection of preamble signals generated by UE, we propose a ToA estimation technique to compensate phase transition with a set of pre-determined phase corrector vectors(PCV) associated with all possible ToA values. Furthermore, we optimize PCVs by build a reduced and essential PCV candidate as a smaller search space for more efficient phase recover and ToA estimation. Simulation results show that the performance of proposed method and its variants can fulfill the requirements of 3GPP standard with lower computational complexity.