Weak Signal Acquisition Algorithm for Indoor Positioning Receiver

Positioning receivers are required to be capable of receiving weak signals to satisfy indoor applications. When searching weak signals, the receiver may unsuccessfully be acquired due to the noise. This paper is focused on the problem of weak signal acquisition in Time and Code Division-Orthogonal Frequency Division Multiplexing (TC-OFDM) system which is based on the mobile broadcast networks. We provide theoretical analysis of the TC-OFDM signal, and propose a new acquisition algorithm based on coherent/noncoherent integral for weak signal acquisition. This algorithm compensates noncoherent integral loss for considering the effect of decision threshold that caused by noncoherent integral loss, which can increase the relative acquisition peak and achieve weak signal acquisition effectively. The experimental results indicate that the proposed algorithm can significantly improve the TC-OFDM receiver's ability of weak signal acquisition by 1-3 dB, and reduce the probability of weak signal acquisition leakage.