Performance comparison of combining algorithms for polarization-diversity receiving in phase-sensitive OTDR

Abstract

We investigate three different combining algorithms for polarization-diversity receiving in phase-sensitive optical time-domain reflectometry (φ-OTDR) system. The algorithms are equal gain combining(EGC), selective combining(SC) and max-ratio combining(MRC). We compare the performance of the three combining algorithms in three aspects, which are the SNR of the locating signal, the SNR of the recovered vibration signal and the computation cost of the algorithms. The results show that the SC algorithm has a poor locating performance and is unsuitable for locating of the system. The EGC algorithm has the lowest complexity and general locating performance, which can be applied in real-time locating of external vibration. The performance of MRC algorithm is optimal, which is a promising tool in the high SNR intrusion location system. The proper combining algorithms we chosen will contribute to achieving optimal performance and optimal resource allocation of the φ-OTDR system.