Redundant Forward Gateway in Heterogeneous WLAN and LTE-M Networks for Reliable Metro Communication

摘要

With the advance of urban railway transportation and wireless communication technology, an increasing concern is placed on the reliability and low latency of urban mass transit communication system. Nowadays, both of WLAN and LTEM systems, known as two mainstream subway communication systems, are deployed redundantly with single communication network in case of unexpected failure. However, using a single communication system has irresistibility to frequency interference and traditional redundant cold backup manual has an intolerable delay in switching. In this paper, we adopt a multipath transmission network architecture with heterogeneous communication systems to solve the problems mentioned above. To realize the hot backup networks, the Redundant Forward Gateway (RFG) device is designed to connect terminals to the two networks. Information forwarded by source RFGs can be transmitted redundantly and simultaneously via both WLAN and LTE-M communication systems. At the other side, the redundant data packets will be removed before being forwarded to the destination terminals. Besides, tests were performed in various communication scenarios to evaluate the availability and effectiveness of the RFG and the network architecture. The results indicate that the RFG has a negligible processing delay and improves the robustness and performance compared to the traditional LTE-M network according to the transmission delay and packet loss tests. In conclusion, it is considered that the RFG and the heterogeneous LTE-M and WLAN networks are of vital importance in enhancing reliability in the metro communication system.