A multi-mode multi-channel adaptive transmission system for online state monitoring of the trolleybus

The dramatic growth of online state monitoring for low speed train, like trolleybus et al, gives rise to the new requirements on high quality-of-service of wireless train-ground communication networks. Generally these kinds of train are running at urban area, because of the signal coverage of base station, single mode of mobile network for the train-ground communication may be not reliable, especially when the train runs at the gap between two base stations. In this paper, we designed a multi-mode multi-channel train-ground communication system by fusing the public 2G/3G/4G mobile networks. The system can use the three kinds of wireless communication mode, and switch among the mode automatically. A multi-mode adaptive wireless data transmission method is proposed. In which, the multimode wireless communication network access technology integrated with GSM, CDMA2000 and WCDMA, TD-SCDMA, TDD-LTE and FDD-LTE are studied and a multi-mode multi-channel model is established to estimate channel. It uses the analytic hierarchy process (AHP) and entropy value method for channel selection according to the channel quality of the predicted and the current detection. Then the data from multiple resources (TCMS, PIS, CCTV) are packed and transported in different ways. The bandwidth of the multi-mode communication links can be effectively used and the online transmission of TCMS information, PIS and video and other data of the train are realized. Simulation results are presented to show the feasibility of the proposed multi-mode multi-channel adaptive transmission method.