Wireless Communications for High Speed Rail

Current standards for the implementation of train backbone networks are based on wired point-to-point links connecting the backbone nodes. The overall goal of this project is to develop a wireless implementation of the backbone network based on the WiFi standard IEEE 802.11n. A specific goal of the project is to apply the wireless network to the train topology discovery, a process known as inauguration.

Due to the high speed of the train, wireless links between backbone nodes are subject to highly time-varying channels. In addition, due to the high bandwidth of the signals, these channels are frequency selective.  The traditional way to mitigate the distortion caused by the channel is to first estimate its effect by leveraging pilot symbols, and then use this estimate in order to detect the information streams.

To this end, wide area networks, such as LTE, reserve a sufficient amount of time-frequency resource to support channel estimation and tracking. In contrast to wide area networks, local area networks such as IEEE 802.11n, prescribe a number of pilots that is significantly smaller than the total number of parameters to be estimated or tracked. The project is implemented in two phases.

The goal of Phase 1 is to assess the performance of an 802.11n-based  communication network in a high-speed train environment, and to devise algorithms that enable this network to support the train inauguration process. The inauguration process itself is the topic of the Phase 2 of the project.

Faculty: MengChu Zhou, Osvaldo Simeone, Alexander Haimovich

Graduate students: Shahrouz Khalili, Yu Liu, N. Pelin Yalcin