Challenges and improvements in communication with vehicles and devices moving with high-speed

摘要

In this paper several shortcomings in communication with high-speed users in different communication scenarios are identified. This includes conventional communication systems as well these especially designed for use with railways systems, e.g. GSM-R. In the high-speed scenario there are several challenges including Doppler Effect, short duration of stay in a cell, and rapidly changing propagation delay. This causes a lot of control messages, resulting especially in too long lasting cell reselection and handover. The improvements discussed cover network planning, coach design, inter coach network implementation and handover procedures. For the evaluation a special network topology concept and a suited mobility model have been designed. They are used in simulations carried out with MatLab and ns-2 to prove that the solutions proposed really improve the quality of the connection. It can be shown that the problems with handovers in real systems can mostly be solved by using suited handovers and can completely be solved adding integrated network planning. Anyway the solution always has to be an integrated approach comprising planning, hardware, protocols and interaction of different networks to provide the best service. This is the only way to cope with shortcomings in the standards for high-speed scenarios.