Achieving Stable Handover Delays in LTE Railway Systems

The stable A3 offset control for the stabilized average handover delay was proposed and the performance was evaluated by the OPNET network simulator. in the paper. The LTE railway system typically requires the short inter-cell site distance (ISD) in order to high safety and reliable wireless control, so that the stable handover delay against frequent handover is essential to wireless remote train control system design. The performance relative to handover delay was analyzed at train speeds of 50 and 100 km/h. The average handover delay was mostly affected by variation of A3 offset values as mentioned in the simulation results. It means that the stable average handover delay by adjusting A3 offsets can be achieved. The results showed us that there were unstable and stable region to average handover delay in terms of RSRP and RSRQ regarding variation of A3 offset values. In this way, we can achieve the stable and predictable average handover delay for wireless remote train control system by controlling them in the stable region.