Table 1 Key features of high-speed rail broadband mobile communications

Doubly selective channel

The high-speed rail radio channel is both time selective and frequency selective

Fast and frequent (group) handover

All passengers in the train move at the same direction and conduct handover almost simultaneously, resulting high handover failure rate due to signaling storm and long process delay

Predictable train location and channel condition

The high-speed rail train operates on a fixed course repetitively. This is in sharp contrast to traditional cellular systems where the mobile stations move randomly