Pilot structure design to increase wireless channel capacity for high-speed railway

In this paper, we design a pilot structure in an orthogonal frequency division multiplexing (OFDM) system for high-speed railway (HSR). Ergodic capacity is derived and its lower bound is obtained in closed form. Two schemes of pilot placement in time and frequency domains are proposed which maximizes the lower bound of the ergodic capacity. The ergodic capacities of the two proposed schemes are obtained by computer simulation and compared. It is shown that the proposed schemes achieve higher ergodic capacity than the random pilot placement scheme.