Capacity of shadow fading channels on high-speed railway with delayed feedback

Due to feedback delay, the capacity of water filling power allocation will degrade, even worse than the fixed power allocation. This problem may be more serious when mobile terminal moves at high velocity, for example in high-speed train. Through analysis of the distance correlation properties of shadow fading, this paper presents an improved water-filling power allocation approach, which adjusts power allocation according to feedback delay. Simulation results show that the proposed approach can improve capacity of shadow fading channel with delayed feedback and satisfies power constraint.