Highly dynamic or semi-static: Resource allocation for high-speed mobile terminals in 4G

When mobile terminals are with high speed, the channel coherence time becomes quite short due to the large Doppler shift. If resource allocation (RA) schemes are fast enough, it could be used like in normal-speed cases. However, existing RA schemes have difficulty to satisfy this requirement. This paper presents our study on highly dynamic and semi-static schemes. The highly dynamic scheme is fast but is heuristic hence not optimal. Instead, the semi-static scheme does not need to catch up with the fast change of the received signal strength (RSS), so it is optimal in terms of the average RSS. With a 2-cell scenario, we find that the optimal semi-static scheme could achieve comparable performance to the heuristic highly dynamic scheme. With a 19-cell scenario, we further simulate fractional frequency reuse (FFR) scheme and find that the total capacity can be significantly improved by carefully designing the inner radius. Our near future work is to combine the optimal semi-static scheme with FFR to further improve the performance.