Resource Allocation in the Uplink of GEO Satellite Relay System with Dynamic Doppler Shift

In a relay satellite system, low earth orbit (LEO) satellites are the users of a geosynchronous earth orbit (GEO) satellite, and each highly dynamic GEO-LEO link has a different Doppler shift due to the movement of LEO satellites, which causes serious inter-resource-block(RB) interference and leads to significant degradation of capacity. In this paper, to reduce interRB interference caused by different Doppler shift and maximize the uplink capacity, we derive the mathematical formulae to describe the inter-RB interference with a fixed Doppler shift and propose a resource allocation approach. The problem is formulated as a non-convex optimization model and Lagrangian duality method is used to solve it. Finally, we present a subgradient algorithm to get the results. Simulation results show that the proposed resource allocation method compared to the QPSO (quantum-behaved particle swarm optimization) resource allocation algorithm has a better capacity after decreasing interRB interference.