Frequency allocation in a SDMA satellite communication system with beam moving (ICC 2012)

International audienceSpatial Division Multiple Access (SDMA) is a principle of radio resource sharing that separates communication channels in space. It relies on adaptive and dynamic beamforming technology and well-designed algorithms for resource allocation. As satellite communication systems move towards greater capacity in both the number of users and throughput, SDMA becomes one of the most promising techniques that can achieve these two goals. This paper studies static Frequency Assignment Problem (FAP) in a satellite communication system involving a satellite and a number of users located in a service area. The objective is to maximise the number of users that the system can serve while maintaining the signal to interference plus noise ratio of each user under a predefined threshold. Traditionally, interference is binary and fixed. In this paper, the interference is cumulative and variable depending on how the frequency is assigned. To solve the problem, we work on both discrete and continuous optimizations. Integer linear programming formulations and greedy algorithms are proposed for solving the discrete frequency allocation problem. The solution is further improved by beam moving algorithm which involves continuous adjustment of satellite beams and deals with non-linear change of interference