Pilot Sequence Design for GEO Multi-Beam MIMO Satellite Communication System

The inter-beam interference has been shown to be a critical factor in multi-beam satellite communication systems. This paper proposes a novel pilot sequence design criterion aiming at mitigating the inter-beam interferences. The proposed multi-beam optimality criterion is to minimize the worst-case mean square error (MSE) of an least square (LS) based channel estimator. It is shown that we can obtain the optimal pilots eliminating the inter-beam interference on certain condition. To enlarge the size of available pilot sequence set, we give a suboptimal pilot design guideline. Multi-beam pilot sequence design for code division multiplexing (CDM) pilot types is proposed by adopting Chu sequences. Simulation results are presented to verify the theoretical analysis.