Anti-interference analysis of multiplexing methods for GBBF system

Ground-Based Beam Forming (GBBF) is one of the key technologies for satellite mobile communication systems. In the GBBF system, Frequency Division Multiplexing (FDM), Time Division Multiplexing (TDM) and Code Division Multiplexing (CDM) are three major multiplexing methods in transmitting feeding signals to gateway stations on the ground. This paper discusses the channel modeling in GBBF systems. The simulation model focuses on the Geosynchronous Satellite Channel (GSC) transmission. By applying the three multiplexing methods to GSC processing, we analyze the Correlation Loss (CL) of feeding signals in the situation of different Signal Noise Ratio (SNR) and Output-power Back-off (OBO) values. After simulation, we observe that for GBBF system, CDM method is less affected by the noise in channel with nonlinear distortion, and has better anti-interference performance than TDM and FDM when SNR is not higher than 22dB.