Variable Polarization Frequency Division Multiplexing (VPFDM) Demodulator Tolerant of Tx and Rx Frequency Asynchronicity Between Polarizations

This paper proposes a new Variable Polarization Frequency Division Multiplexing (VPFDM) demodulator for Ku broadband mobile satellite communications system. VPFDM allows each user to utilize multi-carrier frequency slots of the Vertical and Horizontal polarizations simultaneously. Since the VPFDM demodulator cancels cross-polarization interference by using signal processing, a polarization tracking satellite antenna is not needed, which makes the user earth station simple and economical. Furthermore, VPFDM is based on multi-carrier system that flexibly utilizes unused and scattered frequency slots on the satellite transponder. Therefore, frequency utilization efficiency is improved. In this paper, to increase system flexibility, we introduce a novel VPFDM demodulator that does not depend upon the configuration of the RF module. The new VPFDM demodulator cancels cross-polarization interference even though V/H frequencies are asynchronous among the base station / satellite / user earth station. This paper focuses on the key technologies of the demodulator; details are given, and its performance is evaluated via computer simulations.