Feasibility evaluation of satellite VPFDM modem

摘要

NTT Lab. has been proposing a polarization-tracking-free Ku broadband mobile satellite communications with variable polarization frequency division multiplexing (VPFDM) for future mobile satellite communications. In VPFDM system, a single user utilizes dual polarization simultaneously and does not track the polarization status at all. Therefore, cross-polarization interference should be entailed, but it is cancelled by interference canceller in the receiver. Since different users don't share the same frequency with different polarization, the problem of mutual interference between users does not occur in the proposed VPFDM system. This means that it can eliminate the function of polarization-tracking from a user earth station and VPFDM is exceedingly preferable for an antenna that can hardly track the linear polarization status in the mobile environment. This paper overviews the concept of VPFDM and introduces a newly developed modem for VPFDM systems, and then, its feasibility is also discussed. As a result, it is confirmed that the developed modem can cancel the cross-polarization interference within the degradation of less than 0.5 dB.