Development of Signal Canceller in the Carrier Super-Positioning Satellite Networks

Carrier super-positioning, which allocates the inbound and outbound channels at the same frequency, is an efficient method for improving frequency affiliation efficiency. It requires an interference canceller that cancels unwanted carrier. To establish the canceller, generating replicas of unwanted carriers is a key. This paper addresses the design of two types of signal canceller that are used for two typical types of satellite communications, namely P-MP VSAT (point-to-multi-point very small-aperture terminal) and P-P (point-to-point) paired carrier systems. For P-MP VSAT, we show a simplified method where a replica of an unwanted carrier is generated by demodulating it. We have developed a reference simulator to simulate the behavior and performance. This simulator takes into account degradation due to implementation. The source code developed here is applicable to the implementation of FPGA. We also propose a stable method to generate replicas by measuring the satellite round-trip delay on a real-time basis for P-P, since we cannot apply the same method to this case as we can for VSAT systems.