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Signal Canceller in the Carrier Super-positioning Satellite Networks

Mayumi Osato, Hiroyuki Kobashi, Robert Y. Omaki, Takao Hara, and Minoru Okada
Graduate School of Information Science, Nara Institute of Science and Technology (NAIST), Nara, Japan

Abstract—To establish the interference canceller, generatingreplicas of unwanted carriers is a key. This paper addressesthe design and performances of two types of signal cancellerthat are used for two typical types of satellitecommunications, namely P-MP VSAT (Point-to-Multi-PointVery Small-Aperture Terminal) and P-P (Point-to-Point)paired carrier systems. For P-MP VSAT, we show asimplified method where a replica of an unwanted carrier isgenerated by demodulating it. We have developed areference simulator to simulate the behavior andperformance. This simulator takes into account degradationdue to implementation. The source code developed here isapplicable to the implementation of FPGA. We also proposea method to generate replicas by stably measuring thesatellite round-trip delay by multi-component code (MCC)on a real-time basis for P-P, since we cannot apply the samemethod to this case as we can for VSAT systems. We useMCC (Multi-component Code) to measure the delay asquickly and accurately as possible. It is the key how stablythe acquisition of the code is established in the actualenvironment of satellite channel which is suffered fromheavy noise and large level variation. We show a method tostabilize acquisition process of MCC by normalizing multilevelcorrelation using a level obtained by additional loop.

Index Terms— satellite communications, frequency re-use,interference canceller, multi-component code, acquisitionand synchronization

Cite: Mayumi Osato, Hiroyuki Kobashi, Robert Y. Omaki , Takao Hara and Minoru Okada, "Signal Canceller in the Carrier Super-positioning Satellite Networks," Journal of Communications, vol. 2, no. 7, pp. 68-76, 2007.