JOURNAL OF COMMUNICATIONS (JCM)
ISSN : 1796-2021
Volume : 2    Issue : 7    Date : December 2007

Signal Canceller in the Carrier Super-positioning Satellite Networks
Mayumi Osato, Hiroyuki Kobashi, Robert Y. Omaki, Takao Hara, and Minoru Okada
Page(s): 68-76
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Abstract
To establish the interference canceller, generating replicas of unwanted carriers is a key. This
paper addresses the design and performances 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 method to generate replicas by stably
measuring the satellite round-trip delay by multi-component code (MCC) on a real-time basis for
P-P, since we cannot apply the same method to this case as we can for VSAT systems. We use
MCC (Multi-component Code) to measure the delay as quickly and accurately as possible. It is the
key how stably the acquisition of the code is established in the actual environment of satellite
channel which is suffered from heavy noise and large level variation. We show a method to stabilize
acquisition process of MCC by normalizing multilevel correlation using a level obtained by additional
loop.

Index Terms
satellite communications, frequency re-use, interference canceller, multi-component code,
acquisition and synchronization