Considerations on quasi-synchronous CDMA using cyclic shifted M-sequence

摘要

Highly accurate synchronization is required to implement synchronous CDMA on satellite communications. To cope with this problem, quasi-synchronous CDMA is effective, which allows a little declination of synchronization. In this paper, we propose to apply cyclic shifted M-sequences in order to increase traffic capacity for quasi-synchronous CDMA, and consider a system configuration and its performances. Since the cyclic shifted M-sequences are generated by one M-sequence, it is difficult to distinguish each code. In order to distinguish the cyclic shifted M-sequences, we attempt to use a Pilot signal. And we propose a method how to select a Pilot signal which has constant interference and show the system performances by computer simulation.