Low C/N spread spectrum modem for random access satellite communications

This paper proposes a novel spread spectrum (SS) modem for random access satellite communication systems that employs digital matched filters. The proposed modem employs a parallel structure to ensure detection of packet arrival. Code timing detection with a combination of a coarse detector and a fractional error detector reduces the sampling rate while maintaining the BER performance. An in-symbol pilot multiplexing scheme is also proposed for fast and stable carrier synchronization with simple hardware. A performance evaluation shows that the proposed modem achieves the UW miss-detection probability of 10/sup -4/ at the Eb/No of 0 dB. The overall BER performance achieved in experiments agrees well with simulation.