Development of an FEC combined modem for DS-SSMA communication system
Abstract
The development of a forward error correcting (FEC) modem for low-bit-rate satellite communication systems using direct-sequence spread-spectrum multiple-access (DS-SSMA) communication techniques is described. Utilizing a digital correlator and a convolutional encoder/Viterbi decoder, the modem achieves rapid acquisition time and low bit error rate performance under very low carrier-to-noise (C/N) ratios. Experimental results indicate a mean acquisition time of 220 ms and bit error rate of less than 1 x 10 to the -7th at the received intermediate frequency C/N ratio of -31 dB. The digital matched filter, digital correlator LSI, delay lock loop, and binary phase-shift keying modulator used in the modem are described.
- Publication:
-
GLOBECOM 1990 - IEEE Global Telecommunications Conference and Exhibition, Volume 2
- Pub Date:
- 1990
- Bibcode:
- 1990gtc.....2..746I
- Keywords:
-
- Multiple Access;
- Satellite Communication;
- Signal Processing;
- Spread Spectrum Transmission;
- Very Large Scale Integration;
- Viterbi Decoders;
- Analog To Digital Converters;
- Bit Error Rate;
- Carrier To Noise Ratios;
- Digital Filters;
- Matched Filters;
- Phase Shift Keying;
- Electronics and Electrical Engineering