Development of an FEC combined modem for DS-SSMA communication system

Abstract

The subject addressed here is the development of an FEC (Convolutional encodingNiterbi decoding) combined modem for DS-SSMA communication system aimed at the low bit rate satellite communication system. The developed modem has compact size and low power consumption, which have been accomplished with newly developed digital correlator VLSl and extensive use of digital signal processor (DSP). As the results of experimentation, w e obtain mean acquisition time of 220 msec and bit error rate of less than 1x 10-7 at the received IF U N ratio of -31 dB (BT=2). It is concluded that the developed modem is useful for low rate data transmission such as mobile satellite communication system.