A TDMA Satellite Communication System for ISDN Services

This paper proposes a TDMA (time division multiple access) satellite communication system suitable for both basic and primary ISDN services in addition to B-channel transmission lines among ISDN switchers. To provide these services economically and efficiently, the proposed system employs an offset QPSK burst modem coupled with high-coding gain and rate forward error correction, demand assignment technology for each data burst, and a transmission and reception transponder (carrier) hopping scheme which is the most sophisticated hopping scheme ever utilized. Moreover, to realize cost-effective transmission and subscriber lines and to increase reliability of TDMA terminals, major functions of TDMA terminals have been implemented in large-scale integrated circuits (LSIC’s), monolithic IC’s (MIC’s), and hybrid IC’s (HIC’s). The experimental results show narrow spectrum transmission with little bit error probability (Pe) degradation for the offset QPSK burst modem and perfect operation of demand assignment and carrier hopping capability of the developed system. These results guarantee the first use of an offset QPSK burst modem in commercial systems and full deployment of the developed system to offer ISDN services all over Japan.