A TDMA satellite communication system for ISDN services-offset QPSK burst modem coupled with high coding gain FEC

The authors propose a time-division multiple-access (TDMA) satellite communication system suitable for integrated services digital network (ISDN) services for both basic interface services and primary interface services. The proposed system offers B-channel transmission lines among telephone offices and subscriber lines for basic and primary interface services. To provide these service economically and efficiently, the proposed system uses an offset QPSK burst modem coupled with high-coding gain forward-error correction in addition to demand assignment technology for each data burst and a transmitting and receiving transponder hopping TDMA scheme. Major functions of TDMA terminals have been implemented in LSICs, monolithic ICs, and hybrid ICs. The experimental results show little P_e degradation for the offset QPSK burst modem and perfect operation of the demand assignment and carrier hopping capability of the developed system