120-Mbit/s TDMA modem and FEC codec performance

Introduction of the Intelsat TDMA system into commercial service was preceded by a substantial amount of research and development, particularly for the modems and forward error correction (FEC) codecs required for TDMA operation. The modems are subject to significant compromises between the need for rapid acquisition, robust tracking, and operation in a nonlinear channel. In addition, the performance of the FEC codec is closely related to that of the modem and requires considerable attention to its place in the TDMA system architecture. This paper reviews these operational requirements and presents the results of modem and codec performance measurements which demonstrate the feasibility of meeting Intelsat specifications.