Intelsat V 120 Mbit/s TDMA transmission design

The transmission design of a 120 Mbit/s time-division multiple access (TDMA) system, with digital speech interpolation (DSI), for Intelsat-V satellite application is presented. The modem transmit and receiver filters have been selected to provide the best bit-error-rate (BER) performance and acceptable out-of-band emission performance in a nonlinear channel. The link budget analysis using the specified Intelsat V spacecraft parameter shows that CCIR BER objectives can be met with the use of Forward-Error-Correction (FEC) coding. An analysis has been carried out for the operation of both TDMA and FDM/FM carriers in Intelsat-V co-frequency transponders which demonstrates the feasibility of such operation. A number of FEC codes have been studied for their suitability for Intelsat-V TDMA application and it is concluded that a 128/112 BCH code without differential encoding is the most suitable one for Intelsat TDMA application.