Tdma intertransponder communication

Abstract

Groups of stations operate in TDMA mode relative to associated frequency-separated transponder segments of a satellite repeater. Stations at radio signaling modes in all groups key to a common frame timing reference. The TDMA frame is partitioned repetitively into IN GROUP and CROSS GROUP intervals, each susceptible of containing multiple demand assignable burst time slots. Each node may transmit TDMA bursts (of time compressed and time multiplexed information signals) in assigned slots in either interval (or both). Such bursts are carried only on the transponder radio frequency associated with the respective group. Station receivers are adaptive to switch local oscillator frequencies in synchronism with transitions between IN GROUP and CROSS GROUP periods, and thereby adaptive to receive signals from stations in both groups. A frame reference signal carried on the transponder frequency associated with one of the groups is receivable by stations in the same group during IN GROUP mode reception and by stations in the other group during CROSS GROUP mode reception. Consequently stations in both groups may key to that reference signal. The transition (crossover time) from IN GROUP mode to CROSS GROUP mode can be varied in time position to efficiently accommodate demand within and between groups.