An open loop TDMA communications system includes a transponder located on a spacecraft in quasi-synchronous earth orbit; a reference station periodically transmits a timing marker through said transponder to a plurality of geographically separated earth stations. Spacecraft position varies within controlled...http://www.google.fr/patents/US4292683?utm_source=gb-gplus-shareBrevet US4292683 - Guard band reduction in open loop TDMA communications
Guard band reduction in open loop TDMA communications
