SYSTEMS AND METHODS FOR ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESS (OFDMA) COMMUNICATIONS OVER SATELLITE LINKS

摘要

Methods for controlling orthogonal frequency division multiple access (OFDMA) communications over satellite links. The methods include estimating a differential delay (x ms) in a satellite spotbeam between a mean propagation delay (250 ms) in the spotbeam and a propagation delay ((250-x)ms) between a user terminal in the spotbeam and a satellite, estimating an overlap (215) between an OFDMA uplink frame and an OFDMA downlink frame as a result of the differential delay, and providing a guard band (215) in the OFDMA uplink frame and/or the OFDMA. downlink frame to reduce an overlap between remaining portions of the OFDMA uplink frame and the OFDMA downlink frame other than the guard band. Corresponding systems and devices are also disclosed.