Patent ID: 8027285

Claim:
A star/mesh communication system comprising: a hub; a repeater; and first and second remotes, wherein the first remote is configured to transmit a first signal to the hub via the repeater, the first signal being received at the hub with a frequency offset of RHOffset, as follows RH Offset= TxTDMA Offset(1)+ RUC Offset+SatelliteOffset+ HDC Offset wherein TxTDMAOffset(1) is a frequency offset from a nominal frequency used by the first remote, RUCOffset is a frequency offset introduced during an up-conversion in the first remote, SatelliteOffset is a frequency offset introduced at the repeater during Uplink/Downlink conversion, and HDCOffset is a frequency offset introduced at the hub during a down conversion, the hub is further configured to command the first remote to change the value of TxTDMAOffset(1) to TxTDMAOffset(2) so that RHOffset=0, as follows TxTDMA Offset(2)=−(SatelliteOffset+ HDC Offset)− RUC Offset, the hub is further configured to transmit a second signal to the repeater to be received back at the hub in a loopback mode, the second signal being received at the hub with a frequency offset of HHOffset, as follows HH Offset= HUC Offset+SatelliteOffset+ HDC Offset wherein HUCOffset is a frequency offset introduced during an up-conversion in the hub, and HDCOffset is a frequency offset introduced during a down-conversion in the hub; the hub is further configured to periodically calculate and transmit the value of HHOffset to the first and second remotes, the hub is further configured to transmit a third signal to the second remote via the repeater, the third signal being received at the second remote, which measures a frequency offset of the third signal HROffset, as follows HR Offset= HUC Offset+SatelliteOffset+ RDC Offset wherein RDCOffset is a frequency offset introduced during down-conversion in the second remote, the second remote is configured to transmit a fourth signal to the first remote via the repeater, and prior to receiving the fourth signal, the first remote is configured to estimate a frequency offset RROffset of the fourth signal received from the second remote via the repeater, using values determined from previous star/mesh communication signals, as follows RR Offset= HR Offset− HH Offset.