Patent ID: 7944993

Claim:
A satellite communication system comprising: a plurality of satellites; a gateway with a plurality of antennas, wherein one or more of the plurality of antennas is pointed toward more than one of the plurality of satellites, and the gateway is configured to transmit data using orthogonal frequency-division multiplexing (OFDM); and a plurality of subscriber terminals, wherein each of the plurality of subscriber terminals include an antenna pointed toward at least two of the plurality of satellites and are configured to receive an OFDM signal from the gateway through the plurality of satellites, wherein, for each subscriber terminal, the gateway determines the longest transmission time between the gateway and each subscriber terminal through each of the plurality of satellites; wherein, for each subscriber terminal, the gateway determines the shortest transmission time between the gateway and each subscriber terminal through each of the plurality of satellites; wherein, for each subscriber terminal, the gateway determines the transmission time difference between the longest transmission time and the shortest transmission time for each subscriber terminal; wherein the gateway determines the largest transmission time difference among the transmission time differences for each of the plurality of subscriber terminals; wherein the gateway determines an OFDM symbol time that is greater than the largest transmission time difference; wherein the gateway receives a data stream; wherein the gateway converts the data stream into a plurality of data symbols multiplexed over a plurality of orthogonal sub-carriers to create an OFDM symbol stream, each data symbol, exclusive of the cyclic prefix, having the same symbol time as the OFDM symbol time; and wherein the gateway transmits the OFDM symbol stream to the plurality of subscriber terminals through the plurality of satellites.