Patent ID: 7386056
Filing Date: 2008-06-10
Classification: H04B,H04L

Abstract:
1. A digital data transmission system, comprising: a receiving unit for detecting a transmit signal transmitted from a satellite, the transmit signal produced when a transmitter modulates a primary data stream with a secondary data stream on a carrier wave associated with the satellite; and at least one demodulator coupled to said receiving unit and configured to demodulate the transmit signal, wherein the transmit signal is produced when the transmitter modulates the primary and the secondary data on the carrier wave using a M-PSK modulating scheme, and wherein the transmit signal is produced when the primary and the secondary data are re-encoded on the carrier wave using an OFDM modulation scheme, the OFDM modulation scheme dividing the carrier wave into multiple sub-carrier waves each having one of a M-PSK, D-MPSK and pi/4 D-MPSK modulation scheme.