Abstract: An approach is provided for supporting carrier synchronization in a digital broadcast and interactive system. A carrier synchronization module receives one or more signals representing a frame that includes one or more overhead fields (e.g., preamble and optional pilot blocks and one or multiple segments separated by pilot blocks). The module estimates carrier frequency and phase on a segment by segment basis and tracks frequency between segments. Carrier phase of the signal is estimated based upon the overhead field. Estimates carrier phase of random data field are determined based upon the estimated phase values from the overhead fields, and upon both the past and future data signals. Further, the frequency of the signal is estimated based upon the overhead fields and/or the random data field. The above arrangement is particularly suited to a digital satellite broadcast and interactive system.

Abstract: An apparatus for providing automatic gain control for use in a satellite terminal of a satellite communication system capable of transmitting a plurality of different modes of data. The apparatus includes a demodulator circuit having an analog to digital converter; a first variable attenuator having an attenuation value set on the basis of a measured power level of a predetermined data signal; and a second variable attenuator having an attenuation value set on the basis of the mode of data being received by the satellite terminal, where each of the data modes have a corresponding predetermined attenuation value associated therewith which is utilized as the attenuation value of the second variable attenuator when the satellite terminal receives the data mode.

Abstract: An approach is provided for supporting carrier synchronization in a digital broadcast and interactive system. A carrier synchronization module receives one or more signals representing a frame that includes one or more overhead fields (e.g., preamble and optional pilot blocks and one or multiple segments separated by pilot blocks). The module estimates carrier frequency and phase on a segment by segment basis and tracks frequency between segments. Carrier phase of the signal is estimated based upon the overhead field. Estimates carrier phase of random data field are determined based upon the estimated phase values from the overhead fields, and upon both the past and future data signals. Further, the frequency of the signal is estimated based upon the overhead fields and/or the random data field. The above arrangement is particularly suited to a digital satellite broadcast and interactive system.

Abstract: An approach is provided for communicating in a radio communication system, such as a satellite network, wherein a terminal and a hub station communicates bi-directionally using a composite signal that is transmitted from a relay station and includes an inbound signal overlaid with an outbound signal. The hub station extracts the inbound signal from the composite signal by compensating for a non-linear effect (an optionally filter delay) associated with the composite signal.

Abstract: An apparatus for providing automatic gain control for use in a satellite terminal of a satellite communication system capable of transmitting a plurality of different modes of data. The apparatus includes a demodulator circuit having an analog to digital converter; a first variable attenuator having an attenuation value set on the basis of a measured power level of a predetermined data signal; and a second variable attenuator having an attenuation value set on the basis of the mode of data being received by the satellite terminal, where each of the data modes have a corresponding predetermined attenuation value associated therewith which is utilized as the attenuation value of the second variable attenuator when the satellite terminal receives the data mode.

Abstract: A demodulator for use in a satellite communication system, which is operative for receiving a modulated signal having a data rate R (i.e., the demodulator receives R input samples per second). The demodulator includes a demultiplexer circuit having N shift registers, which functions to receive the R data samples per second as an input signal. The demultiplexer circuit operates to input the R input samples sequentially into the N shift registers such that each of the shift registers receives input samples at a data rate of R/N samples per second. The demodulator further includes signal recovery circuitry for processing the input samples contained in each of the N shift registers so as to regenerate the data contained in the incoming modulated signal transmitted by the satellite.

Abstract: A combined interference cancellation communication system employing forward error code (FEC) decoding for high spectral efficiency satellite communications. The disclosed system enables efficient utilization of available bandwidth through overlapping adjacent channels. A receiver is used to receive a waveform having data information and noise information. A filter bank is coupled with the receiver to receive and filter waveform and output channel information received by the receiver. The channel information received includes a combination of data signals and adjacent channel interference signals. A demodulator is provided to provide an estimation signal representative of an estimation of at least one parameter of the channel information. Soft-input and soft-output decoders are provided to receive the channel information in order to calculate and estimate interference values based on the estimation signal.