Optimized receivers for faster than nyquist (FTN) transmission rates in high spectral efficiency satellite systems

摘要

An approach is provided for increasing transmission throughput rates for a source signal transmitted over a wireless channel, applying faster-than-Nyquist (FTN) signaling rates combined with tight frequency roll-off to the a source signal. A receiver is provided that compensates for ISI effects induced by the FTN rate and tight frequency roll-off, where the complexity of the receiver grows only linearly with the interference memory. The receiver comprises an equalizer configured to compensate for the ISI effects, and a decoder configured to decode the output of the equalizer to determine and regenerate the source signal. The receiver processes the received signal via a plurality of processing iterations. For one processing iteration, the decoder generates a set of a posteriori soft information based on the output of the equalizer, and the equalizer uses the a posteriori soft information as a priori soft information for a subsequent processing iteration.

主权项

1. An apparatus comprising:
a receiver configured to receive a composite signal transmitted over a wireless channel via a high-power amplifier of a multi-carrier transponder,
wherein the received composite signal comprises a plurality of discrete carrier signals, each being of a respective carrier phase and frequency, combined as a single composite transmission signal, and wherein each carrier signal reflects a plurality of source data symbols of a respective source signal with which it was modulated, andwherein the receiver is further configured to process the received composite signal to isolate each of the carrier signals that is intended for receipt by the apparatus based on one or more of its phase and frequency, andwherein each isolated carrier signal includes inter-symbol interference (ISI) effects induced based on a faster-than-Nyquist (FTN) signaling rate and a tight frequency roll-off applied to the respective source signal for transmission over the wireless channel; one or more samplers, each configured to sample a respective one of the isolated carrier signals at the FTN signaling rate to generate a sequence of sampled estimates of the source data symbols of the respective source signal; and a receive processing module configured to process each sequence of sampled source data symbol estimates to determine the original source data symbols of the respective source signal; wherein the receive processing module comprises:
an equalizer configured to compensate for the ISI effects induced based on the FTN signaling rate and the tight frequency roll-off applied to each source signal; anda decoder configured to decode an output of the equalizer to determine and regenerate the respective source signal for each of the isolated carriers.