Efficient, high fidelity transmission of modulation schemes through power-constrained remote relay stations by local transmit predistortion and local receiver feedback

摘要

A system for pre-distorting samples derived from modulated data symbols to compensate, at least in part, for non-linear operation of a power amplifier in a power-constrained remote relay station. A symbol mapper maps successive renderings of an input alphabet into successive modulation symbols such as but not limited to 16-QAM or 64-QAM symbols. Pre-distortion logic pre-distorts samples derived from the symbols, and logic incorporates samples derived from the pre-distorted samples into a transmission signal. The transmission signal is amplified and transmitted over a communications link to the remote relay station. The system may employ a feedback loop to measure the amount of residual distortion still present is a signal relayed from the relay station and derived from the transmission signal. Responsive to this measured residual distortion, the system dynamically adjusts the amount of pre-distortion (at various input levels) which should be applied to its input samples, to drive the distortion to near-zero or zero, given enough adaptation time.