Multicarrier transmission system

摘要

A communication system for sending a sequence of symbols on a communication link. The transmitter receives a sequence of symbols and groups the symbols into a block of symbols for which transmission is to be initiated in a following frame. Each symbol is used to modulate a different carrier. At the receiver, the signal from the communication link is decoded by a plurality of finite impulse response (FIR) filters that are matched to the waveforms modulated by the symbols in the transmitter. Errors arising from synchronization errors between the transmitter and receiver are corrected by forming weighted sums of the symbols decoded by the FIR filters for the current frame and frames received prior to and/or after the current frame. The weights are determined by training samples sent on the communication link prior to the actual transmissions. In systems in which the communication link introduces phase distortions into the signals sent thereon, the receiver includes a second bank of FIR filters that measures the amplitude of the signal in each of the carrier frequency bands after the signal has been phase shifted. The symbols generated by this second bank of filters are included in the weighted sum using weights that are also determined during the training session. The modulated carrier signals extend over a plurality of frames overlapping carrier signals from prior frames which provides improved noise immunity.