Equalizing method and device for a non-linear transmission channel

摘要

The present invention relates to a method for equalizing modulation symbols transmitted on a non-linear transmission channel. The equalizing method operates on a sequence of observables, each non-linearly depending on a predetermined number of consecutive modulation symbols, and is based on a Viterbi algorithm. It comprises a prior step of receiving a pilot sequence of modulation symbols and storing corresponding observables (110), said pilot sequence leading to a path passing through all the branches of the lattice.;In a second step (120), for each symbol to be equalized, for each branch, a branch metric is calculated as a distance between the observable corresponding to the modulation symbol to be equalized and the observable stored for said branch.

主权项

1. A method for receiving modulation symbols transmitted by a transmitter on a wireless transmission channel to a receiver, the signal being modulated by modulation symbols at a symbol frequency (fs),The method comprising:
providing, by a demodulator, observables (yk) at the symbol frequency, the observables corresponding to modulation symbols detected from the signal at the demodulator, each observable non-linearly depending on a predetermined number L of consecutive modulation symbols; operating, by a Viterbi equalizer, on a N-state lattice, each state representing a state of the transmission channel, each branch between two consecutive states of the lattice being associated with a modulation symbol, said equalizer including a branch metric calculation module receiving said observables, a metric calculation and path selection module from said branch metrics, and an in-lattice backtracing module for determining a survivor path; identifying, by a learning module, a pilot sequence of modulation symbols, said pilot sequence leading to a path passing through all the allowed branches of the lattice, and storing in a memory, for each of these branches, the corresponding observable; and calculating, by the branch metric calculation module, the metric of a branch as a distance between the observable provided by the demodulator and the observable stored for said branch.