PROCESS FOR PERFORMING LOG-LIKELIHOOD-RATIO CLIPPING IN A SOFT-DECISION NEAR-ML DETECTOR, AND DETECTOR FOR DOING THE SAME

摘要

A process for computing Log-Likelihood-ratios (LLR) in a detector of a wireless communication receiver, said LLR being used by a channel decoder. The process comprises the steps of: - receiving a signal from a telecom front end, said signal corresponding to data belonging to a finite set of constellation symbols, each constellation symbol being arranged in a lattice constellation impaired by an additive noise and also by a multiplicative channel; - computing a limited set of distances representative of the Euclidian distances between the received signal and a finite set of predetermined constellation symbols, possibly multiplied by the channel; - deriving a set of soft decisions or LLR from said computed set of distances under the constraint of a limited length of the list of distances, and - completing said derived LLR by clipping values read from a look-up table which is simultaneously addressed by the values of the SNR and the bit index. The invention is particularly suitable for embodying an OFDM receiver for a MIMO system.