Efficient Pruning for Infinity-Norm Sphere Decoding Based on Schnorr-Euchner Enumeration

Abstract

An efficient pruning method is proposed for the infinity-norm sphere decoding based on Schnorr-Euchner enumeration in multiple-input multiple-output spatial multiplexing systems. The proposed method is based on the characteristics of the infinity norm, and utilizes the information of the layer at which the infinity-norm value is selected in order to decide unnecessary sub-trees that can be pruned without affecting error-rate performance. Compared to conventional pruning, the proposed pruning decreases the average number of tree-visits by up to 37.16% in 4 x 4 16-QAM systems and 33.75% in 6 x 6 64-QAM systems.