Near-far resistant multi-user detector using energy contours

A multi-user detector with scalable complexity that achieves the maximum likelihood (ML) solution for two users and gives good sub-optimal performance for a higher number of users is proposed. The key idea is to construct a lookup table based on the geometric structure of the signal constellation, and then perform fast decoding based on the lookup table. The proposed detector is near-far resistant and its performance is consistently better than existing sub-optimal detectors when the number of users is greater than the number of dimensions. The robustness of the detector against noise can be controlled at the expense of higher complexity.