Quantum multi-user detection

Abstract

Future wired and wireless communication system will employ multi-user detection techniques, however, at this moment there are only suboptimal solutions available because of the rather high complexity of optimal detectors. Quantum detection techniques promise efficient optimal solutions to this NP (non-polynomial) hard problem. In this paper, we propose a novel approach in the multi-access quantum channel based on the quantum rotation algorithm, by which the minimum average probability of error can be obtained. We evaluate the probability of error under various correlation coefficients and signal-to-interference ratio, and compare them to that of classical optimal solution and the quantum solution under quantum Bayesian minimum cost strategy. The simulation results illustrate that the performance of quantum multi-user detection can be improved greatly when quantum rotation algorithm is employed. Meanwhile, much less time overhead is involved in the calculation.