Detecting Massive MIMO-QAM Signal via ℓ2-Box ADMM Approach

In this letter, we develop two efficient detectors for the massive multiple-input multiple-output (MIMO) system with quadrature amplitude modulation (QAM) signal based on the
$\ell _{2}$
-box intersection technique and the alternating direction method of multipliers (ADMM) approach. Specifically, the first one called ADMM-1 has theoretically-guaranteed convergence under mild conditions, and the second one called ADMM-2 owns cheaper computational complexity. Moreover, all variables are solved analytically in the detection procedure. Simulation results demonstrate the effectiveness of the proposed
$\ell _{2}$
-box ADMM detectors in comparison with the state-of-the-art methods.