Blind Source Separation Algorithms Using Hyperbolic and Givens Rotations for High-Order QAM Constellations

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Blind Source Separation Algorithms Using Hyperbolic and Givens Rotations for High-Order QAM Constellations

This paper addresses the problem of blind demixing of instantaneous mixtures in a multiple-input multiple-output communication system. The main objective is to present efficient blind source separation (BSS) algorithms dedicated to moderate or high-order quadratic-amplitude modulation (QAM) constellations. Four new iterative batch, BSS algorithms are presented dealing with the multimodulus (MM) and alphabet matched (AM) criteria. For the optimization of these cost functions, iterative methods of Givens and hyperbolic rotations are used. A prewhitening operation is also utilized to reduce the complexity of design problem. It is noticed that the designed algorithms using Givens rotations give satisfactory performance only for a large number of samples. However, for a small number of samples, the algorithms designed by combining both Givens and hyperbolic rotations compensate for the ill-whitening that occurs in this case and thus improves the performance. Two algorithms dealing with the MM criterion are presented for moderate-order QAM signals such as 16-QAM. The other two dealing with the AM criterion are presented for high-order QAM signals. These methods are finally compared with the state-of-the-art batch BSS algorithms in terms of signal-to-interference and noise ratio, symbol error rate, and convergence rate. Simulation results show that the proposed methods outperform the contemporary batch BSS algorithms.Manuscript received September 6, 2016; revised April 27, 2017 and August 9, 2017; accepted October 31, 2017. Date of publication November 24, 2017; date of current version February 13, 2018. The associate editor coordinating the review of this manuscript and approving it for publication was Prof. Frederic Pascal. This work was done when S. A. W. Shah was an M.S. student at the Department of Electrical Engineering, King Fahd University of Petroleum and Minerals. This work was supported by the King Abdullah University of Science and Technology Office of Sponsored Research under Award OSR-2016-KKI-2899. This work was done when S. A. W. Shah was an M.S. student at the Department of Electrical Engineering, King Fahd University of Petroleum and Minerals. (Corresponding author: Tareq Y. Al-Naffouri.) S. A. W. Shah was with the Department of Electrical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 34463, Saudi Arabia. He is with the Department of Electrical Engineering, Qatar University, Doha 2713, Qatar (e-mail: [email protected])