Energy-efficient multiuser SIMO: achieving probabilistic robustness with gaussian channel uncertainty

• Published in: IEEE transactions on communications Vol. 57; no. 6; pp. 1866 - 1878
• Main Authors: Zheng, G., Wong, K.-K., Ng, T.-S.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.06.2009; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Antennas; Applied sciences; Array signal processing; Beamforming; Channels; Convex optimization; Detection, estimation, filtering, equalization, prediction; Energy efficiency; Exact sciences and technology; Gaussian; Gaussian channels; Information, signal and communications theory; Interference constraints; Mathematical analysis; Mathematical models; MIMO antenna; Mobile antennas; multiple access channel; Optimization; Radiocommunications; Receiving antennas; robust design; Robustness; S-procedure; SDP relaxation; Signal and communications theory; Signal to noise ratio; Signal, noise; Studies; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Transmission and modulation (techniques and equipments); Transmitting antennas; Uncertainty; multiple-access channel; Parameter estimation; Random matrix; Base station; Iterative method; Power allocation; Beam forming; Optimization; SDP relaxation; Convex optimization; Channel estimation; Minimum energy; Robustness; SIMO system; Antenna array; Uplink; S-procedure; Multiple access; Probabilistic approach; Outage; MIMO antenna; Gaussian channel; Global optimum; Algorithm; Transmitting antenna; Power control; robust design; Signal to interference plus noise ratio
• ISSN: 0090-6778; 1558-0857
• DOI: 10.1109/TCOMM.2009.06.070574

This paper addresses the joint optimization of power control and receive beamforming vectors for a multiuser singleinput multiple-output (SIMO) antenna system in the uplink in which mobile users are single-antenna transmitters and the base station receiver has multiple antennas. Channel state information at the receiver (CSIR) is exploited but the CSIR is imperfect with its uncertainty being modeled as a random Gaussian matrix. Our objective is to devise an energy-efficient solution to minimize the individual users' transmit power while meeting the users' signal-to-interference plus noise ratio (SINR) constraints, under the consideration of CSIR and its error characteristics. This is achieved by solving a sum-power minimization problem, subject to a collection of users' outage probability constraints on their target SINRs. Regarding the signal power minus the sum of inter-user interferences (SMI) power as Gaussian, an iterative and convergent algorithm which is proved to reach the global optimum for the joint power allocation and receive beamforming solution, is proposed, though the optimization problem is indeed non-convex. A systematic scheme to detect feasibility and find a feasible initial solution, if there exists any, is also devised. Simulation results verify the use of Gaussian approximation and robustness of the proposed algorithm in terms of users' probability constraints, and indicate a significant performance gain as compared to the zero-forcing (ZF) and minimum mean square- error (MMSE) beamforming systems.