Title :
Energy-efficient multiuser SIMO: achieving probabilistic robustness with gaussian channel uncertainty
Author :
Zheng, Gan ; Wong, Kai-Kit ; Ng, Tung-Sang
Author_Institution :
Dept. of Electron. & Electr. Eng., Univ. Coll. London, London
fDate :
6/1/2009 12:00:00 AM
Abstract :
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.
Keywords :
Gaussian processes; MIMO communication; antennas; approximation theory; concave programming; interference (signal); iterative methods; matrix algebra; minimisation; probability; Gaussian approximation; Gaussian channel uncertainty; base station receiver; channel state information; convergent algorithm; energy-efficient solution; interuser interferences power; iterative algorithm; joint optimization; joint power allocation; multiuser singleinput multiple-output antenna system; nonconvex optimization; outage probability constraints; power control; probabilistic robustness; random Gaussian matrix; receive beamforming vectors; signal-to-interference plus noise ratio constraints; single-antenna transmitters; sum-power minimization problem; systematic scheme; users probability constraints; Array signal processing; Energy efficiency; Gaussian channels; Interference constraints; Mobile antennas; Receiving antennas; Robustness; Signal to noise ratio; Transmitting antennas; Uncertainty; Convex optimization, MIMO antenna, multiple access channel, robust design, SDP relaxation, S-procedure.;
Journal_Title :
Communications, IEEE Transactions on
DOI :
10.1109/TCOMM.2009.06.070574