Journal ArticleDOI
Robust Downlink Beamforming Based on Outage Probability Specifications
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TLDR
A new approach to multi-antenna downlink beam- forming is proposed that provides an improved robustness against uncertainty in the downlink channel covariance matrices caused by errors between the actual and estimated channel values.Abstract:
A new approach to multi-antenna downlink beam- forming is proposed that provides an improved robustness against uncertainty in the downlink channel covariance matrices caused by errors between the actual and estimated channel values. The proposed method uses the knowledge of the statistical distribution of such a covariance uncertainty to minimize the total downlink transmit power under the constraint that the outage probability does not exceed a certain threshold value. Although our approach initially leads to a non-convex optimization problem, it can be reformulated in a convex form using the semidefinite relaxation technique. The resulting convex optimization problem can be solved efficiently using the well-established interior point methods. Computer simulations verify performance improvements of the proposed technique as compared to the robust transmit beamforming method based on the worst-case performance optimization with judicious selection of the upper bounds on channel covariance errors.read more
Citations
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Journal ArticleDOI
Hybrid Digital and Analog Beamforming Design for Large-Scale Antenna Arrays
Foad Sohrabi,Wei Yu +1 more
TL;DR: This paper establishes that if the number of RF chains is twice the total number of data streams, the hybrid beamforming structure can realize any fully digital beamformer exactly, regardless of the numberOf antenna elements, and shows that such an architecture can approach the performance of a fully digital scheme with much fewer number ofRF chains.
Journal ArticleDOI
Convex Optimization-Based Beamforming
Alex B. Gershman,Nicholas D. Sidiropoulos,Shahram Shahbazpanahi,Mats Bengtsson,Bjorn Ottersten +4 more
TL;DR: It is demonstrated that convex optimization provides an indispensable set of tools for beamforming, enabling rigorous formulation and effective solution of both long-standing and emerging design problems.
Journal ArticleDOI
Distributed Beamforming for Relay Networks Based on Second-Order Statistics of the Channel State Information
TL;DR: It is shown that using semidefinite relaxation, the problem of distributed beamforming is considered for a wireless network which consists of a transmitter, a receiver, and relay nodes and is efficiently solved using interior point methods.
Book
Optimal Resource Allocation in Coordinated Multi-Cell Systems
TL;DR: The use of multiple antennas at base stations is a key component in the design of cellular communication systems that can meet high-capacity demands in the downlink.
Journal ArticleDOI
Exploiting Known Interference as Green Signal Power for Downlink Beamforming Optimization
Christos Masouros,Gan Zheng +1 more
TL;DR: A data-aided transmit beamforming scheme for the multi-user multiple-input-single-output (MISO) downlink channel that minimizes the transmit power for generic phase shift keying (PSK) modulated signals and a robust beamforming technique to deal with imperfect CSI is proposed.
References
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Journal ArticleDOI
Using SeDuMi 1.02, a MATLAB toolbox for optimization over symmetric cones
TL;DR: This paper describes how to work with SeDuMi, an add-on for MATLAB, which lets you solve optimization problems with linear, quadratic and semidefiniteness constraints by exploiting sparsity.
Journal ArticleDOI
Application of antenna arrays to mobile communications. II. Beam-forming and direction-of-arrival considerations
TL;DR: This paper provides a comprehensive and detailed treatment of different beam-forming schemes, adaptive algorithms to adjust the required weighting on antennas, direction-of-arrival estimation methods-including their performance comparison-and effects of errors on the performance of an array system, as well as schemes to alleviate them.
Journal ArticleDOI
Robust adaptive beamforming using worst-case performance optimization: a solution to the signal mismatch problem
TL;DR: A new approach to robust adaptive beamforming in the presence of an arbitrary unknown signal steering vector mismatch is developed based on the optimization of worst-case performance.
Journal ArticleDOI
Solution of the multiuser downlink beamforming problem with individual SINR constraints
Martin C. Schubert,Holger Boche +1 more
TL;DR: The optimality and global convergence of the algorithm is proven and stopping criteria are given, and the global optimum of the downlink beamforming problem is equivalently obtained from solving a dual uplink problem, which has an easier-to-handle analytical structure.
Journal ArticleDOI
Transmit beamforming and power control for cellular wireless systems
TL;DR: Joint power control and beamforming schemes are proposed for cellular systems where adaptive arrays are used only at base stations and the performances of these algorithms are compared with previously proposed algorithms through numerical studies.