Coordinated linear beamforming in downlink multi-cell wireless networks

• Published in: IEEE transactions on wireless communications Vol. 9; no. 4; pp. 1451 - 1461
• Main Authors: Venturino, L., Prasad, N., Xiaodong Wang
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.04.2010; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Antennas; Applied sciences; Array signal processing; base-station coordination; Broadcasting; Channels; Computer simulation; Detection, estimation, filtering, equalization, prediction; Downlink; Downlink multi-cell network; Equipments and installations; Exact sciences and technology; Frequency; Information, signal and communications theory; Interference; interference mitigation; Iterative algorithms; linear beamforming; Mobile radiocommunication systems; Networks; non-convex optimization; Optimization; power balancing; Radiocommunications; Receiving antennas; Signal and communications theory; Signal processing algorithms; Signal, noise; space-division multiple-access; Stations; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Transmission and modulation (techniques and equipments); Transmitting antennas; Wireless communication; Wireless networks; Performance evaluation; Non convex programming; Noise reduction; Cochannel interference; Base station; Wireless telecommunication; Downlink; Iterative method; Cell network; Beam forming; Implementation; linear beamforming; Mobile antenna; Antenna array; interference mitigation; Mobile radiocommunication; base-station coordination; power balancing; Algorithm; Frequency reuse; Interference suppression; space-division multiple-access; Space division multiple access; non-convex optimization; Simulation; Signal processing; Wireless network; Objective function; Downlink multi-cell network
• ISSN: 1536-1276; 1558-2248
• DOI: 10.1109/TWC.2010.04.090553

We consider a multi-cell wireless network with universal frequency reuse and treat the problem of co-channel interference mitigation in the downlink channel. Assuming that each base station serves multiple single-antenna mobiles via space-division multiple-access, we jointly optimize the linear beam-vectors across a set of coordinated cells and resource slots: the objective function to be maximized is the instantaneous weighted sum-rate subject to per-base-station power constraints. After deriving the general structure of the optimal beam-vectors, a novel iterative algorithm is presented which attempts to solve the Karush-Kuhn-Tucker conditions of the non-convex problem at hand. The proposed algorithm admits a distributed implementation which we illustrate. Also, various approaches to choose the initial beam-vectors are considered, one of which maximizes the signal-to-leakage-plus-noise ratio. Finally, simulation results are provided to assess the performance of the proposed algorithm.