LiBeam: throughput-Optimal Cooperative Beamforming for Indoor Visible Light Networks


Indoor Visible Light Communications (VLC) are a promising technology to alleviate the looming spectrum crunch crisis in traditional RF spectrum bands. This article studies how to provide throughput-optimal WiFi-like downlink access to users in indoor visible light networks through a set of centrally-controlled and partially interfering light emitting diodes (LEDs). To reduce the effect of interference among users created by the partial overlap of each LED's field of view, we propose LiBeam, a cooperative beamforming scheme, based on forming multiple LED clusters. Each cluster then serves a subset of users by jointly determining the user-LED association strategies and the beamforming vectors of the LEDs. The paper first proposes a mathematical model of the cooperative beamforming problem, presented as maximizing the sum throughput of all VLC users. Then, we solve the resulting mixed integer nonlinear nonconvex programming (MINCoP) problem by designing a globally optimal solution algorithm based on a combination of branch and bound framework as well as convex relaxation techniques. We then design for the first time a large programmable visible light networking testbed based on USRP X310 software-defined radios, and experimentally demonstrate the effectiveness of the proposed joint beamforming and association algorithm through extensive experiments. Performance evaluation results indicate that over 95% utility gain can be achieved compared to suboptimal network control strategies.

Meeting Name

2019 IEEE Conference on Computer Communications, INFOCOM 2019 (2019: Apr. 29-May 2, Paris, France)


Computer Science


This work is based upon work supported in part by ONR grant N00014-17-1-2046 and NSF CNS-1618727.

Keywords and Phrases

Cooperative Beamforming; Programmable Testbed.; throughput Optimization; Visible Light Networking

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International Standard Serial Number (ISSN)


Document Type

Article - Conference proceedings

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© 2019 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

02 May 2019