Multi-Element Vlc Networks: Led Assignment, Power Control, And Optimum Combining

Keywords

Combining receivers; free space optics (FSO); optical wireless communications (OWC); space division multiple access (SDMA)

Abstract

Visible light communications (VLCs) are a promising technology to address the spectrum crunch problem in radio frequency networks. A major advantage of VLC networks is that they can use the existing lighting infrastructure in indoor environments, which may have large number of LEDs for illumination. While LEDs used for lighting typically have limited bandwidth, presence of many LEDs can be exploited for indoor VLC networks, to serve each user by multiple LEDs for improving link quality and throughput. In this paper, LEDs are grouped and assigned to the users based on received signal strength from each LED, for which different solutions are proposed to achieve maximum throughput, proportional fairness, and quality of service. Additionally, power optimization of LEDs for a given assignment is investigated, and the Jacobian and Hessian matrices of the corresponding optimization problem are derived. Moreover, for multi-element receivers with LED grouping at the transmitter, an improved optimal combining method is proposed. This method suppresses interference caused by simultaneous data transfer of LEDs and improves the overall signal-to-interference-plus-noise-ratio by 2-5 dB. Lastly, an efficient calculation of channel response is presented to simulate multipath VLC channel with low computational complexity.

Publication Date

1-1-2018

Publication Title

IEEE Journal on Selected Areas in Communications

Volume

36

Issue

1

Number of Pages

121-135

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1109/JSAC.2017.2774378

Socpus ID

85035128585 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85035128585

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