Linear Precoding for Multiuser Visible-Light Communication With Field-of-View Diversity

• Published in: IEEE photonics journal Vol. 8; no. 2; pp. 1 - 8
• Main Authors: Feng, Renhai, Dai, Mingjun, Wang, Hui, Chen, Bin, Lin, Xiaohui
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.04.2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Communication systems; Illumination; Imaging; Light emitting diodes; Lighting; Mathematical models; Messages; MIMO; Multiple Input Multiple Output; Optimization; Power consumption; Precoding; Receivers; Transformations; Ultraviolet sources; Visible Light Communication; multiple-input—multiple-output (MIMO); Visible-light communication (VLC); precoding
• ISSN: 1943-0655; 1943-0647
• DOI: 10.1109/JPHOT.2016.2542985

The multiple-input-multiple-output (MIMO) indoor visible-light communication (VLC) system with multiple users, where several light-emitting diodes (LEDs) send messages to several photodiodes (PD), is studied. To enhance the diversity, each user is assumed to be equipped with multiple PDs with a different field of view. The objective is to minimize the LEDs' maximum power consumption subject to multiple constraints, including illumination constraint and capacity constraint. Under the assumption of maximum-ratio combining at the receivers, a linear precoding method is proposed. Detailed operation of this precoding method includes two steps: First, with matrix transformation and semi-definite relaxation, the original nonconvex optimization problem is transformed into solvable convex optimization subproblems. Afterward, based on the solution of the subproblems, it is proved that a linear precoding solution can be reformulated using a rank-1 decomposition theorem. Numerical results show that our proposed scheme with different system parameters outperforms the traditional method.