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On Using Curved Mirrors to Decrease Shadowing in VLC

Borja Genoves Guzman, Ana Garcia Armada, Maïté Brandt-Pearce

TL;DR

It is shown that curved mirrors, when developed with proper dimensions, may reduce the shadowing probability to zero, while static plane mirrors of the same size have shadowing probabilities larger than 65%.

Abstract

Visible light communication (VLC) complements radio frequency in indoor environments with large wireless data traffic. However, VLC is hindered by dramatic path losses when an opaque object is interposed between the transmitter and the receiver. Prior works propose the use of plane mirrors as optical reconfigurable intelligent surfaces (ORISs) to enhance communications through non-line-of-sight links. Plane mirrors rely on their orientation to forward the light to the target user location, which is challenging to implement in practice. This paper studies the potential of curved mirrors as static reflective surfaces to provide a broadening specular reflection that increases the signal coverage in mirror-assisted VLC scenarios. We study the behavior of paraboloid and semi-spherical mirrors and derive the irradiance equations. We provide extensive numerical and analytical results and show that curved mirrors, when developed with proper dimensions, may reduce the shadowing probability to zero, while static plane mirrors of the same size have shadowing probabilities larger than 65%. Furthermore, the signal-to-noise ratio offered by curved mirrors may suffice to provide connectivity to users deployed in the room even when a line-of-sight link blockage occurs.

On Using Curved Mirrors to Decrease Shadowing in VLC

TL;DR

It is shown that curved mirrors, when developed with proper dimensions, may reduce the shadowing probability to zero, while static plane mirrors of the same size have shadowing probabilities larger than 65%.

Abstract

Visible light communication (VLC) complements radio frequency in indoor environments with large wireless data traffic. However, VLC is hindered by dramatic path losses when an opaque object is interposed between the transmitter and the receiver. Prior works propose the use of plane mirrors as optical reconfigurable intelligent surfaces (ORISs) to enhance communications through non-line-of-sight links. Plane mirrors rely on their orientation to forward the light to the target user location, which is challenging to implement in practice. This paper studies the potential of curved mirrors as static reflective surfaces to provide a broadening specular reflection that increases the signal coverage in mirror-assisted VLC scenarios. We study the behavior of paraboloid and semi-spherical mirrors and derive the irradiance equations. We provide extensive numerical and analytical results and show that curved mirrors, when developed with proper dimensions, may reduce the shadowing probability to zero, while static plane mirrors of the same size have shadowing probabilities larger than 65%. Furthermore, the signal-to-noise ratio offered by curved mirrors may suffice to provide connectivity to users deployed in the room even when a line-of-sight link blockage occurs.
Paper Structure (10 sections, 10 equations, 10 figures, 2 tables)

This paper contains 10 sections, 10 equations, 10 figures, 2 tables.

Table of Contents

  1. Introduction
  2. System model
  3. Line-of-sight received power
  4. Non-line-of-sight received power
  5. Figures of merit
  6. NLoS shadowing probability
  7. Signal-to-noise power ratio
  8. Irradiance performance of curved mirrors
  9. Analytical and simulation results
  10. Conclusion

Figures (10)

  • Figure 1: Reflective surfaces: (a) plane mirror (specular reflection), (b) plane wall (diffuse reflection), (c) proposed convex mirror (broadening specular reflection ).
  • Figure 2: System model including a large source, a point detector, and a convex mirror.
  • Figure 3: Impact of source size in the LoS-link blockage. Shadowed area represents locations in which the user can not potentially receive a LoS link from the source, and the rectangle located in the middle of the room represents the light source. Light source sizes are: (a) 2 cm x 2 cm, (b) 50 cm x 50 cm and (c) 1 m x 1 m.
  • Figure 4: Curved mirrors evaluated: (a) paraboloid and (b) semi-sphere.
  • Figure 5: Ray-tracing for a curved-mirror-assisted VLC.
  • ...and 5 more figures