Asymmetrical Emission Beams based Visible Light Communication Access Points Design

Abstract

In conventional visible light communications (VLC), access points (AP) are designed with symmetrical Lambertian beams. This azimuthally isotropic radiation characteristic induces that the emitted optical power is uniformly distributed in all azimuth. Nevertheless, in most indoor situations, merely limited users are located in partial indoor area. This means most optical power is emitted to the azimuth uselessly. For focusing more optical signal power to the user terminals, one optical beam-switchable AP is proposed using asymmetrical emission beams. By setting the uniform azimuth spacing between the asymmetrical beams, the receiver plane is divided into several mini sectors. In each mini sector, at least one optical beam is available. In typical indoor mini sector, compared to the conventional AP configuration, the proposed scheme could enhance the average signal noise ratio (SNR) level up to more than 5 dB. Moreover, this design is easily compatible to the limited or centralized AP site location.