Visible Light Communication has the potential to provide a licence free solution to implementing high data rate wireless communication within indoor environments. Although VLC systems offer many attractive features, a number of deployment barriers remain such as the impact of sunlight irradiance on performance, line-of-sight connections, uplink issues and the 'illumination on' operational mode. The research investigates the design of VLC systems in the presence of sunlight irradiance. The foundation of the investigation is a sunlight irradiance model that generates hourly levels of natural light intensity over the year for different locations. System behaviour over different metrological conditions and extended to consider the effect of cloud coverage, is analysed for a range of the most common surfaces found in indoor environments using Matlab and Monte Carlo simulations. The evaluation of system performance considers both Line-of-Sight and Non-Line-of-Sight components (up to the fifth reflection) at a range of data rates. A comparative analysis of system performance with reported results assuming noise owing to sunlight follows Gaussian statistics is conducted. Optimum placement of LED sources is investigated. System performance characterisation is conducted for different room sizes and as a function of distance from sources of sunlight such as windows and doors. Optimum LED layout maximises the SNR, fulfils the illumination constraint as governed IEC standards and minimises the variation of the SNR across the room. The design guidelines are applicable to any room size, LED specification, wall reflectivity, location and illumination level. An approach to managing the 'illumination on' scenario is developed. Operational performance as a function of the number of energised LEDs and LED panel layout for different room sizes, surface reflectivity, different operating conditions and applications is evaluated. In summary, the research provides an in depth analysis of VLC system performance in the presence of sunlight irradiance, the results forming the foundation for future system designs and applications.
|Date of Award||16 Apr 2015|
- University Of Strathclyde