Fundamental Limits on Localization in Single Input Multiple Output Visible Light Systems
M.S. in Electrical and Electronics Engineering
Assoc. Prof. Dr. Sinan Gezici
The seminar will be on Thursday, September 14, 2017 at 14:00 @ EE-314
Visible light system have been considered as an effective and promising solution for indoor positioning recently, which aroused a popular and significant research topic. In this thesis, a theoretical accuracy analysis is conducted for position estimation in visible light systems based on received signal strength (RSS) measurements. Considering a single light emitting diode (LED) at the transmitter and multiple photo-detectors (PDs) at the receiver, the Cramer-Rao lower bound (CRLB) is derived for both a generic three-dimensional scenario and specific configurations of the PDs at the receiver. For the special case in which the height of the receiver is known, a compact expression is derived for the CRLB, considering a uniform circular layout and the same elevation angle for all the PDs. Asymptotic analysis and accuracy of derived compact expression is investigated for this configuration of the system. In addition, the optimal placement of the PDs at the receiver is investigated by taking the effects of the elevation angle parameter of the PDs into consideration. The optimal values are obtained theoretically and also verified by simulations. Numerical examples are provided to illustrate the impacts of system parameters on localization accuracy, namely radius of the uniform circular layout, elevation angle and number of PDs. Finally, theoretical limits are compared against the maximum likelihood estimator (MLE) as a benchmark to evaluate the performance of receiver position estimation.
Keywords: Cramer-Rao lower bound, estimation, visible light, positioning, single input multiple output (SIMO), Lambertian pattern, received signal strength, maximum likelihood estimator.