Home // International Journal On Advances in Telecommunications, volume 7, numbers 3 and 4, 2014 // View article

Transmitter Based Look-Up Tables for Optical Wireless IR-UWB Systems

Authors:
Mohammed Al-Olofi
Andreas Waadt
Guido H. Bruck
Peter Jung

Keywords: Hybrid Optical/Radio systems, IR-UWB, LUT, OWC.

Abstract:
This paper investigates a design for impulse radio ultra-wideband communication over optical wireless link using optical front-ends. The migration between IR-UWB and optical wireless communications introduces a solution for radio spectrum congestion and limited IR-UWB transmission power governed by spectrum mask. Nevertheless, the nonlinear effects of light emitting diodes (LED) limit the power dynamic range that modulates signal pulses. In this work, a transmitter based digital look-up table (LUT) is proposed. This transmitter allows of storing pulse samples values in form of binary codewords. The LUT’s binary output switches LEDs groups and hence controls transmission power. This parallel switching enables power-efficient optical representation of pulses and avoids the nonlinear effects caused by LED operation characteristics. The utilization of LUT excludes the necessity of digital to analog converter (DAC) or transconductance amplifier (TCA) employed in common optical transmitters to perform the electrical-optical conversion. The selection of codeword length and LUT size are done based the BER performance generated by computer simulations. Moreover, the channel effects in presence of line of sight (LOS) and diffuse links are simulated and analyzed. The system simulations are described for a mobile user in indoor office environment. The BER performances for different mobility scenarios will be discussed.

Pages: 45 to 55

Copyright: Copyright (c) to authors, 2014. Used with permission.

Publication date: December 30, 2014

Published in: journal

ISSN: 1942-2601