Modelling and analysis of M ‐ary variable pulse position modulation for visible light communications

Abstract

Visible light communication (VLC) is an emerging communication paradigm that supports illumination and data transmission simultaneously. To provide dimming control functionality, a range of dimmable modulation methods have been exploited. Among them, the variable pulse position modulation (VPPM) scheme, which is deployed using the IEEE 802.15.7 VLC standard is very simple and easy to implement. On the other hand, it has a limited data rate because it just uses binary PPM for data transmission. This study proposes the M-ary VPPM (M-VPPM) scheme to increase the data rate of the VPPM scheme. To evaluate the performance of this scheme, the modelling of the transmitter, optical wireless channel and the receiver for M-VPPM are provided. In addition, the error probability according to the dimming ratio and modulation order was analysed mathematically. The simulation results showed that the analytical bounds on the error probability are tight, which provides key insights into the performance trade-off of M-VPPM in a dispersive VLC channel environment.

An In-depth Survey of Viisiiblle Liight Communiicatiion Modullatiing and Codiing schemes for Diimmiing/Flliicker Avoiidance Technollogiies

“…To avert Flicker, the changes in brightness must be pulsation within the maximum flickering time period (MFTP). The MFTP is defined as the utmost time period over which the light intensity can change without the human eye recognizing it [1,18].…”

“…PWM can also improve the dimming levels over traditional OOK [25][26], where PWM-based dimming control provides a wide range of dimming levels [18,[27][28]. A key advantage is enhancing power consumption [27,29].…”

“…To achieve the increasing demands of multimedia services in VLC, this proposes an M-VPPM scheme that provides a higher data rate than that of VPPM. The transmit-receive modem structure and optical wireless channel were modeled which provide a guideline for M-VPPM operation satisfying both lighting and communication abilities for a given environmental condition [18].…”

Optimization of Visible-Light Optical Wireless Systems: Network-Centric Versus User-Centric Designs

“…The light should be dimmable arbitrarily in VLC systems, without the communications becoming interrupted, which means that the data should be modulated in such a way that any desired level of dimming is supported [14]. Numerous valuable modulation schemes supporting dimming control have been proposed for the LEDs, such as the variable OOK [48], [72], variable PPM [73], pulse width modulation with DMT [74], etc. When the light intensity changes, it should be flickering above the human eyes' fusion frequency, so that the human eye cannot perceive it.…”

Performance Comparison of Inverted Modulation Formats

“…The variable pulse position modulation is one of the leading techniques from among the dimmable techniques [2,3]. In order to increase bit number in one symbol, the M-ary variable pulse position modulation techniques has been improved [4].…”