This paper describes state-of-the-art modulation techniques for visible-light-communications (VLCs) and proposes a new modulation technique, which is so-called generalized spatial pulse position modulation (GSPPM). Several modulation techniques, i.e., on-off-keying, pulse position modulation, pulse amplitude modulation and spatial modulation, are explained as background information for understa...

Indoor optical wireless systems provide an attractive alternative for realizing next generation Wireless Local Area Networks (WLANs). In this paper, the potential of non-directed, equalized optical wireless systems is theoretically investigated, taking into account the indoor channel impulse response and the characteristics of ambient light noise and thermal noise at the receiver. Three modulat...

Abstract Pulse-Position Modulation (PPM) is a modulation method that only makes every pulse in the carrier sequence change with time but without changing shape and amplitude of signal. In this paper, PPM system designed. Firstly, an appropriate mathematical model established to represent transmission, signal After that, we write code add white Gaussian noise channel. Then transmission process s...

This paper presents an alternative method for determining exact expressions for the bit error probability (BEP) of modulation schemes subject to Nakagami-m fading. In this method, the Nakagami-m fading channel is seen as an additive noise channel whose noise is modeled as the ratio between Gaussian and Nakagami-m random variables. The method consists of using the cumulative density function of ...

A ny RF communications system that uses carrier on/off pulses can be designed to have better receiver sensitivity by using negative or zero group delay narrow band filters in the receiver. These filters greatly reduce the bandwidth normally required by removing the sidebands, while retaining the necessary information in the pulsed on/off carrier. SNR improvements greater than 40 dB are being ob...

On-Off Keying (OOK) and Pulse Position Modulation (PPM) are the most commonly used modulation techniques in Free Space Optical (FSO) communications. In this paper, the performance of an FSO system with OOK and various PPM schemes has been analysed. The log-normal turbulence model for weak atmospheric turbulence and Avalanche Photo Diode (APD) receiver are considered for the system performance e...

We address the possibility to control high power pulses extracted from the maximally compressed pulse in a nonlinear optical fiber by adjusting the initial excitation parameters. The numerical results show that the power, location and splitting order number of the maximally compressed pulse and the transmission features of high power pulses extracted from the maximally compressed pulse can be m...