Dual Amplitude-Width Pulse Interval Modulation for Optical Wireless Communications

In this paper, a new modified digital pulse interval modulation called Dual Amplitude-Width Pulse Interval Modulation (DAWPIM) is presented, on the basis of Pulse Amplitude Modulation (PAM) and Pulse Width Modulation (PWM), and its properties are presented. After introducing symbol structure, data rate improvement, average normalized power requirement and bandwidth efficiency are studied. The proposed concept showed to be well suited to use in Optical Wireless Communications links by virtue of its increased data rate, high spectral efficiency and the absence of receiver synchronization problems. We present theoretical expressions of spectral efficiency, power requirements, and the data rate improvement normalized to PPM, and we present comparison results to DPIM and the hybrid PAM-DPIM.