AH-MPPM a new modulation scheme for free space optical communication systems

Multi-Pulse pulse position modulation (MPPM) has proved to be more bandwidth efficient than other modulation schemes such as Pulse Position Modulation (PPM), however MPPM is steel not a strong candidate when the bandwidth efficiency is taken into account, and steel suffers from the clock recovery problem. In this paper we propose Anisochronous Harmonic Multi-Pulse Pulse Position Modulation (AH-MPPM) as a new modified digital pulse modulation, presented on the basis of Multi-pulse Pulse Position Modulation (MPPM), and on Pulse Amplitude Modulation (PAM). This method is presented to achieve the best compromise between complexity, data rate, power efficiency, spectral efficiency and symbol synchronization possibility. We present the expressions of spectral efficiency, power requirements, and the data rate improvement normalized to PPM, and we present comparison results to MPPM and conventional Dual Amplitude MPPM.