Aiming at the demand of high spectrum efficiency and low bit error rate of Wireless Optical Communication (WOC) technology

a joint modulation method of Pulse Amplitude Modulation (PAM) and Pulse Position Modulation (PPM) is proposed. The method makes full use of wireless communication bandwidth resources

which can improve transmission rate compared with traditional modulation technology. The system maps different amplitude pulses to specific lasers using Space Mapping (SM)

and realizes multi-link layered transmission mapping relation. Being different from the traditional single-modulation methods

the joint modulation method uses the amplitude of the pulse and the change of the time slot position to transmit information through the coordination of the coding mechanism. The time slot position and amplitude information of each data pulse are sent and detected at the same time

using the joint modulation layered transmission technology. The experimental results demonstrate that the proposed method not only improves both spectral efficiency and transmission rate

but also improves the error performance. The experimental results provide a new technical method for the subsequent application research.