The Modified PPM Modulation for Underwater Wireless Optical Communication

Pulse position modulation (PPM) has the advantages of low transmitting power and better anti-noise performance and has been used to be an attractive option for optical wireless communications. However, the limitation in low bandwidth utilization makes the PPM modulation de-efficiency for a large amount of data transmission, e.g. multimedia information. In this paper, we proposed and demonstrated a modified PPM transceiver scheme to improve the transmission performance. The modified PPM transceiver system may be used for image transmission for designing underwater optical communication system. The simulation results of bandwidth, transmission power and anti-noise performance at the same signal to noise ratio conditions is presented and compared. It is shown that the modified PPM modulation scheme has the similar performance of the PPM in error controlling with improved bandwidth utilization. Furthermore, it can be more convenient to combine the error control coding to improve the reliability of signal transmission and lower the complexity of the transceiver.