Shorten Pulse Position Modulation for Underwater Wireless Optical Communications

Underwater communication plays an important role in remote control in offshore oil industry pollution monitoring in environmental systems , mapping of the ocean floor for detection of objects as well as for the discovery of new resources. Optical wireless communication has been proposed as the best alternative to meet this challenge. 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 a modified PPM transceiver scheme (SPPM) to improve the transmission performance. The Shorten 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 are presented and compared. It is shown that the SPPM 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.