Underwater Optical Communication: An Approach Based on LED

摘要

One of the major obstacles in the use of underwater robots on a large scale is the difficulty in communicating with the platforms during missions, since the most common methods of communication (via radio or other electromagnetic waves) used in commercial systems, use waves strongly attenuated in water. Alternatively, acoustic-based solutions have long been the default wireless communication method for underwater applications, since it allows reasonable ranges. However, due to the severe limitations in bandwidth and the slow data rates with high latency, is not the most efficient solution. Summing up, using acoustics, applications such as monitoring and controlling remote operations are not practical. In this project, is intended to take advantage of the recent developments of LED, (specially with the higher light output and more precise tuning of the wavelength) and photo-sensor technology. These will be used to develop an improved communication module, in response to the growing demand of robotic solutions for the marine environment. Which features a high speed communication system at short ranges, where low power, complexity and small dimensions are pretended. Using high brightness blue, cyan and green LED based transmitter and a blue/green enhanced photo-diode based receiver, the main goal is to achieve, with an abundant number of tests in all sort of conditions and environments, data transmission rates up to 1 Mbps over 5 meters with the capability of transmitting either in sea or river waters. The final step consists of the creation of an operational platform, to test multiple combinations of Tx/Rx configurations and relative orientations, and, using the information obtained through the tests, tune up the system, so its maximum efficiency can be reached, matching up all the delineated objectives.