Underground Wireless Communication System Based On White LED

With the rapid development of technology of LED light emitting diode, the characterssuch as energy conservation, environmental protection, long service life andanti-electromagnetic interference are consistently concerned about and widely used by us. Thewhite LED wireless communication is a kind of technology combining lighting and wirelesscommunication with the development of white LED technology, and underground white lightLED communication is precisely a new expansion of it. Because the underground complexenvironment with heavy dust, the higher demands are put forward in white light wirelesscommunication technology when we want to implement both uplink and downlinkcommunications.Based on the existing white wireless communication technology, the white LED wirelesscommunication technology is applied in the underground environment and theimplementation the underground white light LED wireless communication system is raised inthis paper. The advantages of underground white light communication and the communicationchannel of the system is also analyzed. Different system models and modulation scheme areused for the different characteristics of the underground optical communication uplink anddownlink, and the corresponding research of them is also presented.There is a serious dust environment underground, so both the light intensity attenuationcaused by reflection and scattering of light caused by the underground dust are taken intoconsideration for the analysis of the underground channel. The wireless iterative algorithmand Mie scattering theory based on fixed point are applied into research of undergroundchannel, and several channel models that may exist in the underground environment areestablished and also analyzed by calculation and simulation. For the different characters ofuplink and downlink channel, different modulation such as SC-FDMA and ACO-OFDM areused to achieve two-way communication. The impact of multipath interference on thewireless optical communication is reduced, and improved the system performance.It is shows that the application of white light LED for underground environment cannot only realize wireless communication but also improve level of illumination and make a better underground work environment. The different modulation modes of uplink anddownlink，not only can overcome the multipath effect of the whole link, still can reducethe ber of downside link and simplify the complexity of uplink transmitting equipment.