The Research Of The Occupancy Of TV White Space In The South China Sea

To serve the tens of millions of fishermen and vessel movements on the South China Sea, the Government is in the process of implementing wireless network coverage on the South China Sea. Frequency band selection for wireless networks is a prerequisite for realizing sea Wi-Fi project. Wireless signal transmission in wireless environment on the sea and on land in different environments, marine base station construction difficult, long-distance, less shelter, reflection and absorption of electromagnetic waves, humidity, water conductivity of seawater, ocean surface wind speed and other factors are different from terrestrial wireless coverage in the communication distance is far enough, also take into account the Earth’s radius of curvature on the diffraction of electromagnetic waves and so on. In order to adapt to the poor radio propagation environment on the sea, we need to find the spectrum band which is absorbed by seawater, penetrating power, transmission distance, the channel capacity to be the working frequency band for the wireless networks.To look for the available band for the sea wireless network in the lack spectrum resources, and to understand the occupy situation about the VHF/UHF band in the Sea regional, now a measurement research has been done on the band in sea part waters and the island to find the spectrum occupy degrees information. The measured data showed that, the occupation of700MHz band within the measurement waters range with the distance away from coast obviously reduced, at a distance about10km,the broadcast TV signal on is very weak, even flooded in background noise, which can speculated that, farther west on the South China Sea, the frequency band occupied almost to zero, so the band distribution is not even in time and geographical, and most of the bands are free. The other hand, due to the development of radio and TV earlier, and it needs a large quantity of information transmission, so it chooses the Golden band of the electromagnetic spectrum. Now the radio sector is trying the conversion from analogue television to digital television, after the transformation is complete, the radio and television government will give up some spectrum for wireless broadband development, so that they can be reused to complete the wireless network coverage in marine engineering.