This article presents experimental and simulation results
for the use of TV band devices (TVBDs) in TV white space, considering the presence
of interference by incumbent services. Digital TV (DTV) services are major
incumbent services currently operating in the TV bands.
With DTV service, co-channel and adjacent channel
deployment scenarios of TVBD networks are introduced. To safely protect the incumbent
service, a minimum separation distance from the DTV protected contour, which is
called the keep-out distance, is required. We estimate the keep-out distance
for different ranges of TVBD transmit antenna height by using several
propagation models and measurements of ultra-high-frequency signals in Korea. We
also investigate the hidden node problem for the spectrum sensing operation
mode of TVBDs.
According to the results of these measurements, the
hidden node margin should be at least 38 dB in order to protect DTV service.
Finally, the service coverage reduction of TVBD networks caused by neighboring
DTV service is discussed. It is shown that the service coverage of a wireless local
area network system decreases about 50 percent by co-channel interference from neighboring
DTV service when the field strength of the DTV received signal is 41 dBu. GET FURTHER INSIGHTS FROM THE PRESENTATION BELOW.