ANALYSIS OF SPECTRUM HOLE IN DVB-T BAND

Digital terrestrial television (DTV) covers an area with radius as large as 60 km. FCC and Ofcom suggests detection of DTV signal at signal strength of as low as -114 dBm and -120 dBm respectively. Thus, Detection of DTV signals in low signal-to-noise ratio (SNR) is vital. Continual pilot (CP) positions in all the DTV signals are fixed. Digital Video Broadcasting Terrestrial (DVB-T), a DTV standard, is followed by most of the countries of the world. In this paper we propose a correlation based CP detection which can detect DVB-T signal at low SNR. One CP carrier was generated at the receiver which was correlated with the received orthogonal frequency division multiplexing (OFDM) signal sequence. The correlation coefficient was then compared with a threshold correlation coefficient to identify the existence of the CP to detect the presence of DVB-T signal and thereby spectrum hole. It was found from the simulation study for additive white Gaussian noise (AWGN) channel that signal detection at low SNR is possible compared to time domain symbol cross-correlation (TDSC) method.