Implementation Of Energy Detection Spectrum Sensing Using USRP N210 And Gnu Radio
In this era of wireless technology, scarcity of wireless channels pose a severe dilemma for service providers and
telecom operators. Cognitive radio technology provides a novel solution for significantly improving spectrum utilization. A
cognitive radio consists of 4 cyclic steps- spectrum sensing, spectrum management, spectrum mobility and spectrum sharing
out of which spectrum sensing is the most important and complex step. In this paper, the energy detection spectrum sensing
mechanism has been investigated using GNU Radio and USRP N210 operating at a centre frequency of 825 MHz and within a
bandwidth of 20MHz. An important point to note is that the bandwidth under consideration is kept fixed and thus, the delay
associated with tuning of centre frequency is absent. The sensing mechanism employed is the Energy Detection spectrum
sensing technique with 1024 point FFT. The entire experimental setup was initially made in the GNU Radio Companion
(GRC) and later the corresponding python program generated was modified externally. Data for 30 different time frames each
comprising of 1024 samples was recorded for analysis. Finally, in order to determine the optimum threshold value, the
probability of false alarm (Pfa) was calculated and plotted from the data recorded earlier for 5 different threshold values of -98
dB, -99 dB, -100 dB, -101 dB and -102 dB. The final target is to choose a threshold such that Pfa lies just below 5%.
Index Terms— GNU Radio, USRP N210, GRC, spectrum sensing, spectrum management, spectrum mobility, spectrum
sharing, energy detection.