ABSTRACT
The performance of energy detection (ED) degrades under low SNR, noise uncertainty (NU), and fading. The generalized energy detector (GED) is obtained by changing the squaring operation in ED by an arbitrary positive number p. This chapter investigates the signal-to-noise ratio (SNR) wall for GED under diversity and cooperative sensing, considering noise uncertainty and fading. The p-Law combining (pLC) and p−law selection (pLS) diversity techniques are considered. Cooperative spectrum sensing is analyzed for both hard decision combining and soft combining. First, the SNR walls considering the AWGN channel are derived. The analysis is then extended to the channel with Nakagami fading, where it is shown that the SNR wall increases significantly. As a byproduct of this work, we also study the effect of noise uncertainty and fading on the detection performance and show that above a certain value, the effect of noise uncertainty is more severe when compared to the fading. The effect of p on the performance is also analyzed.
