Asymptotically optimum detection of primary user in cognitive radio networks

Abstract

Traditionally, the frequency spectrum is licensed to users by government agencies in a fixed manner where the licensee has exclusive right to access the allocated band. However, with increasing demand for the spectrum and scarcity of vacant bands, a spectrum policy reform seems inevitable. Meanwhile, recent measurements suggest the possibility of sharing spectrum among different parties subject to interference-protection constraints. In order to enable access to an unused licensed spectrum, a secondary user has to monitor licensed bands and opportunistically transmit whenever no primary signal is detected. Spectrum-sharing between a primary licensee and a group of secondary users has been studied. The structure of an asymptotically optimum detector based on the measurements of all secondary users is derived and the effect of the quantisation error in such a system is evaluated. Also, it is shown that by using the proposed detector in a sequential detection structure, it is possible to shorten the decision time needed by the detector. The results show the superiority of the proposed detector to other schemes.

A Fault-Tolerant Cooperative Spectrum Sensing Algorithm over Cognitive Radio Network Based on Wireless Sensor Network

“…The false alarm probability of the proposed method for N = 50, N = 100, N = 200, N = 200 and N = 300 are depicted in Figure 3 and is compared with EGC method [5]. As can be seen from Figure 3, the proposed trust algorithm works quite well in the presence of noticeable percentage of malicious nodes.…”

“…Match filtering; cyclo-stationary feature detection and energy detection are three well-known methods which are used to sense the CR spectrum [4]. The proposed method in this paper is based on energy detection A. Taherpour et al [5] proposed an energy-detection based data fusion method and show that in fading channels Equal Gain Combining (EGC) data fusion has near-optimal performance without the requirement of channel gains estimation. According to their method if the measured energies average that is reported by coordinated nodes becomes larger than a specific threshold value the presence of the PU can be assumed to be true, otherwise the absence of the PU becomes true.…”

On the Performance of Hadamard Ratio Detector-Based Spectrum Sensing for Cognitive Radios

“…A great closeness is observed between those approximations and Monte Carlo simulations for the different modulation types in all values of SNR even when the received signal is sampled at N ss = 2. Note that the performance degradation at N ss = 2 with respect to N ss = 1 results from the decrease in the SNR due to oversampling 6 . Fig.…”

Detection of Small-Scale Primary Users in Cognitive Radio Networks

“…EGC is known to have near-optimal performance without requiring the estimation of channel gains [30], and has the following decision statistic T Σ ns n=1 T n , where T n is the test statistic (i.e., measured RSS) of the energy detector at sensor n, and n s is the number of cooperative sensors. EGC will be used to characterize the impact of fusion range on detection performance (in Section IV).…”