Complexity Reduction of Cyclostationary Sensing Technique Using Improved Hybrid Sensing Method

Abstract

In cognitive radio system, the spectrum sensing has a major challenge in needing a sensing method, which has a high detection capability with reduced complexity. In this paper, a low-cost hybrid spectrum sensing method with an optimized detection performance based on energy and cyclostationary detectors is proposed. The method is designed such that at high signal-to-noise ratio SNR values, energy detector is used alone to perform the detection. At low SNR values, cyclostationary detector with reduced complexity may be employed to support the accurate detection. The complexity reduction is done in two ways: through reducing the number of sensing samples used in the autocorrelation process in the time domain and through using the Sliding Discrete Fourier Transform (SDFT) instead of the Fast Fourier Transform (FFT). To evaluate the performance, two versions of the proposed hybrid method are implemented, one with the FFT and the other with the SDFT. The proposed method is simulated for cooperative and non-cooperative scenarios and investigated under a multipath fading channel. Obtained results are evaluated by comparing them with other methods including: cyclostationary feature detection (CFD), energy detector and traditional hybrid. The simulation results show that the proposed method with the FFT and the SDFT successfully reduced the complexity by 20% and 40% respectively, when 60 sensing samples are used with an acceptable degradation in the detection performance. For instance, when Eb/N0 is 0 dB , the probability of the detection of Pd is decreased by 20 % and 10% by the proposed method with the FFT and the SDFT respectively, as compared with the hybrid method existing in the literature.

Hybrid Spectrum Sensing Using MD and ED for Cognitive Radio Networks

“…Table 4 shows a comparison of different hybrid sensing techniques performed previously and the results are compared with our proposed HD model based on the requirement of the IEEE 802.22 WRAN standard. The proposed HD model that performs the best in terms of PD is 0.98 (case 1) or 1 (case 2) and PFA is 0 under the CSS environment compared to other previous work shown in [17][18][19]. The proposed HD model along with four CSS users' results are shown to be better when compared to the results shown in [36] along with 15 CSS users.…”

“…We achieved the best results, i.e., a P D of 0.98 for case 1 and a P D of 1 for case 2, while P FA is 0 under −20 dB SNR under the CSS scenario using the HD model to determine the spectrum holes for the IEEE 802.22 WRAN standard using the proposed HD model. In Table 4, a comparison of our proposed HD model is shown with the previous hybrid detectors shown in [17][18][19]. Our HD model proves better in all the previous work performed in this field.…”

“…In distributed CSS, each CR user can take decisions by themselves while in centralised CSS, each CR user reports to the fusion centre (FC) (one CR acts as the FC) and a decision is taken by the FC jointly based on the available reports submitted to FC [16]. Research proves that, instead of traditional/ normal sensing techniques such as ED or MD, hybrid sensing [17][18][19][20] performance is always better. In hybrid sensing, two or more detectors are joined together and a decision is taken jointly which improves the detection capabilities of a single detector along with CSS.…”

Improvement of spectrum sensing performance in cognitive radio using modified hybrid sensing method

“…In [20], the hybrid method consists of five types of detectors, each one having its special functions to detect the spectrum whether it is free or occupied. In [21], the hybrid sensing method is proposed based on ED and cyclostationary detector with a reduced computational complexity and an improved detection performance. In [22], the idea of the proposed method is similar to [12], it reduced the computational complexity with a good performance, its process is based on the optimal parameter selection strategy for choosing detection parameters of the cyclic frequency and lag.…”

Compressive sensing based on novel chaotic matrix for cognitive radio

“…By using CR, these opportunities can be utilized in the spectrum such as in TV band and 4G cellular networks to overcome the spectrum problem and optimize resources usage. In this framework, cognitive users, called secondary users (SUs), can recognize the spectrum holes and use them to communicate among themselves without causing interference to the licensed users, called PUs 3,4 . Several spectrum sensing techniques have been proposed to dynamically detect unused spectrum channels in a band of interest 5,6 .…”