A survey on spectrum sensing techniques for cognitive radio

Abstract

Spectrum Sensing is an important functionality of Cognitive Radio (CR). Accuracy and speed of estimation are the key indicators to select the appropriate spectrum sensing technique. Conventional spectrum estimation techniques which are based on Short Time Fourier Transform (STFT) suffer from familiar problems such as low frequency resolution, high variance of estimated power spectrum and high side lobes/leakages. Methods such as Multi Taper Spectrum Estimation successfully alleviate these infarctions but exact a high price in terms of complexity. On these accounts, it appears that the filter bank spectrum estimation formulated by F. Boroujeny and wavelet based spectrum estimates are the most promising and pragmatic approaches for CR applications. This article surveys and appraises available literature on various spectrum sensing techniques and discusses spectrum sensing as a key element of CR system design.978-1-4244-4583-7/09/$25.00

The Possibilities of 5G Communicationusing Xampling Process

“…In the i th channel, x(t) is multiplied by a periodic waveform p i (t) with period T, lowpass filtered by h(t) with cutoff 1/2T, and then sampled at rate f s =1/T. The basic parameter setting is [4] m≥4N, f s =1/T, f s ≥B Here we require the sampling rate is on the order of mf s ≈ 4NB log(M/2N + 1) At first sight, the RD and MWC technologies seem similar, at least in their sampling stages, which involve mixing followed by integration or low-pass filtering as shown in the Fig.2 [8] The software solutions assume that the input is sampled at the Nyquist rate f NYQ = 2f max Which is twice the highest wideband frequency f max . No analog pre-processing is needed and samples can be shared with the subsequent CR stages.…”

“…By default, the MATLAB take the given frequency in the Hz"s only. But we want GHz signals as per our requirement [2], [5], [8]. So we will multiply the input value with 10 9 in the background, we should write a simple code for that multiplication.…”

“…Why we use this method? [8], [9], [1].Because this type of modulation is the robust of all PSKs since it takes the highest level of noise or distortion to make the demodulator reach an incorrect decision.…”

A Novel Multi-minislot Cooperative Spectrum Sensing Scheme in Cognitive Radio Networks

“…The frame duration is T, sensing time is t s, and reporting time is t r. All the secondary users sense in the sensing block and send their results to fusion center one after one. If fusion center takes decision that the primary user is present they initiate data transmission otherwise they start sensing again [7,8,9]. …”

Performance of Energy Detector for Cognitive Radio System over AWGN and Rayleigh Channel

“…Complexity of the mechanism is another issue. Since CRs are envisioned to operate on wireless nodes with small size and power, the spectrum sensing [7].…”