Cluster-Based Differential Energy Detection for Spectrum Sensing in Multi-Carrier Systems

Abstract

Abstract-This paper presents a novel differential energy detection scheme for multi-carrier systems, which can form fast and reliable decision of spectrum availability even in very low signalto-noise ratio (SNR) environment. For example, the proposed scheme can reach 90% in probability of detection (PD) and 10% in probability of false alarm (PFA) for the SNRs as low as −21 dB, while the observation length is equivalent to 2 multi-carrier symbol duration. The underlying initiative of the proposed scheme is applying order statistics on the clustered differential energy-spectral-density (ESD) in order to exploit the channel frequency diversity inherent in high data-rate communications. Specifically, to enjoy a good frequency diversity, the clustering operation is utilized to group uncorrelated subcarriers, while, the differential operation applied onto each cluster can effectively remove the noise floor and consequently overcome the impact of noise uncertainty while exploiting the frequency diversity. More importantly, the proposed scheme is designed to allow robustness in terms of both, time and frequency offsets. In order to analytically evaluate the proposed scheme, PFA and PD for Rayleigh fading channel are derived. The closed-form expressions show a clear relationship between the sensing performance and the cluster size, which is an indicator of the diversity gain. Moreover, we are able to observe up to 10 dB gain in the performance compared to the state-of-the-art spectrum sensing schemes.Index Terms-Differential, energy detection, low signal-tonoise ratio (SNR), multi-carrier, spectrum sensing.

Energy detection–based spectrum sensing with constraint region in cognitive LTE systems

“…In a previous study, the proposed cyclostationary spectrum density estimation could achieve greater than 90% detection probability on BPSK signals with SNR of ‐18dB, when the probability of false alarm is less than 10%. In another study, the proposed energy detection scheme for multicarrier systems could reach 90% in probability of detection and 10% in probability of false alarm for the SNRs as low as ‐21dB. Although the achieved sensing SNR in both previous studies could maintain a relative low level, the effect of varying PUs' spectrum utilizations on the sensing performance was not taken into account.…”

“…In another study, the proposed energy detection scheme for multicarrier systems could reach 90% in probability of detection and 10% in probability of false alarm for the SNRs as low as ‐21dB. Although the achieved sensing SNR in both previous studies could maintain a relative low level, the effect of varying PUs' spectrum utilizations on the sensing performance was not taken into account. Therefore, a closed‐form expression between PUs' spectrum utilization ratio and the threshold is derived by considering the constraint region required by the IEEE 802.22 standard in this paper.…”

Timing and carrier synchronization in wireless communication systems: a survey and classification of research in the last 5 years

“…2) The joint timing and carrier synchronization is proposed in [348,353,354,355,360], where as identified in second column of The number of primary users are listed under the "PUs" column. As detailed in Table XV, the categorized papers differ in channel model, providing joint channel estimation, requiring CSI or training, proposing estimation or compensation, or providing lower bound.…”

Stochastic resource allocation for hybrid spectrum access OFDMA-based cognitive radios

“…In practice, there are inevitable uncertainties associated with the spectrum monitoring information caused by the adverse characteristics of the wireless environment [6]. In this paper, we invoke spectrum sensing capabilities at CRs via energy detectors which are commonly used due to their relatively low infrastructure price and favorable compatibility with legacy systems [7].…”