Two-stage spectrum sensing for cognitive radio under noise uncertainty

Abstract

The robustness to uncertainty of noise power is one of main challenges to spectrum sensing technique. Since the occurrence of noise power uncertainty causes the detection performance of spectrum sensing techniques significantly degrade. In this paper, we propose two novel schemes of twostage spectrum sensing for cognitive radio under environment as noise power uncertainty. The two-stage spectrum sensing technique combines two conventional spectrum sensing techniques to perform spectrum sensing by exploiting their individual advantages. The proposed two-stage spectrum sensing scheme exploits the merits of ED, MME and CAV techniques to determine the existence of the primary user. The ED performs spectrum sensing within a short time and offers a reliable detection at high SNRs condition. MME and CAV are robust to noise power uncertainty. Due to the combination of these techniques, the proposed schemes offer much more reliable detection when the uncertainty of noise power occurs. Even though the proposed technique takes the longest time in sensing period among two-stage spectrum sensing techniques, it is worth using this period of time to protect the primary user from harmful interference caused by the secondary user.

Feature Extraction in Local SpectrumSensing for Next Generation CognitiveRadios � A Review

“…It is defined as such a value of the received signal power that is lower than the noise uncertainty, so that reliable signal detection cannot be achieved even if the sensing time is increased. This phenomenon is addressed in some studies that simulate a low SNR environment ( [33,34]) by utilizing a more rigorous sensing algorithm in case the noise uncertainty is too significant. A more comprehensive solution is proposed in [35].…”

“…A substantial portion ( [34,40,52,[68][69][70]) of the algorithms in this group, introduce a hybrid sequence of different spectrum sensing methods and logical decision making operations. In [40], a hybrid method is proposed that combines ED and CD.…”

“…Variants of this approach are explored in [52,70]. Similarly, [34] combines ED and EBDbased methods whose test statistics are composed of the highest eigenvalue, covariance, or MME. In relation to noise uncertainty, [68] proposes combining standard ED with a method which uses the Akaike information criterion based on singular matrix decomposition.…”

Performance evaluation of single-stage and two-stage spectrum sensing techniques for cooperative cognitive radio systems under shadowing environments

“…In this section, we summarize the concept of seven spectrum sensing techniques [10]. All of spectrum sensing methods can be classified into two groups including singlestage and two-stage.…”

“…Many spectrum sensing techniques, which can be broadly classified to two types such as single-stage and two-stage spectrum sensing, were proposed. Four well-known of single-stage spectrum sensing techniques include energy detection (ED) [8][9][10][11], covariance absolute value detection (CAV) [12][13], maximum-minimum eigenvalue detection (MME) [14] and maximum eigenvalue detection (MED) [15]. These singlestage spectrum sensing techniques have different of advantages and disadvantages [10].…”