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This paper proposes two non-uniform quantization schemes and also introduces an implementation system based on Software Defined Radio (SDR) consisting of GNU Radio and Universal Software defined Radio Peripheral (USRP) to sense a spectrum. In cognitive radio (CR) systems, detection and error probability are representative indicators of system performance. These performance indicators are influenced...
In this paper, we investigate the impact of the carrier-sensing range on the link performance in a dense wireless network. Considering small-scale fading effects, we fix the carrier-sensing threshold and adaptively adjust the carrier-sensing range. At first, we assume a close transmitter-receiver distance and model the network nodes as a homogeneous Poisson point process (PPP). Then we obtain the...
The spectrum sensing strategy plays a vital role in Amplify-Forward (AF)-Cognitive Radio Networks (CRNs). However, AF-CRN cannot obtain maximal throughput, when existing sensing strategies are applied to AF-CRNs. In this paper, we present a superposition approach in AF-CRNs, in which firstly a Secondary User (SU) extends its sensing time until right before the beginning of its reporting time slot,...
This paper proposes a new spectrum access algorithm based on the Partially Observable Markov Decision Process (POMDP) for Cognitive Radio Networks (CRNs). The proposed algorithm uses the Maximum Likelihood to estimate the licensed channel state transition probabilities based on historical statistics information of the channels. Then, the number of channels sensed by the secondary users in each time...
Spectrum sensing is the fundamental technology of Cognitive Radio (CR). This paper proposes a novel multiple-antenna based spectrum sensing method with random arrivals of primary users (PUs). The method first constructs a local test statistic for each antenna based on the assumption that the PU is randomly arriving, and then calculates the estimated optimum coefficient for every local test statistic...
Spectrum sensing is the important aspect of cognitive radio (CR). In order to use the vacant spectrum, cognitive radio user must be able to identify the presence of empty spectrum efficiently. A non-cooperative spectrum sensing faces the problem of shadowing and hidden terminal due to which the CR user fails to monitor the vacant spectrum. To solve the problem of hidden terminal and shadowing in non-cooperative...
In this preliminary work, we study the problem of {\it distributed} authentication in wireless networks. Specifically, we consider a system where multiple Bob (sensor) nodes listen to a channel and report their {\it correlated} measurements to a Fusion Center (FC) which makes the ultimate authentication decision. For the feature- based authentication at the FC, channel impulse response has been utilized...
This paper addresses the problem of choosing the right sources to solicit data from in sensing applications involving broadcast channels, such as those crowdsensing applications where sources share their observations on social media. The goal is to select sources such that expected fusion error is minimized. We assume that soliciting data from a source incurs a cost and that the cost budget is limited...
To overcome the hidden terminal problem a secondary user (SU) may encounter, cooperative spectrum sensing (CSS) is proposed and gained much attention in the last decades. However, due to the selfish nature, SUs may not cooperate unconditionally as most previous works have assumed. Therefore, how to stimulate SUs to play cooperatively is an important issue. In this paper, we propose a reputation-based...
In Cognitive Radio scenario achieving maximum secondary user capacity has always been a challenging task along with high detectability of primary user. Detection of primary user signal in presence of noise and channel fading condition is very conveniently carried out by energy detection scheme due to its less complexity in its structure. Further, for improving system performance under limited bandwidth...
This paper investigates the use of deception in combating the deceiving attack in IEEE 802.22 cognitive radio networks. The deceiving attack is a coordinated combination of diverse jamming attacks sourced by the same malicious platform. In this paper, a deception-based defense scheme is proposed to counteract the deceiving attack. The non-existence of the pure strategy Nash equilibrium was proven...
Compared with conventional cognitive radio networks (CRNs), the efficiency can be improved if secondary users (SUs) have full duplex (FD) communication capabilities. We discuss FD spectrum sensing in non-time-slotted CRNs and study two work modes of SUs, transmitting-sensing (TS) mode and transmitting-receiving (TR) mode. SUs work alternately in two modes. In such a context, we analyze the sensing...
Learning-based sensing policies for multi-band flexible spectrum use, in particular cognitive radios operating in non-stationary radio environments are proposed. The proposed policies stem from the stochastic non-stationary restless multi-armed bandit formulation of opportunistic spectrum access. The non-stationary radio environment assumed in this paper is an appropriate model for a realistic cognitive...
In cognitive radio network, through efficient spectrum utilization the analysis of secondary user (SU) capacity maximization is an important work. In this paper we analyze the maximization of the secondary user capacity through threshold (λopt), probability of detection (Pd) and number of user (N) in the dual threshold scheme of cooperative spectrum sensing by considering two priority scheme PUOP...
This paper proposes two channel assignment models to manage channel blocking of the primary users (PUs) and the secondary users (SUs) in cognitive radio (CR) networks. The proposed models provide priority based channel assignment strategies for the PUs and SUs. In order to manage the blocking of PUs and SUs, channel blocking analysis for both models is performed using the Markov chain process. Further,...
Radar-detection metrics are assessed in outcomes of sparse-signal processing (SSP) with test statistics based on the subgradient and the dual feasibility in the SSP optimization via an approach separating false alarms (FAs) from targets. In radar, SSP is aimed for estimating a sparse solution whose FAs are fixed and whose detection of targets is optimal as in traditional detection. Existing detection...
The rapid growth of modern wireless applications results in spectrum and energy scarcity. Cognitive radio (CR) technology is pivotal to resolve spectrum shortage. However, energy consumption is a critical issue in CR networks (CRNs) due to the unique functionality of spectrum sensing. Besides RF energy harvesting has come up as a potential solution to provide energy to CR devices. In this paper, we...
This paper discusses a typical cooperative sensing model where the local observations are conditionally dependent. The primary user sends a binary phase-shifted keying modulated signal and the hard combining strategy is implemented among second users. Two low-complexity local quantization schemes corresponding to the choice of quantizing either the amplitude or the sign as the one-bit reported message...
The maximum and minimum eigenvalue (MME) spectrum sensing algorithm with features such as low complexity, no need of the prior information of authorized users, etc. However, because of its detection distribution function is not clear, researchers have improved the MME spectrum sensing algorithm from the point of view of the distribution function, but cannot solve the insufficient detection performance...
Remote sense values of the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) suffer from the effect of ragged terrain. In this study, the effect of ragged terrain was internalized into the FAPAR model based on recollision probability (FAPAR-P), by improving FAPAR-P in two aspects: calculating the shielding factor to correct for the fraction of diffuse sky radiation to the total radiation,...
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