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This paper presents a novel centralized cooperative scheme which combines compressed sensing (CS) method based on the analog-to-information converter (AIC) with statistical and graphical chi-square Quantile-Quantile (QQ) plot detector. The received signal at every cognitive radio (CR) user in the presence of Additive-White-Gaussian-Noise (AWGN) and intentional interference attack signal (jamming)...
Energy efficient cognitive radio networks can simultaneously improve spectrum efficiency (SE) and energy efficiency (EE) of wireless communication networks. This paper studies energy efficient spectrum sensing interval, spectrum sensing energy and transmit power allocation scheme of the secondary user (SU) in CR networks. The EE maximization problem subject to the transmit power constraint and average...
With the constant advances in wireless technology, radio spectrum has become a very scarce resource. Cognitive Radio (CR) has emerged as a viable way to deal with our inefficient use of the radio spectrum by utilizing unused spectrum holes or white spaces, as they are referred to. Using Software Defined Radio (SDR) we are able to realize CRs and their unique properties. Most of the research that has...
The cognitive radio (CR) have been proposed to improve spectral efficiency and to meet growing demands for higher data rates in mobile communications and satellite communications. In this paper, we propose a blind estimation algorithm for a secondary user to estimate transmission parameters of the primary signal in an OFDM overlay system, using only the available fast Fourier transform (FFT) component...
In this paper, minimum MSE based interference alignment (IA) algorithm is developed for the interfering broadcast channel (IBC), which models the multi-cell downlink system, underlying cognitive radio, device-to-device and other scenarios. The IA precoders and decoders are computed to minimize the MSE. Cascade design is used for IA precoder design, where the first component precoder is obtained by...
This paper investigates the performance of a cooperative spectrum sharing protocol for cognitive two-way amplify-and-forward (AF) relaying system. In the proposed framework, two primary users (PUs), PU1 and PU2 coexist with a secondary user (SU) in the same frequency band albeit with different priorities. Primary users by virtue of having a license to operate over the frequency band have higher priority...
This paper analyzes and evaluates joint effect of primary interference and artificial noise on information securing capability of cognitive radio networks (CRNs) under interference power constraint, peak transmit power constraint, and Rayleigh fading. An exact formula for an important security performance metric, secrecy outage probability, is first derived and then validated by computer simulations...
Channel assignment is a key problem in Cognitive Radio Networks. The channels are leased to the secondary users when the licensed or primary users are OFF, provided that the secondary users will leave those channels as soon as the primary users are reactivated. Therefore, to achieve a high performance of the network, we should lease a channel to a secondary user while both of them achieve the best...
A novel distributed scheduling method for minimizing packet routing delays in multi-hop multi-band cognitive radio networks is proposed. The proposed scheduling method exploits spectral awareness in the form of spatial potential fields that characterize sources of interference as repulsive forces and packet destinations as attractive forces. The proposed scheduling protocol operates in four phases,...
In this paper, we address the blind rendezvous problem of cognitive radios (CRs) quickly finding each other to establish communication in a multi-channel dynamic spectrum access (DSA) environment. We propose a multi-agent Q-learning based rendezvous strategy that allows CR-based secondary users (SUs) to actively explore a dynamic DSA environment and learn through resulting rewards which channels are...
In this paper, a broadband, inductorless noise-canceling low-noise transconductance amplifier is presented. The proposed circuit is suitable for TV White-Space applications. It has a single-ended input, eliminating the need for an external balun, and a balanced output, which can be followed by a double-balanced current-switching mixer for high IIP2. The circuit is based on a common-gate stage with...
Cognitive radio system is a context-aware technology in communications. Spectrum sensing is an important function in the implementation of cognitive radio systems by detecting the presence or absence of primary users within the frequency spectrum and makes available free channels for secondary users. Cyclostationary Feature Detector is capable of detecting signals at low signal to noise ratios relying...
The new method for the secondary use of an occupied spectrum simultaneously with its primary use is proposed. This concept can be applied for data transmission in the TV sound band. Efficiency of the combination in this band of the main application and data transmission by the secondary user is shown.
Recently, the demand for faster and more reliable data transmission has brought up complex communications systems. As a result, it has become more difficult to carry out closed-form solutions that can provide insight about performance levels. In this paper, different from the existing research, we study a cognitive radio system that employs hybrid-automatic-repeat-request (HARQ) protocols under quality-of-service...
In this paper, we propose a cooperative approach to improve the security of both primary and secondary systems in cognitive radio multicast communications. During their access to the frequency spectrum licensed to the primary users, the secondary unlicensed users assist the primary system in fortifying security by sending a jamming noise to the eavesdroppers, while simultaneously protect themselves...
The availability of channel state information (CSI) about the interference links from the secondary transmitters to the primary receivers is widely assumed in the literature on underlay cognitive radio (CR) in order to control the interference caused to the primary network. However, when multiple primary receivers are present, acquiring such CSI about all the interference links in a timely and scalable...
An efficient spectrum sensing scheme is proposed for detecting a primary signal corrupted by a Generalized Gaussian Noise (GGN). It is assumed that the power of the primary signal is much smaller than the noise power, and secondary users are equipped with multiple antenna receivers. The proposed scheme, referred to as sigmoid detector, uses a sigmoid soft limiter. The sigmoid limiter is characterized...
We investigate the global throughput maximization of distributed spectrum reusing (DSR) in cognitive radio (CR) network, which reaches the two-dimensional spectrum multiplexing. Most previous works only consider the temporal-domain accessing, which greatly underutilize the spectrum resources. In this paper, we propose a new temporal-spatial spectrum reusing scheme by fully exploiting the location...
We consider a single channel energy harvesting cognitive radio system, where the joint optimization of spectrum sensing, channel probing and transmission power control is considered with the goal to maximize the throughput. We model this control problem as a two-stage continuous-state Markov decision process with one stage for sensing and probing control, and the other for transmission power control...
This paper studies the application of non-orthogonal multiple access (NOMA) to a cooperative multicast system (termed CM-NOMA). In particular, the multicast subscribers are served as secondary users underlaying a primary user. To enhance the secondary user fairness and compensate for the primary user, a two-stage cooperative strategy is proposed by selecting a certain secondary user to perform NOMA...
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