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The paper describes the MANET Cognitive Radio test bed. The proposed architecture consists of a number of CR nodes connected to the RF Switch Matrix, and enables simulation, scenario definition and management. Proposed procedures for Opportunistic Spectrum Access in MANET CR are described as well and chosen results of simulations obtained during laboratory tests are presented. The performance of these...
In Cognitive Radio Network (CRN) secondary users (SUs) opportunistically access the channel whenever it is not being used by primary users (PUs). The CRN Medium Access Control (MAC) protocol needs to sense the channel to find out the availability of spectrum. In this paper we propose a hybrid sensing mechanism for SUs to access the channel in CRN environment. In the proposed hybrid sensing mechanism...
An accurate detection of unused part of the spectrum is a key requirement in cognitive radio system. In this context, it is necessary to set an appropriate threshold between signal and noise. As noise power is instantaneous in nature, a periodic estimation of noise power is required. In this paper, we have proposed a combination methodology, that uses Rank order filtering in tandem with a gradient...
Cognitive radio (CR) can improve the utilization of the spectrum by making use of licensed spectrum in an opportunistic manner. The sensing reports from all the CR nodes are sent to a Fusion Centre (FC) which aggregates these reports and takes decision about the presence of the PU, based on some decision rules. Such a collaborative sensing mechanism forms the foundation of any centralised CRN. However,...
In cognitive radio networks, cooperative spectrum sensing schemes improve the reliability of the detection by exploiting decisions made locally by several secondary users (SUs). Soft energy combining schemes provide optimal detection performance by combining the actual sensed information from the SUs, resulting in high cooperation overhead in terms of time, computational complexity, and bandwidth...
The demand for increased power delivery, the extensive incorporation of distributed generators, such as the ones utilizing renewable energy sources, and the adoption of modern electronic devices with processing and communication capabilities, are transforming the power grid into a smart grid. In this work, we provide a brief review of smart grids and, particularly, an integral subsystem, the so-called...
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, cognitive machine to machine (CM2M) gateway in e-healthcare systems are presented by accessing several channels via periodic sensing and spectrum handoff. An optimal energy efficient spectrum management mechanism with multiple thresholds is proposed. The developed mechanism aims to reduce energy consumption in the system by optimizing the spectrum sensing and channel switching, while...
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...
In cognitive radio (CR), changing the primary user's status diminishes the achievable throughput for secondary user. Traffic of primary user is inversely proportional to throughput of secondary user. Increasing sensing time increases the primary user protection, but has a negative effect on the throughput of secondary user. Solving the dilemma of sensing-throughput tradeoff is to find the optimal...
In this paper, big Radio Frequency (RF) data assisted optimization is considered for future wireless networks employing cognitive radio technology with machine learning capability. A cognitive radio network (CRN) with multiple Secondary Users (SUs) may coexist with other wireless systems such as Small Cells (SC) and Radar systems, both Primary Users (PUs) with different level of priorities. Traditional...
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...
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...
Cognitive Radios are secondary radio systems which can use the vacant bands of a Primary radio for communication. Cognitive radios are reconfigurable radios with signal processing and Machine learning capabilities. The spectrum usage is controlled by different spectrum regulatory authorities and agencies. Majority of the agencies are following a static spectrum allocation technique and CRs are looking...
In this paper we present a novel dynamic spectrum sensing and access model in cognitive radio networks. This model allows secondary user (SU) to sequentially sense two times if necessary due to the false alarm, and choose different accessing manner according to the sensing result. In practice, sensing results often affect the data transmission in cognitive radio systems. Therefore, a hybrid interweave/underlay...
This paper presents a design of a wideband autonomous cognitive radio (WACR) for anti-jamming and interference-avoidance. The proposed system model allows multiple WACRs to simultaneously operate over the same spectrum range producing a multi-agent environment. The target of each radio is to predict and evade a dynamic jammer signal as well as avoiding transmissions of other WACRs. The proposed cognitive...
The paper presents an exhaustive visualization of different problems encountered in efficient utilization of spectrum for advanced wireless communication. It is a well known fact that there is a crisis for available radio spectrum due to incredible expansion and advancement of the communication systems and technologies. But in reality, there is no shortage of available spectrum but only lack of advance...
With the increasing development of industrial wireless technologies and standards, the scarce spectrum in the industrial, scientific, and medical (ISM) band has been extremely overcrowded, which can be mitigated by harvesting more spectrum in licensed bands with the emerging cognitive radio technology. In industrial cognitive radio networks (ICRNs), security is one of the most important problems....
Increased demand of wireless spectrum in current wireless environment needs the proper utilization of spectrum. Cognitive Radio (CR) is defined as the technology which handles the problem of spectrum underutilization in the wireless media. Sensing is the main objective of CR. There are different algorithms available for spectrum sensing which includes Energy based detection, Matched filter detection,...
Reliable detection of intrusion is the basis of safety in cognitive radio networks (CRNs). So far, few scholars applied intrusion detection systems (IDSs) to combat intrusion against CRNs. In order to improve the performance of intrusion detection in CRNs, a distributed intrusion detection scheme has been proposed. In this paper, a method base on Dempster-Shafer's (D-S) evidence theory to detect intrusion...
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