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In this work, a relay-selection scheme is proposed for underlay cognitive radio networks, with fixed and adaptive relaying power. The relay-selection and power allocation is based on the calculation of the log-likelihood ratio (LLR) value, calculated at each of the relay nodes available in the secondary network. No interference is caused to the primary network, through the satisfaction of a low power...
In our paper, a novel method is proposed to obtain the optimal positions of secondary base stations (SBSs) for cognitive radio Internet of Things (IoT) sensor networks and to select the optimal operating channel in order to maximize the secondary capacity, while also protecting the primary systems. We proposed an appearance probability matrix for secondary IoT sensor devices in order to maximize the...
In this paper, we investigate the resource allocation for the video streaming service in the cognitive radio network (CRN) based on orthogonal frequency division multiple access (OFDMA). Considering the channel estimation error between secondary transmitters (STx) and primary receivers (PRx), we address the probabilistic interference constraint model. With imperfect CSI between STx and secondary receivers...
This paper investigates the resource allocation problem in heterogeneous cognitive radio networks (HCRNs). In this paper, two types of users, i.e., multi-homing and single-network cognitive radio users (CRUs), are considered to coexist in HCRNs. Multi-homing CRUs can access multiple networks simultaneously, while single-network CRUs can be served by only one network at a time. With the aim of maximizing...
In this paper, a non-orthogonal multiple access cognitive radio network with simultaneous wireless information and power transfer is studied under a practical non-linear energy harvesting model. A multi-objective optimization problem(MOOP) is formulated to maximize the harvesting power of each energy harvesting receiver. This problem is non-convex and challenging to be solved. The weighted Tchebycheff...
This paper analyzes secrecy outage probability (SOP) of underlay cognitive radio systems (UCRSs) interfered by signals from primary networks, impaired by channel information inaccuracy and Rayleigh fading, constrained by peak transmit power and tolerable interference power. The analytical result is presented in an exact expression and corroborated by computer simulations. Multiple results illustrate...
We study a cognitive radio network in which two sources communicate with each other through multiple relays operating in non-overlapping frequency bands in the radio spectrum. We consider the problem of optimizing the transmission powers of the sources and relays so that the minimum of the two sources' transmission capacities is maximized. Thanks to the non-overlapping nature of the relays' signals,...
In this paper, we investigate the secrecy performance of a cognitive untrusted relay network with a direct link using selection combining (SC) scheme, where a secondary source communicates with a secondary destination through an untrusted relay. We first examine the connection outage probability (COP) and secrecy outage probability (SOP) to investigate the reliability and security performance of the...
The paper proposes a customized frequency domain energy detection spectrum sensing scheme. It is needed to fulfill requirements provided by the IEEE 802.22 standard, aimed at extending Internet services to Television White Space frequencies. It provides a detection scheme allowing to achieve strict sensitivity required by the protocol either in sensing time or in detection capabilities. In particular,...
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...
In this work, we consider a cognitive radio network comprising a pair of sources and multiple relays exercising the amplify-and-forward cooperation in a shared frequency band. For such a network, we consider the problem of determining transmit powers of the sources and relays so that the lesser of the achievable error-free data rates from the two sources is maximized. The formulated problem is a non-convex...
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...
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...
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...
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....
In this paper, energy efficient transmit antenna selection in underlay cognitive radio (CR) multiple-input multiple-output (MIMO) systems from a cross layer perspective, is investigated. Conventional energy efficient antenna selection optimizes an energy efficiency (EE) metric defined in terms of the system capacity and energy consumption, making it a physical layer criterion. In this work, we propose...
This work investigates the downlink resource allocation (RA) problem in orthogonal frequency division multiplexing (OFDM)-based cognitive radio networks. The objective of this work is to develop a fair RA-algorithm that maximizes the capacity of secondary users (SUs) and in the same time limits the interference caused to the primary users. The fairness condition is formulated as a minimal data condition...
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,...
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