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Accurate spectrum sensing plays a decisive role in determining the performance of any cognitive radio network (CRN). Spectrum sensing enables the unlicensed secondary users (SUs) to operate in the licensed band until the primary user (PU) is detected. By allowing SUs in the same band to cooperate, we can reduce the detection time and increase overall agility and this forms the basis of cooperative...
Efficient spectrum sensing is a crucial function in cognitive radio (CR) networks and that enables secondary users (SUs) to detect primary user (PU) activities and make a decision to utilize vacant channels in the spectrum. Cooperative spectrum sensing, which is a prominent sensing approach in the literature due to its ability to increase sensing accuracy, is based on sharing information about channel...
Frequency spectrum scarcity has been a strong research motivation. Those researches have focused on developing methodologies to utilize frequency spectrum as much as it could be. Meanwhile, this spectrum utilization and its great revenue should not affect the quality of services being provided by network providers. In most cases, statistics have shown that only quarter of the spectrum is well utilized...
Efficient and accurate spectrum sensing is a necessary part in cognitive radio networks. A simple and efficient spectrum sensing technique is proposed to solve the bad performance of spectrum sensing in non synchronous OFDM signals with low SNR regimes. Through the decomposition of the traditional OFDM signal spectrum sensing technology based on cyclostationarity, the real part and the imaginary part...
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...
This paper considers a cooperative spectrum sensing scheme for cognitive radio network that uses a power splitting mode for simultaneous sensing and harvesting of energy. The objective is to maximize the residual harvested energy over the total energy consumption in the sensing process. An optimization problem is formulated in terms of the number of secondary user (sensing) nodes, the number of samples...
In this paper, we have intended and delineated about discerning the white space in the spectrum which is precious. The Cognitive Radio is transpiring because of its idiosyncratic nature of exploiting the unused spectrum for various praxis. Initially, we have discerned the unused frequencies in the TV band which comprises from 585 to 698 MHz and in the FM band which comprises from 87.5 MHz to 108.0...
Cognitive radio (CR) is a form of wireless communication in which a transceiver can wisely detect communication channels that are in use and those which are not, and immediately move into vacant channels while avoiding occupied ones. In such systems, spectrum sensing (SS) is a crucial operation. It consists to detect the available frequency bands. Many spectrum sensing techniques are presented in...
We present a composite suite of technologies for spectral coexistence of existing communication and radar systems using the Xampling framework. For a stand-alone communication system, we consider a cognitive radio (CRo) that receives multiband signals with unknown carrier frequencies and directions of arrival, and demonstrate joint spectrum sensing via CompreSsed CArrier and Direction-ofarrival Estimation...
One of the important trends which is supposed to have more attention in the system of cognitive radio is wireless security models. Security requirements for CRNs are the same as the general wireless networks, taking into consideration that the frequency band changes dynamically adding a specific feature when we deal with security of CRNs. A new category of security issues and challenges have been...
In this paper, we consider a cognitive radio system, consisting of a primary user (PU), a secondary user (SU) transmitter, and a SU receiver. The SUs are equipped with directional antennas. The SU transmitter first performs spectrum sensing (with errors) and then transmits data. We assume the SU and PU can coexist and the SU transmits at two power levels, according to the result of spectrum sensing...
Cognitive Radio requires both efficient and reliable spectrum sensing of wideband signals. In order to cope with the sampling rate bottleneck when dealing with such signals, sub-Nyquist methods have been proposed. However, these techniques decrease the signal to noise ratio (SNR) due to aliasing effects. Cyclostationary detection, which exploits the periodic property of communication signal statistics,...
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...
Cognitive radio (CR) systems need to detect the presence of a primary user (PU) signal by continuously sensing the spectrum area of interest. Radiowave propagation effects like fading and shadowing often complicate sensing of spectrum holes because the PU signal can be weak in a particular area. Cooperative spectrum sensing is seen as a prospective solution to enhance the detection of PU signals....
Wideband spectrum sensing aims to identify the occupied frequency bands. Conventional methods for single antenna spectrum sensors threshold the received power spectra to detect discrete frequency bins that are occupied. However, such methods neither group bins that are occupied by the same signal nor aggregate occupied bins over time to learn distinct frequency bands occupied by intermittently transmitting...
In this work, we study the wideband sensing problem of detecting intermittently transmitting signals that may have partial spectral overlap. We aim to estimate the frequency bands occupied by transmitters using standards with overlapping frequency bands, such as IEEE 802.11, and those without guard bands, such as LTE-Advanced. Multiple power spectrum measurements are used to distinguish the distinct...
Opportunity detection at secondary transmitters (TXs) is a key technique enabling cognitive radio (CR) networks. Such detection however cannot guarantee reliable communication at secondary receivers (RXs), especially when their association distance is long. To cope with the issue, this paper proposes a novel MAC called sense-and-predict (SaP), where each secondary TX decides whether to access or not...
This paper describes the design, experimental assessmant and Software Defined Radio (SDR) implementation of a Secondary User (SU) link for the IEEE DySPAN Challenge 2017. The objective is to successfully discern the behavior of and coexist with a Primary User (PU), whose channel access patterns vary over time. For that end, we utilize sensing, deep learning and dynamic optimization.
The problem of cooperative spectrum leasing among multiple primary users (PUs) and secondary users (SUs) is considered. A hybrid Stackelberg-coalition formation game theoretic algorithm is proposed that enables the PUs to identify a group of cooperative SUs by looking at the reputation history of their cooperative behavior. The coalition formation approach also promotes collaboration among the SUs...
Cognitive radio network (CRN) is one of theprominent technology for the next generation wirelessnetworks. Due to the CR version, the userswere classified into two types which are the primaryusers (PUs) and secondary users (SUs) which arealso named as licensed and unlicensed users. Themain objective of CRN is to access the underutilizedlicensed bands of PUs by SUs without any interferenceto the PUs...
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