The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Wireless covert systems use low probability of detection (LPD) techniques to hide transmission and protect the transmitter. Traditionally, spread spectrum has been used to hide the covert signal in noise. Recently, research has focused on covert systems that sense the RF channel and hide their transmission in the RF band of a primary network (PN). A widely used metric to quantify covertness is the...
Recently, cognitive radio (CR) technology is proposed to be combined with femtocell networks, which enables femtocells to access the available spectrum bands in an opportunistic manner. In practice, the available spectrums in CR femtocell networks are heterogeneous and range from hundreds of megahertz to several gigahertz. These heterogeneous spectrums have very different path- losses which may result...
Abstract-A max-min fairness resource allocation is studied for wideband cognitive radio under sensing-based spectrum sharing with simultaneous wireless information and power transfer. Specifically, the throughput of the worse-case secondary user is maximized by jointly optimizing the sensing time, transmit power and subchannel allocation, subject to constraints on energy harvesting, interference power...
Basically, a WBAN consists of few wearable sensors attached to body parts, clothes, implanted underneath the skins or inner body. A WBAN consists of a central hub (i.e., base station) that controls and communicates with sensors. WBANs may deeply overlap on each other in a crowded area such as hospital because of their rapid mobility, small network size, flexible topology, and higher network density...
Cognitive radio technology is used to alleviate the contradiction between the scarcity problem and low utilization rate of spectrum resources. However, the existence of unbelievable data leads to an inaccurate judge for some available resources, which causes the failed network behaviors and interferes the authorized networks. The traditional security techniques can't defense this threat efficiently...
Cognitive automatic identification system (CAIS) based on spectrum sensing has been investigated by us in more recent years. As a key technology, the spectrum sensing can be used to solve spectrum scarcity and improve the spectrum utilization, which is important not only for cognitive radio system but also for the CAIS. A lot of methods have been presented for the spectrum sensing. Among them, the...
This paper presents a time division multiple access MAC protocol that is specifically designed for applications requiring periodic sensing of the sensor field. Numerical analysis is conducted to investigate the optimum transmission scheduling based on the signal to interference-noise-ratio (SINR) for ground level propagation model applied on wireless chain topology. The optimised transmission schedule...
Driven by rapid growth in wireless demand, spectrum sharing has recently been the focus of extensive research. A common concern is how to address coexistence-related interference, especially when the involved systems operate under different protocols. In this paper, we outline a framework for exploiting full-duplex (FD) capabilities to support coexistence in a heterogeneous spectrum sharing environment...
This paper presents a multichannel assignment problem in a centralized cognitive radio sensor network (CRSN). The basic aim of this problem is to maximize the overall system throughput and minimize the overall energy consumption of the CRSN. First, a weighted sum based optimization problem is formulated. Then the problem is represented using bipartite graph and solved using matching based hungarian...
Secondary users can utilize the spectrum in the absence of primary users (PU) in cognitive radio networks (CRN). Hence there is a need to sense the spectrum perfectly. Because of hidden node problem, the sensing information given by single SU may not be reliable information. In cooperative spectrum sensing, local sensing is performed by number of SUs and report their local decisions to fusion center...
In this paper, we propose a joint decoding and signal processing scheme for NAND flash memory. The proposed scheme provides a considerable improvement of error correcting capability when the raw error rate depends on programming voltage levels, equivalently user data, of the target memory cell and/or adjacent cells. It will be shown that the proposed scheme also requires a fewer number of voltage...
In this paper, we consider a multi-level power allocation scheme for cognitive users in the cognitive radio networks. The proposed system uses a new frame structure to improve overall throughput of the cognitive radio systems. We propose a strategy in which, the licensed user can transmit with multiple levels of power which seems to be more realistic and practical. In this work, the proposed strategy...
Wireless Body Area Network(WBAN) has made progress in technology and is gaining momentum in healthcare field. As the number of WBAN increases, WBANs coexistence is becoming prevalent which brings a negative effect on communication quality. In healthcare field, data reliability and power efficiency are attracting more attention. Many power control mechanisms based on TDMA have been provided to improve...
In this paper, we propose a cooperative spectrum sensing method where the nodes detecting the primary user and those sending the sensing results are respectively selected in order to achieve energy efficiency. We formulate the problem of node selection and derive the optimized solution. The results show that the proposed method saves the energy compared to the case where the node selection is not...
IEEE 802.15.6 is a radio interface standard for wireless connectivity of wearable and implantable sensors located inside or in close proximity to the human body (i.e. a Body Area Network). Medical applications requirements impose stringent constraints on the reliability, and quality of service (QoS) in these networks. Radio interference from other co-located BANs or nearby devices that share the same...
This paper presents the multi-UAVs cooperative target observation and tracking considering the communication interference and the propagation loss. UAVs are assigned to the appropriate target group which maximises information defined by the Fisher information matrix (FIM). We propose multi-UAVs cooperative target optimal measurement and tracking models considering the communication factors. Using...
Spectrum prediction, as one enabling technique for dynamic spectrum access (DSA), has recently been received ever-increasing research attention. Most related studies (explicitly or implicitly) assume that spectrum prediction is useful for DSA. However, it does't fundamentally clear when spectrum prediction is really beneficial. To address this issue, this paper firstly provides a high-level review...
Green cognitive radio has attracted significant research attention as an effective means of alleviating spectrum scarcity and energy-saving problem in wireless communications. In this paper, we focus on the power allocation for maximizing the transmission throughput and energy efficiency (EE) of secondary users (SUs). More specifically, we propose a multi-band power allocation scheme, where multiple...
Spectrum data, which is usually characterized by many dimensions, such as location, frequency, time and signal strength, presents formidable challenges in terms of acquisition, processing and visualization. In practice, a portion of spectrum data entries may be unavailable due to the interference during the acquisition process or the compression during the sensing process. However, the completion...
Recently, researches on mobile cognitive radio network (CRN) has been paid more attention to, involving spectrum sensing, power control and spectrum access, while no schemes considering both the power and spectrum assignment at the same time. In this paper, an efficient resource allocation (RA) scheme is proposed for the orthogonal frequency division multiple access (OFDMA)-based mobile underlay CRN...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.