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.
In this paper, we consider the case where two communicating cognitive radio users are not near to each other or have no direct line of sight(LOS). Some secondary users don't need the entire spectrum available to them because of their traffic demand being low. If we are able to use this unused spectrum to relay the data of other secondary users through these rich nodes, the performance of the system...
Opportunistic spectrum access creates the opening of under-utilized portions of the licensed spectrum for reuse, provided that the transmissions of secondary radios do not cause harmful interference to primary users. Such a system would require secondary users to be cognitive-they must accurately detect and rapidly react to varying spectrum usage. Therefore, it is important to characterize the effect...
In this paper, we propose a new statistical interference model for cognitive network based on the amplitude aggregate interference, which accounts for the parameters related to the sensing procedure, spatial reuse protocol employed by secondary users, and environment dependent conditions like channel fading and shadowing. We derive the characteristic function and the nth cumulant of the cognitive...
In this paper, we describe the cognitive radios sharing the spectrum with licensed users and its effects on operational coexistence with unlicensed users. Due to the unlicensed spectrum band growing needs and usage by many IEEE 802.11 protocols, normal wireless radio operation sees high interference leading to high error rates on operational environments. We study the licensed bands and the characteristics...
In this paper, we analyze the outage performance of cognitive Z-interference channel where two-path cognitive relaying is used to improve bandwidth utilization efficiency of cognitive user transmission while simultaneously leading to improvement in outage performance of primary user. Cognitive relays have non-causal message knowledge of cognitive user and use interference pre-cancellation scheme to...
Multichannel sensing scheduling and interference avoidance are two major challenges for medium access in Cognitive Radio Networks (CRN). In this paper, we propose an adaptive sensing cycle scheme for scheduling multichannel sensing with interference avoidance in CRN. The principle of the proposed adaptive sensing cycle scheme is to prioritize the multichannel sensing and access based on interference...
In this paper, we provide a comprehensive analysis of aggregated interference by opportunistic radios accessing the white spaces of the digital television taking into account the “hidden node” problem. We propose a new statistical interference model for cognitive network in the white space context based on the amplitude aggregate interference, which accounts for the parameters related to the sensing...
In this paper, we investigate how cognitive radio (CR) enabled devices can self-organize to form a tactical mesh network and operate on non-dedicated (secondary) spectrum. Each node in the network constantly senses the environment and maintains an up-to-date spectrum usage report. This report is used by a central controller (CC) to initialize the network formation. Then the other CR nodes gradually...
IEEE P1900.4 is an emerging standard for optimized radio resource utilization where cognitive radio technologies are used for efficient spectrum utilization. In this paper, we design and implement a cognitive wireless network system based on open documents of IEEE P1900.4, and evaluate its performance using UDP streaming and HTTP download. Our experiments show interesting results that total network...
The rapid growth in wireless technologies has intensified the demand for the radio spectrum. On the other hand, the research studies reveal that the spectrum utilization is unevenly distributed, which leads to the conclusion that there is a problem with the spectrum management and allocation rather than the scarcity of the spectrum itself. This inefficiency in spectrum usage in addition to the escalating...
Cognitive radios permit dynamic control of physical layer resources such as transmission power and constellation size; these degrees of freedom can be employed to achieve significant improvements in network throughput above that obtainable using conventional radios (with fixed transmission power and constellation size). In this paper we present a unified framework for coordinated resource allocation...
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.