The Experts below are selected from a list of 180 Experts worldwide ranked by ideXlab platform
Jiang Xie - One of the best experts on this subject based on the ideXlab platform.
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prospect a proactive spectrum handoff framework for cognitive radio ad hoc networks without common control channel
IEEE Transactions on Mobile Computing, 2012Co-Authors: Yi Song, Jiang XieAbstract:Cognitive Radio (CR) technology is a promising solution to enhance the spectrum utilization by enabling unLicensed Users to exploit the spectrum in an opportunistic manner. Since unLicensed Users are temporary visitors to the Licensed spectrum, they are required to vacate the spectrum when a Licensed User reclaims it. Due to the randomness of the appearance of Licensed Users, disruptions to both Licensed and unLicensed communications are often difficult to prevent, which may lead to low throughput of both Licensed and unLicensed communications. In this paper, a proactive spectrum handoff framework for CR ad hoc networks, ProSpect, is proposed to address these concerns. In the proposed framework, Channel-Switching (CW) policies and a proactive spectrum handoff protocol are proposed to let unLicensed Users vacate a channel before a Licensed User utilizes it to avoid unwanted interference. Network coordination schemes for unLicensed Users are also incorporated into the spectrum handoff protocol design. Moreover, a distributed channel selection scheme to eliminate collisions among unLicensed Users in a multiUser spectrum handoff scenario is proposed. In our proposed framework, unLicensed Users coordinate with each other without using a Common Control Channel (CCC), which is highly adaptable in a spectrum-varying environment. We compare our proposed proactive spectrum handoff protocol with a reactive spectrum handoff protocol, under which unLicensed Users switch channels after collisions with Licensed transmissions occur. Simulation results show that our proactive spectrum handoff outperforms the reactive spectrum handoff approach in terms of higher throughput and fewer collisions to Licensed Users. Furthermore, our distributed channel selection can achieve higher packet delivery rate in a multiUser spectrum handoff scenario, compared with existing channel selection schemes.
Michael Street - One of the best experts on this subject based on the ideXlab platform.
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Security Aspects in Software Defined Radio and Cognitive Radio Networks: A Survey and A Way Ahead
IEEE Communications Surveys & Tutorials, 2012Co-Authors: Gianmarco Baldini, T. Sturman, Abdur Rahim Biswas, R. Leschhorn, G. Godor, Michael StreetAbstract:Software Defined Radio (SDR) and Cognitive Radio (CR) are promising technologies, which can be used to alleviate the spectrum shortage problem or the barriers to communication interoperability in various application domains. The successful deployment of SDR and CR technologies will depend on the design and implementation of essential security mechanisms to ensure the robustness of networks and terminals against security attacks. SDR and CR may introduce entirely new classes of security threats and challenges including download of malicious software, Licensed User emulation and selfish misbehaviors. An attacker could disrupt the basic functions of a CR network, cause harmful interference to Licensed Users or deny communication to other CR nodes. The research activity in this area has started only recently and many challenges are still to be resolved. This paper presents a survey of security aspects in SDR and CR. We identify the requirements for the deployment of SDR and CR, the main security threats and challenges and the related protection techniques. This paper provides an overview of the SDR and CR certification process and how it is related to the security aspects. Finally, this paper summarizes the most critical challenges in the context of the future evolution of SDR/CR technologies.
Yi Song - One of the best experts on this subject based on the ideXlab platform.
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a joint power adaptation and spectrum handoff scheme in mobile cognitive radio networks
2015 International Conference on Computing Networking and Communications (ICNC), 2015Co-Authors: Dan Wang, Yi Song, Zhitao YangAbstract:Cognitive radio (CR) technology is regarded as a promising solution by enabling unLicensed Users to exploit the Licensed spectrum unused by the Licensed User in an opportunistic manner. Since in a mobile CR network, if unLicensed Users move away from each other, their relative distance changes. Thus, the unLicensed User transmission power needs to be adapted to maintain their communications. In the meantime, since the spectrum availability is location-varying, the unLicensed Users may also need to perform spectrum handoffs to avoid harmful interference to PUs caused by the increase of the transmission power. In this paper, in order to address this problem, a joint power adaptation and spectrum handoff scheme is proposed in mobile CR networks. The throughput of the unLicensed User transmission is used to evaluate the performance of the proposed algorithm. Simulation results show that our proposed algorithm achieves very high throughput when the unLicensed receiver is mobile. To the best of our knowledge, this is the first paper that jointly investigates both the power adaptation and the spectrum handoff in mobile CR ad hoc networks.
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prospect a proactive spectrum handoff framework for cognitive radio ad hoc networks without common control channel
IEEE Transactions on Mobile Computing, 2012Co-Authors: Yi Song, Jiang XieAbstract:Cognitive Radio (CR) technology is a promising solution to enhance the spectrum utilization by enabling unLicensed Users to exploit the spectrum in an opportunistic manner. Since unLicensed Users are temporary visitors to the Licensed spectrum, they are required to vacate the spectrum when a Licensed User reclaims it. Due to the randomness of the appearance of Licensed Users, disruptions to both Licensed and unLicensed communications are often difficult to prevent, which may lead to low throughput of both Licensed and unLicensed communications. In this paper, a proactive spectrum handoff framework for CR ad hoc networks, ProSpect, is proposed to address these concerns. In the proposed framework, Channel-Switching (CW) policies and a proactive spectrum handoff protocol are proposed to let unLicensed Users vacate a channel before a Licensed User utilizes it to avoid unwanted interference. Network coordination schemes for unLicensed Users are also incorporated into the spectrum handoff protocol design. Moreover, a distributed channel selection scheme to eliminate collisions among unLicensed Users in a multiUser spectrum handoff scenario is proposed. In our proposed framework, unLicensed Users coordinate with each other without using a Common Control Channel (CCC), which is highly adaptable in a spectrum-varying environment. We compare our proposed proactive spectrum handoff protocol with a reactive spectrum handoff protocol, under which unLicensed Users switch channels after collisions with Licensed transmissions occur. Simulation results show that our proactive spectrum handoff outperforms the reactive spectrum handoff approach in terms of higher throughput and fewer collisions to Licensed Users. Furthermore, our distributed channel selection can achieve higher packet delivery rate in a multiUser spectrum handoff scenario, compared with existing channel selection schemes.
R Hekmat - One of the best experts on this subject based on the ideXlab platform.
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performance analysis of multichannel medium access control algorithms for opportunistic spectrum access
IEEE Transactions on Vehicular Technology, 2009Co-Authors: Przemyslaw Pawelczak, Sofie Pollin, Ahmad Bahai, R V Prasad, R HekmatAbstract:In this paper, different control channel (CC) implementations for multichannel medium access control (MAC) algorithms are compared and analyzed in the context of opportunistic spectrum access (OSA) as a function of spectrum-sensing performance and Licensed User activity. The analysis is based on a discrete Markov chain model of a subset of representative multichannel OSA MAC classes that incorporates physical layer effects, such as spectrum sensing and fading. The analysis is complemented with extensive simulations. The major observations are given as follows: 1) When the CC is implemented through a dedicated channel, sharing such dedicated channel with the Licensed User does not significantly decrease the throughput achieved by the OSA network when the data packet sizes are sufficiently large or the number of considered data channels is small. 2) Hopping OSA MACs, where the CC is spread over all channels, are less susceptible to Licensed User activity than those with a dedicated CC (in terms of both average utilization and on/off times). 3) Scanning efficiency has a large impact on the achievable performance of Licensed and OSA Users for all analyzed protocols. 4) The multiple rendezvous MAC class, which has yet to be proposed in OSA literature, outperforms all the multichannel MAC designs analyzed in this paper.
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quality of service assessment of opportunistic spectrum access a medium access control approach
IEEE Wireless Communications, 2008Co-Authors: Przemyslaw Pawelczak, Sofie Pollin, Ahmad Bahai, R Prasad, R HekmatAbstract:Opportunistic spectrum access (OSA) is a promising new spectrum management approach that will allow coexistence of both Licensed and opportunistic Users in each spectrum band, potentially decreasing the spectrum licensing costs for both classes of Users. However, this has significant implications on the QoS experienced by the Licensed and opportunistic spectrum Users. In this article we investigate how tolerant to secondary User activity a Licensed User should be so as to provide dependable communication with sufficient QoS to an opportunistic User. We also look at key multichannel MAC features for such OSA networks proposed in the literature, and discuss how the design of control channel management affects the QoS of opportunistic Users as a function of the tolerance of Licensed Users. We quantify the trade-off between dependability of the OSA network and the dependability of Licensed Users. The main conclusion is that opportunistic Users can indeed achieve good QoS, as long as the Licensed Users are not highly active. For example, in one of the scenarios we studied, opportunistic Users can achieve a delay below 100 ms if Licensed User activity stays below 30 percent.
Tao Tian - One of the best experts on this subject based on the ideXlab platform.
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a stackelberg game spectrum sharing scheme in cognitive radio based heterogeneous wireless sensor networks
Signal Processing, 2016Co-Authors: Songlin Sun, Na Chen, Tiantian Ran, Junshi Xiao, Tao TianAbstract:In this paper, we focus on spectrum sharing in heterogeneous wireless sensor networks (HWSNs) and consider Stackelberg game exploiting the cognitive radio (CR) technology to utilize those scarce resources. In the game, the Licensed network controls and prices the available spectrum resource which the WSN relay: actor nodes can purchase and use to serve the attached sensor nodes as well as offload some nodes in Licensed network. Both kinds of nodes try to maximize their own utility which is consisted of data rates, earning and expenditures on spectrum trading. During the dynamic interaction of the game, the interference coordination features of the heterogeneous sensor network and CR technology are employed so that the change of spectrum allocation can be fully exploited. According to simulation result, we evaluate the impact on throughput performance after implementing proposed game strategy in HWSN. And we prove that the proposed approach can significantly improve the throughput of victim Licensed nodes with slightly decreasing network total throughput. HighlightsWe focus on spectrum sharing in heterogeneous wireless sensor networks (HWSNs) and consider Stackelberg game exploiting the cognitive radio (CR) technology to utilize those scarce resources. In our scheme, the Licensed User impose a price on the shared frequency band and the cognitive radio sensor network (CRSN) nodes have to buy the band to serve their own networks. As the dynamic game continues, equilibrium can be achieved with the optimal parameters.Introducing Stackelberg game enables the Licensed network and actor nodes act dynamically and intelligently to handle the frequency allocation issue, and makes the underlying HWSN work in a self-organized manner.The data rate of the victim nodes and edge nodes is guaranteed due to the proposed scheme. During the dynamic interaction of the algorithm, because of employing the interference coordination features of HWSN and CR technology, the change of spectrum allocation is fully exploited.The frequency resources can be allocated efficiently and adaptively to Licensed network and actor nodes in response to the dynamic status of nodes density.