68 research outputs found
Information, Energy and Density for Ad Hoc Sensor Networks over Correlated Random Fields: Large Deviations Analysis
Using large deviations results that characterize the amount of information
per node on a two-dimensional (2-D) lattice, asymptotic behavior of a sensor
network deployed over a correlated random field for statistical inference is
investigated. Under a 2-D hidden Gauss-Markov random field model with symmetric
first order conditional autoregression, the behavior of the total information
[nats] and energy efficiency [nats/J] defined as the ratio of total gathered
information to the required energy is obtained as the coverage area, node
density and energy vary.Comment: Proceedings of the 2008 IEEE International Symposium on Information
Theory, Toronto, ON, Canada, July 6 - 11, 200
Optimal Node Density for Two-Dimensional Sensor Arrays
The problem of optimal node density for ad hoc sensor networks deployed for
making inferences about two dimensional correlated random fields is considered.
Using a symmetric first order conditional autoregressive Gauss-Markov random
field model, large deviations results are used to characterize the asymptotic
per-node information gained from the array. This result then allows an analysis
of the node density that maximizes the information under an energy constraint,
yielding insights into the trade-offs among the information, density and
energy.Comment: Proceedings of the Fifth IEEE Sensor Array and Multichannel Signal
Processing Workshop, Darmstadt, Germany, July 21 - 23, 200
Large Deviations Analysis for the Detection of 2D Hidden Gauss-Markov Random Fields Using Sensor Networks
The detection of hidden two-dimensional Gauss-Markov random fields using
sensor networks is considered. Under a conditional autoregressive model, the
error exponent for the Neyman-Pearson detector satisfying a fixed level
constraint is obtained using the large deviations principle. For a symmetric
first order autoregressive model, the error exponent is given explicitly in
terms of the SNR and an edge dependence factor (field correlation). The
behavior of the error exponent as a function of correlation strength is seen to
divide into two regions depending on the value of the SNR. At high SNR,
uncorrelated observations maximize the error exponent for a given SNR, whereas
there is non-zero optimal correlation at low SNR. Based on the error exponent,
the energy efficiency (defined as the ratio of the total information gathered
to the total energy required) of ad hoc sensor network for detection is
examined for two sensor deployment models: an infinite area model and and
infinite density model. For a fixed sensor density, the energy efficiency
diminishes to zero at rate O(area^{-1/2}) as the area is increased. On the
other hand, non-zero efficiency is possible for increasing density depending on
the behavior of the physical correlation as a function of the link length.Comment: To appear in the Proceedings of the 2008 IEEE International
Conference on Acoustics, Speech and Signal Processing, Las Vegas, NV, March
30 - April 4, 200
Superallocation and ClusterāBased Cooperative Spectrum Sensing in 5G Cognitive Radio Network
Consequently, the research and development for the 5G systems have already been started. This chapter presents an overview of potential system network architecture and highlights a superallocation technique that could be employed in the 5G cognitive radio network (CRN). A superallocation scheme is proposed to enhance the sensing detection performance by rescheduling the sensing and reporting time slots in the 5G cognitive radio network with a clusterābased cooperative spectrum sensing (CCSS). In the 4G CCSS scheme, first, all secondary users (SUs) detect the primary user (PU) signal during a rigid sensing time slot to check the availability of the spectrum band. Second, during the SU reporting time slot, the sensing results from the SUs are reported to the corresponding cluster heads (CHs). Finally, during CH reporting time slots, the CHs forward their hard decision to a fusion center (FC) through the common control channels for the global decision. However, the reporting time slots for the SUs and CHs do not contribute to the detection performance. In this chapter, a superallocation scheme that merges the reporting time slots of SUs and CHs by rescheduling the reporting time slots as a nonfixed sensing time slot for SUs to detect the PU signal promptly and more accurately is proposed. In this regard, SUs in each cluster can obtain a nonfixed sensing time slot depending on their reporting time slot order. The effectiveness of the proposed chapter that can achieve better detection performance under ā28 to ā10 dB environments and thus reduce reporting overhead is shown through simulations
Satellite Clustering for Non-Terrestrial Networks: Concept, Architectures, and Applications
Recently, mega-constellations with a massive number of low Earth orbit (LEO)
satellites are being considered as a possible solution for providing global
coverage due to relatively low latency and high throughput compared to
geosynchronous orbit satellites. However, as the number of satellites and
operators participating in the LEO constellation increases, inter-satellite
interference will become more severe, which may yield marginal improvement or
even decrement in network throughput. In this article, we introduce the concept
of satellite clusters that can enhance network performance through satellites'
cooperative transmissions. The characteristics, formation types, and
transmission schemes for the satellite clusters are highlighted. Simulation
results evaluate the impact of clustering from coverage and capacity
perspectives, showing that when the number of satellites is large, the
performance of clustered networks outperforms the unclustered ones. The viable
network architectures of the satellite cluster are proposed based on the 3GPP
standard. Finally, the future applications of clustered satellite networks are
discussed.Comment: 7 pages, 7 figures, 1 table, submitted to IEEE Vehicular Technology
Magazin
Reconfigurable Intelligent Surface for Physical Layer Security in 6G-IoT: Designs, Issues, and Advances
Sixth-generation (6G) networks pose substantial security risks because
confidential information is transmitted over wireless channels with a broadcast
nature, and various attack vectors emerge. Physical layer security (PLS)
exploits the dynamic characteristics of wireless environments to provide secure
communications, while reconfigurable intelligent surfaces (RISs) can facilitate
PLS by controlling wireless transmissions. With RIS-aided PLS, a lightweight
security solution can be designed for low-end Internet of Things (IoT) devices,
depending on the design scenario and communication objective. This article
discusses RIS-aided PLS designs for 6G-IoT networks against eavesdropping and
jamming attacks. The theoretical background and literature review of RIS-aided
PLS are discussed, and design solutions related to resource allocation,
beamforming, artificial noise, and cooperative communication are presented. We
provide simulation results to show the effectiveness of RIS in terms of PLS. In
addition, we examine the research issues and possible solutions for RIS
modeling, channel modeling and estimation, optimization, and machine learning.
Finally, we discuss recent advances, including STAR-RIS and malicious RIS.Comment: Accepted for IEEE Internet of Things Journa
Impact of Correlation and Pointing Error on Secure Outage Performance over Arbitrary Correlated Nakagami Turbulent Fading Mixed RF-FSO Channel
Funding Information: Manuscript received September 8, 2020; revised February 11, 2021; accepted February 14, 2021. Date of publication February 16, 2021; date of current version March 10, 2021. This research was supported in part by the National Research Foundation of Korea grant funded by the Korean government (Ministry of Science and ICT; 2019R1A2C1083988), in part by the Ministry of Science and ICT, Korea, under the Information Technology Research Center support program (IITP-2020-2016-0-00313) supervised by the Institute for Information & Communications Technology Planning & Evaluation, and in part by Sejong University through its faculty research program (20212023). (Sheikh Habibul Islam, A. S. M. Badrud-duza, and S. M. R. Islam contributed equally to this work and co-first authors.) Corresponding authors: A. S. M. Badrudduza; Heejung Yu (e-mail: [email protected]; [email protected]).)Peer reviewedPublisher PD
Security at the Physical Layer over GG Fading and mEGG Turbulence Induced RF-UOWC Mixed System
This work was supported in part by the National Research Foundation of Korea grant funded by the Korean Government (Ministry of Science and ICT) under Grant 2019R1A2C1083988, in part by the Ministry of Science and ICT, South Korea, under the Information Technology Research Center Support Program supervised by the Institute for Information and Communications Technology Planning and Evaluation, under Grant IITP-2021-2016-0-00313, and in part by Sejong University through its Faculty Research Program under Grant 20202021.Peer reviewedPublisher PD
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