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Database access strategy for TV white space cognitive radio networks
- in SECON ’14: Proc. of the IEEE International Conference on Sensing, Communication, and Networking
"... Abstract—Very recently, city administrations launched TV White Space wireless networks to enable the smart city paradigm. These initiatives leverage the possibility allowed by regulations of unlicensed access to the TV White Space spectrum. All theses rulings rely on a periodic access to a database ..."
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Abstract—Very recently, city administrations launched TV White Space wireless networks to enable the smart city paradigm. These initiatives leverage the possibility allowed by regulations of unlicensed access to the TV White Space spectrum. All theses rulings rely on a periodic access to a database service as the primary mechanism for the unlicensed users to determine the White Space availability. Nevertheless, the specifics of such a mechanism are yet to be determined. In this paper, we address this issue by designing a database access strategy that allows unlicensed users to: i) respect the requirements imposed by the existing rulings; ii) maximize the expected communication opportunities provided by the TV White Space through the on-demand database accesses. To this aim, we prove the database access problem can be modeled as a Markov Decision Process and we provide the closed-form expressions of the transition probabilities. The analytical results are finally validated through simulations.
Joint optimal rate, power, and spectrum allocation in multi-hop cognitive radio networks
- in Proc. IEEE ICC
, 2012
"... Abstract—Interference due to the sharing of common spec-trum band among links and congestion due to the contention among flows sharing the same link have become obstacles to good performance in wireless networks, especially in multi-hop cognitive radio networks (MHCRNs). Consequently, the high end-t ..."
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Abstract—Interference due to the sharing of common spec-trum band among links and congestion due to the contention among flows sharing the same link have become obstacles to good performance in wireless networks, especially in multi-hop cognitive radio networks (MHCRNs). Consequently, the high end-to-end throughput for MHCRNs calls for a framework of cross-layer optimization design. In this paper, by taking into account the problem of joint optimal rate, power, and spectrum allocation (JORPS), we propose a new cross-layer optimization framework for MHCRNs under spectrum underlay manner using orthogonal frequency division multiple access (OFDMA). The formulation is shown to be a mix-integer non-linear non-convex optimization problem, which is
An Overview of WLAN Performance, Some Important Case-Scenarios and their Associated Models
"... Abstract—The study of the 802.11 standard has been very intense for more than a decade now. Several works have striven at understanding its performance, even in the simplest topology of a wireless local area network (WLAN) with a single access point (AP). The present survey is an effort to classify ..."
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Abstract—The study of the 802.11 standard has been very intense for more than a decade now. Several works have striven at understanding its performance, even in the simplest topology of a wireless local area network (WLAN) with a single access point (AP). The present survey is an effort to classify and present the enormous literature on the subject into several important case-scenarios, and summarizes the current understanding of WLAN performance. The resulting performance and associated models are discussed (and sometimes extended) and simulation results are used to illustrate them. We also highlight interesting open research problems that we believe the community should address. I.
EURASIP Journal on Wireless Communications and
"... Networking and is made available as an electronic reprint ..."
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"... Key Words: CR, TVWS, geo-location database, wideband compressive spectrum sensing, database regulations Cognitive radio (CR) technology based on geo-location database access approach and/or wideband spectrum sensing approach is absolutely vital in order to recognize available frequency bands in whit ..."
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Key Words: CR, TVWS, geo-location database, wideband compressive spectrum sensing, database regulations Cognitive radio (CR) technology based on geo-location database access approach and/or wideband spectrum sensing approach is absolutely vital in order to recognize available frequency bands in white spaces (WSs), and efficiently utilize shared spectrums. This paper presents a new structure for the TVWS database access protocol implementation based on Internet Engineering Task Force (IETF) Protocol to Access WS database (PAWS). A wideband compressive spectrum sensing (WCSS) scheme using a modulated wideband converter is also proposed for the TVWS utilization. The developed database access protocol technology which is adopted in both the TV band device (TVBD) and the TVWS database operates well in the TV frequency bands. The proposed WCSS shows a stable performance in false alarm probability irrespective of noise variance estimation error as well as provides signal detection probabilities greater than 95%. This paper also investigates Federal Communications Commision (FCC) regulatory requirements of TVWS database as well as European Telecommunications Standards Institute (ETSI) policy related to TVWS database. A standardized protocol to achieve interoperability among
Social Optimization and Pricing Policy in Cognitive Radio Networks with an Energy Saving Strategy
"... The rapid growth of wireless application results in an increase in demand for spectrum resource and communication energy. In this paper, we firstly introduce a novel energy saving strategy in cognitive radio networks (CRNs) and then propose an appropriate pricing policy for secondary user (SU) pack ..."
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The rapid growth of wireless application results in an increase in demand for spectrum resource and communication energy. In this paper, we firstly introduce a novel energy saving strategy in cognitive radio networks (CRNs) and then propose an appropriate pricing policy for secondary user (SU) packets. We analyze the behavior of data packets in a discrete-time singleserver priority queue under multiple-vacation discipline. With the help of a Quasi-Birth-Death (QBD) process model, we obtain the joint distribution for the number of SU packets and the state of base station (BS) via the Matrix-Geometric Solution method. We assess the average latency of SU packets and the energy saving ratio of system. According to a natural reward-cost structure, we study the individually optimal behavior and the socially optimal behavior of the energy saving strategy and use an optimization algorithm based on standard particle swarm optimization (SPSO) method to search the socially optimal arrival rate of SU packets. By comparing the individually optimal behavior and the socially optimal behavior, we impose an appropriate admission fee to SU packets. Finally, we present numerical results to show the impacts of system parameters on the system performance and the pricing policy.
RESEARCH Open Access
"... Spectrum sensing with spatial signatures in the presence of noise uncertainty and shadowing Sadiq Ali*, Gonzalo Seco-Granados and José A López-Salcedo In this paper, we consider a system of cognitive radios that collaborate with each other with the aim of detecting the random waveforms being emitted ..."
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Spectrum sensing with spatial signatures in the presence of noise uncertainty and shadowing Sadiq Ali*, Gonzalo Seco-Granados and José A López-Salcedo In this paper, we consider a system of cognitive radios that collaborate with each other with the aim of detecting the random waveforms being emitted from licensed users. We study the problem of fusing the statistics from collaborating sensors, assuming that they send their statistics to a base station, where the final decision is made. The main contribution of this work is the derivation of a cognitive detector based on the generalized likelihood ratio test and the use of spatial signatures, a novel concept that allows the detector to capture the spatial correlation inherently embedded in measurements coming from neighboring sensors. The problem is formulated in terms of a model order detection problem, where a set of active and inactive sensors can be distinguished, thus allowing the detector to operate with a rank-reduced version of the observed covariance matrix. Since the estimation of this matrix may be a challenge in large-scale networks, we study the application of shrinkage techniques to cope with the problem of having more sensors than available observations. Finally, we analyze the performance of the proposed detection scheme in the presence of log-normal shadowing effects and noise power uncertainties, the latter due to presence of interferences. For the proposed detector, numerical results are drawn, showing a significant gain in performance compared to traditional approaches. 1
Research Challenges
"... Cognitive radio technology gets much attention of wireless network research environments as a new way to utilize the precious spectrum efficiently. IEEE 802.22, Wireless Regional Area Network, is the first international standard based on cognitive radio technology which intends to provide broadband ..."
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Cognitive radio technology gets much attention of wireless network research environments as a new way to utilize the precious spectrum efficiently. IEEE 802.22, Wireless Regional Area Network, is the first international standard based on cognitive radio technology which intends to provide broadband access by utilizing unused TV channels, also known as TV white spaces. This standard provides PHY and MAC layers functionalities in an infrastructure-based wireless access network. In this article, we describe overview of 802.22 standard from MAC perspective and discuss research challenges related to it. We mainly discuss for two research issues, QoS and coexistence. 1.
