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NeXt generation/dynamic spectrum access/cognitive Radio Wireless Networks: A Survey

by Ian F. Akyildiz, Won-Yeol Lee, Mehmet C. Vuran, Shantidev Mohanty - COMPUTER NETWORKS JOURNAL (ELSEVIER , 2006
"... Today's wireless networks are characterized by a fixed spectrum assignment policy. However, a large portion of the assigned spectrum is used sporadically and geographical variations in the utilization of assigned spectrum ranges from 15% to 85% with a high variance in time. The limited availabl ..."
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Today's wireless networks are characterized by a fixed spectrum assignment policy. However, a large portion of the assigned spectrum is used sporadically and geographical variations in the utilization of assigned spectrum ranges from 15% to 85% with a high variance in time. The limited available spectrum and the ine#ciency in the spectrum usage necessitate a new communication paradigm to exploit the existing wireless spectrum opportunistically. This new networking paradigm is referred to as NeXt Generation (xG) Networks as well as Dynamic Spectrum Access (DSA) and cognitive radio networks. The term xG networks is used throughout the paper. The novel functionalities and current research challenges of the xG networks are explained in detail. More specifically, a brief overview of the cognitive radio technology is provided and the xG network architecture is introduced. Moreover, the xG network functions such as spectrum management, spectrum mobility and spectrum sharing are explained in detail. The influence of these functions on the performance of the upper layer protocols such as routing and transport are investigated and open research issues in these areas are also outlined. Finally, the cross-layer design challenges in xG networks are discussed.

Technical challenges for cognitive radio in the tv white space spectrum

by Stephen J. Shellhammer, Ahmed K. Sadek, Wenyi Zhang - In Proc. of Information Theory and Applications Workshop , 2009
"... Abstract — The FCC recently issued the regulatory rules for cognitive radio use of the TV white space spectrum. These new rules provide an opportunity but they also introduce a number of technical challenges. The challenges require development of cognitive radio technologies like spectrum sensing as ..."
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Abstract — The FCC recently issued the regulatory rules for cognitive radio use of the TV white space spectrum. These new rules provide an opportunity but they also introduce a number of technical challenges. The challenges require development of cognitive radio technologies like spectrum sensing as well as new wireless PHY and MAC layer designs. These challenges include spectrum sensing of both TV signals and wireless microphone signals, frequency agile operation, geo-location, stringent spectral mask requirements, and of course the ability to provide reliable service in unlicensed and dynamically changing spectrum. After describing these various challenges we will describe some of the possible methods for meeting these challenges. rules provide limits on out-of-band (OOB) emissions which impact the spectral mask of any cognitive radio network using this spectrum. The challenges of this strict spectral mask are described in Section VII. Finally, though not a strict FCC rule, it is important to provide reliable operation in these channels given the unlicensed nature of these cognitive radio devices. The ability to provide reliable operation is critical to the success of any wireless network. The challenges of providing reliable operation in this dynamic spectrum is described in Section VIII.
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CogNet- An Architectural Foundation for Experimental Cognitive Radio Networks within the Future Internet

by Dipankar Raychaudhuri, Narayan B. Mandayam
"... {ray,narayan} @ winlab.rutgers.edu This paper describes a framework for research on architectural tradeoffs and protocol designs for cognitive radio networks at both the local network and the global internetwork levels. Several key architectural issues for cognitive radio networks are discussed, inc ..."
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{ray,narayan} @ winlab.rutgers.edu This paper describes a framework for research on architectural tradeoffs and protocol designs for cognitive radio networks at both the local network and the global internetwork levels. Several key architectural issues for cognitive radio networks are discussed, including control and management protocols, support for collaborative PHY, dynamic spectrum coordination, flexible MAC layer protocols, ad hoc group formation and cross-layer adaptation. The overall goal of this work is the design and validation of the control/management and data interfaces between cognitive radio nodes in a local network, and also between cognitive radio networks and the global Internet. Protocol design and implementation based on this framework will result in the CogNet architecture, a prototype open-source cognitive radio protocol stack. Experimental evaluations on emerging cognitive radio platforms are planned for future work, first in a wireless local-area radio network scenario using wireless testbeds such as ORBIT, and later as part of several end-to-end experiments using a wide-area network testbed such as PlanetLab (and GENI in the future).
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Distributed Coordination Schemes for Multi- Radio Co-existence in Dense Spectrum Environments: An Experimental Study on the ORBIT Testbed

by Xiangpeng Jing, Shanmuga S An, Mesut Ali Ergin, Ivan Seskar, Dipankar Raychaudhuri
"... Abstract—This paper presents an experimental study on the spectrum coexistence 1 problems between multi-radio platforms in dense-radio physical world environments. Computing and communication devices such as laptops and cellular phones with multiple radios including WiFi, Bluetooth, UWB, WiMax and Z ..."
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Abstract—This paper presents an experimental study on the spectrum coexistence 1 problems between multi-radio platforms in dense-radio physical world environments. Computing and communication devices such as laptops and cellular phones with multiple radios including WiFi, Bluetooth, UWB, WiMax and Zigbee in a small conference room face significant interference problems. A realistic small office/home office (SOHO) scenario with ~10-25 multi-radio platforms is mapped onto the ORBIT radio grid testbed, and system throughput results are obtained experimentally, demonstrating significant degradation due to inter-platform interference. The CSCC (Common Spectrum Coordination Channel) protocol proposed in earlier work is used as the basis for implementing a set of distributed spectrum coexistence algorithms intended to improve system performance. Detailed results from ORBIT testbed experiments are given for the proposed CSCC-based distributed spectrum coordination algorithms. The results show significant performance gains due to CSCC coordination, typically achieving ~2x improvement in system throughput for WiFi/Bluetooth dual radio scenarios. Keywords-Multi-radio coexistence; Distributed spectrum coordination; CSCC; ORBIT I.
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Cognitive UWB-OFDM: Pushing ultrawideband beyond its limit via opportunistic spectrum usage

by Hüseyin Arslan, Mustafa E. Şahin - Journal of Communication and Networks , 2006
"... In a continuously expanding wireless world, the number of ra-dio systems increases every day, and efficient spectrum usage be-comes a more significant requirement. Ultrawideband (UWB) and cognitive radio are two exciting technologies that offer new ap-proaches to the spectrum usage. The main objecti ..."
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In a continuously expanding wireless world, the number of ra-dio systems increases every day, and efficient spectrum usage be-comes a more significant requirement. Ultrawideband (UWB) and cognitive radio are two exciting technologies that offer new ap-proaches to the spectrum usage. The main objective of this paper is to shed the first light on the marriage of these two important approaches. The strength of orthogonal frequency division multi-plexing (OFDM) based UWB in co-existing with licensed systems is investigated. The opportunity concept is defined, and the require-ments of the opportunistic spectrum usage are explained. It is pro-posed to take the UWB-OFDM from the current underlay imple-mentation, and evolve it to a combined underlay and opportunistic spectrum usage technology, leading to cognitive UWB-OFDM. This way, we aim at making UWB more competitive in the wireless mar-ket with extended range, higher capacity, better performance, and a wide variety of applications.
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CogNet - an architecture for experimental cognitive radio networks within the future internet

by Dipankar Raychaudhuri, Narayan B. M, Joseph B. Evans, Benjamin J. Ewy, Srini Seshan, Peter Steenkiste - In Proc. of MobiArch , 2006
"... Abstract — CogNet is an architectural framework for research into architectural tradeoffs and protocol design approaches for cognitive radio networks at both local network and the global internetwork levels. The framework provides facilities for the evaluation of a number of architectural issues inc ..."
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Abstract — CogNet is an architectural framework for research into architectural tradeoffs and protocol design approaches for cognitive radio networks at both local network and the global internetwork levels. The framework provides facilities for the evaluation of a number of architectural issues including control and management protocols, support for collaborative PHY, dynamic spectrum coordination, flexible MAC layer protocols, ad hoc group formation and cross-layer adaptation. This architectural effort is intended to lead to the design of control/management and data interfaces between cognitive radio nodes in a local network, and also between cognitive radio subnetworks and the global Internet. Future work in protocol design and implementation based on this architecture will result in a prototype open-source cognitive radio protocol (the CogNet stack) and extensive experimental evaluations on emerging cognitive radio platforms, first in a wireless local-area radio network scenario with moderate numbers of cognitive radio nodes, and later as part of several end-to-end experiments using a wide-area network testbed such as PlanetLab (and GENI in the future). R I.
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Addressing the hidden terminal problem for heterogeneous coexistence between TDM and CSMA networks in white space

by Kaigui Bian, Jung-min “jerry Park, Senior Member, Lin Chen, Xiaoming Li, Senior Member - IEEE Transactions on Vehicular Technology , 2014
"... Abstract—Cognitive radio (CR) technologies have led to sev-eral wireless standards (e.g., IEEE 802.11af and IEEE 802.22) that enable secondary networks to access the TV white-space (TVWS) spectrum. Different unlicensed wireless technologies with different PHY/MAC designs are expected to coexist in t ..."
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Abstract—Cognitive radio (CR) technologies have led to sev-eral wireless standards (e.g., IEEE 802.11af and IEEE 802.22) that enable secondary networks to access the TV white-space (TVWS) spectrum. Different unlicensed wireless technologies with different PHY/MAC designs are expected to coexist in the same TVWS spectrum—we refer to such a situation as heterogeneous coexistence. The heterogeneity of the PHY/MAC designs of the coexisting CR networks can potentially exacerbate the hidden terminal problem. This problem cannot be addressed by the conventional handshaking/coordination mechanism be-tween two homogeneous networks employing the same radio access technology (RAT). In this paper, we present a coexistence protocol, called Spectrum Sharing for Heterogeneous Coexistence (SHARE), that mitigates the hidden terminal problem for the coexistence between two types of networks: one that employs a TDM-based MAC protocol and one that employs a CSMA-based MAC protocol. Specifically, SHARE utilizes beacon transmissions and dynamic quiet periods to avoid packet collisions caused by the hidden terminals. Our analytical and simulation results show that SHARE reduces the number of packet collisions and guarantees weighted-fairness in partitioning the spectrum among the coexisting secondary networks. I.
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Review Cognitive radio technology: From distributed spectrum coordination to adaptive network collaborationI

by Dipankar Raychaudhuria, Xiangpeng Jinga, Ivan Seskara, Khanh Lea, Joseph B. Evansb , 2008
"... This paper presents an integrated view of cognitive radio technologies for efficient wireless services in dense spectrum environments. The rationale for cognitive radio based systems is discussed, leading to an identification of the available design space that ranges from reactive interference avoid ..."
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This paper presents an integrated view of cognitive radio technologies for efficient wireless services in dense spectrum environments. The rationale for cognitive radio based systems is discussed, leading to an identification of the available design space that ranges from reactive interference avoidance to spectrum etiquette and eventually network collaboration. After reviewing prior work in the dynamic spectrum area, a specific distributed spectrum etiquette protocol called “common spectrum coordination channel (CSCC) ” is introduced. Performance gains achieved with CSCC relative to simpler reactive time/frequency/power control algorithms are evaluated for example in WiFi/Bluetooth and WiFi/WiMax co-existence scenarios. The next level of system performance can be achieved through opportunistic collaboration between radios to form ad hoc multi-hop networks in which neighboring nodes associate with each other at high bit-rate and low power. Adaptive wireless networks of this type will require new protocol architectures which integrate flexible PHY/MAC and cross-layer capabilities with ad hoc network discovery and multi-hop routing. A specific “CogNet ” protocol architecture based on the concept of a “global control plane (GCP) ” is described. Major CogNet protocol modules for bootstrapping, discovery, data path setup and naming/addressing are outlined, and representative ns-2 simulation results are provided for validation. In conclusion, the paper gives a preview of the network-centric WiNC2R prototype under development at WINLAB as an experimental cognitive radio platform.
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ABSTRACT OF THE THESIS Distributed Spectrum Coordination for Multi-Radio Platform Co-Existence: An Experimental Study on the Orbit Testbed

by Sundaram Anandaraman, Sundaram Anandaraman, D. Raychaudhuri , 2008
"... and approved by ..."
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and approved by
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Simultaneous Operation of Multiple Collocated Radios and the Scanning Problem

by Michel Barbeau
"... Abstract—Simultaneous operation of multiple collocated radios refers to the capability of a wireless device to operate at the same time into several modes, standards and frequencies. For instance, most of the mobile phones are able and try to operate in multiple modes. Each wireless communication un ..."
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Abstract—Simultaneous operation of multiple collocated radios refers to the capability of a wireless device to operate at the same time into several modes, standards and frequencies. For instance, most of the mobile phones are able and try to operate in multiple modes. Each wireless communication unit is called a radio interface. The software defined radio technology facilitates the integration and simultaneous operation of several radio interfaces in the same hardware device. Simultaneous operation produces interference and hardware conflicts, which can be addressed using a turn-based model. Each radio interface operates periodically for an interval of time. In this paper, the focus is on one radio interface that operates periodically for a short interval of time. The radio interface scans channels to uncover beacons periodically sent by transmitters. The goal of the scanning activity is to uncover the beacons within the shortest possible time. We call this the scanning problem. We model and compare four strategies to solve the scanning problem: sequential scanning, sliding-window scanning, pseudo-concurrent scanning and truly-concurrent scanning. I.
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