Cooperative spectrum sensing in cognitive radio networks: A survey

This document provides updates to IEEE Std 802.16's MIB for the MAC, PHY and asso- ciated management procedures in order to accommodate recent extensions to the standard.

IEEE Standard for Local and Metropolitan Area Networks Part 16: Air Interface for Fixed Broadband Wireless Access Systems Draft Amendment: Management Information Base Extensions

The Transmission Control Protocol.

With the rapid deployment of new wireless devices and applications, the last decade has witnessed a growing demand for wireless radio spectrum. However, the fixed spectrum assignment policy becomes a bottleneck for more efficient spectrum utilization, under which a great portion of the licensed spectrum is severely under-utilized. The inefficient usage of the limited spectrum resources urges the spectrum regulatory bodies to review their policy and start to seek for innovative communication technology that can exploit the wireless spectrum in a more intelligent and flexible way. The concept of cognitive radio is proposed to address the issue of spectrum efficiency and has been receiving an increasing attention in recent years, since it equips wireless users the capability to optimally adapt their operating parameters according to the interactions with the surrounding radio environment. There have been many significant developments in the past few years on cognitive radios. This paper surveys recent advances in research related to cognitive radios. The fundamentals of cognitive radio technology, architecture of a cognitive radio network and its applications are first introduced. The existing works in spectrum sensing are reviewed, and important issues in dynamic spectrum allocation and sharing are investigated in detail.

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Advances in cognitive radio networks: A survey

Intelligent reflecting surface (IRS) is an enabling technology to engineer the radio signal propagation in wireless networks. By smartly tuning the signal reflection via a large number of low-cost passive reflecting elements, IRS is capable of dynamically altering wireless channels to enhance the communication performance. It is thus expected that the new IRS-aided hybrid wireless network comprising both active and passive components will be highly promising to achieve a sustainable capacity growth cost-effectively in the future. Despite its great potential, IRS faces new challenges to be efficiently integrated into wireless networks, such as reflection optimization, channel estimation, and deployment from communication design perspectives. In this paper, we provide a tutorial overview of IRS-aided wireless communications to address the above issues, and elaborate its reflection and channel models, hardware architecture and practical constraints, as well as various appealing applications in wireless networks. Moreover, we highlight important directions worthy of further investigation in future work.

Intelligent Reflecting Surface-Aided Wireless Communications: A Tutorial

To achieve efficient authentication on emergency events in vehicular ad hoc networks, we introduce a novel aggregated emergency message authentication (AEMA) scheme to validate an emergency event. We make use of syntactic aggregation and cryptographic aggregation techniques to dramatically reduce the transmission cost, and adopt batch verification technique for efficient emergency messages verification. Compared with existing emergency message authentication approaches, our scheme shows the superiority on generality, enhanced security and efficiency.

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AEMA: An Aggregated Emergency Message Authentication Scheme for Enhancing the Security of Vehicular Ad Hoc Networks

Preface. 1. Introduction. 2. Control and Management Architecture. 3. Routing and Wavelength Assignment (RWA): Overview. 4. Algorithms for Dynamic Routing and Wavelength Assignment. 5. Routing and Wavelength Assignment With Multi-Granularity OXCS. 6. Protection and Restoration. 7. Spare Capacity Allocation. 8. Survivable Routing With Dynamic Traffic. 9. Optical Burst Switching. Appendix A: Loop-Less K-Shortest Paths Algorithm in Directed Graphs. Appendix B: Maximum-Flow Algorithm. Acronyms. Symbols. Glossary. Index.

Optical Networks: Architecture and Survivability

The concept of p-cycle (preconfigured protection cycle) allows fast and efficient span protection in wavelength division multiplexing (WDM) mesh networks. To design p-cycles for a given network, conventional algorithms need to enumerate cycles in the network to form a candidate set, and then use an integer linear program (ILP) to find a set of p -cycles from the candidate set. Because the size of the candidate set increases exponentially with the network size, candidate cycle enumeration introduces a huge number of ILP variables and slows down the optimization process. In this paper, we focus on p-cycle design without candidate cycle enumeration. Three ILPs for solving the problem of spare capacity placement (SCP) are first formulated. They are based on recursion, flow conservation, and cycle exclusion, respectively. We show that the number of ILP variables/constraints in our cycle exclusion approach only increases linearly with the network size. Then, based on cycle exclusion, we formulate an ILP for solving the joint capacity placement (JCP) problem. Numerical results show that our ILPs are very efficient in generating p -cycle solutions.

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ILP formulations for p-cycle design without candidate cycle enumeration

As an emerging application scenario of wireless technologies, vehicular communications have been initiated not only for enhancing the transportation safety and driving experiences, but also for a new commercial market of on-board Internet services. Due to extraordinarily high mobility of vehicles in a vehicular network, frequent handover requests will be a norm, which initiates the demand for an effective and fast authentication scheme that can maintain the service continuity in presence of the frequent handover events. However, previously reported authentication schemes, although with minimized handover latency and packet loss rate, may disclose the location information of the mobile user to the third party, which will seriously violate the location privacy of the user. In this paper, we propose a location privacy preserving authentication scheme based on blind signature in the elliptic curve domain. The scheme cannot only provide fast authentication, but also guarantee the security and location anonymity to the public. To analyze the proposed scheme, a theoretical traceability analysis is conducted, which shows that the probability of tracing an vehicle's route is negligibly small. We will also examine the authentication speed of the scheme, and show that the scheme can satisfy seamless handover for fast moving vehicles.

A Location Privacy Preserving Authentication Scheme in Vehicular Networks

This paper proposes a scalable design for next-generation optical cross-connects (OXCs). We present a novel strategy for dimensioning the switching capability as a long term planning. Switching fabrics in OXCs have to be expanded according to traffic growth, which may incur a scalability problem due to the exponentially increasing cost in manufacturing and maintenance. The proposed scheme expands the switching capacity of OXCs with waveband- and fiber-switching components (or, equivalently, expands the network capacity with waveband- and fiber-switching tiers). To minimize the number of extra fibers for waveband- and fiber-switching tiers required to satisfy a given traffic matrix, we formulate the problem of routing and wavelength assignment (RWA) with tunnel allocation (RWAT) into a constraint programming (CP) process. The CP is simplified as two integer linear programming (ILP) processes that are performed sequentially. Experiments are conducted on four examples to compare the throughput and the number of switching points when different switching architectures are adopted under different traffic increase. The benefits of our approach are demonstrated. Finally, we conclude that the proposed optimization scheme can dimension the networks with expandability and scalability to the growing traffic demand.

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Pin-Han Ho

Papers

AEMA: An Aggregated Emergency Message Authentication Scheme for Enhancing the Security of Vehicular Ad Hoc Networks

Optical Networks: Architecture and Survivability

ILP formulations for p-cycle design without candidate cycle enumeration

A Location Privacy Preserving Authentication Scheme in Vehicular Networks

A scalable design of multigranularity optical cross-connects for the next-generation optical Internet