ALBERT

Description: Mobile broadband services have expanded considerably in recent years, driving operators to improve and densify their radio access network (RAN). It has become clear that small cells as well as macrocells must be included in a heterogeneous network, due to the scale of densification required. In order to maximize the end user experience, some level of radio coordination between these small and macrocells is needed ?? this coordination will be signaled across a mobile backhaul network. Mobile backhaul typically refers to the network between the base station site and the network controller site, but can also include interconnection between base station sites. Mobile backhaul includes a spectrum of networks and network technologies, including the RAN and core networks. There is considerable market interest on the development of small cell backhaul solutions that are an evolution of existing backhaul networks. Packet synchronisation mechanisms that are being developed are key to support the mobile backhaul application. Various standards bodies such as the Next Generation Mobile Networks Alliance (NGMN), Small Cell Forum (SCF), Metro Ethernet Forum (MEF), and Broadband Forum (BBF) are also studying what the implications would be on their defined mobile backhaul network architectures.

Description: In this article, we introduce the EstiNet OpenFlow network simulator and emulator, and present its support for testing the functions and evaluating the performances of software-defined networks?? OpenFlow controller??s application programs. EstiNet uses an unique kernel reentering simulation methodology to enable unmodified real applications to run on nodes in its simulated network. As a result, without any modification, real NOX/POX or Floodlight OpenFlow controllers can readily run on a host in an EstiNet simulated network to control thousands of simulated OpenFlow switches. EstiNet has the characteristics of a simulator and an emulator at the same time. It combines the advantages of the simulation and emulation approaches without their respective shortcomings. EstiNet uses real OpenFlow controller programs, real network application programs, and the real TCP/IP protocol stack in the Linux kernel to generate correct, accurate, and repeatable SDN application performance results. In this article, we compare EstiNet with ns-3 and Mininet regarding their capabilities, performance, and scalability.

Description: This article discusses novel wireless and optical technologies to address the radical new challenges of small cell mobile backhaul (MBH). Specifically, we examine 60 GHz and 70??80 GHz millimeter-wave technologies for high-capacity last mile and pre-aggregation backhaul, and orthogonal frequency-division multiple access passive optical networks as the optical technology complement for enabling flexible cost-efficient hybrid backhaul coverage. Flexible high-capacity hybrid millimeter wave/optical MBH network operation is next verified via network simulations in the context of a demanding, urban small-cell backhaul application. Finally, a novel software defined networking tool called the backhaul resource manager is introduced for automated dynamic resource provisioning and capacity-aware path computation that improves fairness, network utilization and end-to-end user quality of experience. The introduction of the novel wireless, optical, and software-defined technologies thus has the potential to truly revolutionize the future MBH network.

Description: In this article we discuss different technology alternatives for small cell backhaul, and we present high-frequency microwave technology as a very interesting alternative for wireless backhauling of small cells. In fact, we demonstrate that high-frequency microwave technology can be used for NLOS wireless backhauling of small cells, which opens up new applications for microwave technology. We discuss urban NLOS channel propagation at high frequencies, and we show both measurement and simulation results to validate the use of high-frequency microwave technology for NLOS small cell backhaul.

Description: Currently, online social networks such as Facebook, Twitter, Google+, LinkedIn, and Foursquare have become extremely popular all over the world and play a significant role in people??s daily lives. People access OSNs using both traditional desktop PCs and new emerging mobile devices. With more than one billion users worldwide, OSNs are a new venue of innovation with many challenging research problems. In this survey, we aim to give a comprehensive review of state-of-the-art research related to user behavior in OSNs from several perspectives. First, we discuss social connectivity and interaction among users. Also, we investigate traffic activity from a network perspective. Moreover, as mobile devices become a commodity, we pay attention to the characteristics of social behaviors in mobile environments. Last but not least, we review malicious behaviors of OSN users, and discuss several solutions to detect misbehaving users. Our survey serves the important roles of both providing a systematic exploration of existing research highlights and triggering various potentially significant research in these topics.

Description: Spectrum sharing potentially holds the promise of solving the emerging spectrum crisis. However, technology innovators face the conundrum of developing spectrum sharing technologies without the ability to experiment and test with real incumbent systems. Interference with operational incumbents can prevent critical services, and the cost of deploying and operating an incumbent system can be prohibitive. Thus, the lack of incumbent systems and frequency authorization for technology incubation and demonstration has stymied spectrum sharing research. To this end, industry, academia, and regulators all require a test facility for validating hypotheses and demonstrating functionality without affecting operational incumbent systems. This article proposes a four-phase program supported by our spectrum accountability architecture. We propose that our comprehensive experimentation and testing approach for technology incubation and demonstration will accelerate the development of spectrum sharing technologies.

Description: One of the IEEE's current membership priorities is India. As of July, India has 39,814 IEEE members, the highest in any country outside of the United States. India has 11 sections. The number of student members is very large. However, retaining them after graduation is not a success story, and this is where the sections in India become involved. Recognizing the large number of IEEE Members and an active volunteer base, the IEEE India Office was opened in 2010 in Bangalore. It is poised to see further expansion. The office helps IEEE to continue its outreach efforts to representatives from academic, government, and industry, and explore additional business opportunities in India. The office encourages India's participation in global standards developments and promotes the IEEE Computer Society's software development certificate program. It also promotes continuing education and accreditation programs. These and the India sections' Communications Society (ComSoc) activities are briefly summarized.

Description: Provides a notice of upcoming conference events of interest to practitioners and researchers.

Description: Reviews the FSW SIGNAL AND SPECTRUM ANALYZER (by Rohde & Schwarz); The VECTOR SIGNAL GENERATOR SERIES (by Stanford Research Systems, Inc.); a BALANCED PHOTODETECTOR WITH 70 GHZ 3DB BANDWIDTH (from u 2 t Photonics AG); and SMALL CELL RF FORMAT FRONT-END SOLUTIONS (from Avago Technologies).

Description: In recent years, large-scale data centers have continued to be built out as the global Internet traffic has grown exponentially. These include both multi-tenant carrier-neutral ones and private data centers, and host many Internet application servers.

Description: Data center and cloud architectures continue to evolve to address the needs of large-scale multi-tenant data centers and clouds. These needs are centered around seven dimensions: scalability in computing, storage, and bandwidth, scalability in network services, efficiency in resource utilization, agility in service creation, cost efficiency, service reliability, and security. This article focuses on the first five dimensions as they pertain to networking. Large data centers are targeting support for tens of thousands of servers, exabytes of storage, terabits per second of traffic, and tens of thousands of tenants. In a data center, server and storage resources are interconnected with packet switches and routers that provide for the bandwidth and multi-tenant virtual networking needs. Data centers are interconnected across the wide area network via routing and transport technologies to provide a pool of resources, known as the cloud. High-speed optical interfaces and dense wavelength-division multiplexing optical transport are used to provide for high-capacity transport intra- and inter-datacenter. This article reviews various switching, routing, and optical transport technologies, and their applicability in addressing the networking needs of large-scale multi-tenant data centers.

Description: Six products are announced.

Description: This article surveys recent work in optical switching technologies and presents a fast optical circuit switch that intimately integrates the control electrics at the chip level using a novel wafer-scale heterogeneous integration technique.

Description: Intra-data-center traffic is estimated to be about four times global Internet traffic and is continuously increasing. Applying optical switching to data center networks will increase network bandwidth and reduce power consumption while meeting the traffic requirements. One of the major attributes of the optical switch must be scalability. The wavelength routing switch is a promising technology for the development of 1000 ?? 1000 scale large port count optical switches. Recent advances are demonstrated.

Description: Mega data centers and their interconnection networks have drawn great attention in recent years because of the rapid public adoption of cloud-based services. The unprecedented amount of data that needs to be communicated between data centers imposes new requirements and challenges to inter-data-center optical networks. In this article, we discuss the traffic growth trends and capacity demands of Google??s inter-data-center network, and how they drive the network architectures and technologies to scale capacities and operational ease on existing fiber plants. We extensively review recent research findings and emerging technologies, such as digital coherent detection and the flexgrid dense wavelength-division multiplexed channel plan, and propose practical implementations, such as C+L-band transmission, packet and optical layer integration, and a software-defined networking enabled network architecture for both capacity and operational scaling. In addition, we point out a few critical areas that require more attention and research to improve efficiency and flexibility of an inter-data-center optical network: optical regeneration, data rate mismatch between Ethernet and optical transport, and real-time optical performance monitoring.

Description: This article addresses the synchronization needs for mobile backhaul networks when deploying LTE small cells. Existing synchronization solutions for both FDD and TDD macro networks are discussed as well as the applicability of those solutions to small cells deployed in LTE TDD and LTE FDD networks. The benefits of using radio coordination features in a small cell environment and the corresponding demands placed on synchronization solutions are highlighted. Potential issues relating to synchronization of small cells are also discussed, and some additional synchronization solutions are proposed to address those issues.

Description: ompted me to reflect on ComSoc accomplishments over recent years. Consequently, I thought it would be interesting to review some pertinent published material reflecting on contributions of the six most recent Past Presidents, beginning with 2000, and running through to the end of the term of Byeong Gi Lee in 2011. Finding this material was actually easy, as the ComSoc Presidents have traditionally published a column each month in IEEE Communications Magazine. Generally, these columns were co-authored with the Vice Presidents, Directors, Committee Chairs and other contributors, providing an opportunity to share and highlight their accomplishments.

Description: As the number of wireless users and per-user bandwidth demands continue to increase, both the vendor and carrier communities agree that wireless networks must evolve toward more dense deployments. So-called heterogeneous networks are a commonly proposed evolution, whereby existing macrocellular networks are supplemented with an underlay of small cells. The placement of new small-cell sites is typically determined based on various location-dependent factors such as radio propagation calculations, user densities, and measurements of congestion and demand. The backhaul network, which can account for a significant portion of the total cost of the deployment, is then designed in reaction to the placement of small cells. In contrast, we describe a design method that first considers the locations of existing fibered and powered facilities that might be leveraged to provide inexpensive backhaul. Naturally, such a method is only feasible if the carrier has a legacy local fiber network. This article describes an efficient fiber backhaul strategy for a small-cell network, which leverages facilities associated with an existing FTTN residential access network. Once potential small-cell sites are determined from among all FTTN remote terminals, optimization techniques are used to choose the most efficient subset of sites for maximum coverage, and to design the fiber backhaul architecture.

Description: Warehouse-scale data center operators need much-higher-bandwidth intra-data center networks (DCNs) to sustain the increase of network traffic due to cloud computing and other emerging web applications. Current DCNs based on commodity switches require excessive amounts of power to face this traffic increase. Optical intra-DCN interconnection networks have recently emerged as a promising solution that can provide higher throughput while consuming less power. This article provides an update on recent developments in the field of ultra-highcapacity optical interconnects for intra-DCN communication. Several recently proposed architectures and technologies are examined and compared, while future trends and research challenges are outlined.

Description: The ubiquitous Ethernet has great potential to become an easy-to-install cost-effective backhaul solution for mobile small cells. However, limited Ethernet bandwidth is a practical constraint. Not only is small cell capacity limited by Ethernet bandwidth, but also the synchronization between cells can be substantially compromised. In this article we discuss small cells with Ethernet backhaul, focusing on two practical and important aspects: backhaul bandwidth requirements and tolerance to synchronization errors. The aspects become challenging in indoor small cell applications where the cells need to cooperatively suppress strong interference, producing a large amount of backhaul traffic. To address the challenges, we introduce a new distributed scheme of cooperative small cells over Ethernet. Exploiting a soft information combining technique, the scheme allows the signals of cooperative cells to be combined at aggregate switches along their backhaul paths, reducing backhaul traffic in Ethernet and distributing computational complexity. Our case study shows that the distributed scheme can reduce small cell backhaul traffic by 64 percent, compared to a conventional centralized approach. It is also tolerant to a large frequency error of ??4.6 ppm in a ??freerun?? state where synchronization is lost. Given the substantially reduced backhaul traffic, the new distributed scheme is able to support three times the cooperative small cells of the conventional centralized approach.

Description: Among the received eight submissions from the last call, we have accepted four of them, with one from academia, one from a national laboratory, one from industry, and one from a combined team of academia and industry. At the time of writing this editorial for these four articles, we have also finished the first-round review process of the next batch of nine submissions, and shall move to the second-round review process. Most accepted papers received the decision of major revision in the first-round review and needed to go through the second-round review. The number of submissions remains stable, and we should be able to pick at least one from product vendors, test laboratories, and test equipment vendors, which gives enough industrial flavor to this Series. The due dates remain June 1 and December 1 each year.

Description: A large body of research has recently addressed the channel assignment problem in multi-radio wireless mesh networks. In order to reduce interference, many proposals require radio interfaces to (more or less frequently) switch channels to exploit the availability of multiple orthogonal channels. However, such proposals have been almost exclusively evaluated by means of simulations and the impact of switching channels on the network performance has not been experimentally evaluated so far. In this article, we aim to fill such a gap and present the results of a thorough experimental campaign we conducted on the ORBIT wireless testbed to study the effects of switching channels in a multiradio wireless mesh network. Our experiments show that in common scenarios a channel switch causes a non-negligible interruption in the connectivity among nodes, which is on the order of 10 seconds. Also, our tests reveal that a rapid recovery from link failures caused by channel switches is prevented by a rather slow update of the advertised link quality. Inspired by the analysis of the experiments we conducted, we also propose and evaluate a preliminary technique to reduce the interruption in the delivery of packets caused by a channel switch.

Description: Circuit Switched Fallback (CSFB) is the most commonly used method to support voice services over Long Term Evolution (LTE) networks today, as the deployment of IP Multimedia Subsystem (IMS) is still in its infancy. In this article, we discuss the performance of CSFB voice traffic redirection from LTE to UMTS using data from live commercial networks. The key factors impacting CSFB call setup delay are highlighted. Data from multiple cell geometries including stationary and mobility conditions are presented for Mobile Originated (MO) calls towards landlines, Mobile Terminated (MT) calls from landlines and Mobile-to-Mobile (M2M) CSFB calls. Analysis results in well optimized deployments show that on an average, MO/MT call-setup time for CSFB from LTE to UMTS is around 1 sec greater than legacy UMTS. However, the results can vary depending on the network configuration and the conditions of the measurement. To illustrate the optimization of CSFB performance in real networks, we also highlight the principal call set up optimization and implementation factors impacting CSFB call setup delay and success rates. This article demonstrates that in well optimized networks, CSFB to UMTS call setup success rates can be very close to those achieved in the legacy UMTS systems.

Description: The evolution of centralized radio access networks is discussed from a pragmatic perspective, taking into account the network and radio requirements. The use of wavelength-division multiplexing technology to support this evolution is proposed, and the opportunities for network operators in terms of operational cost, energy efficiency, reuse of already deployed infrastructures, and network convergence are discussed.

Description: Listing of the advertisers represented in this issue.

Description: The December page is devoted to IEEE Communications Society Awards and the Awards Committee that receives the nominations and processes them to identify the recipients. ComSoc Awards are meant to honor colleagues who in some ways, either via scientific/technical contributions or exemplary services, have reached significant, widely recognized achievements in our telecommunications community. Owing to their high significance and value, they need to be awarded through a fair and transparent process, and this is the essential, yet difficult and heavy task of the Awards Committee. It is my pleasure to introduce Lajos Hanzo, the Chair of the IEEE Communications Society Awards Committee, who will describe the awards and the procedure followed by the Awards Committee.

Description: Presents the front cover for this issue of the publication.

Description: Cellular phone networks are often paralyzed after a disaster, as damage to fixed infrastructure, loss of power, and increased demand degrade coverage and quality of service. To ensure disaster victims and first responders have access to reliable local and global communication, we propose EmergeNet, a portable, rapidly deployable, small-scale cellular network. In this article, we describe EmergeNet, which addresses the challenges of emergency and disaster areas. EmergeNet provides free voice calling and text messaging within a disaster area, and enables users of unmodified GSM handsets to communicate with the outside world using the Skype VoIP network. We evaluate EmergeNet???s ability to provide robust service despite high load, limited bandwidth, and software or hardware failures. EmergeNet is uniquely well suited to providing reliable, fairly allocated voice and text communication in emergency and disaster scenarios.

Description: A wireless sensor network is liable to suffer faults for several reasons, which include faulty nodes or even the fact that nodes have been destroyed by a natural disaster, such as a flood. These faults can give rise to serious problems if WSNs do not have a reconfiguration mechanism at execution. It should be noted that many WSNs designed to detect natural disasters are deployed in inhospitable places and depend on multihop communication to allow the data to reach a sink node. As a result, a fault in a single node can leave a part of the system inoperable until the node recovers from this failure. In light of this, this article outlines a solution that entails employing unmanned aerial vehicles to reduce the problems arising from faults in a sensor network when monitoring natural disasters like floods and landslides. In the solution put forward, UAVs can be transported to the site of the disaster to mitigate problems caused by faults (e.g., by serving as routers or even acting as a data mule). Experiments conducted with real UAVs and with our WSN-based prototype for flood detection (already deployed in S??o Carlos, State of S??o Paulo, Brazil, have proven that this is a viable approach.

Description: The last 15 years have heralded many developments and advances in consumer communications, from early developments of device-specific challenges in interoperability and configuration that are well captured by the concept of plug and play to a more recent emphasis on mobility and service personalization. The one constant technical challenge, and to a great extent a business success, is home networking in its many forms. There is not a modern home without some variant of a set-top box. The three articles in this issue provide a good overview of current and topical requirements in consumer communications.

Description: With the ratification of the IEEE 802.11ad amendment to the 802.11 standard in December 2012, a major step has been taken to bring consumer wireless communication to the millimeter wave band. However, multi-gigabit-per-second throughput and small interference footprint come at the price of adverse signal propagation characteristics, and require a fundamental rethinking of Wi-Fi communication principles. This article describes the design assumptions taken into consideration for the IEEE 802.11ad standard and the novel techniques defined to overcome the challenges of mm-Wave communication. In particular, we study the transition from omnidirectional to highly directional communication and its impact on the design of IEEE 802.11ad.

Description: Although it performs an increasingly important role in our lives, the home network remains a bit of a mystery when end users wish to know what is ???happening on the inside.??? This article introduces Homenet3D, an open source project that allows users to view their home network???s state as objects in 3D space within a web browser window. Homenet3D maps quantitative state to the shape, size, spin, bounce, and/or color of selected objects to qualitatively communicate what is happening on the network. We describe our Homenet3D implementation for routers running OpenWRT, and discuss the potential for visualizing multirouter/ multi-subnet home networks.

Description: Millimeter-wave communication is one way to alleviate the spectrum gridlock at lower frequencies while simultaneously providing high-bandwidth communication channels. MmWave makes use of MIMO through large antenna arrays at both the base station and the mobile station to provide sufficient received signal power. This article explains how beamforming and precoding are different in MIMO mmWave systems than in their lower-frequency counterparts, due to different hardware constraints and channel characteristics. Two potential architectures are reviewed: hybrid analog/digital precoding/combining and combining with low-resolution analog- to-digital converters. The potential gains and design challenges for these strategies are discussed, and future research directions are highlighted.

Description: Virtual traffic lights (VTL) is a new technology that holds the promise of revolutionizing traffic control in urban areas. The original VTL idea was based on 100 percent penetration of VTL technology. In this article, contrary to conventional wisdom, it is shown that 100 percent penetration is not a necessary condition for deploying VTL technology as it can be implemented with partial or low levels of penetration. Furthermore, based on game-theoretic arguments, it is shown that the adoption of VTL technology can be accelerated by providing incentives to vehicles equipped with VTL technology.

Description: Cognitive radio technology allows the reuse of the underutilized frequency spectrum on an opportunistic and non-interfering basis by means of introducing, besides the legitimate primary users of the spectrum, a new kind of users called cognitive or secondary users. Thus, reliable spectrum sensing is critical to dynamically detect available licensed frequency bands and mitigate the primary signals, but it remains realistically difficult to carry out. In fact, although distributed collaborative sensing has turned out to be fruitful for the cognitive radio environment, its accuracy is often affected by the selfish and autonomous behavior of users. In this article, we model distributed spectrum sensing and channel allocation as a non-cooperative game, and apply the minority game to bring forth and study the cooperative behavior of users. The novelty brought by our study consists of alleviating the number of users contending for primary channels by giving them the opportunity to choose between the two, either sensing the channel or being inactive during the time slot. To address the trade-off faced by the SUs, we evaluate the performance of two secondary systems in a green communications context: energy consumption and transmission delay.

Description: In this 14th issue of the Automotive Networking and Applications Series, we are pleased to present three articles that address ??? Release 1 of the cooperative intelligent transport systems (C-ITS) standards in Europe ??? The implementation of a virtual traffic lights application with only partial market penetration ??? The usage of multihop wireless communications for intra-car sensor networking By timely information exchanges among vehicles, and between vehicles and roadway infrastructure, vehicles can transform from autonomous systems into cooperative systems, thereby enabling applications such as active road safety and traffic efficiency. Cooperative intelligent transport systems (C-ITS) standards are crucial to achieve interoperability among communications equipment made by different manufacturers for vehicles and roadway infrastructure. Release 1 of the C-ITS standards was completed in early 2014, and it covers base standards for ITS-G5 radio (also named wireless access in vehicular environment, or WAVE, in the United States), ad hoc networking and transport with GeoNetworking and Basic Transport Protocol (BTP), the facilities layer such as messaging protocols CAM and DENM, security, privacy and requirements for applications, among others. The first article, "Cooperative Intelligent Transport Systems Standards in Europe" by A. Festag, provides a comprehensive overview of release 1 of the C-ITS standards in Europe. The article first gives a brief overview of the C-ITS core standards set and compares it with the U.S. dedicated short-range communications (DSRC) standards in IEEE 1609 and SAE J2735. The author then provides more detailed overviews of the Release 1 C-ITS standards covering the access layer, the networking and transport layers, the facilities layer, and applications, security, and management in the subsequent sections of the article. The article concludes with a brief outlook on the expected C-ITS corridor pilots in Europe starting in 2015, as well- as future standardization directions.

Description: A review of a number of ongoing SDN standardization and open-source activities, this article also discusses the interactions both actual and potential in various standards bodies.

Description: I am honored to have been given the opportunity to initiate this supplement on Communications Standards. It is clear to me that standards enable the global market place to offer interoperable products and services at affordable cost. Standards Development Organizations (SDOs) bring together stake holders to develop consensus standards for use by a global industry. The importance of standards to the work and careers of communications practitioners motivated the creation of this publication on standards. This new quarterly publication will be incubated as a Communication Standards Supplement to IEEE Communications Magazine, which if successful, may transition into a new magazine. It is a platform for presenting and discussing standards-related topics in the areas of communications, networking, and related disciplines.

Description: As I serve the remaining days of my tenure as the president of the IEEE Standards Association (IEEE-SA), I ponder the future of technology: what's been achieved today and where would this amazing world be without standards?

Description: As Vice President of Standards Activities of the IEEE Communications Society, I want to welcome you to the first issue of the IEEE Communications Magazine supplement on Communications Standards. This supplement is the culmination of the efforts of many people to create a publication that serves the interests of the members of the global standards community who develop, use, or are otherwise interested in communications and networking standards. The aim of this publication is to cover a broad spectrum of communications and networking standards as well as standards-related disciplines, including innovation and standardization theory and methodologies, standards-related research, and standards regulations, as well as the intellectual property and socio-economic aspects of standards.

Description: Self-Organizing Networks (SON) is a common term for mobile network automation, critical to the cost-efficient deployment, operation and maintenance of mobile networks. This article provides an overview of SON standardization in 3GPP, including both existing and planned functionalities. It also provides an operator perspective on the relevance and use of 3GPP SON functionalities at different stages of the network design-and-operations cycle. In the long-term it is envisaged that automation will become a natural component in network operations, although the success of SON will depend on automation???s benefits in relation to its cost.

Description: An ever-growing demand for pervasive Internet access has boosted the deployment of wireless local networks in recent decades. Nevertheless, wireless technologies face performance limitations due to unstable propagation conditions and mobility of devices. In face of multi-path propagation and low-data-rate stations, cooperative relaying promises gains in performance and reliability. However, cooperation procedures are unstable, due to their dependence on current channel conditions, and introduce overhead that can endanger performance, especially when nodes are mobile. This article presents an introduction to cooperative relaying, and describes a novel link layer protocol, called RelaySpot, able to implement cooperative relaying in dynamic networks, based on opportunistic relay selection, cooperative relay scheduling, and switching.

Description: Social networking applications have gained huge popularity. With the widespread use of smart devices (e.g., on-board units, smartphones), these social networks are increasingly going mobile. As a result, a new trend of networking has emerged, referred to as vehicular social networking (VSN), which combines the wireless communications between vehicles with their social relationships. In a broader view, VSNs are social networks formed on roadways by users who have social relationships, interactions, and common interests. The exploitation of vehicular users??? social properties provides better networking and social support to innovative applications and services. This article overviews recent achievements in VSN by providing an organized view of existing approaches. Its contribution lies in a taxonomy for content dissemination approaches in the context of VSN. Also, a framework is outlined to tackle a major new challenge: supporting user satisfaction. Finally, this article emphasizes open research and future trends.

Description: The following two books are reviewed: IPV6 Deployment and Management (Michael Dooley and Timothy Rooney;2013); Flow networks: Analysis, and Optimization of repairable flow networks, with disturbed flow, static flow networks and reliability networks (Michael T. Todinov;2013).

Description: Presents the front cover for this issue of the publication.

Description: The IEEE Communications Society (ComSoc) is one of 45 technical societies and councils that provide the foundation for the IEEE???s broad range of technical, professional, and humanitarian activities. These societies and councils are also part of a much broader, higher-level framework that includes Organizational Units (OUs) such as Member and Geographic Activities, Standards Activities, Educational Activities, etc. ComSoc and the extensive IEEE organization offer a wide range of valuable products and services to their members and the broader, global community. To succeed in fulfilling its mission, it is important that ComSoc recognize the wider IEEE landscape, and avoid "silo" thinking. This month's column, shared with Doug Zuckerman, provides perspectives on how the activities of ComSoc and its parent IEEE go hand in hand to enhance the value offered to IEEE and Society members by being, "One for All and All for One!"

Description: Following the opening article by Prof. Andrea Goldsmith (former ETC chair), published in IEEE Communication Magazine in the December 2013 issue, I am very pleased to write the second edition of this column to further promote emerging technologies in the broad field of communications and related areas.

Description: This article introduces new methods for evaluating and improving resilience of network connectivity to attacks on nodes of the network. Network connectivity is evaluated using a centrality measure that quantifies sensitivity of the size of the largest connected component to node removals. Based on this centrality measure, a new method for improving resilience is introduced, called edge rewiring. The topology of the power grid of western U.S. states is used to illustrate the proposed method. Using the proposed centrality measure, we show that the power grid topology is especially vulnerable to nodal attacks. In particular, using the proposed centrality measure, an attacker could reduce the largest component size by nearly a factor of two by only targeting 0.2 percent of the nodes. More importantly, we show that network resilience can be greatly improved via a few edge rewires without introducing additional edges in the network.

Description: Wi-Fi systems have been continuously evolving to provide a 10-fold increase in data rates every five years, exploiting higher frequencies and larger bandwidths. With each evolution, there has been an improvement in power efficiency along with data rates. This power efficiency improvement is becoming harder to sustain with increasing data rates, and power efficiency is suggested in this article as the next big challenge for multi-gigabit-per-second Wi-Fi systems. The impact of increased bandwidth on the baseband, mixed-signal, and RF design of Wi-Fi systems is studied. A low-power architecture suitable for large-bandwidth Wi-Fi systems is proposed to address the power efficiency challenge. This architecture scales with bandwidth and adapts bandwidth to the data rate requirements.

Description: The articles in this special section focus on the optic of optical access networks.

Description: While energy conservation and reach-extension technologies are being developed for broadband access networks, this article focuses on the intersection between these two topics. Specifically, it reviews several architectural enhancements that can enable energy conservation in longreach broadband access networks using methods such as turning off idle transceivers and other network elements, shedding transmission speed, and adaptively reconfiguring itself based on current traffic characteristics.

Description: Next month, optical communications and networking professionals from around the world will once again convene at the leading event for the field, the Optical Fiber Communication/ National Fiber Optic Engineers Conference (OFC/NFOEC). OFC/NFOEC prides itself on staying at the forefront of innovation and this year will cover topics like virtualization and Software Defined Networks (SDN), 100G/400G network design and optimization, cloud and data center networking, flexible grid networks, space division multiplexing, beyond 1 Tb/s networking, high-speed photonic integration and optical/wireless convergence. New products, cutting-edge technology and vital research at the forefront of communications will be presented through more than 800 peer-reviewed and invited presentations, an extensive exhibit hall with more than 550 leading optical communication companies, numerous workshops, panels, short courses and other special events. OFC/NFOEC 2013 will be held at the Anaheim Convention Center March 17-21 in Anaheim, Calif.

Description: The articles in this special section focus on the topic of third generation networking Long Term Evolution standards and protocols.

Description: The growing popularity of mobile data services necessitates a rapid rise in network capacity not only on the air interface to the end user, but also in the backhaul network. The latter is quite important for the mobile operator business model, affecting capital investment, operational expenses, service deployment, and customer experience. Fiber infrastructure is inevitably the only long-term solution, and the deployment of passive optical networks presents an opportunity for a cost-effective, scalable, and future-proof solution. In this article we investigate the use of PONs for mobile backhaul and propose a resource allocation framework building on the efficiency of PONs to share resources, dynamically allocate bandwidth in real time, and enhance efficiency by improved statistical multiplexing. The main objective of this work is to exploit existing standardized technologies, and provide design and deployment guidelines regarding PON MAC operation, enabling a gradual and future-safe infrastructure upgrade of mobile backhaul systems.

Description: This paper briefly describes Internet development in the Republic of Korea (South Korea), which started research and development on computer networking in the late 1970s. Korea became one of the first countries to deploy the Internet in 1982 [1], and organized one of the first global Internet conferences in 1985 [2]. In the late 1990s, Korea put much effort into development of broadband networks, starting from a master plan in 1995. Korea became a world leader with widely available wired and wireless broadband networks. Korea also led in Internet applications including online games, search engines and social networking services. As one of the earlier Internet countries, Korea has been vulnerable to newly arising problems on the Internet such as cybersecurity, net abuse and game addiction. Korea has been trying to solve these problems in collaboration with other leading countries. Korea has also shared its Internet experience with other countries, in particular with developing countries. A book is in preparation on the early history of the Internet in Korea [3] together with another, co-authored with Internet pioneers in other countries, on the early history of the Internet in Asia.

Description: The next major step in the evolution of LTE targets the rapidly increasing demand for mobile broadband services and traffic volumes. One of the key technologies is a new carrier type, referred to in this article as a Lean Carrier, an LTE carrier with minimized control channel overhead and cell-specific reference signals. The Lean Carrier can enhance spectral efficiency, increase spectrum flexibility, and reduce energy consumption. This article provides an overview of the motivations and main use cases of the Lean Carrier. Technical challenges are highlighted, and design options are discussed; finally, a performance evaluation quantifies the benefits of the Lean Carrier.

Description: Mobile Internet applications run on devices such as smartphones and tablets, and have dramatically changed the landscape of applicationgenerated network traffic. The potent combination of millions of such applications and the instant accessibility of high-speed Internet on mobile devices through 3G and now LTE technology has also changed how users themselves interact with the Internet. Specifically, the radio states in LTE such as RRC_Connected and RRC_Idle were designed with more traditional applications such as web browsing and FTP in mind. These traditional applications typically generated traffic only during Active (Connected) state, and once the user session ended, usually the traffic ended too, thus allowing the radio to move to Inactive (Idle) state. However, newer applications such as Facebook and Twitter generate a constant stream of autonomous and/or user generated traffic at all times, thus erasing the previously clear demarcation between Active and Inactive states. This means a given mobile device (or user equipment, in LTE parlance) often ends up moving between Connected and Idle states frequently to send mostly short bursts of data, draining device battery and causing excessive signaling overhead in LTE networks. This problem has grown and attracted the research community's attention to address the negative effects of frequent back and forth transitions between LTE radio states. In this article, we first explore the traffic characteristics of these emerging mobile Internet applications and how they differ from more traditional applications. We investigate their impact on LTE device power and air interface signaling. We then present a survey of state-of-the-art solutions proposed in literature to address the problems, and analyze their merits and demerits. Lastly, we discuss the solutions adopted by 3GPP including the latest developments in Release 11 to handle these issues, and present potential future research directions in this field.

Description: These days there is a clear trend toward extending the reach of passive optical networks to cover large geographical areas, which enables reduction of the number of central offices and hence has the potential of cost saving in network operation. On the other hand, this reach extension necessitates the design of efficient dynamic bandwidth allocation schemes in order to tackle performance degradation caused by the increased propagation delay in long reach PONs. Among many existing approaches, the multithread- based DBA scheme where several bandwidth allocation processes are performed in parallel is considered one of the most effective options to improve network performance in LRPONs. We have found that without proper intercommunication between the overlapped threads, multi-thread DBA may lose efficiency and even perform worse than the conventional singlethread algorithm. With this in mind, this article reviews different inter-thread scheduling schemes for LR-PONs, and proposes a novel approach of integrating the key ideas of the existing ones. Extensive simulation results confirm that our proposed scheme can significantly improve DBA performance for LR-PONs under a variety of scenarios with consideration of different values of network load and reach.

Description: 3GPP LTE, or Long Term Evolution, the fourth generation wireless access technology, is being rolled out by many operators worldwide. Since LTE Release 10, network densification using small cells has been an important evolution direction in 3GPP to provide the necessary means to accommodate the anticipated huge traffic growth, especially for hotspot areas. Recently, LTE Release 12 has been started with more focus on small cell enhancements. This article provides the design principles and introduces the ongoing discussions on small cell enhancements in LTE Release 12, and provides views from two active operators in this area, CMCC and NTT DOCOMO.

Description: As the capacity and performance of the LTE data channels are progressively improved, the downlink control channels can potentially become the bottleneck. To address this issue, an enhanced physical downlink control channel (EPDCCH) has been introduced in 3GPP LTE Release 11. The design goals of the EPDCCH include the ability to support increased downlink control channel capacity, beamforming and improved spatial reuse, and frequency-domain intercell interference coordination, while taking into account the coexistence with legacy terminals. This article explains the principles and considerations behind the EPDCCH design in Release 11, and describes the corresponding specification support.

Description: As the number and variety of applications and workloads moving to the cloud grows, networking capabilities have become increasingly important. Over a brief period, networking support offered by both cloud service providers and cloud controller platforms has developed rapidly. In most of these cloud networking service models, however, users must configure a variety of network-layer constructs such as switches, subnets, and ACLs, which can then be used by their cloud applications. In this article, we argue for a service-level network model that provides higher- level connectivity and policy abstractions that are integral parts of cloud applications. Moreover, the emergence of the software-defined networking (SDN) paradigm provides a new opportunity to closely integrate application provisioning in the cloud with the network through programmable interfaces and automation. We describe the architecture and implementation of Meridian, an SDN controller platform that supports a service-level model for application networking in clouds. We discuss some of the key challenges in the design and implementation, including how to efficiently handle dynamic updates to virtual networks, orchestration of network tasks on a large set of devices, and how Meridian can be integrated with multiple cloud controllers.

Description: In this article, we deconstruct scalability concerns in software-defined networking and argue that they are not unique to SDN. We explore the often voiced concerns in different settings, discuss scalability trade-offs in the SDN design space, and present some recent research on SDN scalability. Moreover, we enumerate overlooked yet important opportunities and challenges in scalability beyond the commonly used performance metrics.

Description: Seamless roaming over wireless networks is highly desirable to mobile users, but ensuring the security and efficiency of this process is challenging. Although the same may be said for all communication systems, roaming services have special requirements and vulnerabilities, and therefore deserve special attention. Over the years, we have seen a variety of authentication protocols emerging to address this issue. However, which protocol is the most effective is still debatable. In this article, we first identify the challenges unique to roaming services as a set of mandatory and optional requirements. Next, we provide a brief state-of-the-art survey of existing work and point out their limitations in securing roaming services, especially in resistance against denial of service attacks, efficient authentication, flexible roaming in mobile contexts, as well as backward and forward non-linkabilities. To complement the security provided by the existing work, we then propose some mechanisms that can meet the aforementioned security and efficiency requirements. Finally, we present challenges that need to be addressed in roaming authentication.

Description: The articles in this special section focus on the optic of software defined networks.

Description: Conferences are one of the most important parts of business for the IEEE societies for a variety of reasons. This month¿s President¿s Page is shared with Abbas Jamalipour, ComSoc¿s Vice President¿Conferences for 2012-2013.

Description: The First Women's Workshop on Communications and Signal Processing was held at the Banff International Research Station (BIRS) July 13-15. It brought together 27 women researchers for a weekend of technical presentations, posters and networking. The workshop was organized by Sheila Hemami (Cornell University), Urbashi Mitra (University of Southern California), Milica Stojanovic (Northeastern University), and Katie Wilson (Santa Clara University). The primary focus of this workshop was academic research, but we believe this workshop model could be adapted for women in industry as well. We would like to thank BIRS, the Office of Naval Research, the IEEE Signal Processing Society, and the IEEE Communications Society for their grants, which helped make the workshop possible. More information can be found at http://www.birs.ca/events/2012/2-day-workshops/12w2147.

Description: Provides a listing of upcoming conference events of interest to practitioners and researchers.

Description: 3GPP studies indicate that for mobile networks to be competitive for mass machine-type applications, it is important to optimize their support for the expected huge growth of connected devices due to uptake of machine-type communications. In this article we briefly describe the architectural enhancements in 3GPP systems to better facilitate machine type communication. We highlight key architectural changes, functionality of new network elements to support new features such as device triggering, packet switched subscriptions including short message service via PS domain and SMS in MME. We also describe overload control mechanisms to prevent overload situations caused by synchronous connection requests from large numbers of MTC devices to the 3GPP system. Finally, we discuss how this work is expected to evolve in future 3GPP releases.

Description: As a companion effort to the development of the Wireless Communication Engineering Technologies (WCET) certification, ComSoc also invested in the creation of a book covering much of the material that forms the basis for the WCET certification examination. To be clear, A Guide to the Wireless Engineering Body of Knowledge (WEBOK) was never intended to be a study guide for the exam or to cover every topic that might be the subject of a question on the exam. Indeed, no editor or contributing author to the WEBOK has any role in writing or selecting questions for the exam, nor is anyone involved in the creation of the exam a contributor to the WEBOK.

Description: As global deployments of Long Term Evolution (LTE)-based fourth generation (4G) networks are gaining momentum, the effective realization of a mobile broadband experience is facing new challenges and increasing expectations from the perspectives of both network operators and end users. Not only is mobile data traffic growing exponentially, but new multimedia applications on smart mobile devices and also the more stringent demands on the quality of service.

Description: Advanced interference mitigation techniques relying on multipoint coordination have attracted significant attention from the wireless industry and academia in the past few years. In 3GPP LTE-Advanced, a work item on Coordinated Multiple Point transmission and reception (CoMP) was initiated in September 2011, and it is one of the core features of Release 11. The objective of this work item is to provide the necessary specification support to efficiently realize the benefits of cooperative transmission in the downlink and cooperative reception in the uplink. This article discusses the specification support for CoMP and the motivations behind the specific design choices. The deployment scenarios that were considered for the application of CoMP in Release 11 are also presented.

Description: Transmissions in different cells of a time-division duplex system are typically synchronous in order to eliminate the base station-to-base station and terminal-to-terminal interference. The synchronous operation limits dynamic resource configuration for downlink and uplink transmissions. Today, as a large percentage of mobile traffic is generated in hotspots and indoor environments, heterogeneous networks comprising high-power/wide-area and low-power/local-area network nodes are becoming a reality. Such heterogeneous networks provide opportunities to exploit dynamic uplink-downlink configuration in TDD systems, adapting to the individual traffic needs of a specific cell area. This article presents a tutorial overview of dynamic uplink-downlink configuration and interference management in time-division Long Term Evolution, including motivations, target deployment scenarios, opportunities and challenges, system requirements, design aspects, and performance evaluations.

Description: The Third Generation Partnership Project defined multimedia broadcast/multicast service in 2005 to optimize the distribution of video traffic. This standard covers the terminal, radio, core network, and user service aspects. This MBMS standard has evolved into enhanced MBMS (eMBMS) that builds on top of the 3GPP Long Term Evolution standard. eMBMS evolution brings improved performance thanks to higher and more flexible LTE bit rates, single frequency network operations, and carrier configuration flexibility. 3GPP Rel-11 also brings improvements in the areas of service layer with, for example, video codec for higher resolutions and frame rate, and forward error correction. eMBMS allows offloading of the LTE network and backhaul. It enables the possibility to deliver premium content to many users with secured quality of service in defined areas. Other important use cases are pushed content via user equipment caching and machine-to-machine services. This article describes the relevant use cases for eMBMS in terms of service. It then gives a tutorial on eMBMS, in particular highlighting the evolution over MBMS. The scope comprises the radio access, core network, and service layer.

Description: Recently, a workshop on ¿Antenna Design and Fabrication¿ was held at Mehran University of Engineering and Technology (MUET), Jamshoro, Pakistan, on 3-4 Sep 12 . However, this was no ordinary workshop because not only were the participants students but the organisers and instructors for the event were also students.

Description: Markets for network resources have become increasingly important. Such resources include bandwidth in wireline networks to wireless spectrum. It is clear that if the markets are not properly designed, they can function rather poorly, even leading to market failure. This then leads to suboptimal use of network resources. In this article, we present the game theoretic framework behind the market design principles for network resources. We present some of the extant work on network market mechanisms in the context of wireline networks in part I. Part II [1] relates to network market design in the context of wireless systems. We also discuss some of the key challenges for the future.

Description: The tremendous growth in demand for broadband data is forcing ISPs to use pricing as a congestion management tool. This changing landscape of Internet access pricing is evidenced by the elimination of flat rate data plans in favor of usage-based pricing by major wired and wireless operators in the US and Europe. But simple usage-based fees suffer from the problem of imposing costs on all users, irrespective of the network congestion level at a given time. To effectively reduce network congestion, appropriate incentives must be provided to users who are willing to time-shift their data demand from peak to off-peak periods. These pricing incentives can either be static (e.g., two-period daytime/nighttime prices) or computed dynamically (e.g., dayahead pricing, real-time pricing). Data plans that offer such incentives to consumers fall under the category of time-dependent pricing (TDP). Many ISPs across the world are currently exploring various forms of TDP to manage their traffic growth. This article first outlines the sources of today¿s challenges, and then discusses current trends from regulatory and technological perspectives. Finally, we review representative pricing proposals for incentivizing the time-shifting of data.

Description: Mobile data traffic is expected to grow exponentially in the next few years due to the explosive growth of mobile web and video traffic on smartphones. Wireless operators have invested heavily to make infrastructural improvements by installing new cell towers and offloading cellular data traffic to Wi-Fi to resolve congestion. They are also exploring the use of behavioral and economic interventions to manage congestion. To understand the role of interventions, we distributed smartphones to students at Purdue University, loaded with applications to perform monitoring and location tracking with user consent. We conducted two experiments: first with 14 phones of one type, then with 30 phones of two types. Wi-Fi traffic and cellular network data usage were collected and analyzed to characterize and quantify the changes in usage behaviors; the second experiment also captured location data during compliance/non-compliance to incentive messages. The trial seeks not only to experiment with incentives and disincentives to observe their effectiveness, but also to understand current mobile broadband and Wi-Fi usage behaviors in a campus environment. Our results indicate a high level of compliance with economic incentives and disincentives. Detailed analysis further showed correlation with two psychological measures of each user (agreeableness and neuroticism). In addition, we found schemes with probabilistic payments of higher incentive amounts getting more positive results compared to schemes with definite payments with lower incentive amounts, despite similar total payout.

Description: Auction theory, as a subfield of economics, provides useful tools to model, analyze, and optimize radio resource management in cognitive radio environments. By using an auction, radio resources such as subchannel, time slot, and transmit power can be allocated among licensed and unlicensed users in the system, following market laws. Due to the flexibility of mechanism design, there are various auction mechanisms that have been applied to cognitive radio systems with different characteristics. In this article, we first provide an overview of the basics of general auctions. Then the motivations and specific design issues in applying auctions to wireless network architectures and protocols are discussed. Then we review the state of the art in the use of auction theory and mechanism design in cognitive radio networks. This will enable the readers to have a general view of auction fundamentals, as well as the recent development and applications of auction theory in the emerging cognitive wireless networks.

Description: In this article, we discuss a spectrum trading mechanism implemented by the spectrum broker in TV whitespaces. TVWS are spectrum frequency bands unused by DTV, interleaved in both frequency and space. Underutilization of these bands results from the fact that the DTV transmission systems now operational in the spectrum from 470 to 790 MHz are multifrequency systems employing high tower and high power network geometries, and must be managed for interference between transmitters. We motivate the use of a spectrum broker, an entity that manages the TVWS secondary spectrum market. Such a TVWS broker¿s responsibilities include planning the possible broad uses of the available spectrum in the TVWS; packaging the spectrum for short-term disposal through trading mechanisms; serving the broker¿s customers, with spectrum-leasing contracts; and acting as the port of call to handle interference caused by its customers to the primary DTV systems or between its customers themselves. We discuss the spectrum broker¿s merchant and auction modes for spectrum trading. In the merchant mode, the base price is decided by the allocation procedure, which considers various factors influencing the value of TVWS in a given place. In the auction mode, the customers¿ demands and bids decide the final price of the spectrum. We discuss the auction design and show results of the spectrum trading mechanisms, which have been successfully applied in a real-world test scenario in the area of Munich, Germany.

Description: This issue of the Consumer Communications and Networking series, featuring four articles, touches on four different aspects of emerging technologies from radio communications in a digital home to workflow management in connected smart homes and inter-destination synchronization for multimedia applications to mobile application stores. Let us look into the details of each article.

Description: In the Internet of Services, users are surrounded by lots of connected devices and remote services with the potential for real-time interaction. While users could manually command their operation, it will be extremely convenient to have an environment where interaction workflows could easily be defined so that services could operate autonomously following those patterns. This article presents a system to allow individuals with no specific programming skills to define and execute those interaction workflows using graphical abstractions. The system has been validated inside a smart home scenario, as a good representative of the future Internet of Services environment due to the presence of multiple heterogeneous devices and services from different domains.

Description: Currently, the media consumption paradigm is changing from a single end user to a group shared experience. Now, social communication opportunities may be exploited (e.g., conferencing while watching television), facing lots of technological (e.g., synchronization, universal session handling, scalability) and perceptual (e.g., presence awareness, QoE) challenges. This article focuses on one of these major challenges ahead in new emerging social interactive multimedia applications, which is the synchronization of different media streams across multiple locations, known as inter-destination multimedia synchronization (IDMS). We describe the three kinds of temporal multimedia synchronization, and summarize some related work and examples of applications in which IDMS is needed. The article includes a discussion about an RTP/ RTCP-based IDMS solution the authors have been working on, as well as the standardization status regarding this kind of synchronization.

Description: The mobile user experience has been significantly altered with the arrival of mobile broadband widespread deployments, massive improvements in available smartphones, and a shift in user habits toward a more participative, communicative role. In this context, mobile application stores have revolutionized software and content delivery. These stores focus on the applications, building around them an ecosystem of developers and consumers. The store greatly lessens the barrier between these agents, providing significant benefits to both developers and consumers. In this article we analyze this phenomenon, describing its originating factors and fundamental characteristics. We also perform a more detailed study on the two most successful application stores, identifying different approaches to implementing the model.

Description: Telecommunications service providers continue to focus on providing additional network capacity to meet growing needs for bandwidth in their access, metro, and long-haul networks. Global optical transport industry suppliers have accelerated their efforts over the past three years on improving spectral efficiency while reducing cost per bit. While the industry has witnessed the growing use of advanced modulation formats such as DP-QPSK and coherent detection, a broad-based search for approaches to increase transmission speeds for each optical channel, a larger number of wavelength- division multiplexing (WDM) channels, and space multiplexing over a larger number of fiber cores is in progress.

Description: Network traffic demands are forecast to increase for the foreseeable future, with the challenge being to meet the demand while maintaining or lowering network costs. Simply increasing capacity will not be sufficient; overall bandwidth utilization also needs to improve. A combination of improved transport capacity through increased spectral efficiency and bit rate along with better network utilization by integrating subchannel electrical grooming into the transmission system will be required. Smarter ways to utilize optical capacity are key since transmission costs have been decreasing slower than grooming and switching costs. Integrated transport and switching can improve the efficiency of the client network using techniques such as port virtualization and transit traffic reduction. The baseline for transport networks will be 100 Gb/s PM-QPSK using 50 GHz channel spacing. Moving from a fixed DWDM channel arrangement to support flexible grid and super channels will allow tighter channel (carrier) spacing and should increase capacity by 30 to 50 percent. For shorter distances higher-order modulation such as 16-QAM can double network capacity. To better optimize network efficiency, an architecture that flexibly combines lower rate (sub-100 Gb/s) clients to form channels (carriers) and then superchannels will be required.

Description: Minimization of drive tests is a feature introduced in 3GPP Release 10 that enables operators to utilize users¿ equipment to collect radio measurements and associated location information, in order to assess network performance while reducing the OPEX associated with traditional drive tests. However, in the increasingly complex wireless packet data networks of today, performance is affected by many different factors and cannot easily be estimated by simple radio measurements. Therefore, in 3GPP Release 11 specifications, MDT is enhanced in order to provide a more complete view of network performance. This article describes the MDT enhancements added in Release 11, explains how measurements collected by MDT can be used to draw conclusions that are relevant for network management, and discusses similarities and differences between MDT and traditional drive tests.

Description: Market-based approaches have promising potential for allocating network resources. Part I of this article introduced the game theoretic underpinnings of market design and argued for the need to jointly consider market design with the underlying engineering issues in communication networks. Example research questions in this area were reviewed for wireline networks. In this part, we turn to network market design for wireless systems and in particular for the flexible sharing of wireless spectrum. We use this as a vehicle for discussing challenges that arise in the design of markets in the presence of externalities.

Description: Today¿s communication networks are highly complex, carry heterogeneous traffic in diverse environments, and are often owned by multiple profit-making entities. To successfully maintain, optimize, and upgrade such large distributed networks, it is important to design new economic incentive mechanisms as well as develop new technologies. The market deregulation of the telecommunication industry in many countries makes such economic consideration even more urgent, as there are often conflicting goals between the regulators and the commercial operators. In this feature topic we present six articles that naturally group into three trendy topics in this important emerging research discipline.

Description: With the ever growing usage of various wireless technologies and services, more and more handheld devices are equipped with multiple radio transceivers (e.g., LTE, WiFi, Bluetooth, and GNSS). As a result, in-device coexistence interference has become a serious problem due to the extreme proximity of multiple radio transceivers within the same device. It has been shown by the studies of 3GPP that for some specific frequency bands, concurrent operations of LTE and ISM/GNSS radios working in adjacent or sub-harmonic frequencies will result in significant in-device coexistence interference that cannot be completely eliminated by filter technology. This motivates 3GPP to introduce signaling mechanisms and procedures, which enable the devices to effectively solve the indevice coexistence problems with help from the LTE network. This article first discusses the scenarios in which coexistence interference may happen, and then provides an overview of main solutions and related procedures specified in 3GPP Release-11 standards for LTE. In addition, some aspects of device-internal coordination and implementation to facilitate the coexistence scenarios are also discussed.

Description: The future digital home (DH) is envisioned as a place where a plethora of diverse personal and machine-to-machine communications will coexist to support different applications in areas such as information and entertainment, home automation, home health care and home security and management. Wireless technologies are usually the preferred solution to cope with DH communications for their ease of installation and use. However, expected capacity demand and the lack of coordination between an increasing number of diverse wireless devices in use within the DH is seriously challenging the performance and usability of wireless technologies. This article outlines a novel technical solution intended to enhance capacity and quality of DH wireless communications. The proposed solution establishes a radio-independent coexistence framework where key operational radio settings of DH devices are coordinately determined, and new spectrum sources other than traditional ISM bands can be exploited for DH communications. The addressed solution enables a business player to offer management services for DH wireless communications so that ordinary users can be relieved of complex management tasks likely to arise within the DH. The article discusses how potential management service providers could benefit from the proposed solution. Besides, the functional architecture of the proposed solution together with the set of procedures necessary for the management of the DH wireless communications are outlined. A realistic indoor scenario is presented as an illustrative use case to show how proper decision making logic in managing the DH could improve the efficiency by selecting the most suitable spectrum for in-house wireless communications. Finally, the main implementation issues are identified and discussed in order to outline a feasible roadmap

Description: As line interfaces in communications chassis transition to 100 Gb/s and higher per port, many in the industry question when electrical backplanes inside these chassis will give way to optical ones. Provided that the maximum card-to-card distance over a backplane remains at one meter, two observations point to an electrical-to-optical transition near the end of this decade: commercial links transition from electrical to optical at the bandwidth-distance product of 100 Gb/s .m [1], and backplane line rates double every two process nodes and will reach 100 Gb/s in four process nodes. But optical solutions will need to overcome incumbency, or economics will call for electrical backplane solutions. To set up a framework for comparing backplane solutions, this article first defines a canonical backplane model to enumerate possible backplane implementations. Using this model, this article identifies 10 practical future backplane implementations, of which four are electrical and six optical. This article further describes how electrical solutions could be viable beyond this decade. It then outlines three necessary conditions for optical solutions to unseat the incumbent. Finally, it argues that optical solutions have an inherent advantage to scale systems with inter-chassis links, an advantage that could tip the balance in favor of optics in future backplanes.

Description: The bandwidth efficiency and relative costs for 100 Gb/s WDM transport and switching architectures are compared in North American and pan-European long-haul networks. The first architecture uses muxponders and ROADMs for end-to-end wavelength transport with no digital sub-wavelength grooming. The other two utilize digital OTN switching, as either a standalone OTN switch or a converged integrated WDM/switch system, to efficiently groom services onto WDM wavelengths. Results show the integrated WDM/switch architecture utilizes the fewest WDM wavelengths and client service interfaces, and an integrated WDM/switch architecture using photonic integrated circuit technology provides the lowest operational costs.

Description: The purpose of this article is to examine some of the models commonly used to represent fading as well as the information-theoretic metrics most commonly used to evaluate performance over those models. We raise the question of whether these models and metrics remain meaningful in light of the advances that wireless systems have undergone over the last two decades. A number of weaknesses are pointed out, and ideas on possible fixes are put forth. Some of the identified weaknesses have to do with models that, over time, have become grossly inadequate. Other weaknesses have to do with changes in the operating conditions of wireless systems, and others with the coarse and asymptotic nature of some of the most popular performance metrics (¿diversity¿ and ¿multiplexing¿).

Description: Running desktop-as-a-service solutions in remote data centers is an emerging means of delivering virtual PCs in an inexpensive, secure, and easy-to-maintain way. The fact that such solutions rely on the presence of connectivity between users and their virtual PCs poses a challenging operational question: what is the quality of experience of the user when running a particular application inside the thin-client protocol? The challenge is to understand whether the path between the client and the server has enough resources to sustain the rendering of the specific application. To address this question, we propose a method that exploits statistical classification to infer on-the-fly the class of applications running inside a given thin-client connection. We then correlate such information with the key factor that limits thin-client performance (i.e., network latency) to obtain the current user¿s QoE. We evaluate how machine-learning techniques can robustly detect applications that exchange data over the Microsoft Remote Desktop Protocol, with promising results (over 80 percent of accuracy for multimedia content). To the best of our knowledge, this is the first attempt of using statistical techniques to monitor thin-client applications for QoE detection.

Description: Bitstream-based methods are intuitively suited for quality assessment of networked video services, and are currently under intense investigations in terms of research and standardization activities. This article examines the factors that may affect the quality of the networked video, and reviews the state-of-the-art techniques as well as standardization progress in bitstreambased video quality assessment. According to different levels of access to the bitstream, three types of models are described and compared: the parametric, packet layer, and bitstream-layer models.

Description: Listing of the advertisers represented in this issue.