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Communications Magazine, IEEE

Issue 4 • Date April 2009

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Displaying Results 1 - 25 of 30
  • IEEE Communications Magazine

    Page(s): c1
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    Freely Available from IEEE
  • Table of contents

    Page(s): 2 - 4
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    Freely Available from IEEE
  • Comsoc serving humanity - a global example [The President's Page]

    Page(s): 6 - 8
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    Freely Available from IEEE
  • Society members named to Fellow grade [Society News]

    Page(s): 10 - 12
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    Freely Available from IEEE
  • Supporting carrier grade services over wireless mesh networks: The approach of the European FP-7 STREP CARMEN [Very Large Projects]

    Page(s): 14 - 16
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (65 KB) |  | HTML iconHTML  

    CARMEN is a three-year Specific Targeted Research Project (STREP) funded by the European Commission within the 7th Framework Program. The CARMEN access network will complement existing access technologies by exploiting low cost mesh networking techniques, thus minimizing deployment and maintenance costs. The CARMEN architecture introduces an abstraction layer that hides the specifics of the underlying access technology providing an abstract interface on top of which higher layers can be easily developed. This allows for the integration of current and future heterogeneous wireless technologies to provide scalable and efficient mobile ubiquitous Internet access, able to adapt to different environments and user requirements. Following these goals, CARMEN aims to define, study and implement link and technology abstractions, mobility support, and quality of service. The architecture also includes advanced monitoring features that allow for dynamic self-configuration, thereby reducing the installation and operational costs. View full abstract»

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  • Emerging Technologies in Wireless LANs: Theory, Design, and Deployment (Bing, B., Ed.; 2008) [Book review]

    Page(s): 18
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  • Armstrong's invention of noise-suppressing FM [History of Communications]

    Page(s): 20 - 23
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (149 KB) |  | HTML iconHTML  

    Edwin H. Armstrong is well known as the inventor of wide-deviation or wideband FM. His patent on this invention was granted December 26, 1933, followed soon thereafter by demonstrations of his system before engineers, papers on the subject of wideband frequency modulation (FM) and its noise-suppression property, and eventually, of course, after World War II, widespread acceptance of FM by the radio industry and the public at large. The years in between were devoted to a bitter court fight between Armstrong and RCA, leading eventually to Armstrong's tragic suicide in 1954. This is well documented in the book by Lessing devoted to Armstrong's life (1969). What is not clear is precisely how and when Armstrong had the intuitive leap, his Eureka! moment, that led to this truly momentous invention. Armstrong was notorious for leaving very little documentation on his inventions. Lessing does note that Armstrong was fully occupied with his FM work, carrying out thousands of experiments, from 1928 to 1933, but no attempt to further narrow this interval of time down or discuss how he came to develop the wide-deviation FM concept is offered. We try, in this brief note, using documentation available in the Armstrong papers housed at Columbia University, to come to grips with these questions. View full abstract»

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  • Investing in yourself - [certification corner]

    Page(s): 24
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  • Conference calendar

    Page(s): 26
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  • New products

    Page(s): 28 - 29
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  • The SENSEI project: integrating the physical world with the digital world of the network of the future

    Page(s): 1 - 4
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  • Some reflections on scholarly reviewing [Commentary]

    Page(s): 36 - 39
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  • LTE part II: Radio access [Guest Editorial]

    Page(s): 40 - 42
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  • LTE: the evolution of mobile broadband

    Page(s): 44 - 51
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (275 KB) |  | HTML iconHTML  

    This article provides an overview of the LTE radio interface, recently approved by the 3GPP, together with a more in-depth description of its features such as spectrum flexibility, multi-antenna transmission, and inter-cell interference control. The performance of LTE and some of its key features is illustrated with simulation results. The article is concluded with an outlook into the future evolution of LTE. View full abstract»

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  • The LTE link-layer design

    Page(s): 52 - 59
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (124 KB) |  | HTML iconHTML  

    The LTE radio interface for 3GPP Release 8 was specified recently. This article describes the LTE link-layer protocols, which abstract the physical layer and adapt its characteristics to match the requirements of higher layer protocols. The LTE link-layer protocols are optimized for low delay and low overhead and are simpler than their counterparts in UTRAN. The state of- the-art LTE protocol design is the result of a careful crosslayer approach where the protocols interact with each other efficiently. This article provides a thorough overview of this protocol stack, including the sub-layers and corresponding interactions in between them, in a manner that is more intuitive than in the respective 3GPP specifications. View full abstract»

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  • Coexistence studies for 3GPP LTE with other mobile systems

    Page(s): 60 - 65
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (122 KB) |  | HTML iconHTML  

    To ensure LTE systems can coexist with other mobile systems operating in the same geographical area, or the LTE Base Station (BS) can be collocated with other mobile system BSs, coexistence studies for LTE with other systems have been carried out in 3GPP. In this article, we provide an overview of the coexistence studies that have been done. First we list the terminologies that are commonly used for coexistence studies, and explain how deterministic analysis can be done for the BS to BS interference scenario. Then we provide the system simulation methodology and assumptions used in the coexistence studies, and show some simulation results for the possible impacts with different system parameters. Finally we provide the references to the 3GPP standards where the LTE BS and UE radio transmission and reception requirements are specified to facilitate LTE coexistence with other mobile systems. View full abstract»

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  • Improvements to seamless vertical handover between mobile WiMAX and 3GPP UTRAN through the evolved packet core

    Page(s): 66 - 73
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (130 KB) |  | HTML iconHTML  

    Recent mobile devices are integrated with multiple network interfaces. Users want their devices connected to the network anytime anywhere. It is highly feasible for a user to change connection to another network for users that leave the service area of its current serving network, where handover needs to be executed seamlessly such that ongoing service sessions are not interrupted. The handover operation not only requires switching the interfaces within a device but also involves seamless reconfiguration of the supporting networks. In this article, an improved IP-based vertical handover technology for mobile WiMAX , 3GPP legacy systems (i.e., Global System for Mobile communications and Universal Mobile Telecommunications System), and 3G Long Term Evolution is presented, which is based on existing optimized handover techniques between mobile WiMAX and 3GPP accesses. Formerly proposed 3GPP WiMAX optimized VHO solutions introduced new elements, such as the forward attachment function and access network discovery and selection function. The ANDSF supports the discovery of target access, and the FAF provides the functionality that authenticates the UE before the execution of VHO. However, the previous technique has limitations that result in data loss and abnormal disconnection to the source access. This article provides a solution by introducing an additional network element called the data forwarding function (DFF) that eliminates the data loss during VHO execution. In addition, the DFF resolves the problem of abrupt disconnection to the source network. The simulation results show that the proposed VHO technique is effective in minimizing data loss during VHO execution between mobile WiMAX and 3GPP networks. As the proposed solution of this article is an IP based handover solution, it can be similarly applied to other communication networks. View full abstract»

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  • Interference coordination and cancellation for 4G networks

    Page(s): 74 - 81
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (125 KB) |  | HTML iconHTML  

    This article provides an overview of contemporary and forward looking inter-cell interference coordination techniques for 4G OFDM systems with a specific emphasis on implementations for LTE. Viable approaches include the use of power control, opportunistic spectrum access, intra and inter-base station interference cancellation, adaptive fractional frequency reuse, spatial antenna techniques such as MIMO and SDMA, and adaptive beamforming, as well as recent innovations in decoding algorithms. The applicability, complexity, and performance gains possible with each of these techniques based on simulations and empirical measurements will be highlighted for specific cellular topologies relevant to LTE macro, pico, and femto deployments for both standalone and overlay networks. View full abstract»

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  • The LTE/SAE trial initiative: Taking LTE-SAE from specification to rollout

    Page(s): 82 - 88
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (429 KB) |  | HTML iconHTML  

    Now that the standards for LTE/SAE are functionally frozen, we consider the activities needed to implement the technology and prepare it for commercial rollout: prototyping, interoperability testing, and field trials. The LSTI is a global initiative of operators and vendors who are coordinating and reporting progress on these activities to ensure that everyone has a realistic understanding of what performance and functionality to expect from LTE, and the readiness of the technology for commercial roll out. The LSTI aims to accelerate commercialization of LTE/SAE by fostering technology alignment across all key vendor participants. This article provides an overview of the activities and gives an update on the results published so far. View full abstract»

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  • Topics in design and implementation III [Series Editorial]

    Page(s): 90 - 91
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  • XMPP: lessons learned from ten years of XML messaging

    Page(s): 92 - 96
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (89 KB) |  | HTML iconHTML  

    Can an entire technology ecosystem be designed? Although we usually think of design and implementation in relation to particular features or applications, overall technologies - such as the session initiation protocol for voice over IP or the hypertext transfer protocol for the World Wide Web - can constrain the set of possible solutions to more well-bounded problems. Given the large scope of a technology ecosystem (including protocols, software implementations, application types, service deployments, and various stakeholders), we would expect to find that some of its aspects can be designed, some aspects can be guided in an approximate fashion, and other aspects exhibit an emergent order or no order whatsoever. To investigate such issues, this article summarizes some of the challenges faced, and lessons learned, by the extensible messaging and presence protocol developer community since 1999. View full abstract»

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  • Service broker architecture: Location business case and mashups

    Page(s): 97 - 103
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (620 KB) |  | HTML iconHTML  

    In recent years, costly and slow integration has created an unnecessary gap between the telephone companies (or telco) and IT worlds. However, collaboration between Internet and telecom standards is essential for future development. The service broker concept has been developed to fill this gap. Indeed, the service broker provides a flexible layer in the telecom architecture to bridge these two worlds. Such a concept is essential to coordinate the diverse future services and provide mashup opportunities through a single point of entry. In this article we present the concept and an actual implementation of a specific service broker: a location service broker. Moreover, we also present a sample mashup called MoPoint that we implemented to better demonstrate the functionality of the location service broker. MoPoint is a Web site where the user can see the current location of his or her mobile displayed on a map along with local weather and advertisements. View full abstract»

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  • The design and implementation of an extensible, user-management service for communications applications

    Page(s): 104 - 110
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    Many network administration organizations, including communication service providers, are faced with the problem of managing a growing number of applications with fewer administrators. Administrators are required to provision and administer application-specific data in order for users (e.g., subscribers) to access and use communication applications. Although there are several approaches for solving the problem of sharing identity data across applications, a general solution for provisioning and sharing the complete user or subscriber profile has not been defined. This article describes the design and implementation of an extensible, user-management service that solves the problem of the redundant data entry required in provisioning and maintaining multiple communication applications. An important aspect of the design is the capability of the user-management service to be extended at run time without requiring an upgrade of the service and without impacting already deployed applications. Key lessons that can be applied to reduce the time and cost for other organizations faced with implementing user- or subscriber-management projects also are described. View full abstract»

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  • A practical QoS solution to voice over IP in IEEE 802.11 WLANs

    Page(s): 111 - 117
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    In this article we study the behavior of voice over IP traffic in IEEE 802.11 wireless networks. Specifically, we design a QoS provisioning mechanism for VoIP traffic, and propose a practical solution of configuring the 802.11e enhanced distributed control access parameter sets for different types of traffic. We show that media access control layer only methods may be insufficient, but the demonstrated cross-layer (layers 2, 3, and 4) method works simply and efficiently. We find that the EDCA parameter sets of the access point are not always necessarily set more aggressively than those of wireless stations even though the traffic load of AP is much heavier than the stations. With our mechanism, the EDCA parameter sets can be easily configured via software interface for off-theshelf WiFi phone products, and there is no need to modify the operations of APs or 802.11 MAC layer protocols. The performance of our mechanism is evaluated via ns-2 simulations and via laboratory experiments over Quanta's O2 dual mode handsets. The results show our mechanism can provide effective and efficient QoS provisioning for VoIP traffic in IEEE 802.11 WLANs. Since the configuration may be readily configured in the field and the performance is robust across a wide range of environments, we believe that organizations deploying and operating WiFi networks for VoIP may benefit from our work and reduce or eliminate post-deployment tuning and debugging. View full abstract»

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  • The design of a highly available enterprise ip telephony network for the power utility of Serbia company

    Page(s): 118 - 122
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    The Power Utility of Serbia Company intends to migrate portions of its time-division-multiplexing- based telephony network to IP. The high-level, capital project requirements include: (a) building a new VoIP infrastructure; (b) exchanging approximately one-third of the existing TDM-based PBXs with new VoIP based and hybrid PBXs; and (c) integrating these new PBXs with the remaining existing legacy PBXs to create a new hybrid network. Telephony service availability should be five nines (99.999 percent), a requirement that created a derived requirement for network element redundancy. One of the most important elements is the softswitch. The softswitch is the equipment responsible for call control of IP phones and voice gateways at the level of the Power Utility of Serbia Company telephone network. Softswitch redundancy in a failover configuration proved to be most challenging because of a performance requirement to achieve a switchover time of six seconds or less, whereas commercially available softswitches typically support switchover times of a few minutes. Another significant challenge was integrating the legacy PBXs and new (VoIP) PBXs. Although industry marketing promotes SIP trunking as the preferred integration/interconnection method, we found that with the exception of bearer traffic (voice media) pathing, service interoperability between the equipment of different vendors was often problematic. Vendors typically suggest Q.Sig as an interconnection alternative when SIP trunking is infeasible, but some vendor interoperability problems persisted. This article presents technical solutions to these major issues that can benefit similar TDM-to-IP migration and hybridization projects. View full abstract»

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Aims & Scope

IEEE Communications Magazine covers all areas of communications such as lightwave telecommunications, high-speed data communications, personal communications systems (PCS), ISDN, and more.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Sean Moore
Centripetal Networks