IEEE Communications Magazine ~ April 2009, Vol. 47, No. 4

FEATURE ARTICLES

LTE Part II: Radio AccessKalyani Bogineni, Reiner Ludwig, Preben Mogensen, Vish Nandlall, Vojislav Vucetic, Byung K. Yi, and Zoran Zvonar
LTE: The Evolution of Mobile Broadband
The authors provide 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.
David Astély, Erik Dahlman, Anders Furuskär, Ylva Jading, Magnus Lindström, and Stefan Parkvall, Ericsson Research

The LTE Link-Layer Design
The authors describe the LTE link-layer protocols, which abstract the physical layer and adapt its characteristics to match the requirements of higher layer protocols. They provide 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.
Anna Larmo, Magnus Lindström, Michael Meyer, Ghyslain Pelletier, Johan Torsner, and Henning Wiemann, Ericsson Research

Coexistence Studies for 3GPP LTE with Other Mobile Systems
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. The authors provide an overview of these studies.
Man Hung Ng, Shen-De Lin, Jimmy Li, and Said Tatesh, Alcatel-Lucent

Improvements to Seamless Vertical Handover between Mobile WiMAX and 3GPP UTRAN through the Evolved Packet Core
The authors present an improved IP-based vertical handover technology for mobile WiMAX, 3GPP legacy systems, and 3G Long Term Evolution. The technology is based on existing optimized handover techniques between mobile WiMAX and 3GPP accesses.
William J. Song, Jong-Moon Chung, and Daeyoung Lee, Yonsei University Chaegwon Lim, Sungho Choi, and Taesun Yeoum, Samsung Electronics Co. LTD

Interference Coordination and Cancellation for 4G Networks
The authors provide an overview of contemporary and forward looking inter-cell interference coordination techniques for 4G OFDM systems with a specific emphasis on implementations for LTE.
Gary Boudreau, John Panicker, Ning Guo, Rui Chang, Neng Wang, and Sophie Vrzic, Nortel

The LTE/SAE Trial Initiative: Taking LTE/SAE from Specification to Rollout
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 author provides an overview of the activities and gives an update on the results published so far.
Julius Robson, Nortel and LSTI


.html>Topics in Design and Implementation IIISean Moore
XMPP: Lessons Learned from Ten Years of XML Messaging
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.
Peter Saint-Andre, XMPP Standards Foundation

Service Broker Architecture: Location Business Case and Mashups
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.
Salvatore Loreto, Tomas Mecklin, Miljenko Opsenica, and Heidi-Maria Rissanen, Ericsson Research

The Design and Implementation of an Extensible, User-Management Service for Communications Applications
The author 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.
Deborah Hill, Avaya

A Practical QoS Solution to Voice over IP in IEEE 802.11 WLANs
The authors study the behavior of voice over IP traffic in IEEE 802.11 wireless networks. Specifically, they 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.
JengFarn Lee, National Chung Cheng University; Wanjiun Liao, Jie-Ming Chen, and Hsiu-Hui Lee, National Taiwan University

The Design of a Highly Available Enterprise IP Telephony Network for the Power Utility of Serbia Company
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: building a new VoIP infrastructure; exchanging approximately one-third of the existing TDM-based PBXs with new VoIP-based and hybrid PBXs; and integrating these new PBXs with the remaining existing legacy PBXs to create a new hybrid network.
Nenad Krajnovic, University of Belgrade


.html>Topics in Integrated Circuits for CommunicationsCharles Chien, Zhiwei Xu, and Stephen Molloy
Digital Techniques for Integrated Frequency Synthesizers: A Tutorial
Frequency synthesizers are essential components of modern, integrated wireless transceivers. Traditional analog and mixed-signal circuit design techniques are proving ineffective in achieving the challenging performance demands placed on these synthesizers, particularly in very fine fabrication technologies. Digital-intensive architectures and related digital signal processing techniques offer a robust, scalable alternative.
Sudhakar Pamarti, University of California, Los Angeles

Design and Implementation of a CMOS 802.11n SoC
The authors discuss various MAC and PHY level modifications introduced in 802.11n, as well as the architecture, design trade-offs, and implementation details of a two spatial stream CMOS 802.11n-draft-compliant SoC.
Sundar G. Sankaran, Masoud Zargari, Lalitkumar Y. Nathawad, Hirad Samavati, Srenik S. Mehta, Alireza Kheirkhahi, Phoebe Chen, Ke Gong, Babak Vakili-Amini, Justin A. Hwang, Shuo-Wei Mike Chen, Manolis Terrovitis, Brian J. Kaczynski, Sotirios Limotyrakis, Michael P. Mack, Haitao Gan, Meelan Lee, Richard T. Chang, Hakan Dogan, Shahram Abdollahi-Alibeik, Burcin Baytekin, Keith Onodera, Suni Mendis, Andrew Chang, Yashar Rajavi, Steve Hung-Min Jen, and David K. Su, Atheros Communications; Bruce A. Wooley, Stanford University

A Single-Chip CMOS Bluetooth v. 2.1 Radio SoC
Bluetooth® radios are becoming pervasive in small, battery-powered devices. This is being driven by the reduced area requirements, cost, and power consumption of Bluetooth chips. As process technology scales down to 0.13 mm CMOS and beyond, the opportunities to trade off digital complexity to reduce analog requirements can enable optimized radio designs. This article presents an architecture on both the transmitter and receiver that can optimize this digital/analog trade-off while still meeting all system requirements.
Paul Husted, William W. Si, David Weber, Shahram Abdollahi-Alibeik, MeeLan Lee, Richard Chang, Hakan Dogan, Haitao Gan, Yashar Rajavi, Susan Luschas, Soner Ozgur, and Masoud Zargari, Atheros Communications