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Xavier Pérez Costa
NEC Network Laboratories Heidelberg, NEC Europe Ltd.
perez@netlab.nec.de
Abstract
The wide adoption of the IEEE 802.11 wireless LAN technology by home and business users, due to its capability of providing a low cost high speed wireless Internet access, is driving a strong trend toward the inclusion of this technology in mobile devices like cellular phones, personal digital assistants (PDAs) and laptops. Several challenges though need to be addressed with respect to QoS and power saving requirements to achieve a seamless integration of Wireless LAN in such devices. IEEE 802.11e, which defines mechanisms to improve Wireless LAN QoS and power saving performance, represents a basic element toward this integration since it provides the means to support key applications as Voice over IP with stringent QoS requirements and to ensure reasonable battery duration for power-limited devices.
In this tutorial the challenges and available solutions when integrating the 802.11 technology in mobile devices will be discussed covering the IEEE 802.11 and WiFi Alliance efforts and providing results of simulations studies plus practical cases.
Tutorial outline:
�� Overview of the deficiencies of the IEEE 802.11 MAC layer to provide the QoS and power saving performance required by mobile convergence devices
�� Description of the solutions provided by the 802.11e specification:
- QoS mechanisms: Enhanced Distributed Channel Access (EDCA) and HCF Controlled Channel Access (HCCA)
- Power Saving mechanisms: Unscheduled Automatic Power Save Delivery (U-APSD) and Scheduled Automatic Power Save Delivery (S-APSD)
�� Review of the current status of the relevant activities in the IEEE 802.11 and WiFi Alliance working groups, e.g., Task Group E (QoS), R (Fast Roaming) and K (Radio Resource Measurements) for 802.11 and WCC (WiFi Cellular Convergence), VoWiFi (Voice over WiFi) and QoS for WiFi
�� Identification of QoS and power saving algorithms needed for taking advantage of the 802.11e mechanisms, review of related work available in the literature and description of possible solutions for the parts that have not been addressed yet by the research community
�� Analysis of the expected performance of first 802.11e-capable mobile devices, i.e., including a subset of the possible 802.11e QoS enhancements
�� Review of current convergence mobile devices examples, e.g., NEC 3G/WLAN terminal N900iL
�� Overview of open issues and research directions
The intended audience includes students, faculty and engineers interested in the challenges when integrating Wireless LAN in power-limited mobile devices. The attendees are expected to have a basic understanding of computer networking and familiarity with the IEEE 802.11 MAC layer
The work presented in this tutorial is the result of the joint collaboration between Toshiyuki Sashihara, Daniel Camps, Albert Vidal, Jordi Palau, David Rebolleda and Xavier Pérez Costa
Biography XAVIER PÉREZ COSTA:
XavierPérez Costa is a senior researcher at NEC Network Laboratories in Heidelberg, Germany, where he is currently managing a team which evaluates and configures Wireless LAN QoS and power saving mechanisms for NEC's 3G/WLAN mobile terminals. He is the author of several technical papers and patent applications in this area and participates in the 802.11 standardization effort as well as in the WiFi certification program. Xavier did his master thesis at NEC in the area of QoS for wireless LANs in 2000 and was hired after that to focus on IP-based mobility management issues in the framework of the European project Moby Dick. He received both a Telecommunications Engineering degree (2000) and a Telematic Engineering PhD degree (2002-2005) from the Polytechnic University of Catalonia (UPC), Barcelona. His general research interests include, among others, wireless technologies, mobile networking, and theoretical computer science.