Europe and the world have progressed beyond slow-speed radio access based on GPRS. In many countries, 3G UMTS or even the high-speed downlink version HSDPA are becoming commonplace. Mobile and fixed operators are also developing roaming and interworking deals, to allow multi-mode terminals (e.g. terminals with WLAN and with 3G radio access) to smoothly migrate between the two technologies, as the user desires. NEC has had such a product – the N900iL - on the market in Japan, in cooperation with NTT DoCoMo, since October 2004.

The goal of the traffic engineering work is to develop and optimize mechanisms to provide the desired QoS guarantees in such combined IP-based 3G UMTS and WLAN terminals and networks, as well as to consider alternative radio access networks such as WiMAX.

The IEEE 802.11e standard defines mechanisms to provide Quality of Service which are required to guarantee a proper service to certain key applications, e.g., VoIP. However, the proper configuration of these mechanisms as well as the design of the algorithms required for delivering the desired services are left open to implementors. One activity in this area focuses on the design and configuration of the necessary traffic engineering mechanisms for 802.11e to provide the desired levels of QoS and power saving in the case of dual-mode 3G terminals.

Another area of activity, which has gained in visibility with the release of 802.16e, is the use of WiMAX for cellular communications. The IEEE 802.16 technology is a promising alternative to 3G or wireless LAN for providing last-mile connectivity by radio link due to its large coverage area, relatively low cost of metropolitan-area deployment and high speed data rates. However, in order to compete with already well-established wireless technologies, WiMAX has to show that it outperforms legacy wireless technologies significantly. Evaluating the potential of the 802.16 technology, qualitatively and quantitatively, to improve the performance of the already existing technologies, is a key area for the traffic engineering team.

The tool of choice for all this work is the packet-based real-time simulation tool OPNET. Many real-world scenarios and designs have been considered in previous projects. The optimizations undertaken have a direct impact on future product performance. But OPNET is only a tool. Obtaining reliable and valuable results depend on a deep knowledge of the relevant protocols. For example: the project leader was one of the major contributors to 802.11e and the team has a long history of standards and QoS research as shown by the publications list below.

A. Banchs, X. Pérez, W. Pokorski, M. Radimirsch: A Proposal for Wireless MAC Multimedia Extensions. IEEE 802.11-00/205. July 2000.

A. Banchs, X. Pérez, M. Radimirsch, S.Sallent: Service Differentiation Extensions for IEEE 802.11. In 11 th Workshop on Local and Metropolitan Area Networks (LANMAN 2001), Boulder, USA, March 2001.

A. Banchs, X. Pérez, M. Radimirsch, H. Stuettgen: Service Differentiation Extensions for Elastic and Real-Time traffic in 802.11 Wireless LAN. In Proceedings of the IEEE Conference on High Performance Switching and Routing (HPSR 2001), Dallas, USA, May 2001.

A. Banchs, X. Pérez: Distributed Weighted Fair Queuing in 802.11 Wireless LAN. In proceedings of the IEEE International Conference on Communications (ICC2002), New York, USA, April 2002.

A. Banchs, X. Pérez: An Assured Rate Service Extension for 802.11 Wireless LAN. In Proceedings of the IEEE Wireless Communications and Networking Conference (WCNC 2002), Orlando, USA, March 2002.

A. Banchs, M. Radimirsch, X. Pérez: Assured and Expedited Forwarding Extensions for IEEE 802.11 Wireless LAN. In Proceedings of the tenth IEEE/IFIP International Workshop on Quality of Service (IWQoS 2002), Miami, USA, May 2002.

A. Banchs, X. Pérez, D. Qiao: Providing Throughput Guarantees in IEEE 802.11e Wireless LANs. In Proceedings of  the International Teletraffic Congress , Berlin , Germany , August 2003.

X. Pérez, A. Banchs, J. Noguera, S. Sallent-Ribes: Optimal Radio Acess Bearer Configuration for Voice over IP in 3G UMTS networks. Accepted for publication at the European Wireless conference, 2004.

R. Schmitz, H. Hartenstein, T. Melia, X. Pérez-Costa, W. Effelsberg: Der Einfluss von Schwankungen der Übertragungsreichweite auf die Leistungsfähigkeit von Ad-Hoc Netzwerken. 18 DFN Arbeitstagung über Kommunikationsnetze. Published in LNCS, Düsseldorf , Germany , June 2004.

C. Bettstetter, H. Hartenstein, X. Pérez-Costa: Stochastic properties of the random waypoint mobility model. ACM/Kluwer Wireless Networks, Special Issue on Modeling and Analysis of Mobile Networks, vol. 10, no. 5, Sept 2004.

X. Pérez-Costa, D. Camps-Mur: ASPM: Bounding the Downlink Delay for 802.11 Power Save Mode. In Proceedings of IEEE International Conference on Communications (ICC), Seoul , Korea , May 2005.

M. Liebsch, X. Pérez-Costa: Utilization of the IEEE802.11 Power Save Mode with IP Paging, Proceedings of IEEE International Conference on Communications (ICC), Seoul, Korea. May 2005.

X. Pérez-Costa, K. Heinze, A. Banchs and S. Sallent-Ribes: Analysis of Performance Issues in an IP-based UMTS Radio Access Network. ACM Workshop on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWiM), Montreal, Canada, October 2005.

X. Pérez-Costa, A. Vidal, D. Camps-Mur: On the Integration of IEEE 802.11e QoS and Power Saving Mechanisms in Battery-limited Mobile Devices. European Wireless Conference (EW), Athens, Greece, April 2006.

X. Pérez-Costa, D. Camps-Mur: AU-APSD: Adaptive IEEE 802.11e Unscheduled Automatic Power Save Delivery, in Proceedings of IEEE International Conference on Communications (ICC), Istanbul, Turkey, June 2006.