Abstract

Radio resource management is a fundamental task in wireless and cellular networks in order to provide transmission capacity to different traffic flows and to guarantee an adequate Quality of Service (QoS) in terms of different parameters such as delay bound, packet loss, fairness, delay jitter, etc. Moreover, radio resources are scarce and, therefore, need to be employed in an efficient way [1]. Typically, QoS support and resource utilization are conflicting requirements that lead to a significant complexity for the design of the air interface.

The design of new cellular and wireless systems to be integrated into the 4G scenario calls for optimization to achieve a high capacity for radio transmissions while fulfilling the above differentiated QoS requirements.

The conventional ISO-OSI protocol stack is based on independent layers, thus precluding the adaptation of each layer according to changing system conditions. Such architecture consists of a layered stack of protocol modules, each of which solving a specific problem. In such architecture, the communication only happens between adjacent layers. The dynamic nature of wireless communications (i.e., varying radio channel, varying traffic load conditions, varying protocol dynamics, varying network topology, etc.) calls for new solutions to improve the performance and the efficiency of the air interface. It is therefore more and more important to study the interworking and the combination of different techniques on different layers as well as to specify and to exploit the information flow across layers. These techniques are usually referred to as cross-layer design . The scope of this tutorial is to study the new cross-layer approach for the optimization of the air interface protocol stack as a whole, by also exploiting the possibility of interactions among non-adjacent protocol layers. This is an i nterdisciplinary research field that requests new methods and techniques.

New interfaces are needed beyond the classical ones among adjacent layers. These interfaces contain Service Access Points (SAPs) through which control information can be exchanged. The main interest here is on IP-based scenarios.

Dr. Giovanni Giambene

Dipartimento di Ingegneria dell'Informazione, Università degli Studi di Siena,

Via Roma, 56 - 53100 Siena, Italy

Giovanni Giambene was born in Florence, Italy, in 1966. He received the Dr. Ing. degree in Electronics from the University of Florence, Italy, in 1993 and the Ph.D. degree in Telecommunications and Informatics from the University of Florence, Italy, in 1997. From 1994 to 1997, he was with the Electronic Engineering Department of the University of Florence, Italy. He was Technical External Secretary of the European Community COST 227 Action, entitled "Integrated Space/Terrestrial Mobile Networks". He also contributed to the Resource Management activity of the Working Group 3000 within the RACE Project, called "Satellite Integration in the Future Mobile Network" (SAINT, RACE 2117). From 1997 to 1998, he was with OTE of the Marconi Group, Florence, Italy, where he was involved in a GSM development program. In the same period he also contributed to the COST 252 Action ("Evolution of Satellite Personal Communications from Second to Future Generation Systems") research activities by studying the performance of Packet Reservation Multiple Access (PRMA) protocols suitable for supporting voice and data transmissions in low earth orbit mobile satellite systems. In 1999 he joined the Information Engineering Department of the University of Siena, Italy, first as research associate and then as assistant professor. He teaches the advanced course of Telecommunication Networks at the University of Siena. From 2000 to 2003, he contributed to the activities of the "Personalised Access to Local Information and services for tOurists" (PALIO) IST Project within the fifth Research Framework of the European Commission (www.palio.dii.unisi.it). At present, he is involved in the SatNEx network of excellence of the FP6 programme in the satellite field, as work package responsible on radio access techniques (www.satnex.org). He is also vice-Chair of the COST 290 Action (www.cost290.org), entitled "Traffic and QoS Management in Wireless Multimedia Networks" (Wi-QoST). His research interests include third-generation mobile communication systems, medium access control protocols, traffic scheduling algorithms, and queuing theory.