Optimal network selection in heterogeneous wireless multimedia networks Pengbo Si Æ Hong Ji Æ F. Richard Yu Published online: 5 August 2009 Ó Springer Science+Business Media, LLC 2009 Abstract The complementary characteristics of different wireless networks make it attractive to integrate a wide range of radio access technologies. Most of previous work on integrating heterogeneous wireless networks concen- trates on network layer quality of service (QoS), such as blocking probability and utilization, as design criteria. However, from a user’s point of view, application layer QoS, such as multimedia distortion, is an important issue. In this paper, we propose an optimal distributed network selection scheme in heterogeneous wireless networks considering multimedia application layer QoS. Specifically, we formu- late the integrated network as a restless bandit system. With this stochastic optimization formulation, the optimal net- work selection policy is indexable, meaning that the network with the lowest index should be selected. The proposed scheme can be applicable to both tight coupling and loose coupling scenarios in the integration of heterogeneous wireless networks. Simulation results are presented to illustrate the performance of the proposed scheme. 1 Introduction In recent years, with the rapid growth of wireless com- munication systems, the complementary characteristics of different wireless networks make it attractive to integrate a wide range of radio access technology (RAT) standards, including wireless wide area networks (WWANs) like cellular networks, wireless metropolitan area networks (WMANs) like WiMAX networks, and wireless local area networks (WLANs) like IEEE 802.11 based networks. Several internetworking architectures between cellular and other RAT systems have been proposed. Loose cou- pling and tight coupling are the two generic approaches to the integration specified by European Telecommunications Standards Institution (ETSI) [1]. In the loose coupling approach, data flows from different types of networks go to the external IP network directly, and only signaling is required between cellular networks and other comple- mentary networks. In the tight coupling approach, com- plementary networks communicate with the external network through the cellular networks. In addition, an in- ternetworking architecture is developed by the Third Generation Partnership Project (3GPP) to enable the radio resource reuse between the networks as well as the authentication, authorization and accounting (AAA) [2]. To improve the performance of heterogeneous networks and keep users always best connected (ABC) [3], a number of schemes are proposed to deal with the network integration problems. Analytical hierarchy process (AHP) and grey relational analysis (GRA) are used in [4] to combine mul- tiple network selection criteria and decide the weights of the criteria according to the user preferences and service applications. In [5–7], several resource management and admission control schemes are proposed in cellular/WLAN integrated networks. Authors of [8] propose an architectural This work was supported in part by the National Science Foundation of China under Grant 60672124 and 60832009, the Hi-Tech Research and Development Program (National 863 Program) under Grant 2007AA01Z221, and the National Key Basic Research and Development Plan of China (973 Program) under Grant 2009CB320400. F. R. Yu Department of Systems and Computer Engineering, Carleton University, Ottawa, ON, Canada P. Si (&)  H. Ji Key Laboratory of Universal Wireless Communication, Ministry of Education, Beijing University of Posts and Telecommunications, Beijing, People’s Republic of China e-mail: sipb.bupt@gmail.com 123 Wireless Netw (2010) 16:1277–1288 DOI 10.1007/s11276-009-0202-1