Heterogeneous Signaling Framework for End-to-end QoS support in Next Generation networks Rui Prior 1 , Susana Sargento 2 , Diogo Gomes 2 , Rui L. Aguiar 2 1 DCC & LIAAC, Faculdade de Ciências da Universidade do Porto, Portugal 2 Universidade de Aveiro, Instituto de Telecomunicações, Portugal Abstract Next generation wireless communication systems aim to handle diverse types of services across different types of access technologies in a seamless way. This paper proposes a next generation network architecture and evaluates possible associated signaling strategies, focusing in network-level QoS support aspects. The scenarios handled cover terminal-initiated signaling, network controlled signaling, and application-provider controlled signaling. Possible message sequence charts associated with these scenarios are presented and discussed. The paper compares the relative merits of each approach and concludes that the optimum QoS signaling solution depends on the QoS models that will be used, which are directly related to the business models chosen by the operators. 1. Introduction Next generation wireless communication systems will handle diverse types of services, across different types of access technologies. This trend, already present in 3G networks and in the current explosion of hotspots, is expected to become an universal characteristic in communications by the end of this decade. Providing mobility across domains using different access technologies in a seamless way, with no perceived service degradation for the user, is a major requisite for the next generation networks. Scalability concerns make this requirement still harder. Current wireless operators have dozens of millions of customers, and, as cell sizes decrease, handovers will become more and more frequent, potentially reaching the hundred thousands per second in a large telecom operator. The scalable support for end-to-end QoS in such a universal mobile and heterogeneous scenario is one of the main topics in networks research nowadays. This technical problem is further compounded by the complex telecom business, with multiple types of operators foreseen in the market, covering a wide range, from basic transport to intelligent service and multimedia provision. Although the use of the IPv6 protocol as a convergence layer much simplifies the support for seamless mobility and QoS across heterogeneous networks, the provision of multimedia and value-added services in such multi- provider environments requires a common signaling framework for session negotiation, network resource reservation plus session and QoS renegotiation. This framework must integrate application signaling and resource reservation protocols in order to ensure that enough resources are available for a good user-perceived service quality, and that the use of those resources is authorized. Thus, proper interaction between QoS and both mobility and charging mechanisms has to be in place. The aim of this paper is the presentation of a next- generation 4G architecture (focusing on QoS-related entities) and the evaluation of the different associated signaling strategies that may be used. The paper analyzes their merits and shortcomings with regard to session setup and negotiation, session renegotiation and seamless handovers, as well as the security and flexibility provided by each signaling solution. The different concepts of signaling strategies are analyzed according to four major scenarios, discussed at session setup and renegotiation time: (i), the mobile terminal itself performs the QoS requests to a QoS Broker (responsible for resource management at the access network); (ii) a service proxy is responsible for requesting network resources to the QoS Broker; and (iii) a novel network entity, usually co- located at the access router, capable of QoS and application signaling (and signaling parsing and modification) issues the QoS requests. The rest of the paper is organized as follows. Section 2 presents the basic components considered in the network architecture. Section 3 presents the different signaling scenarios and illustrates their main characteristics using message signalling charts. Section 4 performs a comparison between these different strategies, and section 5 discusses our key conclusions. 2. Network architecture Next generation communication systems will aim at providing seamless mobility of users through networks with different access technologies and services. In this sense, the network needs to be capable of supporting heterogeneous access technologies. These communication systems, usually referred to as 4G networks [8], may support network technologies such as Wireless Fidelity (Wi-Fi), Universal Mobile Terrestrial System (UMTS), and new emerging technologies, such as WiMax and Digital Video Broadcast – Terrestrial (DVB-T). These technologies are quite different from each other, ranging 0-7695-2268-8/05/$20.00 (C) 2005 IEEE Proceedings of the 38th Hawaii International Conference on System Sciences - 2005 1