Providing QoS Guarantee in 3G Wireless Networks

The General Packet Radio Service (GPRS), the current enhancement in the Global System for Mobile Communications (GSM) infrastructure (GSM Phase 2+), is developed to provide packet data (Internet) services to mobile users. However, GPRS still has its own limitation in terms of the maximum throughputs (144Kbps) and the QoS features it can offer to mobile clients. Universal Mobile Telecommunication System (UMTS) Release 99 was designed to offer more airlink bandwidth (1Mbps) and QoS features. An important issue in the Internet and consequently in every network connected to it, is support for multimedia applications (voice, video and data). These applications have specific requirements in terms of delay and bandwidth which call for alternative service models and traffic management schemes that can offer the required QoS in IP network. IETF diffserv mechanism is designed to provide xxx. In addition, RSVP signaling mechanism is designed to provide end-to-end QoS negotiation. In order for mobile hosts in UMTS network to enjoy end-to-end QoS for multimedia applications with other IP hosts in an IP network, one needs to understand clearly how the UMTS QoS management functions can be integrated with IP QoS management functions. The rest of the paper is organized as follows: In Section 2, we describe the UMTS QoS architecture. Then, we discuss the QoS management functions available in UMTS network in Section 3. In Section 4, we describe the QoS classes and their attributes. In Section 5, we describe three different end-to-end QoS scenarios. Then, we describe how RSVP signaling can be integrated with UMTS QoS mechanisms for end-to-end QoS negotiation. Next, we describe how QoS can be provided at the airlink, how UMTS QoS classes can be mapped to the QoS classes available at the transport plane. In Section 6, we describe the procedures for handovers between 2G/3G and 3G/2G networks. We also discuss how the QoS parameters for Release 97/98 can be mapped to Release 99 and vice versa. Lastly, we describe enhancements to the QoS renegotiation process across the Iu interface that can help to reduce the handover latency.