QoS Control in the 3GPP Evolved Packet System

In this article we describe the QoS concept of the evolved packet system, which was standardized in 3GPP Release 8. The concept provides access network operators and service operators with a set of tools to enable service and subscriber differentiation. Such tools are becoming increasingly important as operators are moving from a single to a multi-service offering at the same time as both the number of mobile broad-band subscribers and the traffic volume per subscriber is rapidly increasing. The "bearer" is a central element of the EPS QoS concept and is the level of granularity for bearer-level QoS control. The network-initiated QoS control paradigm specified in EPS is a set of signaling procedures for managing bearers and controlling their QoS assigned by the network. The EPS QoS concept is class-based, where each bearer is assigned one and only one QoS class identifier by the network. The QCI is a scalar that is used within the access network as a reference to node-specific parameters that control packet forwarding treatment. This class-based approach, together with the network-initiated QoS control paradigm, gives network operators full control over the QoS provided for its offered services for each of its subscriber groups.