3GPP TS 23.107 describes the QoS concept and architecture. In addition, it provides QoS parameters based on the UMTS bearer service. To ensure the QoS of a network, bearer services with explicit attributes and functions must be set up between the transmitter and the receiver. A bearer service involves all the aspects that are required to ensure specific QoS. These aspects are included in control plane signaling, user plane transmission and QoS management.
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| UMTS QoS Architecture |
As shown in the picture, the traffic from one terminal equipment (TE) to another passes different levels of bearer services. The TE is connected to the UMTS network through a mobile terminal (MT). The end-to-end service at the application layer is implemented through the bearer services of the underlying networks. The end-to-end service consists of the local bearer service, UMTS bearer service, and external bearer service. These services ensure the QoS of the end-to-end service. They are described as follows:
- The local bearer service is beyond the UMTS research scope.
- The external bearer service is coordinated by the telecom operator with the connected networks. Between the UMTS bearer service and the external bearer service, QoS mapping is required. Through the QoS mapping, the QoS requirement is sent to the next network element (NE).
- The coordination and QoS mapping between UMTS bearer services is very important for implementing the end-to-end QoS of UMTS.
The UMTS bearer service consists of the radio access bearer (RAB) service and the core network bearer (CNB) service.
The RAB service is implemented through the radio bearer (RB) service and Iu bearer service. The RB service covers all the aspects of the transmission on the radio interface, and the Iu bearer service provides the transmission between the UTRAN and the CN. For PS services, the Iu bearer service can provide different QoS classes.
The role of the CNB is to provide a negotiated UMTS bearer service. The CN provides different QoS classes for different backbone bearer services. A specific backbone bearer service can be selected to meet the QoS requirement of the CN bearer service.
The RAB service involves the Uu, Iub, Iur, and Iu interfaces.
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