4 General aspects

25.4273GPPRelease 17TSUTRAN Iub/Iur interface user plane protocol for DCH data streams

The specification of Iub DCH and E-DCH data streams is also valid for Iur DCH and E-DCH data streams.

The complete configuration of the transport channel is selected by the SRNC and signalled to the Node B via the Iub and Iur control plane protocols.

The parameters of a transport channel are described in TS 25.301 [1]. Transport channels are multiplexed on the downlink by the Node B on radio physical channels, and de-multiplexed on the uplink from radio physical channels to transport channels.

In Iur interface, every set of coordinated transport channels related to one UE context that is communicated over a set of cells that are macro-diversity combined within Node B or DRNC, is carried on one transport bearer. This means that there are as many transport bearers as set of coordinated transport channels and Iur DCH data ports for that communication.

In Iub interface, every set of coordinated transport channels related to one UE context that is communicated over a set of cells that are macro-diversity combined within Node B is carried on one transport bearer. This means that there are as many transport bearers as set of coordinated transport channels and Iub DCH data ports for that communication.

Bi-directional transport bearers are used.

4.1 DCH and E-DCH FP services

DCH frame protocol provides the following services:

– Transport of TBS across Iub and Iur interface.

– Transport of outer loop power control information between the SRNC and the Node B.

– Support of transport channel synchronisation mechanism.

– Support of node synchronization mechanism.

– [3.84 Mcps TDD and 7.68 Mcps – Transfer of Rx timing deviation from the Node B to the SRNC.]

– Transfer of radio interface parameters from the SRNC to the Node B.

[FDD – E-DCH frame protocol provides the following services:

– Transport of MAC-es or MAC-is PDUs across Iub and Iur interface from Node B to SRNC.

– Transport of outer loop power control information between the SRNC and the Node B.

– Transfer of radio interface parameters from the SRNC to the Node B.

– Transport of network congestion indication from SRNC across Iub and Iur interface.

– Transport of hybrid ARQ information between SRNC and Node B.]

[TDD – E-DCH frame protocol provides the following services:

– Transport of MAC-es or MAC-is PDUs across Iub and Iur interface from Node B to SRNC.

– Transport of outer loop power control information between the SRNC and the Node B.

– Transport of network congestion indication from SRNC across Iub and Iur interface.

– Transport of hybrid ARQ information between SRNC and Node B.]

4.2 Services expected from the Data Transport Network layer

Following service is required from the transport layer:

– Delivery of FP PDU.

In sequence delivery is not required. However, frequent out-of-sequence delivery may impact the performance and should be avoided.

4.3 Protocol Version

This revision of the specification specifies version 1 of the protocol.