7.3.6 Details of MAC-e

25.3193GPPEnhanced uplinkOverall descriptionStage 2TS

There is one MAC-e entity in the NodeB for each UE and one E-DCH scheduler function in the Node-B. The MAC-e and E-DCH scheduler handle Enhanced Uplink specific functions in the NodeB. In the model below, the MAC-e and E-DCH scheduler comprises the following entities:

– E-DCH Scheduling:
This function manages E-DCH cell resources between UEs. Based on scheduling requests, Scheduling Grants are determined and transmitted. The general principles of the E-DCH scheduling are described in subclause 9.1 below. However implementation is not specified (i.e. depends on RRM strategy).

– E-DCH Control:
The E-DCH control entity is responsible for reception of scheduling requests and transmission of Scheduling Grants. The general principles of the E-DCH scheduling are described in subclause 9.1 below.

– De-multiplexing:
This function provides de-multiplexing of MAC-e PDUs. MAC-es PDUs are forwarded to the associated MAC-d flow.

– HARQ:
One HARQ entity is capable of supporting multiple instances (HARQ processes) of stop and wait HARQ protocols. Each process is responsible for generating ACKs or NACKs indicating delivery status of E-DCH transmissions. The HARQ entity handles all tasks that are required for the HARQ protocol.

The associated signalling shown in the figure illustrates the exchange of information between layer 1 and layer 2 provided by primitives.

Figure 7.3.6-1: UTRAN side MAC architecture / MAC-e details (FDD only)

Figure 7.3.6-2: UTRAN side MAC architecture / MAC-e details (TDD only)