E-TFC (E-DCH Transport Format Combination)

Only the UE has accurate knowledge about the buffer situation and power situation in the UE at the time of transmission of the transport block in the UL. Hence the UE is allowed to autonomously select the data rate or E-TFC.

E-TFC is responsible for selecting the TF of the E-DCH and to control MAC-e multiplexing.

NodeB scheduler handles resource allocation between UEs, the E-TFC Selection controls resource allocation between flows within the UE.

E-DCH needs to be coexist with DCHs. Therefore a basic requirement is to serve DCH traffic first and only spend otherwise unused power resources on the E-DCH.
TFC Selection is two step process. First the normal DCH TFC selection is performed then UE estimates the remaining power and TFC Selection step is performed where E-DCH can use the remaining power.