Towards a QoE-Driven Resource Control in LTE and LTE-A Networks

Table 1

Role of the main EPS interfaces.

Interface	Role
Gx	Used by the PCRF to convey policy enforcement to the P-GW
Gxx	Bearer binding and event reporting function
Rx	Used by application function to convey policy data to the PCRF
Sp	Retrieving per subscriber policy data
Sd	Used to identify/inform about the ongoing session details from the TDF
SGi	It is the reference point between the P-GW and the PDN (e.g., Internet)
S5	Signaling interface for establishing bearers between S-GW and P-GW
S6a	Used by the MME to retrieve subscriber data from HSS
S11	Used by the MME to control path switching and bearer establishment in S-GW
S1-MME	Signaling interface between the eNB and the MME
S1-U	User plane between eNB and S-GW
Uu	This is the air interface between UE and eNB
Gy	Online charging information
Gz	Offline charging information