3gpp tr ab cde

System improvements

1. Control and User Plane Separation of EPC nodes

Summary based on the input provided by Huawei in SP-170520.

720008	Control and User Plane Separation of EPC nodes	CUPS	1		SP-160316
690052	Study on Control and User Plane Separation of EPC nodes	FS_CUPS	2	S2	SP-150519
720009	Control and User Plane Separation of EPC nodes	CUPS	2	S2	SP-160316
730001	CT aspects for CUPS	CUPS-CT	2	CT	CP-160579
730039	CT3 aspects for CUPS	CUPS-CT	3	C3	CP-160579
730040	CT4 aspects for CUPS	CUPS-CT	3	C4	CP-160579

This Work Item separates the S/P-GW and the TDF functionality into user plane functions and control plane functions. This is provided as a solution to the ever-growing data traffic while maintaining a low latency for services such as social networks or web browsing.

In addition, a flexible placement of user plane functions (e.g. centrally or closer to the RAN) is enabled, while the control plane functions could still remain centralized and continue to support the interfaces to the other network entities (like MME, PCRF, Charging Systems).

TS 23.214 [1] specifies the stage 2 level functionality for control and user plane separation of EPC's SGW, PGW and TDF. Updates to procedures in other specifications (TS 23.401 [2], TS 23.203 [3], TS 23.402 [4] and TS 23.060 [5]) are described therein as well.

The overall functionality provided by the SGW, PGW and TDF is not changed and none of the other EPC entities is affected, which means:

- Interworking with networks not applying control and user plane separation works as without it (i.e. in case of roaming scenarios);

- Separated network entities can be deployed together with network entities that are not separated within the same network;

- Deployment of Separated network entities does not require any updates for UE or Radio Access Network.

The following figure shows the architecture reference model in the case of separation between control plane and user plane and covers non-roaming as well as home routed and local breakout roaming scenarios. Only the complementary aspects of the architecture reference models specified in TS 23.401 [2] clause 4.2 and TS 23.402 [4] clauses 4.2.2 and 4.2.3 for GTP-based interfaces are shown in this figure.

Figure 12.1-1: Architecture reference model with separation of user plane and control plane for non-roaming and roaming scenarios

NOTE 1: The -C or -U suffix appended to S2a, S2b, S5 and S8 reference points refer to the control plane and user plane components of those interfaces.

NOTE 2: For S2a, S2b, S5 and S8 reference points, this architecture reference model is only supported with GTP-based interfaces. PMIP-based interfaces and S2c interface are not supported.

NOTE 3: The usage of a combined SGW/PGW documented in TS 23.401 [2] is also possible in a deployment with separated control and user planes.

The protocol for Sxa, Sxb and Sxc is described in TS 29.244 [6]. The protocol is a 3GPP owned protocol using UDP as transport. Restoration scenarios when an PGW, SGW are split and one node failes are studied in TR 29.844 [9] and the result is incorporated in TS 23.007 [7]. The CP function may select a UP function using DNS server this is documented in TS 29.303 [8].

References

[1] TS 23.214: "Architecture enhancements for control and user plane separation of EPC nodes ".

[2] TS 23.401: "General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access".

[3] TS 23.203: "Policy and charging control architecture".

[4] TS 23.402: "Architecture enhancements for non-3GPP accesses".

[5] TS 23.060: "General Packet Radio Service (GPRS); Service description; Stage 2".

[6] TS 29.244: "Interface between the Control Plane and the User Plane of EPC Nodes; Stage 3".

[7] TS 23.007: "Restoration procedures".

[8] TS 29.303: "Domain Name System Procedures; Stage 3".

[9] TS 29.844: "Study on Control and User Plane Separation of EPC Nodes".

2. Paging Policy Enhancements and Procedure

Summary based on the input provided by China Unicom in SP-170549.

710004

Paging Policy Enhancements and Procedure

PPEPO_LTE

1

S1

SP-160113

This work item optimizes the paging policies as to reduce the paging signalling caused both by M2M devices and by smart phones' OTT (Over The Top) applications.

These optimizations are based on:

a) the movement of a device, i.e. taking into account whether the UE is static or moving;

b) the application characteristics, such as the application type, the application protocol, the application provider, and the delay sensitivity;

c) the location of the UE within the paging area.

With these optimizations, the network will assess the parameters above as to apply different paging policies.

Note that only Stage 1 has been defined for this feature (covered by CRs to 22.101, while the study is in the dedicated TR 22.838, "Paging Policy Enhancements and Procedure Optimizations in LTE"). There is no impact on Stage 2 nor on Stage 3 since the result of this feature is mostly a change of behaviour of some network entities, and this is not covered by 3GPP.

3.