Content for TR 23.700-41 Word version: 18.0.0

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1 Scope p. 11

The Technical Report studies the gaps and performs evaluations of potential architecture enhancements to support Network Slicing with the following objectives:

Study whether and how to address the following scenario in order to provide service continuity: if an existing network slice or network slice instance cannot serve the PDU session, or if the existing network slice instance cannot meet the performance requirements of the applications. The study should investigate whether deployment optimization is sufficient. Minimized system optimisations can be considered if valuable.
Study whether and how to initiate a registration for a rejected S-NSSAI that was rejected in a first TA of the RA but may be available in another TA of the RA.
Study whether and how to support the following stage one Rel-18 EASNS requirements related to roaming specified in TS 22.261, clause 6.1.2.1, i.e. Requirement on enhancement the information available to the UE in roaming scenarios regarding the availability of network slices in VPLMNs available in the roaming country, in order to allow the UE to select and obtain services from the VPLMN supporting the network slices which UE may wish to use.
Study whether and how to enhance the system to ensure network controlled behaviour of network slice usage including UE registration and PDU Session establishment (e.g. so that when performing NSAC the network slice can serve UEs/PDU Sessions with actual activity).
Study deployment considerations when a service provided has an area of service that does not overlap with the already deployed Tracking Areas and/or have a limited lifetime and how existing mechanisms including network slicing can help support such scenarios. If existing mechanisms are concluded to be not sufficient to achieve the scenarios, study whether and how additional mechanisms can resolve the analysed gap.
Study whether and how to enhance the support of NSAC when more than one NSACF is involved in enforcing a shared maximum allowed number of the UEs or PDU Sessions for a network slice in one PLMN or in roaming, in order to avoid fragmentation of the shared maximum allowed number. This item depends on the outcome of corresponding Rel-17 CRs.

2 References p. 11

The following documents contain provisions which, through reference in this text, constitute provisions of the present document.

References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific.
For a specific reference, subsequent revisions do not apply.
For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.

[1]

TR 21.905: "Vocabulary for 3GPP Specifications".

[2]

TS 23.501: "System architecture for the 5G System (5GS)".

[3]

TR 38.832: "Study on enhancement of Radio Access Network (RAN) slicing".

[4]

TS 22.261: "Service requirements for next generation new services and markets; Stage 1".

[5]

TS 23.502: "Procedures for the 5G System; Stage 2".

[6]

TS 29.571: "5G System; Common Data Types for Service Based Interfaces; Stage 3".

[7]

TS 23.122: "Non-Access-Stratum (NAS) functions related to Mobile Station (MS) in idle mode".

[8]

TS 38.413: "NG-RAN; NG Application Protocol (NGAP)".

[9]

TS 38.304: "User Equipment (UE) procedures in Idle mode and RRC Inactive state".

[10]

TS 22.071: "Location Services (LCS); Service Description".

[11]

TS 38.331: "Radio Resource Control (RRC) protocol specification".

[12]

TS 23.503: "Policy and charging control framework for the 5G System (5GS)".

[13]

TS 28.541: "Management and orchestration; 5G Network Resource Model (NRM)".

[14]

TS 33.501: "Security architecture and procedures for 5G system".

[15]

TS 23.273: "5G System (5GS) Location Services (LCS); Stage 2".

[16]

TS 24.501: "Non-Access-Stratum (NAS) protocol for 5G System (5GS); Stage 3".

3 Definitions of terms and abbreviations p. 12

3.1 Terms p. 12

For the purposes of the present document, the terms given in TR 21.905, TS 23.501 and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905 and TS 23.501.

3.2 Abbreviations p. 12

For the purposes of the present document, the abbreviations given in TR 21.905, TS 23.501 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905 and TS 23.501.

4 Architectural Assumptions and Requirements p. 12

The following architectural requirements apply:

Solutions may include reuse (in part or totally) of existing mechanisms. When reuse is deemed to be possible, whether new approaches shall also be adopted or added shall be subject of evaluation. (i.e. it shall be considered whether the reuse of existing system capabilities is sufficiently effective and efficient in addressing the problem space).