5.27.2.1 General

TSC Assistance Information (TSCAI) is defined in Table 5.27.2-1 and describes TSC traffic characteristics for use in the 5G System. It can also be used for services such as XR services (AR/VR applications) and interactive media services as specified in clause 5.37.

TSCAI may be used by the 5G-AN, if provided by SMF. The knowledge of TSC traffic pattern is useful for 5G-AN as it allows more efficiently scheduling of QoS Flows that have a periodic, deterministic traffic characteristics either via Configured Grants, Semi-Persistent Scheduling or with Dynamic Grants. TSCAI can be provided for both GBR and non-GBR QoS flows.

The TSCTSF determines the TSC Assistance Container (defined in Table 5.27.2-2) based on information provided by an AF/NEF or a DetNet controller as described in clause 5.27.2.3 and provides it to the PCF for IP type and Ethernet type PDU Sessions. In the case of integration with IEEE TSN network, the TSN AF determines TSC Assistance Container as described in clause 5.27.2.2 and provides it to the PCF for Ethernet PDU Sessions. The PCF receives the TSC Assistance Container from the TSCTSF or the TSN AF and forwards it to the SMF as part of PCC rule as described in clause 6.1.3.23a of TS 23.503 [45].

The SMF binds a PCC rule with a TSC Assistance Container to a QoS Flow as described in clause 6.1.3.2.4 of TS 23.503 [45]. The SMF uses the TSC Assistance Container to derive the TSCAI for that QoS Flow and sends the derived TSCAI to the NG-RAN. The Periodicity, Periodicity Range, Burst Arrival Time (BAT), BAT Window and Survival Time components of the TSCAI are specified by the SMF with respect to the 5G clock. The SMF is responsible for mapping the Burst Arrival Time, BAT Window, Periodicity and Periodicity Range from an external clock (when available) to the 5G clock based on the time offset and cumulative rateRatio (when available) between the external clock time and 5GS time as measured and reported by the UPF. The SMF determines the TSCAI as described in clause 5.27.2.4.

A Survival Time, which indicates the time period an application can survive without any data burst, may be provided by TSN AF/AF or by the TSCTSF either in terms of maximum number of messages (message is equivalent to all packets of a data burst) or in terms of time units. Only a single data burst is expected within a single time period referred to as the periodicity.

The SMF may send an update of the TSCAI to the NG-RAN as defined in clauses 4.3.3.2, 4.9.1.2.2 and 4.9.1.3.2 of TS 23.502 [3] or as defined in clause 5.37.8.2.

Table 5.27.2-1: TSC Assistance Information (TSCAI)

Table 5.27.2-2: TSC Assistance Container (TSCAC)