School of Specs 24.501v20.0.0

3GPP 24.501 v20.0.0 — the document's own text

5.3.19A.2 UE operating in SNPN access operation mode

Taught in 4. Inside TS 24.501, the document at the centre (CT1 — the group that writes what your phone says, overview).

The following requirements apply for a UE that is configured to use timer T3245 (see 3GPP TS 24.368 [17]).

When the UE adds an SNPN to the "permanently forbidden SNPNs" list or "temporarily forbidden SNPNs" list which are, if the MS supports access to an SNPN using credentials from a credentials holder, equivalent SNPNs or both, associated with the selected entry of the "list of subscriber data" or the selected PLMN subscription, or sets the selected entry of the "list of subscriber data" or the selected PLMN subscription as invalid for 3GPP access or non-3GPP access, and timer T3245 (see 3GPP TS 24.008 [12]) is not running, the UE shall start timer T3245 with a random value, uniformly drawn from the range between 12h and 24h.

When the UE adds an SNPN to the "permanently forbidden SNPNs for access for localized services in SNPN" list or "temporarily forbidden SNPNs for access for localized services in SNPN" list which are associated with the selected entry of the "list of subscriber data" or the selected PLMN subscription for 3GPP access or non-3GPP access, and timer T3245 is not running:

  • if there is no next valid time period for the SNPN, the UE shall start timer T3245 with a random value, uniformly drawn from the range between 12h and 24h; or
  • if there is next valid time period for the SNPN, the UE shall start timer T3245 with a random value uniformly drawn from the range between the start time point and the end time point of the next valid time period for localized services in SNPN.

NOTE 1: The random value to calculate the value of timer T3245 can be UE implementation-specific value for the UE to perform SNPN selection for localized services in SNPN and receive localized services in the SNPN before the valid time of localized services ends.

Upon expiry of the timer T3245, the UE shall erase the "permanently forbidden SNPNs" list(s) and "temporarily forbidden SNPNs" list(s), "permanently forbidden SNPNs for access for localized services in SNPN" list(s) and "temporarily forbidden SNPNs for access for localized services in SNPN" list(s) and set the selected entry of the "list of subscriber data" or the selected PLMN subscription to valid for 3GPP access and non-3GPP access. When the lists are erased, the UE performs cell selection according to 3GPP TS 38.304 [28].

If the UE is switched off when the timer T3245 is running, the UE shall behave as follows when the UE is switched on and the selected entry of the "list of subscriber data" or the selected PLMN subscription remain the same:

  • let t1 be the time remaining for T3245 timeout at switch off and let t be the time elapsed between switch off and switch on. If t1 is greater than t, then the timer shall be restarted with the value t1 – t. If t1 is equal to or less than t, then the UE will follow the behaviour as defined in the paragraph above upon expiry of the timer T3245. If the UE is not capable of determining t, then the UE shall restart the timer with the value t1.