3GPP TSG-RAN WG2 Meeting #130 R2-2504071
St. Julians, Malta, 19 - 23 May 2025
Agenda item: 8.19
Source: Huawei, HiSilicon, China Southern Power Grid, Turkcell
Title: ETWS geo-fencing for eMTC NTN and for TN
Document for: Discussion and Decision
Discussion
In Rel-19 NR NTN, RAN2 has agreed to support geo-fencing for ETWS message by introducing warning area coordinates to the NR ETWS SIBs. Meanwhile, since RAN is discussing the support of PWS for NB-IoT in Rel-19 IoT NTN, it was also agreed to introducing warning area coordinates to the NB-IoT ETWS SIBs. The corresponding agreements are listed below [1]:
However, it remains a question whether the geo-fencing should be extended to eMTC NTN, and even further to eMTC TN/LTE TN or NR TN. During the discussion in IoT NTN topic, the main concern from companies was that this is not in the scope of Rel-19 IoT NTN since the objective of PWS is only for NB-IoT NTN. Also considering that we need to take eMTC TN/LTE TN and NR TN into account, we think TEI19 should be the right place for this discussion to take place. The following table summarizes all the scenarios and the highlighted scenarios need further discussion:
eMTC NTN
At least in NTN scope, the principle should be similar, i.e., eMTC NTN should follow NR NTN and NB-IoT NTN due to the same motivation (the coverage of one cell may be larger than the ETWS valid area). So we see no reason to leave eMTC NTN out of the ETWS geo-fencing supporting group.
Proposal 1: RAN2 to confirm that ETWS geo-fencing is supported for eMTC NTN and introduce“warning area coordinates” to SIB10 and SIB11.
eMTC TN and LTE TN
When discussing the PWS support for NB-IoT NTN, RAN2 agreed that this can also be made applicable for NB-IoT in TN, if this does not require additional NB-IoT TN specific changes. Here once Proposal 1 is agreed, the newly introduced “warning area coordinates” in SIB10 and SIB11 may also be used TN without extra spec effort. In any case, if it is not useful in TN, NW can choose not to broadcast the coordinates by implementation. Meanwhile, if we want to limit the usage to only NTN, RAN2 can further discuss whether it requires additional restriction in the spec.
Proposal 2: RAN2 to discuss whether ETWS geo-fencing is applied to eMTC TN and LTE TN in case there is no extra spec effort.
NR TN
Similarly since the“warning area coordinates” has been introduce to SIB6 and SIB7 for NR NTN, they may be also used by NR TN without extra spec effort.
Proposal 3: RAN2 to discuss whether ETWS geo-fencing is applied to NR TN in case there is no extra spec effort.
Conclusion
In this paper, we discuss whether to apply the ETWS geo-fencing to eMTC NTN and to TN and have the following proposals.
Proposal 1: RAN2 to confirm that ETWS geo-fencing is supported for eMTC NTN and introduce“warning area coordinates” to SIB10 and SIB11.
Proposal 2: RAN2 to discuss whether ETWS geo-fencing is applied to eMTC TN and LTE TN in case there is no extra spec effort.
Proposal 3: RAN2 to discuss whether ETWS geo-fencing is applied to NR TN in case there is no extra spec effort.
References
R2-2501333, Report from Break-out session on NR-NTN and IoT-NTN |
3GPP TSG-RAN WG2 Meeting#130 R2-2504347
Malta, May 19-23 2025
Agenda item: 8.19 (TEI-19)
Source: EchoStar, Boost Mobile, TerreStar, Qualcomm, TTP Plc
Title: NR-NTN to NB-IoT NTN mobility
Document for: Discussion and Decision
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Conclusion
In this paper, we discussed the need to enable a mechanism for inter-RAT selection to ensure that UEs with NR-NTN (or NR-TN) and NTN-IoT capabilities can perform the necessary selection as needed.
Based on the observation and discussion in this paper, we respectfully ask RAN2 to discuss and consider the following proposal.
Proposal 1: For mobility from NB-IoT NTN to NR-NTN, RAN2 introduce a solution to provide a list of assistance information of NR-NTN carrier frequency and the NR-NTN satellite.
Proposal 2: For mobility from NR-NTN to NB-IoT NTN, define a new IE ntn-NeighCellConfigList-NB-r19 in SIB19 to provide the list of NB-IoT satellite information and NB-IoT carrier information.
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