Over the weekend, I wanted to take a closer look at the 3GPP Earthquake and Tsunami Warning System (ETWS) for GSM, UTMS and LTE. I was expecting to find proper stage 1, 2 and 3 documents in place by now so implementations could follow soon. It turns that of the three documents, only stage 1 (3GPP TS 22.168) has made it so far into Release 8. However, it seems that the specification might have been withdrawn at SP-43 in Biarritz in March 2009.
The same applies for the stage 2 documentation 3GPP TS 23.168, it's current state is "withdrawn". There is a pointer to Technical Report (not a specification!) TR 23.828 which gives an overview of the different options analyzed and the proposal at the end to go for solution 5. Solution 5 would be to send a first warning to the mobiles via a special paging message with further details right afterwards in a cell broadcast message. For GSM mobiles already engaged in a voice call, the BTS would create a special SMS and sent it over the slow associated signaling channel while the call is in progress. In UMTS, paging messages can also be received during a call. What's not mentioned is how mobiles currently having a GPRS TBF established would receive the notification as there is no associated circuit switched signaling channel and pagings would not be received over the paging channel. But for the moment, that is beside the pont, since both stage 1 and stage 2 of the specification was withdrawn.
However, there is a link to 3GPP TS 22.268, a stage 1 specification for a much more generalized public warning system (PWS). No stage 2 specification exists so far, so this one is also at the beginning. It's an interesting document as it shows how much time there is to warn the public about an earthquake or a tsunami. Very challenging!
I am a bit puzzled!? Looks like ETWS was already quite well on it's way but now seems to be suddenly stopped? Did it fall short of the requirements? If you know more, please leave a comment below.
The SA Plenary #43 meeting report gives the answer:
“The approval at SA#42 of Stage 1 for Public Warning System (TS 22.268 R9) superseded the Release 9 version of Earthquake and Tsunami Warning System (TS 22.168 R9).
It is proposed therefore withdrawn the R9 version of ETWS TS 22.168
“
Hello Pierre,
good pointer, thanks! But why the sudden change of mind. The TS’s came quite far before they were withdrawn!? What happened behind the scenes???
Cheers,
Martin
ETWS Stage 1 is in TS 22.168 as a Release 8 specification. The implementation of ETWS is in TS 23.401 and TS 23.041, again as a Release 8 feature.
In Release 9, ETWS will become part of a more general Public Warning System (PWS) taking US and European requirements into consideration. TS 22.268 gives the requirements for PWS.
There was an urgent need (expressed by Asia) for ETWS to be made available without delay and hence it is contained in Release 8 to allow early implementation.
Hi Adrian,
I’ve been going through the specs you quoted and it has now become much clearer of why Rel9 goes a different way. Thanks for that!
What I didn’t find, however, is how a user being on a TCH for a phone call in GERAN is alerted as it wouldn’t observe the paging or CBC channel? Any idea how that will be solved by ETWS?
Kind regards,
Martin
Well Martin, now it gets a bit more complicated.
The March 2009 Rel 8 specs only really considered ETWS over an UTRAN network (because this satisfied the requirement for Japan). In the Biarritz meetings (March 2009) 3GPP decided that the service should be supported in a GERAN network. This work has now been drafted in the form of change requests to TS 44.018 and 44.060. The GERAN solution covers the sending of the primary notification in all GERAN modes (idle, dedicated, packet idle, packet transfer and dual transfer modes). The changes will (hopefully) be implemented after the current plenary round is completed (so in a couple of weeks). This work will be included within Release 8.
I must admit that I haven’t read through the change requests in detail yet but all should be clear within a couple of weeks or so.
Hello Adrian,
Great, thanks for commenting again. Wasn’t aware that UTRAN was a priority, but it’s obvious if pushed by Japan.
Will give the specs a couple of weeks and have another look again for in call alerting.
Kind regards,
Martin