This document discusses enabling emergency location services (ELS) for mobile phone users who are roaming in the UK with foreign SIM cards. It describes testing that was conducted using a long phone number format to successfully route location data via SMS to UK emergency call centers. Based on a pilot program, over 5,000 emergency calls from roaming phones were able to provide accurate location data to emergency operators within a few seconds using this method. The document concludes that this solution is useful but may involve small charges to callers, and recommends working with foreign mobile networks to establish zero-rated SMS routes to improve emergency location services for roaming users.

1. © British Telecommunications plc 2017
EENA Conference 2018
AML Future – roaming
26 April 2018 – for presentation, not for
distribution
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2. © British Telecommunications plc 2017
Key
Mobile
Networks
Aggregation
Provider
Stage 1 PSAP(BT
or contracted
supplier)
Stage 2
PSAP
Google/Apple
Location
Service
Ephemeris
provider
(eg Qualcomm)
Default location used
when no AML and to
check consistency of
handset locations

3. © British Telecommunications plc 2017
Roaming way forward
Using existing Android ELS software it is possible to:-
- Identify a mobile phone is in the UK with a non-UK SIM
- Send an SMS to the UK AML destination at the PSAP using a “long number”: a full length number including country
code, e.g.+447789012345
Although it looks like a normal mobile phone number it is a virtual mobile equipment number - it doesn’t terminate on
a mobile phone, but on the PSAP server
This avoids the issue of the foreign SIM’s home SMSC not being able to route the normal 999 number for AML
messages back to the UK AML destination for UK PSAP.
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4. © British Telecommunications plc 2017
Routing of roaming information - schematic
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Home
Country
Visited
Country(UK)
Home SMSC
SMSC hosting Virtual
Mobile Number
SMS host SMSC
SMS Aggregator
Roaming handset
makes emergency
call
MSC
STP
STP
PSAP
STP

5. © British Telecommunications plc 2017
Roaming way forward – test results from HELP 112 project
SIMs from Ireland, Lithuania, Italy and Belgium, plus South Africa
The messages came through very quickly, taking just a few seconds to arrive at our server.
The normal high standard of GNSS and WiFi locations are obtained
The individual test results show that using a long number for AML enables foreign roamer emergency calls to be
matched with the caller’s location, whether the caller has brought their phone from within or outside of Europe
It’s still possible to determine an accurate location if roaming data is switched off.
The only case we didn’t receive a message was when the caller had no credit……….

6. © British Telecommunications plc 2017
Pilot for foreign roamers in UK
Following successful testing under HELP 112 project, BT PSAP and UK MNOs have been running a pilot to
enable Android ELS information for roamers.
This uses the configuration change mentioned to a long virtual number +447786200XYZ
About 5,000 calls processed so far:–
- two mobile networks in the pilot
- ELS configuration for UK roaming received for handsets active in home countries
- Normal, very good locations via the long number as expected (many countries….)
- Allowing Google to refine how dual SIM cases are managed [easier with later OS versions]
- Very small numbers of messages from outside UK - declining as older phones updated
- Some examples where data SMS message not received from a limited number of SMSCs
Mobile networks monitoring to see if any billing queries: all UK networks aware of the long number
concerned. No issues reported.
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7. © British Telecommunications plc 2017
Managing any charges for AML locations
Using a long SMS delivery number there is a charge to the caller for each message sent to that number.
1. Some messages won’t get through due to lack of credit
2. Most callers will not notice – don’t track individual SMSs on bills (and many are within allowances…….)
3. Some callers may complain about charges for SMS transporting AML: unlikely to object for help for real emergency
4. Some callers may object to their mistaken emergency calls (misdial, phone in pocket, etc) costing them money : still not very likely
due to relatively low cost of texts……
An obvious solution is to make the AML endpoint a zero-rated number. The charge for sending SMS messages from abroad is composed of
three portions:
i) The retail cost charged by the network provider of the roaming subscriber
ii) The wholesale SMS cost charged by provider of the long number to the network provider of the roaming subscriber
iii) The wholesale roaming cost charged by the UK network on which the subscriber is roaming to the network provider of the roaming
subscriber.
It is straightforward to set up a long number hosted by a single UK network, but to avoid subscriber costs an agreement would be needed with
each foreign network not to charge for the particular UK long number used.
This is likely to be impractical with large numbers of mobile networks, but a pragmatic approach would be to agree this with networks for the
most common countries that visit the UK, and would be especially useful in countries with large numbers of commuters from one country to
another, or with very high proportions of tourists.7

8. © British Telecommunications plc 2017
Conclusions : Foreign roamers dialling emergency numbers in the UK
A long SMS number configured in the existing Android ELS software is being used to deliver location for roamers to UK PSAP.
Useful for callers and for mobile networks where roamers are not normally positioned in any other way (as in UK)
This will normally cause a small charge to be raised between networks and requires callers to have credit
In the short term (and for more occasional roamers) a small charge appears to be acceptable (no issues…..a few eurocents)
Recommend that, particularly where there’s a large population of roamers, that mobile networks establish a zero rating for texts to long
numbers used for most common roamers (eg commuters).
BT Pilot has delivered benefits with no customer issues reported
BT continuing to investigate/monitor examples where locations not received (solution not perfect for all handset/SMSC scenarios!) and
expecting to rollout to other 2 UK networks
Google is adapting/refining functionality through monitoring the pilot (eg Dual SIM cases)
Recommend other PSAPs in other countries to now consider extending AML to roamers and contact Google when ready…….

9. © British Telecommunications plc 2017
Back-up slides if needed – use of AML in UK

10. © British Telecommunications plc 2017
UK Emergency Service
BT Public
Network
Fixed/Mobile
Networks
BT 999 Call Centres
Stage 1 PSAP
BT (6 sites)
~ 30m calls/year
Public networks
(BT and others)
Police 47%
Ambulance 49%
Fire 4%
Coastguard <1%
999/112
(139 Local Controls – Stage 2 PSAPs)
999/112 call handling : Voice + Location
- Voice : Mobile, Fixed, VoIP
- eSMS for hearing impaired ( also ITUv21 text over voice, real time text using special terminals)
- Telematics in certain vehicles that includes a voice call + separate SMS data message
~62%
Mobile
>100
Communication
Providers (CPs)
PSTN-IP
Gateways
VoIP CPs
Location Hub – uses
network and
handset location
Location
VPNHandset locations
via SMS – AML
Network Location –
GMLC for mobiles

11. © British Telecommunications plc 2017
Current UK results from AML
On making an emergency call (999 or 112 in the UK), the handset tries
to establish its location for 15-20 seconds while the emergency voice
call is established, and the handset location is transmitted to the PSAP
using SMS (either standard text or with Android ELS’s different Data
Coding Scheme to standard texts)
For 14 April 2018 the split over 25k AML location messages
[all MNOs]
51% GNSS
37% WiFi
6% Cell
7% No Location
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Reported
Accuracy
Percent
No location 7%
0-9m 8%
10-19m 51%
20-49m 15%
50-99m 14%
100-999m 3%
999+m 1%