Subject: [Ecrit] Privacy Aspects of Location Conveyance

From: Hannes Tschofenig <[email-masked]>
Date: Sun, 20 Aug 2006 11:16:51 +0200

Hi all,

I am reviewing the meeting minutes of the 3GPP CT/IETF ECRIT joint 
session on emergency services. The following text captured the 
discussion we had on privacy aspects of location conveyance:

"
Henning Schulzrinne noted that there are two additional axes for privacy 
consideration.  One is precision; there is location information which 
would be precise enough to route but not precise enough for dispatch by 
a call-taker; the second is the split between information seen by a 
proxy and information seen by a call taker.  In using LoST to derive a 
PSAP URI, for example, a UE might provide precise information, but then 
remove some or all of the data before making a SIP call based on the 
lookup.  Steve noted that the lack of precision is common in the early 
stages of deriving location, and that the determination of a PSAP URI 
mapping before it is precise may be a useful optimization; more precise 
information can be sent to a dispatcher later.
"

Do we need to capture something of this in the Location Conveyance 
document or in the PhoneBCP draft? Do we believe that this is an 
important issue?

Ciao
Hannes

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---

From: "James M. Polk" <[email-masked]>
Date: Mon, 21 Aug 2006 13:35:55 -0500

Hannes

 From a purely ECRIT pov, take a situation of the odd numbers on Main St go 
to PSAP 1 and the even numbers on Main St go to PSAP 2. How does a UE know 
this? If it does not or cannot, it cannot reduce the precision below 123 
Main St (or 124 Main St).  If true, we should be well within someone's 
privacy sphere.

This is not an uncommon means of dividing territories of PSAPs within a 
city.  How does a UE know it is in a city with this type of arrangement, or 
one like a suburb in which there is no "center of a street divider of PSAP 
boundaries"?

Take this an additional step, how would/could the logic in a UE understand 
that 123 Main St is, for example, the Sears Tower in Chicago, and that 124 
Main St is Dave's Donut shop - where the former still has some obscurity 
and the latter does not.

There needs to be a trigger in the UE (i.e. any UA) to understand when 
their current location is actually part of a larger facility that in itself 
promotes some measure of imprecision.

I think this will be hard to achieve, and currently impossible with from 
4119 as written.

 From a Location Conveyance pov, first responders require an exact location 
to go to, to help who called for help.  This is carried in a 4119 PIDF-LO 
by-value or by-reference *to* the call taker.  If the precision of this 
information is reduced to create privacy to the call taker, how can a first 
responder get the right location to render assistance?

At 11:16 AM 8/20/2006 +0200, Hannes Tschofenig wrote:
>Hi all,
>
>I am reviewing the meeting minutes of the 3GPP CT/IETF ECRIT joint session 
>on emergency services. The following text captured the discussion we had 
>on privacy aspects of location conveyance:
>
>"
>would be precise enough to route but not precise enough for dispatch by a 
>call-taker; the second is the split between information seen by a proxy 
>and information seen by a call taker.  In using LoST to derive a PSAP URI, 
>for example, a UE might provide precise information, but then remove some 
>or all of the data before making a SIP call based on the lookup.  Steve 
>noted that the lack of precision is common in the early stages of deriving 
>location, and that the determination of a PSAP URI mapping before it is 
>precise may be a useful optimization; more precise information can be sent 
>to a dispatcher later.
>"
>
>document or in the PhoneBCP draft? Do we believe that this is an important 
>issue?
>
>
>Ciao
>Hannes
>
>

---

From: "Brian Rosen" <[email-masked]>
Date: Mon, 21 Aug 2006 09:48:51 -0400

Yes, I think we need to discuss it in framework, and offer guidance in
phonebcp.

In the emergency case, the most precise location needs to go to the
dispatcher, and routing may happen on less precise data, if that is all that
is available when the call is routed.  That is a common case, and the
current emergency call systems do that most (if not all) of the time.

Brian

> -----Original Message-----
> From: Hannes Tschofenig [mailto:[email-masked]]
> Sent: Sunday, August 20, 2006 5:17 AM
> To: ECRIT
> Subject: [Ecrit] Privacy Aspects of Location Conveyance
> 
> Hi all,
>

---

From: Hannes Tschofenig <[email-masked]>
Date: Mon, 21 Aug 2006 20:51:35 +0200

Thanks James for the quick response. For an emergency scenario your 
arguments are good.

Let us kick this issue into the trashcan.

Ciao
Hannes

James M. Polk schrieb:
> Hannes
> 
>  From a purely ECRIT pov, take a situation of the odd numbers on Main St 
> go to PSAP 1 and the even numbers on Main St go to PSAP 2. How does a UE 
> know this? If it does not or cannot, it cannot reduce the precision 
> below 123 Main St (or 124 Main St).  If true, we should be well within 
> someone's privacy sphere.
> 
> city.  How does a UE know it is in a city with this type of arrangement, 
> or one like a suburb in which there is no "center of a street divider of 
> PSAP boundaries"?
> 
> Take this an additional step, how would/could the logic in a UE 
> understand that 123 Main St is, for example, the Sears Tower in Chicago, 
> and that 124 Main St is Dave's Donut shop - where the former still has 
> some obscurity and the latter does not.
> 
> their current location is actually part of a larger facility that in 
> itself promotes some measure of imprecision.
> 
>  From a Location Conveyance pov, first responders require an exact 
> location to go to, to help who called for help.  This is carried in a 
> 4119 PIDF-LO by-value or by-reference *to* the call taker.  If the 
> precision of this information is reduced to create privacy to the call 
> taker, how can a first responder get the right location to render 
> assistance?
> 
>> Henning Schulzrinne noted that there are two additional axes for 
>> privacy consideration.  One is precision; there is location 
>> information which would be precise enough to route but not precise 
>> enough for dispatch by a call-taker; the second is the split between 
>> information seen by a proxy and information seen by a call taker.  In 
>> using LoST to derive a PSAP URI, for example, a UE might provide 
>> precise information, but then remove some or all of the data before 
>> making a SIP call based on the lookup.  Steve noted that the lack of 
>> precision is common in the early stages of deriving location, and that 
>> the determination of a PSAP URI mapping before it is precise may be a 
>> useful optimization; more precise information can be sent to a 
>> dispatcher later.
>> "
>>