[Standards] XEP-0255 (Location Query)
helge at buddycloud.com
Wed Nov 26 21:43:45 UTC 2008
Some comments to the XEP-0255 / "Location Query" draft (http://xmpp.org/extensions/xep-0255.html):
1) Beacon signal strength seems to have been forgotten in the draft specification. This is a mistake and I will correct it.
2) In the development project from which XEP-0255 was born (Buddycloud), we never considered using Timing Advance (http://en.wikipedia.org/wiki/Timing_advance) for triangulation between cell towers, simply because it was too troublesome getting the deep API access required on Symbian, our main client platform.
However I assume this is something other implementers may want to use, so i think it should be covered by the XEP.
The specification currently uses a generic data type for all radio beacons (cell towers, wifi access points, bluetooth devices). However timing advance would only apply to cell towers. In order to keep this symmetry, and as timing advance translate directly to distance (scaled by a factor of 550m per unit), i am pondering whether to add the somewhat more generic field 'distance' rather than 'timing advance'. I am not sure how a client would derive distance to, say a wifi access point, but I think that is more likely than a timing advance value...
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