1. doc.: IEEE 802.11-05/1096r0 Submission November 2005 Mike Moreton, STMicroelectronicsSlide 1 Emergency Call Support Notice: This document has been prepared to assist IEEE 802.11. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.11. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at.http:// ieee802.org/guides/bylaws/sb-bylaws.pdfstuart.kerry@philips.compatcom@ieee.org Date: 2005-11-08 Authors:

2. doc.: IEEE 802.11-05/1096r0 Submission November 2005 Mike Moreton, STMicroelectronicsSlide 2 Abstract Joe Kwak of InterDigital has described the probable requirement to support emergency calls from VOIP over 802.11 phones. This submission describes a possible way in which this could be implemented

3. doc.: IEEE 802.11-05/1096r0 Submission November 2005 Mike Moreton, STMicroelectronicsSlide 3 Requirement R3M4 “Define IEEE 802.11TM functionality which would be required to support an Emergency Call (e.g. E911) service as part of an overall, multi-layer solution. Specifically: –Capability Advertisement –Authentication issues ”

4. doc.: IEEE 802.11-05/1096r0 Submission November 2005 Mike Moreton, STMicroelectronicsSlide 4 A Recap For New Readers Cellular networks often allow anybody with a suitable phone to make free emergency calls –Even if they’re not subscribed to that network –Even if they’re not subscribed to any network Initially US operators were very reluctant to do this –But they were forced to in the end It is expected that something similar will be required for VOIP over Wireless –Saying “It’s too difficult” may delay the requirement, but is unlikely to avoid it altogether

5. doc.: IEEE 802.11-05/1096r0 Submission November 2005 Mike Moreton, STMicroelectronicsSlide 5 The Issues Need to know that a network supports emergency calling Need a way of establishing a connection with the network Need a way of setting up a call –e.g. SIP??? Need a way of encoding speech Optionally need to give the call priority in 802.11e QoS Of these, the first two don’t exist yet, and the latter two are done in many different ways

6. doc.: IEEE 802.11-05/1096r0 Submission November 2005 Mike Moreton, STMicroelectronicsSlide 6 What We Don’t Want Is a loophole that allows anyone general purpose use of the network if they claim to be making an emergency call

7. doc.: IEEE 802.11-05/1096r0 Submission November 2005 Mike Moreton, STMicroelectronicsSlide 7 “Need to know that a network supports emergency calling” We are planning to advertise multiple “virtual networks” through the same AP –So shouldn’t be a problem to add a defined one for emergency calls Better to do this in a standard way rather than using a special bit –Makes changing it in the future easier. It is expected that regulators would force operators providing VOIP services to assert this bit –It’s not clear yet what will happen with general purpose WISPs

8. doc.: IEEE 802.11-05/1096r0 Submission November 2005 Mike Moreton, STMicroelectronicsSlide 8 “Need a way of establishing a connection with the network” We are already planning to have segmented access isolated from access to other virtual networks. –This would be no different –Prevents users of the Emergency Call service accessing other network services Do we need encryption? –Can’t make the call secure (no pre-established credentials) but we can make casual monitoring more difficult.

9. doc.: IEEE 802.11-05/1096r0 Submission November 2005 Mike Moreton, STMicroelectronicsSlide 9 “Need a way of setting up a call” Once we have an L2 connection, we need to set-up the call –For example protocols such as SIP The call control protocol may vary from network to network –Different flavours of SIP, Skype etc. Call control protocol really serves very little purpose in this case –Emergency services hopefully don’t make much use of call forwarding… Why not let the AP set the call up automatically –The AP knows the call control protocol in use

10. doc.: IEEE 802.11-05/1096r0 Submission November 2005 Mike Moreton, STMicroelectronicsSlide 10 “Need a way of encoding speech” Unlikely that a single, standard Emergency Call Codec can be agreed So will need a way of signalling the codec in use to the AP Assume that the Local Network or Emergency Service has a bank of possible codecs. –Regulatory Authorities may specify a limited list. Not really our problem…

11. doc.: IEEE 802.11-05/1096r0 Submission November 2005 Mike Moreton, STMicroelectronicsSlide 11 “Optionally need to give the call priority in 802.11e QoS” If the AP sets up the call, it can prioritise it immediately the call is accepted