1. doc.: IEEE 802.11-12/1421r1 Submission November 2012 Rich Kennedy, Research In MotionSlide 1 TGaf Response to 802.19 CA Comments Date: 2012-11-16 Authors:

2. doc.: IEEE 802.11-12/1421r1 Submission Introduction O nce upon a time, IEEE 802 wireless standards were designed for different frequency bands, so coexistence was not an issue. In time we began to develop standards that shared frequency bands, so the Coexistence Assurance document was created, asking each wireless task group to indicate how it would avoid interfering with other IEEE 802 wireless standard families. A Technical Advisory Group (802.19) was formed with the sole pupose of reviewing and certifying that the CA document was, in fact, …factual. November 2012 Rich Kennedy, Research In MotionSlide 2

3. doc.: IEEE 802.11-12/1421r1 Submission Introduction [2] T hen along came the opportunity to operate in vacant TV channels on an unlicensed basis, and a number of groups were formed that ventured to use this spectrum. Seeing this as a challenge to the CA process, 802.19 became a Working Group whose charter was to develop coexistence mechanisms for operation in this band. As a result, with regards to this spectrum the group now had two purposes. The first was to require of the Task Groups a document explaining how they would coexist, and the second was to tell them how to coexist. November 2012 Rich Kennedy, Research In MotionSlide 3

4. doc.: IEEE 802.11-12/1421r1 Submission Introduction [3] L ogic would seem to dictate that either the CA document for standards development in the TV bands, or the development of a coexistence mechanism is therefore unnecessary. I n spite of the fact that this process is at best redundant, IEEE 802.11 TGaf filed a CA document as required. It received one negative vote with six comments. W hat follows are the comments as received, and an explanation for why the questions were answered as they were. November 2012 Rich Kennedy, Research In MotionSlide 4

5. doc.: IEEE 802.11-12/1421r1 Submission Comment #1 The document starts with a statement saying: “At this time, there are no approved standards for operation in the TV white spaces bands.” This is unacceptable since IEEE Std 802.22-2011 was approved in July 2011 and is specifically aimed for the TV white space bands. There are pre-802.22 products already out there in the market and some have passed the regulatory approval process. The 802.19 Co-existence Assurance Document deals with “approved” standards, especially IEEE 802 standards, and not actual systems used in the bands. This statement is unacceptable as written.

6. doc.: IEEE 802.11-12/1421r1 Submission Reply #1 At the time the CA document was prepared, January of 2011, there were no approved standards for operation in the TV white spaces bands. The first line of the section headed Introduction was changed to: “At this time, there are two approved standards for operation in the TV white spaces bands: IEEE 802.22-2011 and IEEE 802.22.1-2010.”

7. doc.: IEEE 802.11-12/1421r1 Submission Comment #2 Last sentence of the second section: “But as Part 15 devices, there are no regulatory requirements for coexistence with other non-licensed devices.” is inappropriate since the object of the 802.19 Co- existence Assurance Document is not to respond to regulatory requirements but rather to improve voluntary spectrum usage by coordinating the spectrum use of license-exempt equipment.

8. doc.: IEEE 802.11-12/1421r1 Submission Reply #2 This comment resulted in no changes in the CA document. The comment is based on a different understanding of the rules of FCC Part 15.

9. doc.: IEEE 802.11-12/1421r1 Submission Comment #3 In section 3, it is interesting to note that 802.11 was protecting other 802.11 systems down to -82 dBm (20 MHz) but other types of systems down to -62 dBm, 40 dB [sic] higher. Fortunately, 802.11af seems to have improved the situation by protecting down to -72 dBm. Note that the 802.22 receiver sensitivity level is -95 dBm, some 23 dB lower than the protected level. This will reduce the dynamic range of 802.22 systems by 23 dB which is not negligible and is likely to affect the performance of the 802.22 receivers

10. doc.: IEEE 802.11-12/1421r1 Submission Reply #3 This comment resulted in no change to the CA document as we saw no appropriate way to respond. As the coexistence mechanisms are not yet defined, it is impossible for us to determine if this is actually a coexistence issue.

11. doc.: IEEE 802.11-12/1421r1 Submission Also Comment #3 In section 4, it seems that the location, channel and transmit power will be fed back to the database. This information being fed back to the database is not a regulatory requirement and may not be available centrally to help coexistence. In fact, it is unlikely that the instantaneous transmit power resulting from the TPC will be fed back regularly. This is misleading and needs to be corrected.

12. doc.: IEEE 802.11-12/1421r1 Submission Also Reply #3 This comment resulted in the addition of the following change to the section entitled Location Information: “Ofcom published rules require the WSD masters to inform the database of location and intended channel and power information, and receive acknowledgement from the database before transmitting.” This would seemingly make this comment moot.

13. doc.: IEEE 802.11-12/1421r1 Submission Comment #4 In section 5, it is stated that Mode I devices could be controlled by an “enabling station operated by a licensed operator”. This is not what regulatory rules are specifying since these Mode I devices can be enabled by Mode II or fixed ‘unlicensed’ devices. It is not clear what these licensed enabling stations are. This is new. So far the only licensed users in the TV bands are the broadcasters. Are 802.11AF broadcast stations?

14. doc.: IEEE 802.11-12/1421r1 Submission Reply #4 This comment resulted in no changes in the CA document. Unlicensed devices, like Wi-Fi Hotspots can be operated by licensed operators.

15. doc.: IEEE 802.11-12/1421r1 Submission Subject Paragraph of Comment #5 Basically, a dependent STA shall not transmit, except to authenticate and associate with an enabling AP, unless it has associated with an enabling AP. Furthermore, a dependent STA shall cease to transmit if it has not recently received a Contact Verification Signal from its enabling STA. A dependent STA shall only operate under the control of the enabling AP to which it is associated. November 2012 Rich Kennedy, Research In MotionSlide 15

16. doc.: IEEE 802.11-12/1421r1 Submission Comment #5 This is something that 801.19 needs to take up for all the TVWS standards in 802 – Note in the last paragraph that 80211af also suffers from the catch-22 problem that we have in 802.22 whereby: “…a dependent STA shall not transmit, except to authenticate and associate with an enabling AP, …” As for 802.22, the FCC regulations don’t seem to allow for this even if it may involve very short transmission bursts. They will also need to resolve this catch-22.

17. doc.: IEEE 802.11-12/1421r1 Submission Reply #5 This comment resulted in the addition of this paragraph added following the paragraph in question: “IEEE 802.11 document 11-12/1159r2 describes the operation of a Master/Client system, with particular emphasis on enabling signals.”