Thread Links Date Links
Thread Prev Thread Next Thread Index Date Prev Date Next Date Index

[802SEC] Comments on 802.15 PARs



Bob (I sent this the first time from the wrong email, so it didn't make it to the EC list).

I attended the 802.11 PAR meeting, so most of my comments are contained in that document. I have the following additional comments:

802.15.4w
PAR
  5.2b
   o Add the anticipated range that this new PHY will provide.
   o delete "as needed"
  5.5
o The text says that high link margin is required for interferers, but doesn't put a value on "high". What is high and why don't current PHYs in 802.15.4 meet it? o -140 dBm sensitivity implies -174 dBm/Hz + 10 dB SNR and NF gives -164 dBm/Hz, leaving only 24 dB for BW, or 251 Hz. That would likely give < 1 kb/s, which doesn't work for IoT. From where does this -140 dBm come? o "The end result is the inability to guarantee the required transmission reliability in such scenarios." Wireless networks can never "guarantee the required transmission reliability" and this project won't change that fact. o "receiver sensitivities of -140dBm while delivering multiyear battery life." 802.15.4 aleady provides multi-year battery life with the existing PHYs. There does not appear to be anything proposed with the amendment that would improve battery life. In fact, by spreading the information over a longer period of time, the receiver would be on longer, using more power, not less.

CSD
  1.2.3
   o Quantify "high immunity to interference".

  1.2.5
o None of the reasons given address why this specific, new addition will be similar in cost to existing 802.15.4 devices (which vary widely in cost, depending on which version of 802.15.4 you implement). Are there LECIM devices fielded? o The answer for c) does not address item c), which has to do with installation costs, no manufacturing methods.

P802.15.4x
PAR
 5.2b
  o Provide an estimated range for this PHY mode in the scope.

 6.1.b
o I would suggest that this is no as the PHY won't modify any of the use or definition of addressing. If the RAC wants to review, you can always send them a copy to look at. But the answer to the question is no, you don't anticipate any registration activity.

CSD
 1.2.5
o None of the reasons given address why this specific, new addition will be similar in cost to existing 802.15.4 devices (which vary widely in cost, depending on which version of 802.15.4 you implement). At the very least, these answers should be specific to the widespread deployment of 802.15.4 SUN PHY devices. o The answer for c) does not address item c), which has to do with installation costs, no manufacturing methods. The WG should take the time to actually answer these questions and not just cut and paste previous answers.

P802.15.4z
PAR
 2.1
o I am unaware of any IR-UWB PHYs in 802.15.4. There are LRP UWB and HRP UWB PHYs, but not IR-UWB PHYs. Rename the standard to modify either the HRP or LRP UWB PHYs, which ever is appropriate.
 5.2b
o Include the anticipated range of the PHY developed for this amendment to the scope.

 6.1.b
o I would suggest that this is no as the PHY won't modify any of the use or definition of addressing. If the RAC wants to review, you can always send them a copy to look at. But the answer to the question is no, you don't anticipate any registration activity.

Thanks

James Gilb

----------
This email is sent from the 802 Executive Committee email reflector.  This list is maintained by Listserv.