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Hello Chris et al. Thank you for your contribution – I have several comments against your contribution and oppose the straw poll. Please see some of my comments below. Regards, Payam ~~~~~
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Slide #4: “non-TDD STAs in an overlapping BSS will have no knowledge of a TDD SP”
-- > Non-TDD DMG STAs can decode Announce frames (functional equivalents of Beacon frames) from neighboring BSS’s, which will include both Slot Structure and Slot Schedule IEs. It is the same expectation as decoding beacon frames
from neighboring BSS’s except two more extra IEs need to be decoded. Of course one could argue legacy devices (how many?) do not understand these IEs, but with power levels and antenna gains as we have shown several times this is not even necessary.
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Slide #4: “With no knowledge of the rules of an SP, a non-TDD STA will revert to CBAP and wait until the medium is clear in order to transmit”
-- > There is no default behavior; the non-TDD STA may use SPs itself
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Slide #5: “Coexistence measurements examined in 11-18-0488-01 underestimate the impact of interference, since real devices will be more sensitive than the CCA threshold requirement (-68 dBm)”
-- > I’m surprised at this. Being more sensitive doesn’t change the CCA declaration logic – channel is still declared busy if preamble RSSI is -68 dBm. Receiver can have ultra-low sensitivity but that doesn’t mean it will get penalized
for transmit opportunities. And in fact, operating below sensitivity is actually great, because it will give room for more interference!
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Slide 5: “11-18-0194-01-00ay advocates use of TDD for indoor consumer applications, which, if adopted, would make overlapping TDD / non-TDD common”
-- > Let’s say this is a PBSS concern. Even if this happens (which is an AP use case), then the indoor range would dictate a lower transmit power, may be in twenties of dBm (i.e., the TDD will become an SRD with TPC, the victim) –
while the “other” SRD will go at 40 dBm.
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Slide 6: “The Non-TDD PBSS is essentially shut down when the TDD STA is transmitting”
-- > Let’s assume “essentially shut down” means “essentially blocked” + “link disconnect”.
- For “essentially blocked”, please see the coex slides from the past, and also our slides for today AM2 coex measurements (with CBAP SRDs) (DCN
0749), in particular slide 13, which explains 60 GHz coex is about idle periods and enough SINRs. I will explain in the meeting that blocking is a misconception as once a TXOP (of several milliseconds) is obtained SRDs will transmit with no failure
(and no channel sense).
- For “link disconnect”, there is no reason as beacons will still be sent (CCA is optional) and at -78 dBm Rx sensitivity and dot11MaxLostBeacons it’s hard to lose a network
-- > Further, a point-to-point PBSS is a perfect example of a case where directional antennas can –always – be used
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Slide 6: “When the TDD STA is receiving, the Non TDD PCP restarts, causing interference in the other direction”
-- > TDD will have immunity due to higher gain, most issues ware due to early weak interference that can be resolved if this group agrees with CCI requirements.
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Slide 8: “TDD operation (as defined in D1.1 10.37.6.2.2 SP with TDD channel access) will not co-exist with a neighboring BSS/PBSS of any type, TDD, .11ay CBAP, or legacy CBAP”
-- > The “will not co-exist” is a really wrong term. We have no problem even on the same channel with existing mechanisms, and on top of that we have 6 WiGig cannels for DFS, so no co-existence is a misnomer. To see how rare the situation is – please come to our Tuesday AM2 presentation where we are measuring even the most aggressive scenarios – directional 60 GHz really needs new thinking.
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Slide 9: Allow intra-PBSS / BSS signaling (TBD) to indicate interference from TDD
-- > Probably meant “inter-“, remains to be seen what it means. To unsubscribe from the STDS-802-11-TGAY list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-11-TGAY&A=1 |