[STDS-802-11-TGBN] CID 15182: P-EDCA not enabled when long slot is used in a BSS

["Akhmetov, Dmitry" <dmitry.akhmetov@xxxxxxxxx>]

Hi all,

 

I’d like to start a discussion regarding CID 15182 (see below)

I was presented today and some members have some comments about the resolution, which is to add a NOTE saying that “NOTE: -  A UHR AP that sets Short Slot Time field to zero (see 9.4.1.4 (Capability Information field)) does not enable P-EDCA.”

 

It was proposed to change NOTE to normative text : “A UHR AP that sets Short Slot Time field to zero (see 9.4.1.4 (Capability Information field)) shall not enable P-EDCA.

 

Please let me know you if you have comments or questions

 

15182

Ning Gao

37.2.2

293

45

NOTE 1 justifies the fixed 81 us Duration value by "Duration + AIFS >= 81+25 = 106 > aSIFSTime + aSignalExtension + (AIFSN + CWmax) x aSlotTime = 97 us". The value 97 us assumes aSlotTime = 9 us, aSIFSTime = 16 us and aSignalExtension = 0. In the 2.4 GHz band with the long slot time (aSlotTime = 20 us, aSIFSTime = 10 us, aSignalExtension = 6 us) the maximum P-EDCA backoff countdown is 10 + 6 + (2+7) x 20 = 196 us, which greatly exceeds 106 us, so the NAV set by the DS-CTS frame does not protect the P-EDCA backoff.

Either restrict P-EDCA contention operation to cases where aSlotTime = 9 us, or define the Duration field value as a function of aSIFSTime, aSignalExtension, aSlotTime, P-EDCA AIFSN and P-EDCA CWmax instead of the fixed 81 us.

Revised.   Was deferred in 11-26/1671r1. No additional discussions followed Brought back same resolution:   Added : NOTE 2 — A UHR AP that sets Short Slot Time field to zero (see 9.4.1.4 (Capability Information field)) does not enable P-EDCA.   TGbn Editor: please apply changes marked (#15182) in 11-26/1671r6

 

             

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