Re: [STDS-802-11-REG] EN 300 328, version 1.9.1
Guido, all,
I think some of the uncertainty about whether 802.11-2012 equipment is "automatically" considered compliant comes from the following note in the testing method, clause 5.3.7.2.1.3 Step 2, which indicates that testing must verify the channel access behaviour (with minimum 30% activity ratio, "normal transmissions" traffic while connected to a "companion device") :
"NOTE 2: For the purpose of testing Load Based Equipment referred to in the first paragraph of clause 4.3.2.5.2.2.2 (IEEE 802.11 [i.3] or IEEE 802.15.4 [i.5] equipment), the limits to be applied for the minimum Idle Period and the maximum Channel Occupancy Time are the same as defined for other types of Load Based Equipment (see clause 4.3.2.5.2.2.2 points 2 and 3). The Idle Period is considered to be equal to the CCA or Extended CCA time defined in clause 4.3.2.5.2.2.2 points 1 and 2. "
The definition of the required behaviour is the referenced clause 4.3.2.5.2.2.2 where points 1 and 2 read
"1) Before a transmission or a burst of transmissions, the equipment shall perform a Clear Channel Assessment (CCA) check using energy detect. The equipment shall observe the operating channel for the duration of the CCA observation time which shall be not less than 18 µs. The channel shall be considered occupied if the energy level in the channel exceeds the threshold given in step 5) below. If the equipment finds the channel to be clear, it may transmit immediately.
2) If the equipment finds the channel occupied, it shall not transmit on this channel (see note 1). The equipment shall perform an Extended CCA check in which the channel is observed for a random duration in the range between 18 µs and at least 160 µs. If the extended CCA check has determined the channel to be no longer occupied, the equipment may resume transmissions on this channel.
NOTE 1: The Idle Period in between transmissions is considered to be the CCA or the Extended CCA check as there are no transmissions during this period.
NOTE 2: The equipment is allowed to switch to a non-adaptive mode and to continue transmissions on this channel providing it complies with the requirements applicable to non-adaptive systems. Alternatively, the equipment is also allowed to continue transmissions on this channel providing it complies with the requirements 4.3.2.5.3."
Both of these are from the draft 15 which has had minor editorial edits compared to the output of the previous meeting (draft 13), but the intent is unchanged.
Best Regards
Jens
> -----Original Message-----
> From: *** Regulatory and Spectrum Allocation Topics *** [mailto:STDS-
> 802-11-REG@xxxxxxxx] On Behalf Of Dr. Guido R. Hiertz
> Sent: 12 February 2014 14:11
> To: STDS-802-11-REG@xxxxxxxxxxxxxxxxx
> Subject: Re: [STDS-802-11-REG] EN 300 328, version 1.9.1
>
> Dear Jens,
>
> Thank you very much for your follow-up.
>
> 2014-02-11, 16:24, Jens Tingleff <j.tingleff@xxxxxxxxxxx> wrote:
> > I managed to get hold of some in-house experts and our conclusion is
> > that given that clause 5.3.7.2.1.3 step 2 mandates "normal
> > transmissions" we should be considering the representative traffic to
> > be access category AC_BE which should comply with the 160 us limit.
>
> I appreciate you sharing your experts' opinion with us. In a private
> conversation I learned of an opinion that the initial statement in
> 4.3.2.5.2.2.2 of EN 300 328 already covers 802.11-2012 as compliant. In
> a different private conversation this was questioned, however.
>
> In any case, it is important that version 1.9.1 of EN 300 328 becomes
> effective.
>
> > Anybody else?
>
> Just for completeness. My initial calculation had a wrong value for
> AIFS and of course I meant to type "aSlot" where I had "aSIFS" … I am
> sorry for the mistake. So the correct min/max values for AC_VO 802.11g
> (short mode) are
>
> AIFS (AC_VO) + 0 × aSlot = 28 µs
> AIFS (AC_VO) + 7 × aSlot = 91 µs
>
> Best regards,
>
> Guido
>
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