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Re: [STDS-802-11] CCK should it be Deprecated?

--- This message came from the IEEE 802.11 Working Group Reflector ---
Thanks Graham.
I think a technical justification might be that some STA implementations achieve their very low power consumption and/or complexity requirements by only supporting DSSS/CCK.
Whether or not those device types actually need data bandwidths higher than 2 Mbps may be less relevant, given DSSS can only achieve that tput if the medium is otherwise completely idle, and (per my earlier note) the AP might want to send frames to that STA at rates higher than 2 Mbps even if the STA doesn’t need to transmit at those rates itself.

Thanks
Thomas

On Jan 19, 2023 at 10:08:49 AM, G Smith <gsmith@xxxxxxxxxxxxxxxxxxx> wrote:

Thanks Thomas,

I suppose the question is whether we feel that we should start to discourage use of CCK?  I think in technical terms it is not now needed, so maybe we should just start the process rolling?

Deprecating does just that.

 

Graham

 

From: Thomas Derham <thomas.derham@xxxxxxxxxxxx>
Sent: Thursday, January 19, 2023 9:46 AM
To: G Smith <gsmith@xxxxxxxxxxxxxxxxxxx>
Cc: STDS-802-11@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-11] CCK should it be Deprecated?

 

Thanks for this discussion.

 

As I mentioned when this was discussed in REVme, there are some relatively recent chipsets in the market that only support 11b (up to 11 Mbps) targeting very low power IoT applications. So it is not obvious we can forecast a date at which all 11b-only STAs will be end-of-life.

 

I also noted that WFA’s Optimized Connectivity specification (publicly available on their website) specifies a minimum beacon rate of 5.5 Mbps (i.e. a CCK rate) in 2.4 GHz to help minimize management frame airtime overhead. While in practice many APs that certify for this program might configure use of OFDM beacon rates by default (e.g. 6 Mbps or above), such APs that need to interoperate with 11b-only STAs would necessarily be configured to use 5.5 Mbps CCK instead.

 

Given continued use of CCK rates in the field is expected for some time, I don’t see see a clear justification for deprecating them from the standard.

 

Thanks

Thomas

 

 

 

On Jan 19, 2023 at 8:02:25 AM, G Smith <gsmith@xxxxxxxxxxxxxxxxxxx> wrote:

--- This message came from the IEEE 802.11 Working Group Reflector ---

Thanks Harry,

My only response is that we were seeking to see if that really was the case.  Are there enough 11b only, relying on CCK, out there in the field and remember it would be 8 years before it is obsolete and that does not mean that CCK has to be removed, just that interoperability with every device is not guaranteed.  The DSSS 1 , 2 Mbps is retained of course.

 

Graham

 

From: HARRY BIMS <harrybims@xxxxxx>
Sent: Thursday, January 19, 2023 7:55 AM
To: G Smith <gsmith@xxxxxxxxxxxxxxxxxxx>
Cc: STDS-802-11@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-11] CCK should it be Deprecated?

 

My guess is that if there are 11b-only devices still hanging around after all these years, the manufacturer is not going to want to upgrade them, even if OFDM provides similar performance.

Also, if there is a customer who still uses an 11b-only WiFi deployment to this day after all these years, they likely have a good reason for not upgrading to OFDM, and will not want to change anything.

 

Further, the amount of real estate and power consumed by a working CCK implementation is so minimal compared to the rest of the modem, why would modern chipsets bother ripping it out, given they would have to subject the chip to a series of tests to verify they didn’t accidentally break something.

 

Harry

 

 

On Jan 18, 2023, at 6:49 PM, G Smith <gsmith@xxxxxxxxxxxxxxxxxxx> wrote:

 

--- This message came from the IEEE 802.11 Working Group Reflector ---

Dear 802.11 members,

In 802.11me we are discussing Clause 16 and CCK.  There is a proposal to make CCK “deprecated”.  This is the first step to making it “Obsolete”.

 

Please look at the following presentation and I would be very interested to hear any viewpoints or comments.

 

The presentation makes the case that there is no basic need for CCK as the OFDM 6 and 12Mbps are more than suitable to be used rather than CCK 5.5 and 11 Mbps, and that there is no need for the extra modem that is required.

 

Anyhow, please do read the presentation and please do comment either to the reflector or directly to me.

 

Thanks

 

Graham

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