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From: Martin Brown <'''newspam'''@nonad.co.uk>
Newsgroups: sci.electronics.design
Subject: Re: "Safe" cell phone WiFi capabilities?
Date: Tue, 21 May 2024 10:58:49 +0100
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On 20/05/2024 19:39, Don Y wrote:
> On 5/20/2024 10:03 AM, Dan Purgert wrote:
>>>> It's almost like "the base" isn't what you want then.
>>>> [...]
>>>> Which is why you toss in an 802.11ax AP (or 802.11ac, if the ax units
>>>> are prohibitively expensive for your house/office/whatever), and leave
>>>> it up to the client device to negotiate for the best common option.
>>>
>>> And, when you want to pass a gigabit of data to the phone each second,
>>> how does that AP help the phone GET the data when the pipe TO THE 
>>> HANDSET
>>> is considerably narrower?!

That sort of continuous datarate would probably overheat many (most?) 
mobile phones. Some of them can get quite hot when worked hard.

>> Then I buy a phone that can support 802.11ac Wave2 with 160 MHz channel
>> width, and at least 3x3 spatial streams. Assuming, of course:
>>
>>    - that the AP supports those minimum requirements as well, AND
>>    - The conditions allow for negotiation of MCS8 (~2300 mbps link rate,
>>      ballpark 1gpbs sustained data rate, but WiFi math is "fun") AND
>>    - There aren't other devices also requesting airtime (especially ones
>>      using slower options -- 2x2 streams, 802.11n, MCS5,  etc.) AND
>>    - The server has enough bandwidth (incl. read buffers, disk I/O, etc.)
>>      to sustain that 1gpbs transfer to my phone.
>>    - The phone has enough bandwidth (incl. write buffers, "disk" I/O,
>>      etc.) to sustain a 1gbps transfer from the server.
> 
> Etc.  But, I don't want to FORCE you to buy capabilities that you
> don't ALREADY HAVE -- hence the question as to the prevalence of
> a particular "minimum" WiFi standard in current phones.

> I WANT TO KNOW WHAT SET OF WiFi CAPABILITIES I CAN EXPECT FROM
> PHONES CURRENTLY IN USE.  What's so vague about that?

It varies depending on who is using them. There are a lot of people 
glued to their less than year old super phone 24/7 who have the latest 
of everything and OLED screens. Then there are the people (typically 
parents or grandparents of the above) who have the hand me down phones.

And a bunch of Luddites still on completely dumb phones for their 
extended battery life or other elderly friendly features like large 
buttons. I reckon there are still a fair proportion of totally dumb 
phones in the older generation and a bunch of people in the UK who are 
going to be very surprised when the 3G signals are finally switched off.

I have a feeling that 2.5G will outlive 3G since some remote areas have 
nothing else. 5G is now common in cities and 4G elsewhere.

> Find every phone currently in use.  Determine its WiFi capabilities
> based on its published specifications.  Tabulate these results.
> Identify any patterns observed.

You could probably make a fairly safe assumption that any phone in 
regular use for more than 5 years will be on its last legs now (and/or 
slowed down from as new performance by battery saver tricks).

Just look back to see what network capabilities were most common in 
popular models 5 years ago. Secondhand smart phones from a few years 
back sell for quite low prices these days unless they are iToys.

> I could similarly ask for the nominal WEIGHT of phones currently in
> use.  Or, size.  Or, color.  Or, ...   The approach would be the same.
> Would it MATTER how I was using this information?  Or, why?  Would
> the data CHANGE??

The annoying thing for me is that with each new generation the mobile 
phone gets larger which is good from the point of view of the handset 
being more nearly compatible with the distance form ear to mouth but bad 
from the point of view of it falling out of a shirt pocket!

All of my smart phones eventually end up with chips in their upper top 
edge of the supposedly "unbreakable" Gorilla glass...

-- 
Martin Brown