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From: John R Walliker <jrwalliker@gmail.com>
Newsgroups: sci.electronics.design
Subject: Re: "Safe" cell phone WiFi capabilities?
Date: Tue, 21 May 2024 11:43:28 +0100
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On 21/05/2024 10:58, Martin Brown wrote:
> 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...
> 
I can offer some real-world data that may be of use.  I manage
WiFi access points in offices around the world.  In every case,
i have disabled 802.11b and nobody has complained.  The reason for
doing this is that some devices such as high-definition cameras
and screen sharing devices send large amounts of data using
multi-casting. If one WiFi recipient is connected very slowly
this uses up all the available WiFi bandwidth causing the whole
network to grind to a halt.
Setting a minimum connection speed of 12MHz at 2.4GHz and 24MHz
at 5GHz is also useful and does not appear to cause any problems.

John