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James_B_Crawshaw
James_B_Crawshaw
8/23/2019 | 6:10:21 AM
Re: Data on 5G Indoor
Thanks again
t.bogataj
t.bogataj
8/23/2019 | 5:42:10 AM
Re: Data on 5G Indoor
Very good approximations for obstacle-free space can be found in the ITU-R Recommendation P.676-3, https://www.itu.int/dms_pubrec/itu-r/rec/p/R-REC-P.676-3-199708-S!!PDF-E.pdf.

In indoor environments with obstacles that do not completely block the transmition (these would be concrete, chicken-wire, metals, water, etc), the remaining transmitted signal depends on electrical conductivity of obstacles, and is mostly affected by losses described best by skin-effect formulas -- which are given/approximated by the square root of the frequency.

Interestingly enough, it turns out that specific "lower"-frequency ranges can as well be approximated by the square root, even in obstacle-free spaces, and the approximation aligns well with empirical measurements (in indoor environments).

T.
James_B_Crawshaw
James_B_Crawshaw
8/22/2019 | 1:43:13 PM
Re: Data on 5G Indoor
Excellent article. Thanks for sharing. I see. Do you have a similar explanation of the square root relationship or is that just an empirical observation.
t.bogataj
t.bogataj
8/22/2019 | 8:35:06 AM
Re: Data on 5G Indoor
PS. And of course, the "skin effect-related losses" is just a euphemism for what will be absorbed in our bodies.
t.bogataj
t.bogataj
8/22/2019 | 8:30:25 AM
Re: Data on 5G Indoor
Formally correct, I should have stated that the attenuation coefficient is roughly proportional to the square root of frequency (no, not the square of frequency). BTW, the Friis formula was shown to be an antenna effect and not a wave-propagation effect (for example, see https://www.dsprelated.com/showarticle/62.php).

The dependence on square root of frequency is valid for any propagation medium with non-zero conductivity, i.e. for everything but vacuum. If you are tempted to argue that (dry) air is close to that, I will come back with adding a few obstacles (such as wood, concrete, anything with metal or presence of water) into the model, and point you to the calculation of strength of non-absorbed (propagated through obstacles) signal -- which will be eventually closely dependent on "remainders" after skin effect-related losses.

T.
James_B_Crawshaw
James_B_Crawshaw
8/22/2019 | 7:52:30 AM
Re: Data on 5G Indoor
"Simple physics tells that propagation decreases roughly with the square root of frequency"

I think you mean the signal strength decreases with the square of the frequency. 

https://en.wikipedia.org/wiki/Free-space_path_loss
t.bogataj
t.bogataj
8/22/2019 | 7:02:06 AM
Re: Data on 5G Indoor
It appears that indoor 5G will follow the way Wi-Fi had to walk: shifting from 2.4 GHz to 5 GHz brought more frustration than benefits. Simple physics tells that propagation decreases roughly with the square root of frequency (more or less, add or take a water peak or two), and operation at millimeter waves decreases the reach/coverage even further.

I assume that in a few years, we'll start hearing about "mesh 5G" -- analogous to mesh Wi-Fi -- as the only way to guarantee proper indoor coverage and performance. (Just remember I used this term first. :)

I am also pretty sure that the debate about health implications will heat up (finally). One does not have to have a PhD in physics to understand that signal attenuation translates to absorption -- in walls, water tanks, our pets and our bodies.

T.
frapps12
frapps12
8/21/2019 | 10:49:45 PM
Re: Data on 5G Indoor amazon quiz free recharge apps
Agree with your say bro, these datas are indeed conflicting as per this site. Still, 5G will do great for indoors also in upcoming days.
daveburstein
daveburstein
8/21/2019 | 3:25:12 PM
Data on 5G Indoor
Mike

You're right indoor 5G has problems. But we're getting conflicting data. Rootmetrics found pretty good mid-band indoor coverage in Korea. The data they gave me, which I've checked, shower indoor 5G generally over 100 Mbps and often 400 Mbps.   http://rootmetrics.com/en-US/content/5g-first-look-south-korea-US

Ronan Dunne of Verizon says many of their millimeter wave deployments are now indoors. https://www.verizon.com/about/investors/oppenheimer-22nd-annual-technology-internet-communications-conference I'm pretty sure between 25% and 75% of mmWave customers can get good speeds indoors, but I wish I had data.

Many others agree with your sources that indoor just won't work. If you or anyone reading this has data, please share with me. Dave Burstein


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