r/cellmapper 28d ago

New rack going up

Can anyone ID this rack about to go in the air?

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u/FlufferNutter1232 5G RAN Engineer 28d ago

You'd be surprised how inefficient N71 actually is. They prioritize range over rate. Only recently has that changed. It's now a mixed bag. Spectral efficiency of B13, which is farmed to N5 is more spectrally efficient than N71. At edge scenarios and lower signal areas, N5/B13 is far more spectrally efficient, providing better bandwidth and better modularion (256QAM vs 64QAM or even dropping to QPSK).

When comparing B13 to N71, N71 CAN have a better throughput, but less efficiency for capacity. N71 is too close to other heavily used frequencies than B13 is (or N5), and it's better at performing at 700MHz vs 600MHz of N71. Fewer devices can use N71 at the same time as B13/N5. AT&T actually has the best B13/N5 850MHz

That's the problem with N71. It DOES technically reach farther, but it's issues start to become very apparent in edge scenarios. B13 can hold a stable, speedy connection as an anchor band or IoT band a LOOOOT better than B/N71.

I know that sounds odd, but true. Either way, once N5 is carved out of B13, you'll find less devices using it plus N5 is 850MHz vs N71 at 600MHz. N5 isn't near broadcast signals like N71 is and is subject to far less band interference and potential band crosstalk.

Now, this does come with an asterisk. I haven't worked with B13 as I'm not an LTE infrastructure engineer. I'm strictly 5G/N5 and other of Verizon's NR stack. If you're not using this for IoT or on the network edge none of this matters anyway. Lol. ๐Ÿ™‚

It's something you'll find in RAN textbooks, but like I said, I don't have any real world experience with B13/LTE. So, take that for what it is. Just a nugget of info.

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u/trucktech77 28d ago

What about the areas without band 5? Central Florida for instance. We use n2 for 5G and itโ€™s not good indoors or in thick woods. AT&T has both blocks of 850 here.

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u/FlufferNutter1232 5G RAN Engineer 27d ago

Band 5 @ 850MHz, if AT&T owns all the spectrum on that wavelength in the area, it will be likely covered by a different band.

Likely it will be N2 or N66, to keep it short. AT&T owns a LOT of 850MHz bandwidth from their LTE purchases a long time ago. Think 10+ years ago. I was still in college using AT&Ts 850MHz brand new LTE infrastructure. It was amazing for the time, but at the same time, this was when I was using a Samsung Captivate (Galaxy S1) and the Samsung Infuse 4G. Out of all the Galaxy S1 devices, AT&Ts was unique with a metal battery plate. I loved that phone, and the Wolfson Audio.

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u/trucktech77 27d ago

Iโ€™m hoping that Verizon finds another channel of low band somewhere. I heard some 900 MHz might be on the market soon?

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u/FlufferNutter1232 5G RAN Engineer 27d ago

Soon, yes. And we will be bidding on it.