Attenuation in 3.5ghz is on average 15db per 100meters of foliage. I
got that number from a Telrad engineer, and it seemed to hold up
experimentally. Whether it's Wimax, LTE, etc, there's no reason that
would be different.
LTE can connect with almost nothing for a signal. So a person testing
with a single base station and a single UE might run around and say "wow
I've got 5 megs here and No LOS!", but I think they forget that the
entire base station's capacity is 5meg when it's talking to that single
UE at 5mbps. It's impressive that it worked, but is that actually
useful as a fixed ISP?
Another thing I noticed is that Telrad could turn the Tx Power all the
way to +30dbm, and people were actually doing it, and Telrad support
seemed to be encouraging them to do it. At a training session someone
in Telrad support told me, "Adam, if you're worried about the legal EIRP
limit then you're the only one worried about it." So if you're 8-10db
stronger than the legally operating product, and you can technically
connect with a signal too weak for the other product, that certainly
makes people feel like there's better penetration.
There may also be some "magic" in how LTE allocates resource blocks and
gets feedback from the UE's (CQI) on which resource blocks are working
best for each unit, but I think that's a matter of getting the most
value possible out of a trashy signal. If you're a fixed operator
building for capacity and performance then you hopefully won't be
installing with a trashy signal anyway.
My biggest issue of all is that all of the WISP priced LTE stuff is
clunky and buggy. Frankly, that was true of WiMax too. It seemed like
Telrad's bridging modes never quite worked right for example. You were
better off building an L2 tunnel on your own box behind the UE.
-Adam
On 9/14/2020 12:19 AM, Ken Hohhof wrote:
Ever since I got bamboozled into deploying a WiMax basestation, I have
been skeptical of tree penetration hype.
We have been deploying Cambium 450 in 3.5 GHz / CBRS and it’s great,
but it doesn’t “penetrate” trees. OK, an SM within a mile can go
through 1 or 2 trees, depending on the size/density/type of tree. And
with the usual caveat that trees near the customer are more
problematic than trees in the middle of the path.
Some people say otherwise, but there were all sorts of glowing
testimonials for the WiMax equipment as well.
Maybe LTE has magic properties. I doubt it, but I haven’t tried it, I
don’t want to repeat the WiMax fiasco. So I could be wrong. But when
I’m wrong, usually it’s because I wasn’t pessimistic enough and things
are even worse than I feared. Only on rare occasions do I expect a
lion behind the door and there’s a beautiful lady. Usually there’s 2
lions.
Certainly turning on CBRS made all our 3.5 GHz Cambium stuff work
better, we got several dB higher xmt power, and usually cleaner
spectrum. But the cleaner spectrum thing is only true until other
operators fire up their stuff in 3550-3650. Even if you get a PAL,
it’s not like nobody can use that frequency in the whole county. The
interference at the edge of your PAL protection zone should be below
some level that the SAS uses when authorizing nearby operators to
transmit. But that level isn’t -99 dBm.
LTE gear may be designed with better receiver sensitivity, that will
help if the noise floor is really really low. On the other hand, does
most LTE gear use the highest allowed EIRP? What about the CPE? That
was another problem with the WiMax stuff, the CPE was 3rd party stuff
that typically had kind of wimpy xmt power and not particularly high
antenna gain. Maybe that’s not true of LTE gear, I haven’t looked
into it. But pull out a Cambium 3 GHz 450b high-gain SM spec sheet
and compare to the LTE CPE.
*From:* AF <[email protected]> *On Behalf Of *Trey Scarborough
*Sent:* Sunday, September 13, 2020 4:43 PM
*To:* [email protected]
*Subject:* Re: [AFMUG] LTE vendors
Has anyone done a comparison or know of a whitepaper between LTE and
Cambium? I am mainly looking at tree penetration or lower DB signals
to actual throughput comparison. I have been told that LTE gets a
little better tree penetration but if that is at a low rate that
really doesn't help any.
On 9/12/2020 10:03 AM, Darin Steffl wrote:
It comes down to complexity. Ericsson, Nokia, etc are all cellular
brands and to run and manage those complex LTE networks, you need
full time engineers to manage, debug, and optimize things.
Cambium is so easy, in comparison, there's very little extra
learning to do in order to get it running great. Ericsson LTE
probably would require months of training and needing to hire
someone just to run the gear or hire expensive consultants to do
it for you.
On Sat, Sep 12, 2020, 9:49 AM Kurt Fankhauser
<[email protected] <mailto:[email protected]>> wrote:
450m is the only way to do, especially if your already using
the 450 platform in other parts of your network, there is an
operator in my area with the Ericson system and they had a ton
of issues with getting it up and running, not even sure if
they ever got it all resolved.
On Fri, Sep 11, 2020 at 9:00 PM Sean Heskett <[email protected]
<mailto:[email protected]>> wrote:
Yup what josh said lol.
We tried the LTE thing and glad we switch to 450m...much
easier.
-Sean
On Fri, Sep 11, 2020 at 4:43 PM Josh Luthman
<[email protected]
<mailto:[email protected]>> wrote:
Having done one LTE vendor and 450m the only mistake I
made was not buying the 450m sooner.
Josh Luthman
24/7 Help Desk: 937-552-2340
Direct: 937-552-2343
1100 Wayne St
<https://www.google.com/maps/search/1100+Wayne+St+Suite+1337+Troy,+OH+45373?entry=gmail&source=g>
Suite 1337
<https://www.google.com/maps/search/1100+Wayne+St+Suite+1337+Troy,+OH+45373?entry=gmail&source=g>
Troy, OH 45373
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On Fri, Sep 11, 2020 at 5:54 PM Adam Moffett
<[email protected] <mailto:[email protected]>> wrote:
And yeah, 450m might be expensive, but so is all
the LTE stuff.
You'll max out the legal EIRP with 450m, and get
8x8 MIMO. I think
part of the magic with LTE is that it will connect
with ridiculously
low signal, but on a fixed system you probably
won't really want the
trashy signals anyway.
Cambium also has LTE for whatever it's worth. The
CBRS version
is supposed to be available relatively soon
(though I forget
precisely when).
I don't know if I state it as "fewer issues since
there is no
EPC", but definitely fewer complexities and fewer
things to worry
about. The connection from eNB to EPC has to be
/pristine/,
and the EPC comes with its own set of new
terminology and new
concepts to figure out.
On 9/11/2020 4:06 PM, Darin Steffl
wrote:
I have seen lots to people doing 450M in CBRS
stating coverage is nearly the same as LTE but
way better speeds
and triple the aggregate capacity due to mu-mimo.
Way fewer issues too since there is no EPC. Just
straight layer 2 with no bullshit.
On Fri, Sep 11, 2020, 2:39 PM
David Coudron <[email protected]
<mailto:[email protected]>>
wrote:
We are looking at a new area to
expand out network that has a lot more
tree cover than
our current footprint. We are thinking
with the
combination of CBRS and LTE, that we might
be able to
offer better coverage than with
traditional fixed
wireless options. We have started
conversations with
the following vendors, wondering if anyone
has any hands
on experience with any of them and what their
impressions were:
Blinq
Airspan
Baicells
Ericsson
The Ericsson equipment is in a class
by itself price wise, but the others are
similarly
priced, and somewhere around double the
price of PMP 450
stuff. Normally we would add more tower
sites for
better coverage, but this project will
need to be done
before the end of the year and building
towers isn’t an
option. We have good enough spread on
the towers that
we think we can do this with PMP 450 APs,
but are
thinking we’d get even better coverage out
of LTE. Any
opinions on the reliability and the
manageability of the
four vendors above? Sorry for such an
open ended
question, but not sure what to ask to be more
specific. We know that we will have the
LTE stuff to
deal with like access to an EPC and so on,
so not so
much worried about that as more the
manufacturers
themselves. Baicells concerns us as they
may get
lumped in with Huawei.
Thoughts?
Regards,
David Coudron
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