Microwave link capacity

Mailman List Mirror (Read Only)
1

In a context of providing rural communities with modern broadband.

Reading some tells me that Microwave links can be raised to 1gbps. How
common is that ?

I assume that cell phone towers have modern microwave links (when not
directly on fibre). What sort of capacity would typically be provided ?

And in the case of a remote village/town served by microwave originally
designed to handle just phone calls, how difficult/expensive is it to
upgrade to 1gbps or higher capacity ? Just a change of radio ? or radio
and antenna, keeping only the tower ?

(keeping spectrum acquisition out of discussion as that is a whole other
ball game).

2

There is no simple answer, as the characteristics of each link are unique,
thus the requirements for each potential upgrade are also unique.

Typically an engineering study will be done to determine what exactly is
required, and what the cost will be. It could be as simple and cheap as a
software license upgrade costing a few hundred dollars; to a complete
tear-down and re-build of the towers (to support much larger antennas, for
example), costing hundreds of thousands. It can even involve adding
additional sites as relays, potentially pushing the cost into the millions.

--Eric

3

DragonWave is one of the bigger players in the game offering 1gbps+ throughput.

http://www.dragonwaveinc.com/products/packet-microwave

4

In a context of providing rural communities with modern broadband.

Reading some tells me that Microwave links can be raised to 1gbps. How
common is that ?

for wireless backhaul of cell-towers, some wisp infrastructure and for
this like inter-building point-to-point connectivity. pretty common.

I assume that cell phone towers have modern microwave links (when not
directly on fibre). What sort of capacity would typically be provided ?

an example would be something like

http://www.dragonwaveinc.com/solutions/mobile-backhaul

And in the case of a remote village/town served by microwave originally
designed to handle just phone calls, how difficult/expensive is it to
upgrade to 1gbps or higher capacity ?

well if you're describing at&t longlines or bell canada C-band microwave
relay networks those were built a time when cost was not the primary
consideration, (e.g. there were not signficant alternatives in the 1950s
to 1970s)

Just a change of radio ? or radio
and antenna, keeping only the tower ?

modern radios are dramatically cheaper. use of unii bands or licensed
spectrum are options, distance and spectrum choices tends to dominate
the set of considerations that goes into selecting a system.

examples of unlicensed being something like

5

I do not have direct experience with this, but Ubiquiti's AirFiber 5 seems
like an applicable solution: https://www.ubnt.com/airfiber/airfiber5/

It runs around $1.000USD each

6

AF5 is not in the market for 1 gbps links FYI. The AF5x is a better
product IMO and is $800 per link + dishes.

Josh Luthman
Office: 937-552-2340
Direct: 937-552-2343
1100 Wayne St
Suite 1337
Troy, OH 45373

7

Thanks everyone. I got the sanity check I needed.

The telcos often have old microwave links to rural communities and in
trying to outfit communities with modern broadband (which the telco
hasn't done), there needs to be consideration for the link back to
civilisation.

Up existing microwave links can be upgraded to enough enough capacity
for the community, then perhaps it is a acceptabvle solution at least in
short/medium term.

I know that Telus in the rockies has provided some communities with
microwave links to get over mountains (new installs) in last couple of
years. (but this has added costs since each tower needs to be powered,
have access road or helicopter landing capability etc).

8

And some more options:

Mimosa Netwtk 10 Ghz livensed solutuon, in excess of gigabit throughput. Licensed 10 ghz and 6 ghz can go pretty long distances (20+ miles)

Also check out SAF Tehbika licensed radios, mkstly 366 Mbps throughput but they have a wider band radio now too.

Cambium, Ceragon and Trango are also good platforms.

For short hops (less than a mile or so), check out Siklu 60 Ghz, gigabit, solutions.

If in the US, FCC licensing for PtP links is actually pretty affordable, couple or three grand. It's not like buying spectrum for cell phones.

If you need more info, please feel free to hit me up offlist.

-Mike

9

You might be better served with the lists over at wispa.org. Not saying the people here don't have the answers, but that's what those guys do.

10

A lot of new gear is gigabit. The current price\performance leader is SIAE's ALFOPlus2.

11

Agree with Mike that WISPA is probably the place to get real world experience from people who make a living with microwave links.

We use primarily Dragonwave (in FCC part 101 frequencies: 11, 18, and 23GHz), which can get ~600-800Mbpas over the air, depending primarily on channel width and distance. For shorter links (~1 mile), we use Siklu 80GHz, which can do 1-2Gbps over the air.

12

How well does Siklu handle rain at closer to 1mi. range?

13

How well does Siklu handle rain at closer to 1mi. range?

This is not dependent on the radio, it's dependent on the frequency and rain
zone. http://www.softwright.com/faq/support/Rain%20Rate%20Estimates589.gif

If you're in E, it's going to be much more severe fading due to thunder storms
vs. in the D or F region. There are calculations you can do to figure out
your fading due to rain and how much link availability you need.

The newer radios support adaptive modulation, and will downshift from 2048

1024 >512 >128 > 64 >16 QAM > and some even go down to BPSK. Of course you

lose bandwidth for each down shift, so if you need 800 Mbit 99.999% of the
time, you need to evaluate it at the lowest modulation that will give that.

Horizontal Polarity will be slightly more effected by this, so on any links
you're running both polarities, you need to evaluate horizontal.

The real problem is a radio from x vendor at a given modulation is about as
good as any other vendor. (give or take 3db) Most vendors use a COTS
chip-set for the modulation, and about the only difference is the packaging.

A 2048 QAM radio will need -63 or better signal just to hit that modulation
and in a 40 MHz channel at 18GHz you don't have much distance with out larger
dishes or higher power. You in Crane rain zone E? Shit, better add in 35 dB
for rain fade. You need a -28 or -30 signal! That's 2k (1.6 Mi) for that
path. And you have to rent tower space, pay for engineering, pay for install,
and pay for the gear.

While it's still cheaper than fiber, and deploys faster, a mile of fiber is
not that expensive depending on the area.

Microwave has it's place, but the 20 mile, >1gb links are marketing more than
anything.

14

So existing long distance links to reach rural communities are not good
candidates to upgrade from old microwave that handles just phone to
something that can serve broadband for the town ?

If existing towers are further apart than what is realistic for higher
capacity links, then upgrading would involve new towers at which point,
the economics might point to fibre.

15

There is no simple answer to your question....

Fixed Wireless technology has come a long way, and there maybe a lot of different variety of products available, however when you start your product selection for a particular project, it is not un-common to find one constrained in terms of resources.

While one cane make a statement such as .. You can shoot 1gig, 20 miles however that comes with a lot of cavats...
i.e. What mfg makes equipment that can do this ?
      Do you need one set of radios or are you stacking multiple radios ?
      Do you have the required Freq and Channel available ?
      and a few other things..
              How big is the antenna required for this ?
              Is the Tower Strong Enough to withstand the wind loading ?
              What would it take to strengthen the tower ?

All of these above details can send you down the path, into a rabbit hole which may or may not be constrained.
Then there are different ways to mitigate these constraints .. (making the hop shorter.. ie. and intermediary repeater site.. etc etc etc ).

Delivering 1gig + long distance is not an easy slam dunk task. While Fiber can be a lot of work to put in the ground for 20 miles, it is generally considered to be the better option, because there is a lot of headroom for expanding capacity.
Fixed Wireless, can be deployed quickly, and may possibly be less expensive however there is no headroom for expanding capacity (if the link is designed as per specs of 1gig Capacity).

Hope that makes sense.

Regards.

Faisal Imtiaz
Snappy Internet & Telecom

16

Many companies have link planning software available that can help give you an idea as to speed for your particular scenario.

Ex: https://airlink.ubnt.com/