25 mile backhaul - Nepalwireless project

[bohrahs]

A wireless project in the mountains of Nepal (http://www.nepalwireless.net) is looking for suggestions on hardware for AP, backhaul and repeater sites.

Currently they have been using a mix of Smartbridges, CB3 and Dlink equipment.

Nepalwireless.net wants to make its network more stable and increase the throughput on its backhaul to the nearest town with internet.

Pokhara (nearest town) --- backhaul ----- RelayStation1 ---- RelayStation 2

Pokhara to RelayStation1 is 25 miles.
All other clients and PtP links are less than 6 miles.

RelayStation1 and RelayStation2 will have three PtP links and one AP each.

These are their requirements:
-- Reasonably priced.
-- Reliable (Relay stations are at least two days walk from the nearest road-head. As such, frequent visits won’t be possible!)
-- Low power usage – all sites are solar.
-- Ability to withstand cold upto – 20 degree celcius.
-- Not very difficult to configure and operate – the project will not have easy access to highly trained technical manpower.
-- Backhaul should have at least 7mbps of throughput (25 miles link).


Some of the suggestions Nepalwireless.net has received include use of single WAR board with 4 CM9 cards at each relay station, use of multiple WRAP boards, use of Motorola Canopy 5.7 GHz equipment for backhaul.

What do you suggest?

Your suggestions would be much appreciated.

Thanks.

Hemendra

[lonnie]

I have no trouble advising the WRAP that we sell. It will give more than 7 mbps and the 25 miles is attainable with CM9 and a 3 foot dish. The 6 mile links can be done with CM9 and 2 foot dishes or even the SuperPass 21 dB patches.

The WAR board will also do it, but is overkill in terms of throughput and 4 radios. You might want that in 2 years but for now the WRAP is more than adequate.

Either the WRAP or the WAR are well suited for Solar use. It is no coincidence that we have most of our sites on Solar and this Fall we will have 8 more Solar sites to cover the entire valley we live in.

Before I applied the latest StarOS release to our sites I had some with rel. 4590 that had over 160 days uptime for the Solar sites.

It is important to use the right case. We take a nice aluminum case (that we get custom built) and add 1" of styroforam inside it. This has survived -39C in Winter and +38C in summer. The insulation keeps the cards ncie and "warm" all year and avoids the peaks they would get in a normal case. The aluminum is superior for static discharge since it grounds real well to the tower.

[Skaught]

Remote reboot gear would be mandatory on this project IMHO.

[ninedd]

We do a 26 mile link using WRAP's, StarOS, CM9's and 24 dbi Grids. The link is -68 at 11Mbit and is very stable as a 'b' link. We have the margin to go to a bit higher rate g link, but we don't need the extra speed and we wanted the extra margin for stability. It was turned on in February and is going on 130+ days uptime now. StarOS & WRAP's Rocks. :)

All that being said, if it was two days walk, I'd personally go with redundancy as well, so two WRAP's at each location, two different link, on different channels and different polarizations. Even if one of the links was 'just' an 11mbit link on smaller antennas. Avoid tubro, it'll kill the entire band with very little benefit.

Also, make sure of your measurments via GPS. When you hit the ACK wall, you've hit the wall, period. Atheros can do 26 miles, but they can't do 27 if that's over the ACK limit. I'm not sure precicely what the ACK wall is, but it's not much over 26 miles. You'd hate to get all the gear in place and find out that you're 3/4 of a mile past the ACK limit. If that turned out to the case, you'd have to go back to Lucent / Agere cards and amps (ugh!) but that'll also work fine.

[lonnie]

Some guys are doing 29 miles with 15+ mbps on WRAP boards. The new VxWorks driver will be able to extend that to 120+ miles and get over 7 mbps speed.

I have some dual feed dishes I am evaluating for the redundancy aspect. So far they look pretty nice.

[go.fast]

The new VxWorks driver will be able to extend that to 120+ miles and get over 7 mbps speed.

Ahhh.
another tidbit of a suprise about the new WAR boards.
It's getting better all the time!
George

[lonnie]

And you guys thought we had fallen asleep at the keyboard. But, wait, there's more. hehehe

And that's all I'm gonna say.

[mp3turbo]

> Avoid turbo, it'll kill the entire band with very little benefit.

we are talking nepal here - you have 3895239862589 MHz available :)

[ninedd]

> Avoid turbo, it'll kill the entire band with very little benefit.

we are talking nepal here - you have 3895239862589 MHz available :)As far as I'm concerned, Turbo is Evil. I guess as long as his Nepal system doesn't interfere with me here in Canada, then I guess it's OK with me if he uses it there. :)

[bohrahs]

Thank you all for your suggestions.

There are quite a few WISPs coming up in Pokhara (one end of the backhaul), so interference might become a problem later. But, no radios in the mountains.

The project is also considering extending the network to another area 60 miles away, so the 120+ miles capability that Lonnie is talking about might come in handy. That's only on WAR boards, right?

Both relay stations on the top of the mountains (12000 ft) will have three PtP links and one AP -- four radios. For this requirement would it be better to use 1 WAR board or two WRAP boards ( x 2 for redundancy)?

[dkii]

Before I applied the latest StarOS release to our sites I had some with rel. 4590 that had over 160 days uptime for the Solar sites.


aww come on you mean to tell me that I have more uptime than the makers of star-os? I have a wrap board running build 4367 with 271 days of uptime. the only reason it's not more is because of the hurricanes we got last year. I didn't have enough generators to go around, so it's batteries died a couple of times(the hurricanes wiped out the solar panels)

[lonnie]

The WAR board has less power draw than 2 WRAP boards. There will also be higher throughput on the WAR board. The WRAP boards will be a bit cheaper, though.