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DARPA Begins Work On 100Gbps Wireless Tech With 120-mile Range

samzenpus posted about a year and a half ago | from the greased-lightning dept.

Network 83

MrSeb writes "DARPA has begun development of a wireless communications link that is capable of 100 gigabits per second over a range of 200 kilometers (124mi). Officially dubbed '100 Gb/s RF Backbone' (or 100G for short), the program will provide the U.S. military with networks that are around 50 times faster than its current wireless links. In essence, DARPA wants to give deployed soldiers the same kind of connectivity as a high-bandwidth, low-latency fiber-optic network. In the case of Afghanistan, for example, the U.S. might have a high-speed fiber link to Turkey — but the remaining 1,000 miles to Afghanistan most likely consists of low-bandwidth, high-latency links. It's difficult (and potentially insecure) to control UAVs or send/receive intelligence over these networks, and so the U.S. military instead builds its own wireless network using Common Data Link. CDL maxes out at around 250Mbps, so 100Gbps would be quite a speed boost. DARPA clearly states that the 100G program is for US military use — but it's hard to ignore the repercussions it might have on commercial networks, too. 100Gbps wireless backhaul links between cell towers, rather than costly and cumbersome fiber links, would make it much easier and cheaper to roll out additional mobile coverage. Likewise, 100Gbps wireless links might be the ideal way to provide backhaul links to rural communities that are still stuck with dial-up internet access. Who knows, we might even one day have 100Gbps wireless links to our ISP."

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I'm confused (-1)

Anonymous Coward | about a year and a half ago | (#42315017)

So this is good for the military so we are against it right?

Never going to happen. (0)

Anonymous Coward | about a year and a half ago | (#42315019)

This is so much pie-in-the-sky bullshit I can't even believe it. I hear about this kind of thing year after year, and it never happens.

Re:Never going to happen. (5, Insightful)

SuricouRaven (1897204) | about a year and a half ago | (#42315079)

It should be doable, providing two conditions are allowed:
1. The equipment may be ridiculously expensive (No problem: Around half the US government's budget goes to defence).
2. It'll need to be such high (analog) bandwidth, it'll not comply with any spectrum or power regulations, anywhere (No problem: If you're invading a country, you don't need to be overly concerned with obeying local laws, and even occupiers get some leeway).

Re:Never going to happen. (-1)

Anonymous Coward | about a year and a half ago | (#42315287)

"1. The equipment may be ridiculously expensive (No problem: Around half the US government's budget goes to defence)."

A: You are wrong.

http://en.wikipedia.org/wiki/File:U.S._Federal_Spending_-_FY_2011.png

And B, who the fuck are you to go around spending my money so willingly? Spending IS a problem, all of it.

And it's defense you dumbshit not defence, you have a computer, use the spell check.

Re:Never going to happen. (2, Informative)

Anonymous Coward | about a year and a half ago | (#42315449)

"Defence [oxforddictionaries.com] " is [reference.com] perfectly [merriam-webster.com] acceptable [wiktionary.org] .

Re:Never going to happen. (0)

Anonymous Coward | about a year and a half ago | (#42315483)

It's closer to 1/3:

http://en.wikipedia.org/wiki/Military_budget_of_the_United_States#Budget_breakdown_for_2012

The pie chart you linked to is the result of deliberate efforts, over many years, to make the defense budget look smaller than it actually is by assigning Defense costs to other departments.

Re:Never going to happen. (1)

SuricouRaven (1897204) | about a year and a half ago | (#42315561)

One half, one third... either way, that's a really big pile of money.

Re:Never going to happen. (0)

Anonymous Coward | about a year and a half ago | (#42315969)

Jokes goes that half of the government spending goes to defense, the other half to health care and social security, and another half to everything else.

Not much of a joke, really. 2013 budget looks like this (wikied):
Revenue $2.902 trillion (requested)
Total expenditures $3.803 trillion (requested)
That's 901 billion deficit on a 3803 billion budget, so budgeted spending is 1.3 times budgeted income, the rest is debt spending.

Re:Never going to happen. (1)

Anonymous Coward | about a year and a half ago | (#42315513)

Looks like someone needs to educate this dumbshit about the difference between discretionary spending (of which defense definitely IS) and non-discretionary (as in you will break a law if you don't make that payment).

And you will forgive a foreigner for not fully understanding the intricacies at which the US government spends/wastes money. We do it better than anyone else in the world, naturally. Those socialist europeans don't waste money nearly as well as we do, and they are a bunch of socialists for gods sake!

Seriously, if you are going to start on a bend about spending, at least have the guts to admit that the real problem with socialism in the USA is that we are just fucking terrible at it. We don't know what to do, when, or how much of it, and yet there are countries out there with spending well under control, better public services by a long shot, and we just sit back muttering about how our system is the best.

Re:Never going to happen. (0)

Anonymous Coward | about a year and a half ago | (#42317735)

A large portion of defense spending is typically veterans healthcare and pension which are no more discretionary than social security.

Re:Never going to happen. (4, Insightful)

girlintraining (1395911) | about a year and a half ago | (#42315423)

1. The equipment may be ridiculously expensive (No problem: Around half the US government's budget goes to defence).

Dude, 30 years ago the idea of a hard drive with a "gigabyte" of capacity was something ridiculously expensive, taking up football-field sized buildings, and everyone thought it'd be a really dumb idea anyway; Tape would be better for storage. Now I can get 64GB of storage to fit on my index finger and it's only a fingernail's thickness. The argument of "it'll be ridiculously expensive" dies over a long enough time span.

It'll need to be such high (analog) bandwidth, it'll not comply with any spectrum or power regulations, anywhere.

Ding! We have a winner. Though, not for the exact reason you're thinking. It could in fact work, and even within certain power requirements. But it'll never get regulatory approval, and it has nothing to do with technical requirements, but the fact that (at least if we're talking about the United States) the people in charge are paid large amounts of money to maintain the status quo. Remember that price fixing scandal for digital TV when the FCC fucked up the transition so badly Congress had to intercede... three times? Yeah... what ever happened to them? Oh right... the FCC made billions, the corporations made billions... the taxpayers lost many billions, and... oh right: They were fined, uhh.. less than a penny on the dollar against their profits.

Every attempt to give the general public access to high speed digital communications for cheap has been blown out of the water faster than you can say "Republican in a bathroom stall at an airport."

Re:Never going to happen. (1)

Anonymous Coward | about a year and a half ago | (#42319243)

"30 years ago the idea of a hard drive with a "gigabyte" of capacity was something ridiculously expensive, ...Now I can get 64GB of storage to fit on my index finger and it's only a fingernail's thickness. The argument of "it'll be ridiculously expensive" dies over a long enough time span."

Radio technology is not much older and much more developed than hard drive technology. There is no indication whatsoever that some near future technological advancement will make high power, high frequency technology an order of magnitude cheaper than it is now.

Also the military doesn't want it at some arbitrary time in the future after a "long enough time span" has passed, they want it soon.

Re:Never going to happen. (-1)

Anonymous Coward | about a year and a half ago | (#42315551)

Well, actually 21% of the budget goes to defense. The 50% you're thinking of is what goes toward entitlements for the worthless/poor.

Re:Never going to happen. (0)

Anonymous Coward | about a year and a half ago | (#42317503)

Obvious troll is obvious, -5 points for Gryffindor

Re:Never going to happen. (2)

Ken_g6 (775014) | about a year and a half ago | (#42318107)

2. It'll need to be such high (analog) bandwidth, it'll not comply with any spectrum or power regulations, anywhere

There may be a twisted solution [physicsworld.com] to the spectrum problem, at least.

Re:Never going to happen. (1)

pixelpusher220 (529617) | about a year and a half ago | (#42315271)

Remember, Verizon will charge you $10/GB over 2GB...they will roll this out yesterday.

Re:Never going to happen. (4, Informative)

Baloroth (2370816) | about a year and a half ago | (#42315415)

This is so much pie-in-the-sky bullshit I can't even believe it. I hear about this kind of thing year after year, and it never happens.

This is DARPA, a company for whom "aim at the sky" is more of a directive rather than a metaphor. Some of there other work includes flying tanks, passive radar systems, stealth ships, onion routing, and wide area interconnected computer networks. Most of it doesn't work, of course... but when it does, we get something no one else would have bothered developing.

Re:Never going to happen. (1)

Githaron (2462596) | about a year and a half ago | (#42317389)

Where are my flying tanks!?

Re:Never going to happen. (1)

gargleblast (683147) | about a year and a half ago | (#42319119)

I was wondering that myself, so I googled darpa flying tank. This is what I found. [wired.com]

I think these guys are taking Avatar way too seriously.

Re:Never going to happen. (1)

Anonymous Coward | about a year and a half ago | (#42318973)

As someone who is currently working on a DARPA program (and having worked on another one in the past), there is a term that is commonly bandied around in academic circles... "DARPA hard". DARPA does not fund incremental research that improves something by 2X. They are always on the lookout for funding truly groundbreaking and innovative concepts and their call for proposals always have ridiculous aims. It isn't very often that a team is able to satisfy all the deliverables for a DARPA program, but even in the programs that "fail", tons of useful research comes about, that act as a basis for future innovations. DARPA helps spur innovation in areas that it deems useful and beneficial to the US army and it most often succeeds at doing that. For example, the self driving cars that Google and Stanford have been working on, came about from 2 back to back DARPA challenges for self driving vehicles (I believe the first was in a desert and the 2nd followup program was for city driving).

Re:Never going to happen. (1)

dywolf (2673597) | about a year and a half ago | (#42326329)

Seriously.
Mod up.

Re:Never going to happen. (1)

dywolf (2673597) | about a year and a half ago | (#42326281)

This technology brought to you by DARPA.
The people who scoff at the word impossible.
Enahncing your world one crazy impossible bullshit idea at a time.

can i charge you for my airspace use? (0, Funny)

Anonymous Coward | about a year and a half ago | (#42315057)

I'd like to know if i can charge people for use of my airspace ....might put the foot down on all these beamed tech experiments i ain't exactly happy with. no offence but wireless this powerful ....really tell us really how your gonna beam that much umf that far without passing through beings and frying them

do explain this tech out do all the people know what your doing ....and if it isn't safe FUCK the hell off.

Re:can i charge you for my airspace use? (3, Informative)

mcgrew (92797) | about a year and a half ago | (#42315149)

I don't know why I'm responding since you're AC and won't see it, but if someone else is wondering the same thing, you can hear an FM radio broadcast for a couple hundred miles in some conditions. That radio station has a 50,000 watt transmitter, but the power drops off inversely. By the time it reaches your property it's only milliwatts.

Re:can i charge you for my airspace use? (0)

Anonymous Coward | about a year and a half ago | (#42315293)

I'm an AC (Not the same you replied to.) and I often check back to see if someone have responded to my post.

I also wanted to add that it is likely that DARPA is aiming for a highly directional transmitter to avoid others from listening too much and to keep output power down.
The 50,000 watt radio station is very likely not directional.

Re:can i charge you for my airspace use? (2)

Nethead (1563) | about a year and a half ago | (#42316503)

Since you'll be checking back ;)

An FM broadcast antenna is indeed directional, in the vertical plane. It flattens out the signal from a sphere so that most of the power is on a level plane. That's how an antenna creates gain. On the other axis it is most often omnidirectional. That 50KW is ERP (Effective Radiated Power), the transmitter is likely only putting out about 10KW.

Re:can i charge you for my airspace use? (3)

girlintraining (1395911) | about a year and a half ago | (#42316613)

An FM broadcast antenna is indeed directional, in the vertical plane. It flattens out the signal from a sphere so that most of the power is on a level plane. That's how an antenna creates gain. On the other axis it is most often omnidirectional. That 50KW is ERP (Effective Radiated Power), the transmitter is likely only putting out about 10KW.

Close but not quite. EIRP is where you start; with an idealized transmitter that radiates power equally in every direction. ERP is calculated based on the energy of the antenna's main lobe, which for an FM transmitter typically looks like a small circle and a long oval connected at the antenna. The difference in power between the EIRP model and signal strength in the main lobe of the antenna is the antenna's gain, which is where your ERP calculation comes from. A transmitter with an antenna having 6dB of gain means it can transmit at 10KW and have an equivalent signal strength (in the main lobe) to an ideal antenna radiating in all directions at 40KW.

Re:can i charge you for my airspace use? (1)

Nethead (1563) | about a year and a half ago | (#42316931)

GIT:

I was trying to keep it simple. It's also been a few decades since I've exercised the rights and responsibilities of my old first class ticket.

Re:can i charge you for my airspace use? (0)

Anonymous Coward | about a year and a half ago | (#42319927)

I was trying to keep it simple.

So did I but thanks for clarifying anyway. (Yes, I am the backchecking AC checking back.)

Now, can you give me an example of a truly omnidirectional antenna?

Re:can i charge you for my airspace use? (1)

Nethead (1563) | about a year and a half ago | (#42320581)

Only in theory :)

About as close as you'll get is a dipole [wikimedia.org] but then you still end up with more of a doughnut. [wikimedia.org]

Just about any antenna can be modeled as a dipole. For example, an AM broadcast antenna (AKA a vertical) is just a dipole where the tower is one side and the earth is the other. Actually on an AM tower there is a lot of copper strap laid out radially underground from the base of the tower and the whole tower is electrically insulated from the ground. Same thing with a mobile antenna on a car, the stick is one side and the car body the other.

Re:can i charge you for my airspace use? (1)

Nethead (1563) | about a year and a half ago | (#42320603)

Sorry, that first link should have been: http://en.wikipedia.org/wiki/Dipole_antenna [wikipedia.org] but you knew that.

I'll believe it when I see it. (0)

Anonymous Coward | about a year and a half ago | (#42315069)

For the moment, I don't.
Though, if that actually works, it would be awesome to string a few of these together and have a backup network for when ISPs eventually cave in and start filtering everything worth viewing online.

Enables fleets of tele-op ground vehicles (1)

Anonymous Coward | about a year and a half ago | (#42315085)

With this kind of bandwidth, fleets of tele-operated ground vehicles will become reality. Today there isn't enough bandwidth today to send back video, location, and other sensor info to intelligently navigate more than a vehicle or two. This will save many lives. Bravo DARPA!

Re:Enables fleets of tele-op ground vehicles (1)

CanHasDIY (1672858) | about a year and a half ago | (#42315523)

Today there isn't enough bandwidth today to send back video, location, and other sensor info to intelligently navigate more than a vehicle or two.

Really? You mean, nodes can't act as repeaters for one another?

What a silly notion.

cheaper? (0)

Anonymous Coward | about a year and a half ago | (#42315097)

"100Gbps wireless backhaul links between cell towers, rather than costly and cumbersome fiber links, would make it much easier and cheaper to roll out additional mobile coverage."

That seems to be based on assumption about the cost of such a 100Gbps wireless link.
So far however the per-unit-of-bandwith*per-unit-of-distance cost of wireless is higher than wired.
Of course that doesn't matter much if there's no profit motive and the place of deployment is a war zone.

Quality article, full of technical details (0)

Anonymous Coward | about a year and a half ago | (#42315121)

"Suffice it to say, transmitting 100Gbps through the air is rather difficult; your home WiFi network probably maxes out at around 100Mbps, some hundred times slower. "

Some hundred times? Uh...

Anyway, does anyone have any idea on what kind of tech they are planning to use? What's the highest bandwidth of today's microwave links, for instance?

Re:Quality article, full of technical details (1)

dickplaus (2461402) | about a year and a half ago | (#42315555)

Anyway, does anyone have any idea on what kind of tech they are planning to use?

Couple of Linksys routers with some sooper special version of dd-wrt.

the largest cantanta you have ever seen (1)

lister king of smeg (2481612) | about a year and a half ago | (#42318439)

they plan on buying lots and lots of pringles cans.

Re:Quality article, full of technical details (1)

PlusFiveTroll (754249) | about a year and a half ago | (#42316807)

You can buy 60GHz units that are from the 1Gbps to 2Gbps transfer rates, depending on lots of different factors. There may be faster licensed units then that, but I'm guessing the price would be insane. A 100x increase in bandwidth doesn't sound impossible if you have the free air space and are willing to spend the power.

And 100Gbps is 1000 times more then 100Mbps

100M x 10 = 1G x 100.

Re:Quality article, full of technical details (1)

DrogMan (708650) | about a year and a half ago | (#42317981)

The price is affordable for "carriers" (ie. telcos and thererfore peanuts for mlitary), and you can buy true 1GHz full duplex units off the shelf today.

There is a problem with 60GHz though - range. It's the O2 absorption frequency, so max is 1-2Km...

However there are other frequencies in that area of the spectrum which I know are being investigated/used...

Hum... (0)

Anonymous Coward | about a year and a half ago | (#42315147)

What an interesting article... Santa Claus [youtube.com]

Spectrum bandwidth issue? (1)

Gibgezr (2025238) | about a year and a half ago | (#42315173)

I am guessing that this only works because a huge amount of radio spectrum bandwidth is allocated per user. There probably is no actual method of scaling this up for general-purpose usage. The last line of the OP seems beyond speculative.

Re:Spectrum bandwidth issue? (1)

afidel (530433) | about a year and a half ago | (#42318517)

To achieve that kind of bandwidth the signal is probably going to have to be very narrow and so you can achieve greater throughput using spacial distribution as well and channel distribution. Some of the higher end WiFi systems already do this kind of bandwidth improvement by using beam steering technology to logically switch between multiple clients, the same kind of technology is also used in satellite systems where the same frequencies are reused many times between the ground and transponder.

Re:Spectrum bandwidth issue? (1)

Gibgezr (2025238) | about a year and a half ago | (#42318805)

Spacial distribution, like "channel hopping" to avoid interference? That helps with moving transmitters/receivers, but not within a static local area. In the end, for any given area covered by a transmitter, the frequency availability will be the hard cap on the shared bandwidth for that area. If 10k people in a given coverage area all want to download large files at 100 Gbps, all the trickery in the world won't increase that cap.

Somewhere, someone must have a simple rule-of-thumb for this sucker, like how much frequency spectrum is required for N dedicated 100 Gbps connections. It would be an interesting number to hear.

Re:Spectrum bandwidth issue? (1)

afidel (530433) | about a year and a half ago | (#42319019)

No spacial distribution like using beams 1 degree wide to turn a 100Gbps per 40MHz technology into a 36,000Gbps per 40MHz technology over the area covered by a synthetic array. Of course it doesn't quite scale like that because you have to spread out what part of the 40MHz your clients use so that clients in close proximity aren't using the same frequencies at the same time, but it's fairly amazing just how much bandwidth you can fit into an area using beam steering versus using a simple monopole. Currently most of the WiFi arrays use 45 degree beams and so they can achieve an ~6x improvement in bandwidth per area as compared to the naive approach.

Re:Spectrum bandwidth issue? (1)

jonadab (583620) | about a year and a half ago | (#42318843)

Actually, I'm guessing it could work for commercial usage if all the links were site-to-site links achieved with some kind of directional antennae (perhaps using conic-section backplates), so that they mostly don't pollute the airwaves all around them very much. In other words, an ISP (or any medium-to-large company) could set up a directional antenna in $smalltown and aim it at their other directional antenna in $wellconnectedlocation, creating a high-speed link between the two sites, without running fiber. Spectrum is mostly a non-issue since the two antennae are narrow-casting directly at one another: you can use basically any spectrum you want.

Priorities. (0)

Anonymous Coward | about a year and a half ago | (#42315185)

We definitely have our priorities right. First for war, maybe eventually for the internet that spreads knowledge to the whole world.

120 mile range? (3, Insightful)

rossdee (243626) | about a year and a half ago | (#42315193)

How? Is it airborne or something? You are not going to get any straight line reception at that range due to curvature of the earth, even in the plains.

Re:120 mile range? (0)

Anonymous Coward | about a year and a half ago | (#42315229)

Tethered blimps with radios on them. Cheap enough to get shot at occasionally. I think the pirate bay was going to use this technology first.

Re:120 mile range? (1)

NettiWelho (1147351) | about a year and a half ago | (#42315291)

Why, they dont need to have straight line of sight from any single drone because they plan to blot the sky out with drones so they have floating network of wireless ad-hoc access points!

Re:120 mile range? (1)

SilentStaid (1474575) | about a year and a half ago | (#42315947)

Why, they dont need to have straight line of sight from any single drone because they plan to blot the sky out with drones so they have floating network of wireless ad-hoc access points!

...Then we will browse in the shade?

/ducks

Re:120 mile range? (1)

girlintraining (1395911) | about a year and a half ago | (#42315363)

How? Is it airborne or something? You are not going to get any straight line reception at that range due to curvature of the earth, even in the plains.

It's assumed that the antenna would be mounted on something like, I don't know, say a tower, or building...

height = more problems (4, Informative)

CaptainNerdCave (982411) | about a year and a half ago | (#42316143)

The problem that was already addressed is the curving of earth, because it can be overcome with height. Let's sustain that increasing the altitude of your dishes will allow greater distance without the sphere's shape interfering, you still have all of the factors associated with those heights: weather, cost of getting there, service, general maintenance.

Maintenance: How easy is it to remove ice? Snow? What about the cost of maintaining the tower?

Service: What do you do when you can't communicate with the unit, and you've ruled out everything except the cable between the unit and it's nearest point of contact?

Cost: This is a broader issue than maintenance, because it allows for not owning the tower/building. Tower space is premium, building roof-tops are premium, labor to install, service, or repair is EXTRA premium. Not only do you need guys willing to climb 200+ feet, but they need to be technically capable. http://www.midweststeeplejacks.com/ [midweststeeplejacks.com] charges no less than $250/hr.

Weather: Why don't you see point-to-point connections on towers that are 200ft up on towers? Because the bandwidth requires very high frequencies, and those frequencies are very susceptible to any movement caused by wind. I've seen a gentle breeze (on the ground) turn a wireless link from -45 dbi to -60. Let's not forget rain and snow.

The only good ways to mount an antenna or dish at a height, and ensure reliability, are with a very large antenna (think something with 3 or 4 legs and covering at least 400 feet^2), or a building.

Re:height = more problems (1)

jimbouse (2425428) | about a year and a half ago | (#42317603)

The problem that was already addressed is the curving of earth, because it can be overcome with height. Let's sustain that increasing the altitude of your dishes will allow greater distance without the sphere's shape interfering, you still have all of the factors associated with those heights: weather, cost of getting there, service, general maintenance.

Maintenance: How easy is it to remove ice? Snow? What about the cost of maintaining the tower?

Service: What do you do when you can't communicate with the unit, and you've ruled out everything except the cable between the unit and it's nearest point of contact?

Cost: This is a broader issue than maintenance, because it allows for not owning the tower/building. Tower space is premium, building roof-tops are premium, labor to install, service, or repair is EXTRA premium. Not only do you need guys willing to climb 200+ feet, but they need to be technically capable. http://www.midweststeeplejacks.com/ [midweststeeplejacks.com] charges no less than $250/hr.

Weather: Why don't you see point-to-point connections on towers that are 200ft up on towers? Because the bandwidth requires very high frequencies, and those frequencies are very susceptible to any movement caused by wind. I've seen a gentle breeze (on the ground) turn a wireless link from -45 dbi to -60. Let's not forget rain and snow.

The only good ways to mount an antenna or dish at a height, and ensure reliability, are with a very large antenna (think something with 3 or 4 legs and covering at least 400 feet^2), or a building.

You sound like someone who has never looked at a communication tower, much less installed and used equipment on one.

I run a WISP and have equipment dangling hundreds of feet in the air. With proper planning, amazing results can be achieved. Weather is a factor over 6Ghz but, once again, this is not a problem with proper planning.

Re:height = more problems (1)

CaptainNerdCave (982411) | about a year and a half ago | (#42325065)

Actually, I work for a WISP. I've done my share of climbing 60-100ft antennae to install or repair the equipment we've got up there, and I've experienced the tower sway at that low height. There are a few other locations where there are things mounted around 250 or so, but I haven't tended anything that high up on a flimsy structure. Lots of things are hanging out on top of buildings that are 120-300ft, but most of those installations have enough structure to remain pretty rigid.

I agree that proper planning can eliminate a lot of the issues associated in most situations, but not everyone else is familiar with it. 5Ghz is pretty forgiving, but 28Ghz isn't.

Re:120 mile range? (1)

jonadab (583620) | about a year and a half ago | (#42319549)

I think to achieve a 120-mile range, you're going to need towers at both ends. A quick back-of-the-envelope calculation suggests that if one endpoint is on the ground, the other would have to be elevated about three miles, at which point fiscally speaking you may just about as well put it in low earth orbit.

However, I suspect the "120 mile" figure is probably what they figure the equipment would support GIVEN line of sight as a base assumption. In practice, dealing with topography and whatnot, you're probably going to need repeaters somewhat closer together than that. Still could be cheaper than laying fiber, and MUCH faster to deploy. The latter consideration is highly relevant for the military.

Re:120 mile range? (1)

Anubis IV (1279820) | about a year and a half ago | (#42315475)

I had already heard of airborne wireless base stations being deployed for the U.S. military (possibly reported here a few years back?), so this actually doesn't sound as crazy as you think. As I recall, they have some blimps or zeppelins geared up to do this sort of thing. If not, however, who says you need line of sight? I mostly stick to software, so I'm about as far from an expert as you can get when it comes to radios, but even I know that AM radios can be picked up at these distances, particularly at night once they start using skywave as opposed to groundwave. Whether or not those same principles can be applied here, I can't say, but it's definitely possible to have radios out of line of sight while still being able to pick them up.

Re:120 mile range? (1)

mcgrew (92797) | about a year and a half ago | (#42316203)

I mostly stick to software, so I'm about as far from an expert as you can get when it comes to radios, but even I know that AM radios can be picked up at these distances

It depends on the frequencies. Short wave and AM radio can be heard around the world because the waves bounce off the stratosphere. The term for this is ":atmospheric skip". Other frequencies, such as TV and FM radio, are limited to line of sight, with the earth's curvature being the limiting factor -- the waves don't skip, they keep going into outer space. It's roughly a hundred miles, although when you're coming down the mountains to the south driving towards St Louis you can hear KSHE from hundreds of miles away because you're so high up that those couple hundred miles are still line of sight. Going North from St Louis the signal starts fading about 75-100 miles away, you can hear it in Springfield, IL on a good day with a good reciever.

Re:120 mile range? (3, Informative)

Eevee (535658) | about a year and a half ago | (#42316235)

Well, if Slashdot ever bothered linking to the original article [darpa.mil] , you'd see:

The goal is to create a 100 Gb/s data link that achieves a range greater than 200 kilometers between airborne assets and a range greater than 100 kilometers between an airborne asset (at 60,000 feet) and the ground.

Re:120 mile range? (1)

Areyoukiddingme (1289470) | about a year and a half ago | (#42320291)

That says something far more interesting than any of the rest.

If this idea actually works on a drone, that means it's both lower power and physically compact. No giant dishes, no enormous power budgets. That makes it far more likely that it would be useful in a consumer context.

Something tower-based with typical military power requirements wouldn't nearly as interesting. Sure, it could work, but...

"What was that sizzling sound?"
"Line noise."
"Why is there a dead bird lying on the ground outside?"
"Like I said line noise."

Re:120 mile range? (1)

dywolf (2673597) | about a year and a half ago | (#42326417)

Um...you dont need Line of Sight. It helps, but its not required.
HAM operators have been talking around the globe for years.
I pick up radio stations (AM and FM) from Atlanta in Macon, and from Tulsa in OKC regularly, and I'm definitely over the horizon in both cases, no matter how tall those broadcast antenna are.

The key part of the transmitter is power, and it's the easiest way to extend the range.
But the reciever matters too: the key step in a radio is the quality and design of the circuitry. My KIA car radio can't pick up those stations I just mentioned, but my Santa Fe's radio can. Using the right amps and filters you'd be surprised what you can do.

Being DARPA, using advanced materials and advanced super high quality components in the reciever should be a no brainer.

And the next step is obvious (4, Insightful)

argStyopa (232550) | about a year and a half ago | (#42315215)

And if you manage high-bandwidth 125-mi range, the next step is obvious - a constellation of LEO (200-500mi altitude) satellites serving as a nearly-untouchable* backbone for the theater-WAN.

*ok not for peer-level opponents, but I'm pretty certain that a peer-level conflict
a) will not be based on UAVs for long (my biggest concern about UAV-dependence of our forces), and
b) will be over one way or another pretty fast if it's not going to turn SO nasty that any conventional force tech will be nearly irrelevant anyway (the not-so-comforting corollary that would invalidate my concerns above)

Re:And the next step is obvious (2)

girlintraining (1395911) | about a year and a half ago | (#42315327)

Actually, the next step is for the FCC to ban it under some vague and previously unknown test protocol as causing inteference to devices receiving the signal at -108dB. See also: Every attempt made to bring faster wifi to the masses so far.

Re:And the next step is obvious (1)

bugs2squash (1132591) | about a year and a half ago | (#42318529)

Don't complain about the FCC, they don't make the rules. You should direct your invective toward Shannon, it's all his fault.

Re:And the next step is obvious (1)

afidel (530433) | about a year and a half ago | (#42318629)

If you're talking about the Clearwire 2.4GHz trial, that was correctly halted when it was proven that 80+% of the commercial GPS receivers in the test area were effectively jammed. It shouldn't necessarily be the case that licensed users are responsible for negligible interference on adjacent bands, but the Clearwire trial was provisional on them being able to show that they could leverage those bands without affecting critical national infrastructure and they failed. That the failure was due to the failings in design of the existing users is irrelevant, the FCC correctly decided that pitching the vast majority of existing receivers in order to give one player approval for a new use case wasn't in keeping with the public interest.

Jamming? (2)

evil_aaronm (671521) | about a year and a half ago | (#42315259)

As a tool of our military, wouldn't this be rife for jamming by our enemies? Or is jamming avoidance part of the technology?

Re:Jamming? (0)

Anonymous Coward | about a year and a half ago | (#42315441)

i don't disagree jamming could be an issue, communications do channel frequency hopping to help negate jamming. 100 gigcould be an optimal spec, and if i get 8kb in a war scenario, at least its something.

i do find it interesting their stipulating its 100gig over RF. versus a potential for optical transmission.

Re:Jamming? (1)

LWATCDR (28044) | about a year and a half ago | (#42318691)

Yes, yes, and yes.
One possible solution would be using a directional antenna. A tight beam to the "WAP". Also Jammers have a short life time. Jammers tend to put out a lot of RF. Even missiles like the AIM-120 have a home on jammer mode. If this seems like an issue then the HARM AGM-88 will be updated to home on those jammers. The US also now has a lot of old AIM-7 SARA missiles that could also be updated to be an anti jammer missile. What it comes down to is do you want a fast network that may more may not be jammed or do you not want a fast network.

ISPs (2)

Crimey McBiggles (705157) | about a year and a half ago | (#42315273)

Who knows, we might even one day have 250 Mbps wireless links to our ISP.

There, fixed that for ya.

Re:ISPs (0)

Anonymous Coward | about a year and a half ago | (#42315495)

Who knows, we might even one day have 2.50 Mbps wireless links to our ISP.

Looks like you forgot a decimal for those of us on 3G.

Re:ISPs (1)

PlusFiveTroll (754249) | about a year and a half ago | (#42316905)

If you have the right ISP and are willing to pay the money, you could have 4x that today.

http://www.ubnt.com/airfiber [ubnt.com]

UAVs (0)

Anonymous Coward | about a year and a half ago | (#42315297)

It's difficult (and potentially insecure) to control UAVs or send/receive intelligence over these networks,

With this new development I'm sure terrorists with $100 worth of radioshack gear will love taking control of our drones at ludicrous speeds. Since the US are too fucking dumb to turn on authentication on their drone links

Re:UAVs (1)

N!k0N (883435) | about a year and a half ago | (#42315693)

It's difficult (and potentially insecure) to control UAVs or send/receive intelligence over these networks,

With this new development I'm sure terrorists with $100 worth of radioshack gear will love taking control of our drones at ludicrous speeds. Since the US are too fucking dumb to turn on authentication on their drone links

it's not the authentication that's the problem ... it's that they're choosing to use telnet and/or the r-tools for it.

Well... (0)

Anonymous Coward | about a year and a half ago | (#42315435)

It's sad that war is the reason for a major technical advancement like this.

I think that this is a good idea, BUT.... (1)

WindBourne (631190) | about a year and a half ago | (#42315577)

they also need to focus on beaming energy around, esp. that distance. By being able to beam energy around, they make it possible to provide remote support to forward lines esp. with tanks, FOBs, and even ships at sea.

PROPOSERS’ DAY CONFERENCE FOR 100 Gb/s RF BA (3, Insightful)

Browzer (17971) | about a year and a half ago | (#42315689)

This is actually a DARPA help wanted ad. And from description of the project sounds like a good job opportunity for some slashdoters.

here is the ad:
http://www.darpa.mil/NewsEvents/Releases/2012/12/14.aspx [darpa.mil]

and here is the proposers' day conference:
https://www.fbo.gov/index?s=opportunity&mode=form&id=e21984e31d49c3780966a53983daa4f6&tab=core&tabmode=list&= [fbo.gov]

Suggestion (0)

Anonymous Coward | about a year and a half ago | (#42315797)

1) use more than 11 channels.
2) if you only use 11 channels, at least make them all usable without overlapping.

100Gbps? (0)

Anonymous Coward | about a year and a half ago | (#42316419)

>Who knows, we might even one day have 100Gbps wireless links to our ISP.

Unless you live in the UK, of course.

uh huh (1)

zerodl (817292) | about a year and a half ago | (#42316611)

"Who knows, we might even one day have 100Gbps wireless links to our ISP." And be throttled to less than dial-up like every wireless isp out there. Mine sure does.

Re:uh huh (1)

snadrus (930168) | about a year and a half ago | (#42317983)

With wireless links of that capacity, the competition for ISPs would be through the roof. For that matter, if the regulation allowed it, darknets may start forming (think Open wifi that doesn't connect to the regular internet). That's the best case, if setting-up a router made you a peer on a network of peers (all independently owned), there would be no ISP.

20 seconds (0)

Anonymous Coward | about a year and a half ago | (#42317159)

to a 250gb cap at 100 gbps.

Where is 10Gbps copper? (0)

Anonymous Coward | about a year and a half ago | (#42319461)

100Gbps wireless? Shit we can't even 10Gbps copper in regular consumer computers without taking out a loan :(

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