Google balloons, “cell towers in the sky,” can serve 4G to a whole state | Hacker News Reader

Google balloons, “cell towers in the sky,” can serve 4G to a whole state

arstechnica.com

120 pointsismavis88 comments

Google balloons, “cell towers in the sky,” can serve 4G to a state the size of Rhode Island would be more accurate.

To have a minimum coverage, you would need 140 of them to cover Texas, ~2,000 to cover the USA, ~6,000 to cover Africa (each balloon covers ~5,000km²)

So covering the whole of US could cost them somewhere around ~$1 billion?

Texas has a lot of uninhabited land, as does the USA and Africa. Is that being accounted for?

Definitely not, it's just an estimation of what you would need to have a 4G coverage everywhere.

Areas with a very low population density are not completely uninhabited, there's at least a few persons. But yeah in a big national park or in the middle of a big lake you probably don't need 4G as much

would be interesting to see how people's behaviour would change if they had fast internet no matter where they went

It would be considered exciting and dangerous to go somewhere without the internet. To some degree I suppose it's already true about phone service.

balloons are not stationary. To cover inhabited areas, you also have to cover the uninhabited areas or else you're only going to have service for as long as it takes the balloon to drift overhead.

I wonder what would be the cost of producing/operating a balloon and changing it every 187 days (or probably more often, the probability of having them destroyed by some random objects would increase).

There would need to have a few towers on the ground too

I'm pretty sure that Verizon or AT&T would love to blanket an area of that size for only $1B. While you won't get the same speeds as Fiber, the economics still work out well.

$2B every 6 months? That's a huge cost in my book. Not to mention reliability issues, downstream power limitation and low upstream capacity compared to cell towers.

It's large, but they'll hopefully keep increasing the longevity of the flights and be able to get that cost down. Gaps in coverage will be a huge issue that could possibly balloon the total cost due to tighter density.

You'd need a lot more than that for coverage. These balloons are not stationary. They are constantly traveling around the Earth. At the very least, need the balloons around the circumference of the earth. Also, I doubt that the coverage is a perfect square. I'd think the coverage footprint would be more circular, and so you'd need overlap in order to get coverage.

I think the last time that the Loon project item was posted here a lot of the same comments were made. I think it was verified that they are flying at the 60kft - 90kft range where the winds are typically mild and in the 20mph range. I think one problem I see with it is that ordinary smart phones won't work because they transmit at around 100mw and they won't reach that altitude, you will need an earth station that is capable of at least a couple of watts and presumably then it would act as perhaps a wifi hot spot to serve some remote area. I think in that scenario, then it makes sense as a way to serve remote sparse areas. You are simply not going to be able to get the capacity at that distance to serve downtown San Fran. Also, the issue of backhaul is a question mark in my mind. There is no Google fiber up there, so they will need probably some sort of Microwave link back to earth to connect to the internet. That can be problematic, those types of links are typically very directional so you might have to have steerable antenna's at least on the earth end, which is pretty expensive to do. So I am not sure how they plan on dealing with that part.

Cell phones can transmit up to 50 miles depending on what it uses, CDMA is max at around 38 miles? That seems more then enough to reach 60kft - 90kft

hmmm, not with 100mw, in the old days of CMDA perhaps if the phone had 600mw which some did back then. But Loon is using LTE as I understand it, and I think it said they are using unlicensed spectrum, which, although I have not seen it spelled out, I am guessing in the 5.8Ghz band but even at 2.4Ghz, you are not going 50 miles on 100mw especially not since LTE is not CMDA, in the downlink LTE is OFDMA and in the uplink SC-FDMA, both of which have a much larger Peak to average ratio than spread spectrum so unless you are using an extremely narrow beam antenna (hard to aim while moving), that signal will probably be below the receiver sensitivity).

I could imagine more TX power on the balloon (nobody's in the way so it shouldn't do damage), as well as more sensitive RX antennae, since there isn't the same size or weight restriction as on an airplane or a satellite. Come to think of it, an unmanned balloon is actually the wet dream from an antenna standpoint.

Yup. The downlink is always easy (from the tower to the phone). The uplink is always the weakest link because the size of the device, the limited battery the limited size of the antenna due to the form factor of the phone and so on. If it was strictly a broadcast solution it would be a lot easier, but even if you are streaming youtube, you still need the uplink for TCP and so on.

> I think one problem I see with it is that ordinary smart phones won't work because they transmit at around 100mw and they won't reach that altitude, you will need an earth station

From the article:

"When Loon started, Google was testing a system that delivered Internet service to antennas on people’s homes. Mathe explained that this was due at least partly to technology limitations. Project Loon is now capable of sending signals that can be picked up by the smaller antennas on phones."

Picking up is one thing, getting the signal back from the phone with it's small antenna and low power transmitter seems problematic. But perhaps they have solved that somehow. At those distances, I am guessing the uplink would be very limited due to this. Keep in mind, that cellular carriers over time want the signal of each phone reduced. The reason is that for cellular, to get the capacity up, you want to have more cell site, each site re-uses the same spectrum of the site next to it, so if all the phones had higher power they would all be interfering with each other. They just are not designed to go those kinds of distances. Most cell radii is in the 1 - 5 mile type of range usually. Again, for capacity reasons. In the early days when there were fewer towers spaced farther apart the phones had more power (remember the old "brick phones").

> In the early days when there were fewer towers spaced farther apart the phones had more power (remember the old "brick phones").

Citation needed. What makes you think newer phones have less transmission power than old brick phones?

The working range of a cell site (the range which mobile devices connects reliably to the cell site).. is between between 50 to 70 km (30–45 miles)[1]

1. https://en.wikipedia.org/wiki/Cell_site#Range

> I think the last time that the Loon project item was posted here a lot of the same comments were made. I think it was verified that they are flying at the 60kft - 90kft range where the winds are typically mild and in the 20mph range.

From the article:

"In the same time it took the Earth to complete half of its annual orbit of the sun, our record-breaker managed to circumnavigate the globe 9 times, [...] soaring to a maximum height of 21 km and drifting over more than a dozen countries across 4 continents."

So the maximum altitude reached was 21 km.

Also, won't increasing the antenna size on the balloon enable reception of a weaker signal? Although the antenna size increases by a factor of πd^2, where d is the distance between sender and receiver. So an antenna 80 km away needs to be 64 times larger than an antenna 10 km away in order to compensate for the weaker signal.

Yes, but a larger antenna will have a narrower beam width so it gets harder to aim it in the right place especially with a platform that is moving. If the antenna beam width is too narrow, you end up needing mechanically steered antennas to keep on target, which are expensive and weigh a lot.

Just to level set, I am not being a negative nelly here, I think this is a super cool idea. It is just every time I read an article about it there is so little technical information that I am left with a million questions in my mind that I wonder how to solve.

You could always use non-normal cell phones. I used a Thuraya sat phone for a while and it worked fine to a satellite 35,786 km away. Apparently the transmission power is about 2W, they cost about the same as an iPhone and weigh 140g or so. Mine worked fine off a solar panel. So these things can be dealt with, presumably more easily for a ballon 30km away than a geostationary satellite.

(Here's one on amazon http://www.amazon.com/Thuraya-XT-LITE-Satellite-Phone/dp/B00... )

The cost of these phones (due to lack of mass production) is probably much higher.

There's also the issue of no roaming - users can't go into/out-of that region with existing devices.

The fun begins when people start going out to places currently not well-served by the usual mapping services -- places they normally wouldn't think of going, without extraordinary precautions -- thinking "Hey great, looks like we have this stuff everywhere now. Ain't everything just swell, here in The Future?"

Until of course tricky weather or something else happens, and suddenly, they don't.

http://www.npr.org/2011/07/26/137646147/the-gps-a-fatally-mi...

The difference with GPS is that these balloons (I assume) allow two-way communication, so if you are in trouble you can call for help and there's a good chance someone will actually be able to respond AND know your exact location.

Until the day comes when balloons stop working for some reason.

That's when the fun begins.

As someone with experience of working in remote environments like deserts for weeks at a time, and is thus aware of both the benefits and limitations of technology, can I suggest that you give your smug muscle a rest? I find that people who are at pains to point out how much smarter they are than everyone else get in the way when there's actual work to be done.

Empirical evidence gleaned from day-to-day observation (not to mention numerous news reports) suggest that a significant portion of the population is basically clueless about the limitations of this technology. They're also basically addicted to it (as in: a fair number of otherwise intelligent, well-educated people I know apparently can't, to save their own lives, navigate their own neighborhoods with a mapping service -- whereas 5 years ago they may have just been mildly impaired at the task).

But if you feel the need to attack someone you'll most likely never see or meet as being "smug" for tangentially pointing out this fact (ironically backed by exultations of your own vastly superior experience in both technology remote environments) -- instead of minding whatever work someone is presumably paying you to be doing at this time, as we speak -- well, do what you need to do, I guess.

There's a difference between pointing out that some new technology is likely to have some negative externalities, and framing that observation within repeated sarcastic comments about 'when the fun begins'.

You're reading too much into it. The person I responded to (at the second iteration) seemed not to be aware of precisely these externalities -- so I was providing clarification, nothing more.

You could say this for literally any technology. I don't understand your point.

What is going to happen more and more is search and rescue crews overburdened with saving all the clueless, unprepared morons who think that nothing can happen to them because their cellphone is getting two bars, leading to increased trail closures: http://ktla.com/2014/06/26/popular-dangerous-path-to-eaton-c...

Is that a case of the trail becoming popular because it is on maps? The link doesn't talk about that aspect of it, just that it is not an officially maintained trail and more rescues/recoveries have taken place in recent years.

I wonder if rescue teams could use some sort of portable cell towers (thinking something like the Google [streetview backpack](http://googleblog.blogspot.com/2012/10/trekking-grand-canyon...) to find cellphones and people.

Locating lost/stranded hikers is definitely resource intensive, but you still have to extract them from the area. In that particular case (Eaton Canyon waterfalls), the number of rescues performed by the Forest Service (most of them by helicopter) had climbed to an average of two a week in the year before the closure. That's an unbelievably high number that's caused directly by stupid, unprepared people stranding themselves. Closing the trail was definitely the right decision there. The only other alternative is "we are not going to rescue people anymore because we don't have the manpower and cannot afford to fly our helicopters so much."

Rescuers had no trouble locating these idiots: http://www.nationalparkstraveler.com/2009/10/third-time-was-...

This is a very real, big and growing problem for wilderness rescue services: http://www.nytimes.com/2010/08/22/science/earth/22parks.html

Individuals could have a drone balloon (or a daisy chain of them) that follows them to remote areas to provide cell coverage.

This problem is already addressed by several lines of popular satellite communications products: http://www.findmespot.com/en/

This comment is bizarre.

First the link you have is about people taking outdated/wrong maps on trips, not about technology that might disappear due to conditions.

Second 'when people....' you just made up to prove some weird point.

Why are people going to suddenly go crazy because there is 4G access everywhere? We all know batteries run out and things break. Normal precautions are all still needed.

Because this technology might allow silly people do something silly in a different location we concentrate on that rather than all the lives it will save?

Can someone confirm my guess that this is only useful in very low density regions? My impression is that cell phone data rates are limited more by how dense you need to make the cells to cover the number of users in the area (so NYC has microcells everywhere) rather than the area over which some coverage is possible for a single user.

You can use directional antennas, beamforming and other techniques to achieve sectorization.

But lte's base stations has actually very limited capacity, thats why in cities there are a lot of micro cells for capacity and much less 'full range' cells for coverage.

You can put multiple base stations on the balloon but I'm not sure what the capacity constraints are so I don't know if that would be a reasonable solution.

Yes, but then you also need to stabilize the antenna platform, either physically, or electronically or both. All that increases the cost vs a terrestrial tower where the stabilization requirements will be lower.

Not saying it would be impossible, it would be a fun and interesting problem to work on, but it would be interesting because it seems like there's a nice solution in there at the intersection of all those problems...

It would be pretty trivial to add electronic beamsteering but it's not clear it is even necessary: It should be okay if the cells move a little bit.

One thing people keep overlooking is the amount of power you'd need to draw to communicate with something that is that far. Your phone's battery would be dead in a few hours.

The lead of the Loon project seemed pretty positive about it when I asked him, but I guess his aim is to provide LTE to areas without any coverage at all, instead of trying to use this as a substitute for proper infrastructure.

Unfortunately, that's already reality in some areas with usable (though not great) LTE coverage. Having a more direct LOS to the balloon is a significant mitigating factor.

There's also a factor not being noted here. The population at which a cell tower is feasible may drop substantially if the uplink consists of pointing an antenna at these balloons, increasing the number of relatively tiny villages that can have semi-conventional LTE service.

I wonder (a) how many simultaneous connection the balloon can sustain and (b) how they're storing power.

Yup, it's easy to reach a large area, but it's hard to do that and service a high density of customers/connections at the same time...

True, but the interesting use case is probably low population density areas where building towers is not practical. In that situation, you probably wouldn't need many concurrent connections.

Or use high bandwidth spot beams similar to satellites as backhaul for ground nodes.

I don't think energy storage is that big of a deal. Assuming you need only need to store one night's worth of energy, the weight requirements would be about 85 grams/watt for lead-acid batteries, or 25 grams/watt for lithium-ion. For comparison, commodity solar panels are already about 70 g/W.

I think you mean 25 grams/Watt-hour and keep in mind that you need ~12 hours of energy storage.

No, I meant grams/watt, but I glossed over how I derived those numbers.

My back-of-the-envelope assumption was that you get 4 effective hours of daylight per 24 hours. Which means that for every 1W of power generation at peak, you get 1/6W of average power consumption, which translates to 3.33Wh of storage to keep things running overnight. (For a land-based installation you would probably want a multiple-day power reserve to handle cloudy days, but I'm assuming that's not an issue for a stratospheric balloon.)

So you mean 25 grams of battery per watt of solar panels?

What about using microwaves to transfer energy or charge the balloons?

I think the maximum with lte-advanced and 5 carriers is around a million simultaneous connections.

Considering "wind speeds as high as 291 km/h" I would think that one of the greatest challenges of the Google Loon project is making sure there is always a balloon above a targeted coverage area. I would wager that unless there are an unbelievable number of balloons deployed, the coverage would be intermittent.

Confusing because in their FAQ they state the following:

"We are flying in the stratosphere well above commercial air traffic and weather events, at around 18 - 27 km or 60,000 - 90,000 feet. "

I wonder if the "around the world" flight was done under different conditions?

Wind speeds in the upper atmosphere can be very fast. These balloons will not be stationary. Based on my limited knowledge of the project, the only way they could have consistent coverage would be to have evenly spaced balloons around the Earth. That assumes that wind currents would cause the balloons to travel around the Earth in a dependable pattern. Considering the circumference of the Earth 40,008km and 80km coverage diameter, 40008 / 80 = 500 balloons would be required at minimum if all the balloons traveled at the same speed and in a dependable pattern. I would imagine the wind currents the balloons would travel on would be greater than the Earth's circumference, so more than 500 balloons would be required. Also, I doubt the balloons could maintain a perfect 80km spacing. I can think of other factors that would make dependable coverage difficult.

Here's a wikipedia article explaining it.

http://en.wikipedia.org/wiki/Geostationary_balloon_satellite

These balloons will not be geostationary.

At least read the link that was posted? Because otherwise, you miss parts like this from the linked article:

"This is the ideal height because Air density is 1/10th of what it is at Sea level. This makes the wind at these altitudes 10 times less potent."

No, independent of whether it's possible to make a geostationary balloon, Google's balloons are not going to be stationary. They are steered purely by changing altitude and riding high-altitude winds.

Sure, except, the context of this sub-thread was started by someone claiming that winds in the upper atmosphere "can be very fast." So the link was to correct/explain to them, not to claim that the Google Balloons would be stationary.

Stratospheric wind speeds are very fast. Look it up if you don't believe me. I was just basing this from a quote in the original article "wind speeds as high as 291 km/h".

@coderzach, I've read other articles on Google Loon and a number of the articles mention the balloons moving around the Earth. I have not ready anything about the balloons being geostationary. If you have, please share.

I wonder if they solved the whole issue of the balloons... lost to sea off the coast of NZ?

http://www.stuff.co.nz/technology/digital-living/9012282/Goo...

http://www.stuff.co.nz/national/10182174/Google-to-reimburse...

http://www.stuff.co.nz/technology/digital-living/60107516/go...

Wow. Rhode Island is 1/5th the size of San Diego County, and 1/3rd the population.

also 1/10th of the fun :-)

If I remember correctly, you can drive across RI (east to west) in about 30-35 min. And that route isn't a straight line. RI is a super tiny state.

Seriously, most misleading headline ever.

This has always been an idea/fantasy of mine. This just shows how utterly worthless an (very valuable) idea is without execution behind it.

I hope that access to the web will become available for everyone as soon as possible.

It's either worthless or very valuable. It can't be both.

Sounds perfect for North Korea. twirls moustache

I thought this was called the "loon" program, not Google baloons?

Either way, I love this type of innovation and this is what makes me really respect Google. Yes, I know it is all about bottom line and they will profit handsomely from it, but they are also helping the world become a better and safer place.

Does anyone know why this has not been done already? Having a ton of cell towers on the ground and trying to send signal through mountains and other various terrain does not work. So why not put one tower on the ground in a central area and have an array of balloons floating around?

https://www.youtube.com/watch?v=OX21nHv47ZY Nice! Here's my little cell phone blimp. Can't do a proper altitude test right now because of wind.

...and this network of cell towers in the sky will be dubbed "Skynet".

A whole state... as long as you're not talking about 75% of states in the USA.

Please append this to the headline:

... when that state is Rhode Island.

For how many simultaneous users

What if the balloon "pops"? Falling down might still be a risk if there is heavily populated area...

Weather balloons like this have existed for a long time and don't seem to be an issue. Would still be interested in knowing the failure mode, though.

In the event of an unexpected landing, every Loon balloon is equipped with a parachute to slow its descent

http://www.google.com/loon/faq/

Thanks!

They should add a secondary inflatable cushion like the Mars rover had

Their FAQ also links to a video demonstrating the parachute: https://www.youtube.com/watch?v=2Y5AUHw8pRk

Project Loon also has a "blooper reel" showing a... somewhat different parachute test: https://www.youtube.com/watch?v=XW5PS7lRXwI

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