We may soon have city-spanning 900 MHz mesh networks | Hacker News Reader

We may soon have city-spanning 900 MHz mesh networks

cheapskatesguide.org

I'll let you all in on a little secret - for the last 15+ years there have been lots of cities with 902 Mhz FHSS networks covering every little inch of them. Any of the Utilities (predominantly electrical, but some water) - that have remote meter reading often use that part of the spectrum with enough duty cycle that they can trap nearby GFCI breakers. In the case of companies like the old Silver Spring Networks (itself, a descendent, technologically in many way from Richochet) - it's IPv6 for consumer distribution. 25 Million+ nodes when I left them in 2017. Since merged with Itron, so I'm sure it's doubled or tripled since then.

I still have some Richochet modems. They were nice because you could use them as point-to-point radio modems after the Ricochet network became defunct. But with so many options for low cost and more compact radios in a such a huge plethora of spectrum options they're totally defunct now.

Oh boy do I love the free market!!!!

We have the same where I grew up. Electricity is a national monopoly. Water was one under a national mandate of small provider until the early 2000.

Curious to hear more about this if you don't mind sharing.

I was thinking of France, where the national Electricity provider is rolling out « linky », a 900Mhz capable meter. My understanding is that the 900Mhz range is already in production for french meter since a while as well.

A major utilities provider (A2A) of the Milan, Italy area uses LoRa-enabled (~865MHz) meters to get automatic measurements from the customers

Ahh I see. Curious why that has bled over to the consumer market I wonder.

I had to Google what you mentioned about GFCI breakers. Found this: http://www.arrl.org/gfci-and-afci-devices.

What the 902 to 928 MHz spectrum looks like. All those blips in the waterfall are smart meters or some other IoT device.

http://www.w6rz.net/33cm.png

Is everybody narrowband in this spectrum? Why would they do that instead of spread/hopping or some such? What's going to happen to all these narrow guys when the band starts getting busy?

It's a mix of wideband and narrowband, but everything is frequency hopped.

In the waterfall, the strong wideband bursts have a red colored center frequency. The narrowband bursts are just vertical lines.

> with enough duty cycle that they can trap nearby GFCI breakers.

Do you mean "trip" rather than trap? If not could you explain what this means?

Assume they mean trip. I have never heard of the term trap used for GFCI's.

GFCIs go by a different name in the UK (RCD - Residual Current Device), so I wondered if this was a US specific electrical term I'd not heard of.

Sorry, yeah, trip. Park the Smart Meter too close the GFCI and it induces enough current to cause it to fail-safe, breaking the circuit.

I was surprised to learn that fire suppression systems use 900MHz networks for backup alerting as well. My whole city is enmeshed with it.

For a good example of how such a mesh network can indeed function well, consider Ricochet, which once offered service in a few metro regions, including the Bay. The relay units were typically mounted on utility poles, by arrangement with the relevant agencies.

True, 128kbps wasn't anything that'd compare with 4G, but this was 1999. It wasn't great at handoffs either, but still, I was able to use it on BART regardless. Imagine, connected to the net - on the move!

https://en.wikipedia.org/wiki/Ricochet_(Internet_service)

It was amazing. And then we went on a dry spell for a few years after it was shut down and tethering wasn't a thing.

I had Ricochet. It was OK, but slow. It used little units bolted under street lights, with a little spiral antenna pointed down. It was abandoned in place some years later. You could still use it to talk to nearby locations, but the connection to the external Internet was gone.

It's certainly possible to build a 900MHz mesh network, but it can't deliver much bandwidth. Email and SMS, yes. Voice, only on slow days. Today's web, no way. It would be like building a network for Blackberries.

One of the more successful off-grid comm systems is SailMail.[1] This is worldwide email, over 10MHz, for boats. Down at 10MHz, radio can cross oceans. This was a side project of Stan Honey, who invented car navigation systems. He's seriously into sailing and holds records for crossing the Atlantic, sailing around the world, and such. So he developed this for the long-distance sail community. They maintain about 25 fixed stations around the world, and if you can connect to any of them over HF, you can send and receive email.

[1] https://sailmail.com/

Out of curiosity, do you know if some units are still around? The Wikipedia page isn't clear as to what happened to the existing hardware after the last acquirer's liquidation - was it just left in place, did the municipalities explicitly remove them or repurposed them for something else?

Some were around for years, but I haven't seen one in a while. I suppose they were removed as part of normal street-light maintenance. There may be some nodes, somewhere, still trying to connect.

This give me hope. I have been struggling with starting a small scale city wide mesh wifi... that shit is hard. I don’t need the bandwidth, just some connectivity. It’s pair really well with the bare bone internet that I would like to see back. ( HN being a fancy exemple of that )

Some are -- they pop up on local government auction sites (and even ebay) from time to time. The modems themselves are actually still quite useful, you can direct-dial between two of them using AT-style commands over the serial port, or they can be operated in a packet-radio style mode using tooling like strip: http://man.netbsd.org/NetBSD-6.0/strip.4

(STRIP was actually in the linux kernel, though I assume long gone or defunct -- the only things I still have talking via Ricochet are 2.4-era)

I have a couple of the lightpole radios (they listen for the modems on 900MHz and speak amongst themselves on 2.4GHz) and scored a single tower radio (talks to the lightpole radios and has an ethernet downlink) and have gotten them to speak with each other, but haven't had time to figure out the route mapping steps -- IIRC the deal is that the packet routing path information is stored upstream and delivered to the downstream radios. No idea if anyone ever decoded that format.

I messed around with this a lot in the immediate post-Ricochet era in between flashing silver WaveLAN cards to gold... fun times. It seems like it would be entirely possible now to run a simulated node using SDR.

> Voice, only on slow days

Then why did we have 900 MHz analog cordless phones in the 1990s?

It's not necessarily a limitation of bandwidth possible at 900MHz, it's a limitation of the normal equipment deployed and inefficiencies of mesh routing.

Those 900MHz analog phones were also usually low power, low distance, analog only devices with a few number of channels. Try having dozens of those phones all in the same room and see how useful they all are at once.

In that case, the spectrum was used as a replacement for the cable, in a 2 point system.

A mesh network is a completely different beast, with perhaps hundreds of thousands of nodes, spread around, and a good chuck of bandwidth being used for forwarding data between nodes.

Related: The Winlink system allows for off-grid email over the amateur "ham" radio service. It's available on most (all?) ham bands.

https://www.winlink.org/

Worth noting that the maximum bitrate of the base LoRa encoding is not going to replace your cellphone anytime soon, even for a fantasy re-hash of the text-based Internet that this article suggests.

I believe the maximum speed of LoRaWAN on 900Mhz spectrum is a blazing 27 kbps (that's bits), so the cited 80Kb/s in the linked article for Sidewalk-to-IP communication is several orders of magnitude higher and must contain a lot of (unsurprising) overhead.

LoRa is good for applications where it used, like meter monitoring, control systems (oilfield etc.), and RC airplane control (R9/Crossfire/Ghost). It could certainly be used for the proposed motion detection and lighting use cases. With modern codecs, you could maybe complete 1-2 voice calls at a time over it, maybe. But my guess is that Amazon's play here is "smart home without the WiFi configuration," not "replace your cell phone."

It's not going to replace your cell phone data plan.

Also, with LoRaWAN, devices have duty cycle limitations. They can't hog all the bandwidth for a extended period of time. It is really intended just for short, bursty, infrequent transmissions like you describe.

That limitation is not specific to LoRa but to anything transmitting in ISM band e.g. ~868 MHz in EU, ~900 MHz in US. It limits single transmitters air time to 1% so that one can build radio communication with any modulation, any protocol and limits probability of collision with different devices in range.

I wonder if ISM band will provide dedicated spectrum for LoRa with unlimited airtime.

I don't think that applies to 900MHz in the US. It definitely does to 433 and I think 315, though.

433 and multiples are harmonics.

Most of the ISM bands are harmonically rated (they are referred to as junk bands for obvious reasons)

I'm pretty sure that's not true for 2.4 ghz part 15 devices in the U.S. (i.e. 802.11 wireless).

(I had thought that ISM referred specifically to the 2.4 ghz band, but I guess there is actually more than one band. I do find it funny that that one of the most heavily used spectrum bands is the one where we put all the unintentional radiators like microwave ovens and industrial and medical devices, and then the FCC decided that we might as well let people do unlicensed transmission on that "junk band" because it wouldn't be interfering with anything "important". It's sort of the policy equivalent of the common phenomenon where over time the most important services eventually often end up running on the oldest, slowest computer.)

https://en.wikipedia.org/wiki/ISM_radio_band

I think this depends on the region. In the US you shouldn't exceed a dwell time limit on a single channel.

I tried (and failed) to build a GoTenna competitor using LoRa and what you say here is 100% correct. Large scale mesh networks are incredibly difficult to build and often end up requiring extreme optimizations for specific use cases. We ultimately abandoned mesh networking in favor of a TDMA approach with base stations.

“smart home without the WiFi configuration” is exactly what Amazon’s network is for, but it won’t be anything more than that. The bandwidth and latencies required for content rich applications is simply not there. Sidewalk is cool enough without trying to sell the magic mesh network pipe dream.

A network for Amazon devices is certainly one use case. Another is selling network access to other IoT devices.

I would expect most residential broadband TOS would explicitly prevent reselling their network bandwidth/access. That's what you are doing with networks like Helium, even if it is in the form of a token instead of dollars. Amazon has gotten around this by just not paying. You buy the Amazon device, you provide the network access, Amazon gets the revenue.

Yes, Amazon already offer a Sidewalk SDK as part of AWS IoT offerings. I didn't even think about the cost angle, which is a really interesting point (although, I think ISPs have an argument against the Amazon devices here still as it's effectively connection sharing, which they also usually ban in ToS). My consideration was just for the customer sales pitch, which is "your IoT devices Just Work magically."

That makes sense, I had wondered about the crypto angle on Helium. Then again, even if you were relaying a lot of messages from sensors etc. I wouldn't expect it would actually add up to a very big percentage of your total usage (I guess it'd be 24/7, unlike your Netflix/Zoom consumption). So it seems a little implausible your ISP would care (or notice), unless they wanted to get into that business themselves?

> 27 kbps (that's bits), so the cited 80Kb/s in the linked article for Sidewalk-to-IP communication is several orders of magnitude higher and must contain a lot of (unsurprising) overhead.

That’s not several orders of magnitude, that’s only 3×. Both figures are kilobits per second.

I would also mention that the Amazon Sidewalk thing is for a hybrid of Bluetooth Low Energy and 900 MHz, and it’s quite plausible that that 80 Kbps could only be achieved over the close-range Bluetooth and not in the long-range 900 MHz frequency. As an outsider to the industry with no specific knowledge of what actually caps LoRaWAN’s speed, I’m going to wildly guess that this 900 MHz band, in whatever guise, may be more likely to yield 10–20 Kbps speeds in good conditions.

My fault, I thought the figures in the article were kilobytes (and even then, I suppose it's just a single order of magnitude in base-10!). I don't think this mistake affects my point.

The universal convention is: b = bits, B = bytes. I see errors only rarely, and they’re almost always when people write Mb or Gb instead of MB or GB (just MB, not MB per second or such). It also fascinates me how we conventionally write Mbps (with a p), but MB/s (with a /).

Hey, that's more than an order of magnitude in binary! Great way to make a doubling (or greater) sound bigger than it is.

Still not several. :D

"Order of magnitude" is one of my linguistic pet peeves. I've seen it used referring to base 2, base 10, base 1000, and base 1024. What does it all mean? In base 2^(1/100), trebling is many, many orders of magnitude increase!

“Order of magnitude” is context-dependent, like a great many things in natural language. In the absence of any contrary context, it’ll mean a decimal order of magnitude in English. It will do you no good to rail against the inclusion of cultural context in resolving the meaning of language (and even its structural parsing!), because it’s so very widespread in English and I presume in every other natural language (though logical languages could potentially theoretically evade it).

I’ve never encountered non-integral bases in real life, but https://en.wikipedia.org/wiki/Non-integer_base_of_numeration tells me they are sometimes used. Fun stuff!

Agreed, railing against language and cultural context is literally futile. Factoradic is the one true base. There, "order of magnitude" would depend not only upon (my very unique) cultural context but also the absolute magnitude involved (at the low end, "double" is an order of magnitude; then "triple", then "quadruple", etc).

I love these sorts of discussions. You learn things you’ve never heard of before. I can easily see how it works and how it’d be useful sometimes, but I’ve never come across it before. https://en.wikipedia.org/wiki/Mixed_radix is good related reading (including the concept of measuring time in this way; now that is something that we sometimes do in software, more or less).

I prefer to say “several times larger/greater” and it is even fewer syllables! “Order of magnitude” works better for convincing people to do something your way, though.

The only logical base to use here is 2.71828182.

Exponential too, which as far as I can tell just means non-linear, at least in media.

It doesn't even always mean that. It often just means "a lot bigger"

Pretty sure they're getting the 80Kb/s over LoRa. I've used some Pycom devices [0] to try the protocol out and for mesh [1] and it's rather forgiving. Given the number Ring devices people seem to have these days I'm sure Amazon is going to have some relatively large mesh networks at their disposal.

[0] https://pycom.io/products/supported-networks/#lora [1] https://docs.pycom.io/pymesh/

The fastest LoRaWAN data rate specified in the US is Data Rate 13 LoRa: SF7 / 500 kHz: 21900kbit/s.

Even dropping outside of the highly restrictive LoRaWAN specification and going with the fastest physical parameters available for LoRa on the 900Mhz bands (on-time restrictions aside), BW500 (500kHz bandwidth), Spreading Factor 6, Coding Rate 4:5, you end up with 35700 baud.

You can drop these modems into 2FSK mode and increase speed, but at that point the range isn't particularly appealing.

Regardless, the point stands: not a mesh network WAP internet redux, an IoT tool.

> 21900kbit/s

Correction here, you meant 21900 bits per second (21.9 kibibits per second in SI terms), not kilobits per second.

It also has a proprietary PHY protocol, which always struck me as an major downside to something whose adoption is closing to making it the next de facto standard. DASH7 [1] is an interesting alternative in this regard, good for urban areas, but not quite as long range for very sparse nodes in a rural environment. It does not the same duty cycle limitations that LoRa has and is actually used to complement LoRa even on the same device in some interesting case studies [2] which come from Semtech themselves (the patent holders on the LoRa PHY).

[1] https://dash7-alliance.org/ [2] https://tech-journal.semtech.com/making-the-most-of-the-unli...

I don't often see FPV related knowledge on HN. I've wondered if others were aware of these implementations and it's cool to see them mentioned here.

So basically for IoT.

Maybe Amazon is looking for a way to go back to the old Free Internet Kindles without having to pay carriers.

What about super basic internet and sms like applications ?

I thinking mostly on stuff build on scruttlebutt or Gemini.

The first one is build for on/off crappy connection. The second is basically gopher on steroid.

Any input would be welcome

But it's sufficient for my next TV to report fingerprints of my viewing habits back to HQ, even when I intentionally leave the TV disconnected from my LAN. Yay.

It was inevitable we'd reach this point—if not because of mesh networking, then because of ever cheaper cellular radios. And modern cars are already here. But we're fast losing control and visibility over which of our consumer electronic devices are allowed to talk to the outside world.

Would be enough for reading Hacker News, about 3000 characters per second.

HN frontpage seems to be about 50 kB so it would take about 3 s to load on a 128 kbit link.

The author is conflating max allowed bandwidth from the bridge to Sidewalk server with per-end-node bandwidth. The 80Kbps includes the bundle of all of the LoRaWAN messages it has received for all end-node-devices within range. This is a marketing point to show the Amazon device owner that this won't consume large amounts of their bandwidth. The Things Network suggests a maximum expectation of 250 BITS/s. This is not going to replace cell networks. https://www.thethingsnetwork.org/docs/lorawan/limitations.ht...

The internet and the IP protocol is kinda incompatible with mesh networks.

A city-spanning mesh network which connected to the internet at peoples home broadband connections couldn't reasonably function. Someone who was downloading a file over the mesh wouldn't be able to have their data use any connection to the internet - they would have to keep using the same gateway from the mesh to the internet, because if they switched gateways their IP would change and existing connections would fail.

It's the same reason switching from WiFi to Mobile data and back causes a reconnect in video calls.

There's the Multipath TCP protocol for use cases like this:

https://en.wikipedia.org/wiki/Multipath_TCP

For example, Apple already uses it when you ask Siri a question on an iOS device. Hopefully this standard gains more usage.

Multipath TCP sadly seems to have died... I believe it was incompatible with internal load balancing systems at some big companies, so nobody deployed it.

Apple deployed it in iOS and macos. You can access it as a developer of either.

There is a load balancing issue, but I don't think it's any worse than http/3 which also allows for peers to change IP (http/3 has a much limited scope of changes).

I mean, I haven't deployed it on my own servers just because it still requires a kernel fork to enable on Linux. There was an effort to upstream it as of late 2019 though; not sure if that's stalled, but I can understand it taking a long time as I believe it's a pretty big change to the Linux networking stack.

Not trying to nitpick, but IP handles that just fine (see mosh[1] for a great example of flawless roaming).

It's the TCP that doesn't handle it. Unfortunately HTTP and most other protocols are on top of TCP so suffer from the same problem.

[1]: https://mosh.org/

IP doesn't handle it fine.

If I roam from network A to network B, then someone else cannot send me an IP packet till they know my address on network B.

I can only send out a "Hey, I'm now at this address" message to them if I know they will be wanting to contact me, and I know my own address has changed. Neither of those is guaranteed.

You're not wrong about the other party needing to know your changed IP address, but that's still a result of higher level protocols that are leaking the abstraction of IP for addressing. You could use hostnames instead, or put some other addressing method on top of it to adapt. It's not commonly done since you'd have a DNS lookup before each packet, which would be horribly inefficient, but it's possible because IP itself doesn't handle the details of connections. IP itself is connectionless/stateless.

There is no concept in IP of a "user", "client", or other party that exists beyond the lifetime of that packet. IP is basically a stateless logical address sitting on top of some physical address with a few delivery options to facilitate traffic flow (like congestion handling).

Any connection state or concept of user/client/server/etc is held at either the TCP level, or for UDP-based protocol higher up the stack (commonly at the application level).

If you still insist on IP being at fault here, let's consider an analogue. If a user sets up an Amazon subscribe-and-save, and then moves to another city and has a different physical address, but the user does not inform Amazon by updating their address in Amazon's system (the higher level protocol), would you say that the postal service is at fault when the delivery ends up reaching the an incorrect party?

This is part of the special sauce that LTE adds, so that you can pretend that IP handles roaming just fine. That and also QoS guarantees, which IP also doesn’t do out of the box.

I believe "Mobile IP" was designed to solve this exact problem.

It's unfortunate that WebRTC's use of SCTP doesn't require the multihoming features of SCTP. We had a great chance to sneak that into ubiquitous use, but that ship has sailed at this point. : \

Seamless jumps from mobile networks to wifi were in our grasp.

You currently can't change your endpoint address on existing connections without breaking them, unless you have a protocol that's aware of the possibility and uses a broker or some other method to re-establish the link. This wouldn't really be any different. I don't think you'd want your network address to change on a mesh, it would just find a different path to reach it.

It might make sense to use something similar to MPLS that can encapsulate IP, to hide the details of the mesh network.

There is MobileIP [1]. I have MobileIPv6 compiled into all my mobile devices and home gateway.

[1] https://en.wikipedia.org/wiki/Mobile_IP

IP breaks but there are way to workaround if layer 4 allows. Unfortunately TCP also breaks. UDP allow a workaround over that. So MOSH(SSH) and QUIC(HTTP/3) can deal with this due basically due to having nachnism to handle it and also they are UDP. Also both have some kind of cryptography layer such as SSH or TLS so prob that is use to handle it.

SCPS-TP and SCPS-NP are probably a good starting point for further protocol research into bit-efficient and "hostile" communications environments (long-delay, error prone, etc).

https://en.wikipedia.org/wiki/Space_Communications_Protocol_...

> It's the same reason switching from WiFi to Mobile data and back causes a reconnect in video calls.

This used to be true, but new apps like Duo handle it like a champ. Uninterrupted switchovers between mobile data and wifi.

If I switch off wifi of my phone mid call, it drops 20+ frames. That isn't exactly seamless. It's far worse if I just walk out of range

Hmmm, I don't know what's different in your case. For me it switches very seamlessly if I walk out of wifi range. No dropped frames. I haven't tried manually switching off the wifi though.

> between 500 meters and a mile in urban areas

Good way to confuse both imperialists and metricists

In some metric countries, a "mile" is 10 km.

Which countries?

Wikipedia lists Norway and Sweden. https://en.wikipedia.org/wiki/Mile#Scandinavian_mile

> we can expect that Amazon will do everything in its power to lock every non-Amazon-sanctioned device out of its network

I expect the opposite: for Amazon to sell this as a utility network service to all compatible devices (a la LoraWAN).

If they do, they are likely to quickly eclipse The Things Network and Helium.

“Soon, the mobile phones for which we are now paying $40 US per month or more may work for practically no cost. Won't it be interesting to watch our widely-hated wireless telecommunication companies struggle to stay in business?”

Competing using a shared chunk of 900Mhz? Not likely. 5G uses millimeter bands (20Ghz to 60Ghz) that provide up to 20Gbps of bandwidth. A public shared scheme using 900Mhz isn’t going to compete with that.

Spectrum is the pipe and whoever has the biggest pipes wins. It’s a bit like telling the public they can compete with an oil pipeline using a shared straw.

in the OpenWrt source tree, a large section of the repo is devoted to Freifunk ("Free Radio" in german)

It is a giant mesh network.

https://en.wikipedia.org/wiki/OpenWrt

https://en.wikipedia.org/wiki/Freifunk

Long range isn't a necessity for mesh networks.

Regular wifi would be fine - the vast majority of the world's population lives within 100 yards of another person.

Shorter links actually increases spectrum utilization.

The issue is that wifi never managed to make a decent mesh networking standard. No router you buy today acts as an open mesh node for anyone to mesh with.

> This means in two to five years we may be able to surf the internet or talk on our [phones] while walking down the sidewalk in nearly any city

What a prospect! Can you even imagine?

We need a mesh networking standard which is trustless. Ie. anyone can join the mesh, but not easily disrupt it and be evil.

Today 802.11s is a great mesh standard, but it isn't trustless - all mesh nodes need to know the network password, and if you shared that password with the world, then someone could join and make the entire mesh stop working (and steal all your data).

It's ridiculously easy to disrupt low power wireless networks of any kind, no matter what the protocol or standard.

Anyone can make the whole mesh stop working today, even without a password.

A big one set off from a mile up is the normal way science fiction predicts the chaos begins.

With Wifi, I can easily disrupt within a few hundred yards of my house. But disrupting something a few miles away is much harder.

With a mesh network, the network is much bigger, which makes it important an attacker can only disrupt their small corner of the network.

> But disrupting something a few miles away is much harder.

If you follow the rules. Presumably an attacker wouldn't care about that, and would be happy to dump a few orders of magnitude extra power into their jamming signal.

Yeah, and if they had gasoline and matches they could go around and burn down everyone's houses. The point is that the protocol shouldn't have a flaw that allows local traffic to have harmful nonlocal effects.

I think FCC still cares about jamming signals, although they might make an exception for inexpensive mesh networks...

I think the worst outcome of this yet one more avenue gobbled up by a large tech conglomerate. My understanding is that ISM bands are supposed to be free for personal use and are the last fronts for small scale connectivity innovation

You're still allowed to use them free for personal use, as are the personal users who bought Amazon-branded hardware.

Nothing is being gobbled.

>Nothing is being gobbled.

I mean, I disagree with your opinion here. It's entirely possible that we end up in a world where corporations use all of the unlicensed spectrum to operate their corporate networks (on "user-owned hardware" that is centrally coordinated and controlled), leaving very little of it to alternative uses. There is only so much unlicensed spectrum so this is very much a realistic outcome, especially if the "user-owned devices" are coordinated and designed to maximize the company's use of the spectrum. I think "gobbling" is a pretty accurate description of this.

What you are saying is that our current legislation around these bands permits that use, in the same way that it might be legal for Amazon to house all of its workers on public land in some states. The question to ask is whether this is actually good.

>It's entirely possible that we end up in a world where corporations use all of the unlicensed spectrum to operate their corporate networks (on "user-owned hardware" that is centrally coordinated and controlled), leaving very little of it to alternative uses.

Why does there need to be a distinction? What's the difference between amazon's sidewalk network compared to an at&t wifi router?

The answer to this question depends entirely on what the hardware does and how much it prevents other uses.

Have the 2.4 GHz and 5.8 GHz unlicensed bands become unusable by device proliferation? What makes you fear the 900 MHz band will be meaningfully different?

> Have the 2.4 GHz and 5.8 GHz unlicensed bands become unusable by device proliferation? What makes you fear the 900 MHz band will be meaningfully different?

We are both commenting on an article that describes how a massive corporation (Amazon) might be deploying large-scale mesh networks on this band, and using this to drive huge numbers of devices at near the maximum feasible bitrate. This is obviously a speculative article and maybe none of this will come to pass. But within the bounds of speculation, this seems qualitatively different than what's happened (as of today) on the 2.4 and 5.8 GHz bands.

That's why I cite the other bands; this is what has happened already in the US and Europe on the other unlicensed bands.

Looking at my WiFi network right now, I have 2 APs and 25 clients connected (8 of which are amazon-). When I turn on my TVs, those power up a few additional clients (Chromecasts and FireTVs) on WiFi. I can see between 12 and 18 other networks depending on when I scan (plus who knows how many that aren’t broadcasting SSIDs).

Is Amazon likely to be able to put more devices on Lora than I have on WiFi now? More concentrated than NYC or Paris WiFi is today?

The maximum bitrate the article references is not a Shannon-Hartley bitrate limit, but rather a fairness-limited maximum transmission duty cycle to ensure other, also unlicensed users can access the spectrum.

Edited to rephrase as a question rather than an argument: How much is the "fair duty cycle" mandated by the law, and how much is politeness? My understanding is that multiple providers could be competing in this space and (if this system is popular) they may want larger and larger slices of that cycle. I don't know what the law requires here, so I don't know that there's any requirement that personal WiFi users need to get much if any spectrum once every corporate user has taken their piece.

https://www.law.cornell.edu/cfr/text/47/15.247

Unlicensed spectrum doesn't mean unregulated. It just means individual users of devices don't need operator licenses. To facilitate that operations in unlicensed bands have regulatory operating limits. Devices are under the general rules covering harmful interference (don't cause it), accepting interference from licensed operations (you must accept it), and basic electronic device regulations.

But a corporate player or players can deploy a lot of devices that individually comply and eat up a lot of the available bandwidth, making personal applications like Wifi less functional. And moreover: once there’s a financial incentive to do this (which really resilient mesh networks will provide) the financial incentives to use this bandwidth may be much greater than they have been historically, and saying “well it hasn’t happened yet so it won’t be a problem” offers very little predictive value. This is my concern, and I am open to being convinced that the regulations in place will prevent this. So far none of the comments in this thread have given me a convincing reason not to worry, though it’s helpful that someone actually posted the (individual device) transmission limits.

I'm not intending to defend Amazon but as a general statement about ISM bands: there are regulatory limits (output power, duty cycle, etc) on these bands. The output power limits are meant to limit the propagation distances from isotropic radiators.

So for Amazon's (or any) system to swamp the ISM band(s) they would need to absolutely saturate an area with their radios. That would end up running at cross purposes with their network since their own base stations and user devices would end up interfering with each other.

While I don't trust Amazon to do the "right" thing I do trust them not to step on their own toes.

> My understanding is that ISM bands are supposed to be free for personal use

They are also free for use by businesses and governments. The rules make no distinction (other bands do have eligibility restrictions).

> last fronts for small scale connectivity innovation

Amateur radio operators would beg to to differ. You can do a lot with a relatively easy to get amateur radio license, and it is restricted from commercial use.

There's FCC rules on how the space can be used to prevent what you are describing. Sure, this will increase the noise floor, but Amazon can't show up and start acting like they are the only ones allowed to use it.

What I’m looking forward to is low-cost, mid-bandwidth and ultra-high-latency store-and-forward LEO satellite constellations.

Something that you can use in the middle of anywhere and send/receive text news, messages and short voice recordings. Maybe a handful of photos per day if you want to point your antenna to the sky manually and follow the satellite for a few minutes for max bandwidth on an upload.

There’s a few projects out there, but still out of reach of the consumer because I guess... they can charge more to a corporate user.

This is interesting. Do you mean services like Iridium, or something newer? What projects did you have in mind?

Myriota [1] sounds very interesting. It's exactly what GP describes if I'm not mistaken!

[1] https://myriota.com/

This is one I’ve seen:

https://www.keplercommunications.com

Iridium is a « live » network... with much high costs of construction and operation.

What would you use it for? Some IoT project?

A cabin or hike without (or poor) cell service where this would provide just enough connectivity to real life.

I like the idea of being able to read the news and maintain comms but can live without live 2-way video.

Also cool to imagine there will be a nano/micro cubesats with a enough gbs in SSDs circling earth every couple hours making that possible.

Could have different levels if priorities to balance supply/demand.

Helium network has been growing fast. Just crossed 20,000 hotspots and will probably reach 100,000 this year. It uses a crypto mining incentive so the network expands without any central corporation needing to spend a dime on infrastructure. People are already building cool IoT projects with it from adafruit kits.

https://explorer.helium.com/coverage

Wow, I've never heard of this before but it sounds super interesting.

It's a copy of the open things network that lora such a rise in popularity. Now with "blockchain".

Looks like trying to use cryptocurrency mining to incentivize people running hotspots, which actually sounds like a useful application.

This would be far better if the currency was used to pay for connectivity, and the router was reimbursed for routing.

Connectivity has a cost, and none of these networks will amount to anything unless the model can incentivize all aspects of the infrastructure necessary

I am reminded of the old Ricochet network:

https://en.wikipedia.org/wiki/Ricochet_(Internet_service)

http://daedalus.cs.berkeley.edu/talks/retreat.6.96/Metricom....

It was an idea ahead of its time.

Truly. I used to run Ricochet.wikispaces.com and am sitting on a mountain of docs and stuff. Can't believe they managed to market it into the dirt and burn through five billion bucks.

I still have a couple of the old modems lying around somewhere. There wasn't ever service where I live, but I played around w/ direct modem-to-modem communication. It was fun.

!! do you have the PDFs/etc that the Wayback didn't capture? If so, perhaps I can host them on the Internet Archive? Particularly interested in the Garage Gateway -- I've never seen the code and I have an otherwise working Ethernet Radio & pair of poletops I'd love to get properly running.

E-mail's in my profile -

Any form of Non-Cellular Internet is good as telecommunication industry is at best oligopolies or at worse monopolies in most countries; But unfortunately wireless Internet is still largely dependent upon them.

Apart from other reasons discussed here on why mesh Networks aren't the go-to choice yet, there's another problem I'm noticing in India; 4G(LTE) Internet is cheaper than any other form of Internet delivery here.

It's well-known that India has the cheapest 4G data plans, So in-spite of innovative startups trying their best to crack into city-wide mesh network they just couldn't compete with the pricing of cellular Internet besides 4G data is the means to Internet in most households here and they are not going to change to WiFi when they leave the house.

P.S. I've been tracking the need gap in 'Non cellular network mobile Internet' & I welcome related resources. Link in my profile.

Regulatory duty cycles/time on air (ToA) will prevent the legal use for highish bandwidth applications and are necessary to keep the frequency open for everyone.

See https://lora.readthedocs.io/en/latest/

There are no duty cycle limitations for 900MHz in the US. Its regulated largely like 2.4GHz (see 47 CFR § 15.247). There are rules for frequency hopping systems that limit the amount of time you can dwell on any given channel, but there are less restrictions on non-hopping systems. High-ish bandwidth 900MHz radios are pretty common and can do multiple megabits per second (at least with enough signal-to-noise ratio, which isnt always practical over non-trivial distances).

Can you share some examples of high bandwidth 900 radios? In my experience, it’s difficult to get bitrates above ~100kbps on 900 over any meaningful distance.

Yeah I’d be very happy to be pointed in the direction of a multiple megabit per second 900 radio. Take my money!

I have the Ubiquiti M900 radios. With a (~5-foot) yagi they definitely deliver the advertized 100mbit/sec.

The Ubiquiti Rocket M900 would be a good place to start.

Or if you have a couple old Ricochet E-radios and want to do some packet hacking, they'll do 1Mbaud at whatever modulation you ask.

I work with industrial grade 900MHz radios, and most can do over 1Mbps... with enough SNR, which as I mentioned can be difficult. I would say a typical ~city sized network I've worked on tend to operate in 100-1000kbps modes, with real world throughputs maxing out at more like 300-400 kbps on typically 1-10 mile links.

Manufacturers include FreeWave, GE MDS, XetaWave, 4RF, and others. These are typically ~$1000 radios, so not great for hobbyist use.

In addition to Ubiquiti (already mentioned), Motorola (Cambium) also made some PTP and PTMP radios ("Canopy"?) that were quite popular in the WISP community years ago.

I'd be surprised if you can't easily find both on eBay.

The duty cycle limits by ETSI are in place because of the population/usage density. If FCC does not put in place a regulation there will no shared high bandwidth usage over a long distance in high density areas. Think of 2.4 GHz WiFi.

If you're looking for an open lora-wan network, you might want to investigate helium (https://www.helium.com/)

its got some block-chain hypermegadrive bullshit, but at its heart it looks like a super cheap quite widespread lora network

There's no reason to build a LoRa mesh network if all the devices are connected on WiFi. Instead, it sounds like Amazon is building out a network of LoRa access points where their customers pay for the hardware and operate the access points. It's hard to say what their plans are for the network, but if they wanted to make a tile competitor that could find your stuff in an entire city, this would make it possible.

LoRaWAN's use case isn't that of cellular data or wifi. It is what will be the backbone comm network of billions of edge ML devices by mid-decade.

It would really be great to see license-free 900 MHz radios come to smartphones. Text only store-and-forward would be more than fine for many use cases.

Not sure I see this as a replacement for my cellphone plan as the author suggests. I regularly stream video which I think needs more bandwidth.

I like the idea of mesh networks, but I think they have all the character of do-it-yourself personal data.

So, wait, now I get to bear the burden of understanding how my network traffic is being routed and figuring out when I have issues?

Not keen on that honestly. I might be technically capable, but that doesn't mean I'm interested or have the time to spend on it.

for a taste of citywide mesh: https://www.nycmesh.net/

impressive map: https://www.nycmesh.net/map

I'm not sure about latency...

https://disaster.radio/ is more apt.

NYC Mesh is built from discrete, high bandwidth (very high relative to LoRA) point-to-point radios. Assuming all the links in a path are healthy, latency should be excellent.

or Meshtastic

I use a wireless phone headset from Plantronics that operates in the 900 MHz range. It works so much better than Bluetooth since the range is farther (especially indoors) and the band is less crowded with interference.

The last thing I want to see is a bunch of new random consumer junk cluttering it up.

> new random consumer junk

Like wireless phone headsets?

What makes your use of this public band more important than that of others?

In fairness, that headset is something I rely on every day, for hours of the day.

The article says Amazon began shipping this feature in its products secretly, so 'junk' in the sense that consumers didn't ask for the feature and it's crowding the medium mainly for Amazon's benefit.

(Ps. This was authored before you edited your comment)

Arguably, being able to find a lost pet or wallet is not only Amazon's benefit. (Yes, it's a for-profit company selling the equipment, but isn't that true for headsets as well?)

As long as spectrum fairness is ensured (and I think there are pretty strict rules on duty cycles for the 900 MHz band, i.e. any given device can't be transmitting more than a few seconds every few minutes), I think it is up to the owners of the band to decide what's critical and what isn't: The public.

If you think about it, hours of phone calls every day are probably a more significant use of that spectrum than all lost cats and dogs of a city combined.

Thats true, but it won't be some sort of open platform, it will be a utility for amazon that will come with some sort of monetization scheme. I say this as someone that has deployed 10s of thousands of 900 Mhz radios in devices over the last few years. Conceptually though, some sort of interop standard that would offer end to end encryption and access control could be quite cool. On the other hand, sending the garage door signal over an unknown network path and trusting that there is no chance for manipulation is also a tough sell compared to the relatively short wireless->wired topology that dominates most consumer IoT. I'm sure there are use cases where it could work great though.

Surely the data is over either HTTPS or some encrypted VPN protocol - the only possible attack would be DOS.

Well, you could also attack the implementation.

Around makerspaces, mesh networking plans rank slightly above perpetual motion machines. It's not impossible but there are substantial challenges. Ask any ham involved in packet radio for the past 40 years.

Does this actually solve the network hole problem though? Just because Amazon devices have this capability doesn't mean folks in rural areas have Amazon devices. Perhaps thats not the point of this article.

Check out Helium it’s a proof of coverage crypto currency. The “mining” is proof of coverage. Believe it operates in the 900Mhz ISM band. Something like this could probably solve the hole problem because it incentivizes people to run access points were there isn’t coverage

https://www.helium.com/

I find Althea [1] a lot more interesting than Helium, where their crypto is used basically as an incentive model for bandwidth, with no proprietary hardware or software in the mix.

[1] https://althea.net/

Already do in San Rafael, CA.

http://f3.to/cellsol/ here's firmware and schematics, add to it! :)

"One must also assume that Amazon will do its best to encrypt its network traffic and make its devices as hard to hack as possible."

Somebody feel free to disuade my fears, but all I'm able to think about this weekend is the Microsoft Exchange hack that just ravaged "30,000" organizations we're told. And here Amazon is building a publically usable network based on our Ring doorbells and "Hey Alexa devices". What could possibly go wrong?

Quote 1: " Lately, however, the number of goTennas in operation seems to have declined. Aside from the cost ($189 for two units) ..."

Quote 2: "...using the LoRa protocol for extending ..."

Based on these 2 points I have a question / proposal. How about RaspberryPi, as mesh network, using its WiFi capabilities and definitely faster than LoRa, which is snail in comparison? I mean RPi's are like ~$30 each, 3 times lower than goTennas and WiFi speed, yes?

When the apocalypse comes, these mesh networks might be the only way to communicate. We must have an alternate web that serves these networks.

Systems for email, notifications, etc.

Eh, no. You must be young. Email works perfectly on low bw conns. So does IRC, and Gopher.

Email’s fine for low-bandwidth, high-latency mesh wireless.

IRC and Gopher are not. The latency, and potential unreliability, would kill it.

https://hackaday.com/2020/12/12/irc-over-lora-for-when-thing...

If not, maybe icb uses less bw.

EDIT

Also:

https://github.com/dmahony/LoRa-AX25-IP-Network

But, what will power it? Would each installation have a battery and solar panel? Maybe a good idea, small units should be installed, similar to those cheap night lights, if some fail ok, but enough for basic Comms.

Is there any benign scenario that explains why amazon should do that? They have essentially put listening devices into every home and now they bypass the home owner's network? Am I the only one that thinks this looks like it is about surveillance? What's the next step? Mandatory amazon smart meters? Smoke detectors?

Amazon isn't in the business of being evil to the public. If they did, they would lose massively more revenue than they gain from a few smart meters.

You should be more worried about companies where you are the product not the customer...

I don't even know how a person could type your third sentence and submit it. Amazon already gathers, utilizes, and monetizes data gathered from devices it's sold to customers. It's been doing it for years.

Good old Hydrogen… Mozzerella?

Hondo-mega? hega-mertz? Ronna-hertz & Quecca-hertz just doesn't do it for me.

I love the idea, but this has Tragedy of the Commons written all over it IMHO. It won't take very many bad actors before it's ruined for everyone.

That said, it's not stopping me from participating.

I get the sinking feeling this will replace wired Internet connections and then we'll all have to learn hard lessons about rain fade and packet collisions all over again. Hooray!

Mesh networks are cool, but they are a bit of overkill for solving problem of crappy $40/mo internet :)

(Writing this from my $8/mo 300 Mbps home connection. My 4G is $3/mo.)

A true open wireless mesh network is what the internet needs to become to overcome censorship and similar issues.

{off topic}

I don't normally like pink but I'm loving this black serif text on this shade of pink (#FFD4F5) background.

Fits perfectly with the technology I imagined for the post-apocalypse: Gopher, lynx and text messages!

I can see that this could be exploited by drug dealers creating local anonymous marketplaces or by any resistance movements to coordinate their actions against oppressive governments. Ergo it will be quickly outlawed...

Bitcoin is used by criminals, and it still exists, and it is legal.

So is cash

It is also used to facilitate corruption so it will stay.

And it will be slow with crappy QoS.

How does 802.11ah fit into this?

Why do I want this as a consumer?

Nit: HMz in title looks like a typo. If anyone wants to fix.

Fixed. Thanks!

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