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How New Long-Range Radios Will Change the Internet of Things

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Re: How New Long-Range Radios Will Change the Internet of Things

#61

Post by Natanael_L »

jazzyk wrote: post #17
blhack wrote: post #13

This is un. fucking. real. I work in the IoT space (specifically on health devices), and something like this would be absolutely a GOD SEND for the things that we're doing. The current "hottness" in our space is bluetooth low energy (BLE). This is super low power (or, rather: chips that are really good at going to deep sleep, and then coming online very quickly to burst some data out), but the range on BLE isn't grea…

Cool stuff, sure. But, in my opinion, IoT will be slow to take off until the security aspect is solved - and it is a tough one.

Link encryption and authentication is pretty much "solved" in that we have the components we need already. Then there's the issue of code bugs and lack of updates - I think this should be solved in most cases by devices exclusively talking over a filtered API via a trusted gateway to prevent exploit attempts from succeeding.

Re: How New Long-Range Radios Will Change the Internet of Things

#62

Post by Natanael_L »

slewis wrote: post #60
0898 wrote: post #50

Earlier quoted context omitted.

Just curious – why is range limited by a protocol? Why couldn't you send Bluetooth over hundreds of miles with a big enough antenna, for example?

You can amplify a signal and send it far. But due to FCC regulation in the 900MHz band for example you can only instantaneously transmit at 30W. Another way to make a signal go further is to transmit at a lower data rate (thus spreading your signal out over time so that in effect you have more power in the signal). The FCC limits "dwell time" in a single channel to .4s in the 900MHz band. Yet another way to increase…

Any MU-MIMO technology in sight for these radio protocols? Would be a great way to potentially extend range and throughout if multiple spatial channels could be used on each frequency / radio channel for every pair of connected devices. If it could be done efficiently enough, it could also reduce congestion even in tight crowds for things like wearables by reducing interference.

Re: How New Long-Range Radios Will Change the Internet of Things

#63

Post by dconrad »

wyldfire wrote: post #58
slewis wrote: post #40

Earlier quoted context omitted.

Shawn from BeepNetworks here. Check out OnRamp (now Ingenu). Their coding scheme allows 1600 simultaneously communicating devices per spread factor per channel. That 1600 factor means their base station can handle massive numbers of clients compared to cellular. http://www.scribd.com/doc/273814075/On-Ramp-Wireless-White-P... . That paper is certainly biased in their favor, but the tech is real and they have serious d…

Hm, 1600 sounds like a lot. But depending on the applications it sounds like it might not be that much if it's 1600 over three square miles.

that's 1600 devices simultaneously communicating. a sensor might only spend a fraction of a percent of its time transmitting data, so the number of devices supported is orders of magnitude higher.

Re: How New Long-Range Radios Will Change the Internet of Things

#64

Post by dconrad »

kazazes wrote: post #55
dconrad wrote: post #16

Earlier quoted context omitted.

For LoRa, check out Multitech, LinkLabs, and Libelium. Semtech has a development board, too, though it would need to be paired with a microcontroller. Warning that most of this stuff is not for the faint of heart -- you need to be ready to dive into datasheets, bring up radio drivers, etc. For Sigfox, if you're not in an area with a Sigfox network, there's not much you can do. But TI has some killer FSK dev boards. h…

If you haven't lost your faith in Kickstarter yet, this project has $180k committed. A €40 pledge will get you a LoRa board and €200 for a LoRa gateway and what is essentially a demo dongle. https://www.kickstarter.com/projects/419277966/the-things-ne... Edit: fat thumbs, on mobile.

I love those guys go support them! But you will have to wait a while for their hardware.

Re: How New Long-Range Radios Will Change the Internet of Things

#65

Post by slewis »

Natanael_L wrote: post #62
slewis wrote: post #60

Earlier quoted context omitted.

You can amplify a signal and send it far. But due to FCC regulation in the 900MHz band for example you can only instantaneously transmit at 30W. Another way to make a signal go further is to transmit at a lower data rate (thus spreading your signal out over time so that in effect you have more power in the signal). The FCC limits "dwell time" in a single channel to .4s in the 900MHz band. Yet another way to increase…

Any MU-MIMO technology in sight for these radio protocols? Would be a great way to potentially extend range and throughout if multiple spatial channels could be used on each frequency / radio channel for every pair of connected devices. If it could be done efficiently enough, it could also reduce congestion even in tight crowds for things like wearables by reducing interference.

I haven't seen anything using MIMO yet. Not sure how that would affect power usage. The closest thing now is that a key aspect of Ingenu's solution is receive diversity. All of their client radios require two antennas.

Re: How New Long-Range Radios Will Change the Internet of Things

#66

Post by makomk »

slewis wrote: post #60
0898 wrote: post #50

Earlier quoted context omitted.

Just curious – why is range limited by a protocol? Why couldn't you send Bluetooth over hundreds of miles with a big enough antenna, for example?

You can amplify a signal and send it far. But due to FCC regulation in the 900MHz band for example you can only instantaneously transmit at 30W. Another way to make a signal go further is to transmit at a lower data rate (thus spreading your signal out over time so that in effect you have more power in the signal). The FCC limits "dwell time" in a single channel to .4s in the 900MHz band. Yet another way to increase…

It's important to realise that - at least if I'm understanding spread spectrum technology correctly - there's no such thing as a free lunch, or free receive sensitivity. If you take an ordinary narrowband signal and convert it to spread-spectrum, you can indeed make it disappear beneath the noise floor by spreading it out, and a receiver that knows where to look can despread it and pull a signal out from what looks like noise, but the effective received signal strength and signal to noise ratio after despreading is still exactly the same as it was with the narrowband signal. You haven't gained anything, you're just moving your signal around a bit. The only advantage of this spread-spectrum technique is that other signals that don't use the same spreading code are spread out by the despreading process and look like wideband noise to the receiver.

Re: How New Long-Range Radios Will Change the Internet of Things

#67

Post by petra »

bdamm wrote: post #37

Don't get too excited. Low-power devices get really interesting when they start to scale up in numbers. None of the technologies listed in this article have demonstrated that capability. The coming IoT shakedown is going to leave quite a few ebullient "visionaries" crying in their martini while they consider their next startup. * Star networks are infrastructure heavy, requiring build-outs on part with cellular netwo…

But didn't IBM sided with LoRa ? doesn't it mean they tested it for scaling ?

Re: How New Long-Range Radios Will Change the Internet of Things

#68

Post by makomk »

blhack wrote: post #52
0898 wrote: post #50

Earlier quoted context omitted.

Just curious – why is range limited by a protocol? Why couldn't you send Bluetooth over hundreds of miles with a big enough antenna, for example?

Not limited by the protocol per se, but limited by the design requirements of BLE. BLE; you're talking about power requirements of ~10mA transmit (current consumption), and averages in the Now: how LORA is accomplishing such crazy long ranges when supposedly consuming similar amounts of current goes a little beyond my understanding of RF. There are a few people commenting in this thread that seem to have the knowledg…

They're achieving those ranges by being very, very slow.

It's probably easiest to explain how this works with conventional narrowband digital modulation schemes. For a typical modulation scheme, the bandwidth of the modulated signal is proportional to the bitrate. There's also some minimum signal-to-noise ratio below which the receiver can't decode it. By sending more slowly, you get a narrower signal, which means that the receiver can listen to a narrower slice of spectrum. Even though the received signal's no more powerful than before, because the receiver is no longer hearing all the noise outside of that narrower band the SNR improves and it can decode much weaker signals.

LORA appears to use direct-sequence spread spectrum, which basically means that the transmitter applies a spreading code to convert the narrow signal to a very wide one and the receiver uses the same code to despread it again and pick out the signal. Its range improvement is still based on the exact same principle of speaking very slowly to improve your SNR though.

Re: How New Long-Range Radios Will Change the Internet of Things

#69

Post by zupreme »

dconrad wrote: post #19
blhack wrote: post #13

This is un. fucking. real. I work in the IoT space (specifically on health devices), and something like this would be absolutely a GOD SEND for the things that we're doing. The current "hottness" in our space is bluetooth low energy (BLE). This is super low power (or, rather: chips that are really good at going to deep sleep, and then coming online very quickly to burst some data out), but the range on BLE isn't grea…

Glad you agree. :) We're putting up a LoRa network here in SF, and plan to publish a bunch of our test data, including link error rates and throughput. Urban deployments are new so more data will help us all understand what's doable. (There are a few rural deployments in production; less uncertainty there.)

We (Amerihub) craft custom data transit solutions and manage the networks and tech assets for a lot of medical and manufacturing clients in the Chicago area. This could have HUGE applications in those spaces.

I signed up for your beta via your site. We want in asap.

Re: How New Long-Range Radios Will Change the Internet of Things

#70

Post by makomk »

slewis wrote: post #40
bdamm wrote: post #37

Don't get too excited. Low-power devices get really interesting when they start to scale up in numbers. None of the technologies listed in this article have demonstrated that capability. The coming IoT shakedown is going to leave quite a few ebullient "visionaries" crying in their martini while they consider their next startup. * Star networks are infrastructure heavy, requiring build-outs on part with cellular netwo…

Shawn from BeepNetworks here. Check out OnRamp (now Ingenu). Their coding scheme allows 1600 simultaneously communicating devices per spread factor per channel. That 1600 factor means their base station can handle massive numbers of clients compared to cellular. http://www.scribd.com/doc/273814075/On-Ramp-Wireless-White-P... . That paper is certainly biased in their favor, but the tech is real and they have serious d…

Hmmm. I'd pay very careful attention to the fine print on that. The way their scheme works is that each node chooses a random time to start its transmission, which means that all their chipping sequences are hopefully desynchronised. Then the AP tries decoding from all possible starting points at once. If I'm understanding spread-spectrum correctly, each parallel receiver pulls out only the signal from the node (or nodes) whose chipping sequences are synchronized with it, while all the other node's signals appear as noise to it.

Which is the catch. Run too many nodes at once, and the signal-to-noise ratio will rise and your signals will start to fail to decode. What this generally means is that nodes at the edge of the network - the ones with the lowest SNR budget - start to drop out first. I'd be interested to see what their link budget and range is with 1600 devices on the same node, or conversely how many devices they can fit on a node at the advertised link budget and range. (Also, just how well they cope with a mixture of near and far nodes.)

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