4 ms·

10,000 times lower power, but achieving speeds up to 11Mbps Being named passive wifi. Quite neat and could be useful for IoT considering also approx 100 ft dis

10,000 times lower power, but achieving speeds up to 11Mbps Being named passive wifi. Quite neat and could be useful for IoT considering also approx 100 ft distance

paulddraper 10y ago
You won't be downloading OS images very well, but it's still a lot. That's two HD videos simultaneously, with some to spare.
- azernik 10y ago
  Only if you have the whole channel available for that one device. Wi-Fi is a shared medium - devices at slow bitrates use the same amount of airtime that could be used by a faster device to send much more data. So a) if you're in a dense wi-fi environment, every bit sent with this system takes away much more than 1 bit worth of time from faster devices, and b) assuming the array of sensors mentioned in the article is around a dozen or two devices, we're down into the sub-Mbps range per device. Still better than bluetooth, and very useful for the kinds of data that low-power sensors would send, but not the kind of performance you'd want for pushing media files or really high-detail sensor data. (Hence the performance benefits for large greenfield networks of dropping support for low bitrates - both preventing old clients from hogging the channel, and obviating the need to send control traffic at the slower bitrates.)
- hueving 10y ago
  I take it you've never used 802.11b. You were lucky to get a single YouTube video at 480p to load without downgrading, let alone two HD streams.
  - roryisok 10y ago
    I'm (un)lucky enough that my WiFi has never been slower than my internet connection
- ClassyJacket 10y ago
  5Mbps is an interesting definition of HD...
  - paulddraper 10y ago
    Naturally it depends on compression, bandwidth variability, etc. It's what Netflix recommends, and they have zero incentive to lowball that. https://help.netflix.com/en/node/306 https://help.netflix.com/en/node/306 The biggest issue is that people think they're getting 20mbps but they're lucky if they get 8. And that not a technology problem.
    - wbl 10y ago
      Yes it is. RF does not go in nice straight lines. The noise floor has been steadily rising, making getting a good signal harder and harder and leading to more packet loss. Add to that the fact that most TCP implementations don't deal well with lossy channels like WIFI, and you get a problem.
  - illumin8 10y ago
    Also, not to mention, current best AC3200 wifi is rated at 1Gbps+, however, actual speeds are max 320mbps, or roughly 30% of the rated speed (for a single client right next to the antenna). So, based on that type of math, I expect to see only 4mbps actual throughput to a single client; less if shared by multiple clients. These radios are likely not MIMO, so the antenna will have to "context switch" between multiple clients, so expect bandwidth to be significantly less in multiple device scenarios. All that being said, I think this is fascinating, and quite perfect for the hundreds of various environmental sensors that will inevitably end up in all of our houses to help us live more automated lives. All hail our new IoT sensor streaming, data driven, fully automated smart homes...
jasoncchild 10y ago
100' is a very low distance for real IoT applications I've run across
- Cthulhu_ 10y ago
  It'd be enough to achieve significant power reduction for the <100ft region though; pretty sure wifi modules would be able to support both passive and active modes depending on availability.
- akerro 10y ago
  but 30m is way longer than I need for my IoT. It also makes my devices more secure from various attacks on my network, as less people can see it.
- ryao 10y ago
  A directional antenna at the active wifi radio would enable longer range. One interesting application would be the ability to dogleg a wireless connection between points A and B where there is no LoS to each other, but both have LoS with point C. It would be a low throughput link, but it would allow for an awesome implementation of a private two way communications system. I.e. Several miles without direct LoS between the two end points.
  - jasoncchild 10y ago
    This is already a thing, however data rates tend to be slower
    - jasoncchild 10y ago
      Yeah but it's easier to pair down the antenna and underpower the radio than to go the other direction :)

10,000 times lower power, but achieving speeds up to 11Mbps Being named passive wifi. Quite neat and could be useful for IoT considering also approx 100 ft distance

paulddraper 10y ago

You won't be downloading OS images very well, but it's still a lot. That's two HD videos simultaneously, with some to spare.

azernik 10y ago
Only if you have the whole channel available for that one device. Wi-Fi is a shared medium - devices at slow bitrates use the same amount of airtime that could be used by a faster device to send much more data. So a) if you're in a dense wi-fi environment, every bit sent with this system takes away much more than 1 bit worth of time from faster devices, and b) assuming the array of sensors mentioned in the article is around a dozen or two devices, we're down into the sub-Mbps range per device. Still better than bluetooth, and very useful for the kinds of data that low-power sensors would send, but not the kind of performance you'd want for pushing media files or really high-detail sensor data. (Hence the performance benefits for large greenfield networks of dropping support for low bitrates - both preventing old clients from hogging the channel, and obviating the need to send control traffic at the slower bitrates.)
hueving 10y ago
I take it you've never used 802.11b. You were lucky to get a single YouTube video at 480p to load without downgrading, let alone two HD streams.
- roryisok 10y ago
  I'm (un)lucky enough that my WiFi has never been slower than my internet connection
ClassyJacket 10y ago
5Mbps is an interesting definition of HD...
- paulddraper 10y ago
  Naturally it depends on compression, bandwidth variability, etc. It's what Netflix recommends, and they have zero incentive to lowball that. https://help.netflix.com/en/node/306 https://help.netflix.com/en/node/306 The biggest issue is that people think they're getting 20mbps but they're lucky if they get 8. And that not a technology problem.
  - wbl 10y ago
    Yes it is. RF does not go in nice straight lines. The noise floor has been steadily rising, making getting a good signal harder and harder and leading to more packet loss. Add to that the fact that most TCP implementations don't deal well with lossy channels like WIFI, and you get a problem.
- illumin8 10y ago
  Also, not to mention, current best AC3200 wifi is rated at 1Gbps+, however, actual speeds are max 320mbps, or roughly 30% of the rated speed (for a single client right next to the antenna). So, based on that type of math, I expect to see only 4mbps actual throughput to a single client; less if shared by multiple clients. These radios are likely not MIMO, so the antenna will have to "context switch" between multiple clients, so expect bandwidth to be significantly less in multiple device scenarios. All that being said, I think this is fascinating, and quite perfect for the hundreds of various environmental sensors that will inevitably end up in all of our houses to help us live more automated lives. All hail our new IoT sensor streaming, data driven, fully automated smart homes...

jasoncchild 10y ago

100' is a very low distance for real IoT applications I've run across

Cthulhu_ 10y ago
It'd be enough to achieve significant power reduction for the <100ft region though; pretty sure wifi modules would be able to support both passive and active modes depending on availability.
akerro 10y ago
but 30m is way longer than I need for my IoT. It also makes my devices more secure from various attacks on my network, as less people can see it.
ryao 10y ago
A directional antenna at the active wifi radio would enable longer range. One interesting application would be the ability to dogleg a wireless connection between points A and B where there is no LoS to each other, but both have LoS with point C. It would be a low throughput link, but it would allow for an awesome implementation of a private two way communications system. I.e. Several miles without direct LoS between the two end points.
- jasoncchild 10y ago
  This is already a thing, however data rates tend to be slower
  - jasoncchild 10y ago
    Yeah but it's easier to pair down the antenna and underpower the radio than to go the other direction :)