5 ms·

Lost interest when I read: >The test location had a rocky desert topology with minimal foliage, and tests were conducted using LTE Band 41 (2,500 MHz). T-Mobi

Lost interest when I read: >The test location had a rocky desert topology with minimal foliage, and tests were conducted using LTE Band 41 (2,500 MHz). T-Mobile/Sprint use this band. I have a lot of experience with it because I am located in a semi-rural and hilly area and I use LTE exclusively for internet access. For B41, I have one tower that's approx 2 miles away and 600ft or so down from me in a valley, close to line-of-sight. This signal is only usable if I install an antenna outdoors or use next to a window facing the tower. My real-world speedtests are around 75mbit down, and 2mbit up on a good day. Indoors not in front of a window I cannot force any of the devices I own to connect to this band. I'm also going to mention: Uplink/transmit power on most cellular devices is limited to 200mW (class 1) unless you use a device that supports Sprint's Class 2 High Performance User Equipment (HPUE) at 400mW or you have a router/device that does class 3 High Power User Equipment (also HPUE) at 1.25W. Only class 3 devices have a shot in hell at communicating back to this tower if there's even a small number of trees or a single wall between you and it. Finally, this B41 TD-LTE tends to work worse the further you get outside the cell, since it relies on precise timing of all equipment inside it. Installing cell relay equipment works poorly outside of a mile or so of the transmitting antenna, again due to precise timing issues. (personal experience with a Sprint Magic Box). Ignoring all the other social/anticompetitive issues there is with Facebook proposing this, it stinks like a scam to get a tax writeoff or jump onto the same sort of FCC rural internet grant money Starlink is bilking taxpayers out of. You can't scale a midband macro like this even using a dumb amount of spectrum. Oh totally forgot, there's an 'educational' use case for use of BRS (2500mhz) spectrum that I'll bet Facebook will also try to get their hands on. EDIT: Note on power class, you have certify through the FCC initially to use higher classes, can't just enable it later on without recertification. Also, higher transmit power = less battery life. This is why in urban areas it usually makes more sense to use cell network to save battery (better scheduling/sleep modes, low transmit power) than it does in rural areas where the cell radio is cranked up to its limits and it makes more sense to use a low power radio like wifi broadcasting all the time.

AtlasBarfed 6y ago
Are you excited for Starlink, or will line of sight be a problem for that?
- joecool1029 6y ago
  So long as you don't live in a crater or have skyscrapers blocking your view line of sight should not be an issue for a majority of the population. Starlink wouldn't require a specific southern view of the sky like a GEO system does but it won't do well in 'urban canyons'. MEO consumer things you might be familiar with that experience reduced signal in the described conditions include GNSS (GPS) and SiriusXM.
  - Scoundreller 6y ago
    Sirius is now GEO, but has ground repeaters in problem areas. GPS has the advantage of seeing multiple satellites and working with that by design since its one way. Despite that, Japan launched its own satellite to supplement GPS because it had so many issues. I think we’re spoiled by our phones that supplement GPS with cellular signals, wifi and inertial references.
    - joecool1029 6y ago
      The newest phones actually even do dual-frequency GPS using a newer signal (L5). It's accurate enough to do lane-keeping. Existing systems also supplement GPS network data with russia's GLONASS, as well as sometimes WAAS if the satellite gets picked up (WAAS is GEO system to provide for additional accuracy, since it's further and requires a path facing south, it's not often picked up on phones)
    - jtrip 6y ago
      >Inertial reference Can we really do inertial reference with current phone hardware? I would imagine our usecases don't really even give inertial reference a nice playing field.
      - Scoundreller 6y ago
        Maybe my terminology isn’t ideal, but I figured my NAV apps can tell I’m doing things like a U-Turn based on G-forces. But maybe it’s just using its compass. My old Garmin wouldn’t realize I did a u-turn until I have half way back down the street.
wavefunction 6y ago
This sounds like an appropriate test for equipment deployed into large areas of Africa, Central Asia and the Middle East where T-Mobile/Sprint don't operate.
- madrox 6y ago
  I don't think the problem is the companies but the band itself, which follows physical laws. GP has experience with the limits of this band because it's used by Sprint/T-Mobile.
  - wavefunction 6y ago
    Sure, but perhaps it's an improvement on any existing coverage options or even a lack of any.
    - joecool1029 6y ago
      I just don't buy it. One way to make a system like this work is heavily proxy and strip rich media out of the network (Globalstar sells a device called the SatFi that does this for their MEO constellation, Opera Mini used to do it for featurephones), so you can support quality of service in a remote population. There's a financial incentive for Facebook to provide access to a specially crafted 'walled garden' that's designed for lower bandwidth scenarios. Facebook has tried this shit before in India without touting special network hardware and it was not well received: https://www.cnet.com/news/facebooks-free-basics-internet-service-bashed-in-india/ https://www.cnet.com/news/facebooks-free-basics-internet-ser...
      - petre 6y ago
        Yup, this is exactly "Free Basics” reloaded. Fortunately their sat blew up in their face and then Jio erased any competitive advantage they might have had in India.
        disgruntledphd2 6y ago
LMYahooTFY 6y ago
>Ignoring all the other social/anticompetitive issues there is with Facebook proposing this, it stinks like a scam to get a tax writeoff or jump onto the same sort of FCC rural internet grant money Starlink is bilking taxpayers out of. You can't scale a midband macro like this even using a dumb amount of spectrum. Oh totally forgot, there's an 'educational' use case for use of BRS (2500mhz) spectrum that I'll bet Facebook will also try to get their hands on. Is it very clear that this pessimism/cynicism is warranted? https://www.youtube.com/watch?v=XzXZdipxCuw https://www.youtube.com/watch?v=XzXZdipxCuw
- joecool1029 6y ago
  >Is it very clear that this pessimism/cynicism is warranted? Yes, read some of my earlier comments regarding Starlink, DISH, and general telecom schemes. I'm not coming out of nowhere with this criticism. With that being said I fully understand where their system is better than current MEO/GEO systems for low-latency rural deploys. I'm just not in the cult of Elon, physics/money/practicality have their limits. I'd honestly be more excited with Starlink if they were primarily using it as a replacement for satellite backhaul on very remote cell sites. That way you don't need residential roof antennas and a ton of power to communicate with the network, just need your main power at the cell site. That's more practical for poor rural countries but isn't as big of a writeoff, doesn't look as sexy.
  - Scoundreller 6y ago
    I could see Starlink-fed WISPs or cellular becoming something very real. Starlink CPE is very expensive and probably heavily subsidized. Plenty of villages where 0 can afford it, but collectively they could. Starlink may as well take the money on the table if the constellation will fly overhead anyway.
    - jmacd 6y ago
      This is the business model that Telesat trying to make work. While they are behind Starlink in terms of rollout, they are a credible manufacturer/provider for a service like this https://www.canwisp.ca/resources/Conference%202020/Presentations/11-CanWISP%202020%20Telesat%20Leo%20in%20partnership%20connecting%20everyone%20everywhere.pdf https://www.canwisp.ca/resources/Conference%202020/Presentat...
layoutIfNeeded 6y ago
>This is why in urban areas it usually makes more sense to use cell network to save battery Hmm. Rhen why does Apple recommend using WiFi for power saving? “When you use your device to access data, a Wi‑Fi connection uses less power than a cellular network” https://www.apple.com/batteries/maximizing-performance/ https://www.apple.com/batteries/maximizing-performance/
- tidepod12 6y ago
  There's a lot of confounding factors, but in general: Cell network uses very little power when idle, but a lot when transmitting. Wifi on the other hand uses a medium amount of power when idle, and a medium amount when transmitting. (this is really generalized and there have been a lot of recent advancements to optimize power usage of both). This is why general guidance for years was to use wifi when you are actually using your phone for browsing the internet, taking advantage of wifi's lower power efficiency when in use, but to turn off wifi when your phone is just in your pocket/idle to take advantage of cell network's better idle power efficiency. However, the above is really only true for urban/suburban areas where you have good signal. If you are in an area with poor signal, your phone will use a lot of battery power via the cell network even when "idle" (because in reality even though your phone is "idle", the cell radio isn't actually idle, it's constantly struggling in the background to maintain the connection through the poor signal).
  - joecool1029 6y ago
    Just adding onto your comment, Apple probably recommends use of wifi because: 1. They collect AP's for their mapping/location crap. 2. The wifi chipsets they use are basically their own self-contained computers that can manage scanning at low-power without taxing the CPU. 3. At least for new HW, some of the 5G-NR stuff really isn't well optimized yet, not as bad as LTE originally was... but it's entirely possible the new modems for now are a little power hungry. Turning on wifi makes the cell chipset track less carriers, typically it'll just hug to one low-band carrier for status/push messages instead of as many as 5 or 6 carriers. EDIT: Phones usually only transmit on one channel while receiving anywhere from 1-7 different channels at once, only the recent flagships transmit on 2 or 3 right now.
mNovak 6y ago
Small point, but the idea here is not using additional spectrum, the antenna design lends (in their analysis) up 29dB added link budget. For a more intuitive example, that's roughly the equivalent of pointing a satellite dish at your phone.
jauer 6y ago
> Lost interest when I read: > >The test location had a rocky desert topology with minimal foliage, and tests were conducted using LTE Band 41 (2,500 MHz). Testing was conducted in other locations as well. One use-case being discussed doesn't exclude the others. For example: > The Metcalf location has flat terrain with thick deciduous trees covering the land. Also... > Ignoring all the other social/anticompetitive issues there is with Facebook proposing this, it stinks like a scam to get a tax writeoff or jump onto the same sort of FCC rural internet grant money Starlink is bilking taxpayers out of. Facebook doesn't build and operate this kind of network. This project (and others such as efforts in middle mile fiber construction and funding cable consortiums) are largely intended to help regional carriers outside of the US past hurdles around capacity and density that limit their growth. Since it's not targeted at the US, the FCC's grants, spectrum allocation, and power limits are not relevant. Cui bono? Facebook's learned that just getting people connected to the internet in a content-agnostic way is sufficient for growth. This is why FB funds consortium fiber around and across Africa, funds internet exchanges, and makes free network planning tools available to carriers. https://www.internetsociety.org/issues/ixps/facebook-ixp-partnership/ https://www.internetsociety.org/issues/ixps/facebook-ixp-par... Disclaimer: I'm a Network PE at Facebook, in prod, not in connectivity labs where this project originated, and def not speaking for the company.
- thaumasiotes 6y ago
  > Testing was conducted in other locations as well. One use-case being discussed doesn't exclude the others. Except the comment you're responding to doesn't seem to take issue with the location. It goes on at some length about the problems with LTE Band 41. How does pointing out that testing occurred in other locations address the problems with Band 41?
- spoopyskelly 6y ago
  "It doesn't work in my stupidly weird case, so it must be bad."

AtlasBarfed 6y ago

Are you excited for Starlink, or will line of sight be a problem for that?

joecool1029 6y ago
So long as you don't live in a crater or have skyscrapers blocking your view line of sight should not be an issue for a majority of the population. Starlink wouldn't require a specific southern view of the sky like a GEO system does but it won't do well in 'urban canyons'. MEO consumer things you might be familiar with that experience reduced signal in the described conditions include GNSS (GPS) and SiriusXM.
- Scoundreller 6y ago
  Sirius is now GEO, but has ground repeaters in problem areas. GPS has the advantage of seeing multiple satellites and working with that by design since its one way. Despite that, Japan launched its own satellite to supplement GPS because it had so many issues. I think we’re spoiled by our phones that supplement GPS with cellular signals, wifi and inertial references.
  - joecool1029 6y ago
    The newest phones actually even do dual-frequency GPS using a newer signal (L5). It's accurate enough to do lane-keeping. Existing systems also supplement GPS network data with russia's GLONASS, as well as sometimes WAAS if the satellite gets picked up (WAAS is GEO system to provide for additional accuracy, since it's further and requires a path facing south, it's not often picked up on phones)
  - jtrip 6y ago
    >Inertial reference Can we really do inertial reference with current phone hardware? I would imagine our usecases don't really even give inertial reference a nice playing field.
    - Scoundreller 6y ago
      Maybe my terminology isn’t ideal, but I figured my NAV apps can tell I’m doing things like a U-Turn based on G-forces. But maybe it’s just using its compass. My old Garmin wouldn’t realize I did a u-turn until I have half way back down the street.

wavefunction 6y ago

This sounds like an appropriate test for equipment deployed into large areas of Africa, Central Asia and the Middle East where T-Mobile/Sprint don't operate.

madrox 6y ago
I don't think the problem is the companies but the band itself, which follows physical laws. GP has experience with the limits of this band because it's used by Sprint/T-Mobile.
- wavefunction 6y ago
  Sure, but perhaps it's an improvement on any existing coverage options or even a lack of any.
  - joecool1029 6y ago
    I just don't buy it. One way to make a system like this work is heavily proxy and strip rich media out of the network (Globalstar sells a device called the SatFi that does this for their MEO constellation, Opera Mini used to do it for featurephones), so you can support quality of service in a remote population. There's a financial incentive for Facebook to provide access to a specially crafted 'walled garden' that's designed for lower bandwidth scenarios. Facebook has tried this shit before in India without touting special network hardware and it was not well received: https://www.cnet.com/news/facebooks-free-basics-internet-service-bashed-in-india/ https://www.cnet.com/news/facebooks-free-basics-internet-ser...
    - petre 6y ago
      Yup, this is exactly "Free Basics” reloaded. Fortunately their sat blew up in their face and then Jio erased any competitive advantage they might have had in India.
      - disgruntledphd2 6y ago

LMYahooTFY 6y ago

>Ignoring all the other social/anticompetitive issues there is with Facebook proposing this, it stinks like a scam to get a tax writeoff or jump onto the same sort of FCC rural internet grant money Starlink is bilking taxpayers out of. You can't scale a midband macro like this even using a dumb amount of spectrum. Oh totally forgot, there's an 'educational' use case for use of BRS (2500mhz) spectrum that I'll bet Facebook will also try to get their hands on. Is it very clear that this pessimism/cynicism is warranted? https://www.youtube.com/watch?v=XzXZdipxCuw https://www.youtube.com/watch?v=XzXZdipxCuw

joecool1029 6y ago
>Is it very clear that this pessimism/cynicism is warranted? Yes, read some of my earlier comments regarding Starlink, DISH, and general telecom schemes. I'm not coming out of nowhere with this criticism. With that being said I fully understand where their system is better than current MEO/GEO systems for low-latency rural deploys. I'm just not in the cult of Elon, physics/money/practicality have their limits. I'd honestly be more excited with Starlink if they were primarily using it as a replacement for satellite backhaul on very remote cell sites. That way you don't need residential roof antennas and a ton of power to communicate with the network, just need your main power at the cell site. That's more practical for poor rural countries but isn't as big of a writeoff, doesn't look as sexy.
- Scoundreller 6y ago
  I could see Starlink-fed WISPs or cellular becoming something very real. Starlink CPE is very expensive and probably heavily subsidized. Plenty of villages where 0 can afford it, but collectively they could. Starlink may as well take the money on the table if the constellation will fly overhead anyway.
  - jmacd 6y ago
    This is the business model that Telesat trying to make work. While they are behind Starlink in terms of rollout, they are a credible manufacturer/provider for a service like this https://www.canwisp.ca/resources/Conference%202020/Presentations/11-CanWISP%202020%20Telesat%20Leo%20in%20partnership%20connecting%20everyone%20everywhere.pdf https://www.canwisp.ca/resources/Conference%202020/Presentat...

layoutIfNeeded 6y ago

>This is why in urban areas it usually makes more sense to use cell network to save battery Hmm. Rhen why does Apple recommend using WiFi for power saving? “When you use your device to access data, a Wi‑Fi connection uses less power than a cellular network” https://www.apple.com/batteries/maximizing-performance/ https://www.apple.com/batteries/maximizing-performance/

tidepod12 6y ago
There's a lot of confounding factors, but in general: Cell network uses very little power when idle, but a lot when transmitting. Wifi on the other hand uses a medium amount of power when idle, and a medium amount when transmitting. (this is really generalized and there have been a lot of recent advancements to optimize power usage of both). This is why general guidance for years was to use wifi when you are actually using your phone for browsing the internet, taking advantage of wifi's lower power efficiency when in use, but to turn off wifi when your phone is just in your pocket/idle to take advantage of cell network's better idle power efficiency. However, the above is really only true for urban/suburban areas where you have good signal. If you are in an area with poor signal, your phone will use a lot of battery power via the cell network even when "idle" (because in reality even though your phone is "idle", the cell radio isn't actually idle, it's constantly struggling in the background to maintain the connection through the poor signal).
- joecool1029 6y ago
  Just adding onto your comment, Apple probably recommends use of wifi because: 1. They collect AP's for their mapping/location crap. 2. The wifi chipsets they use are basically their own self-contained computers that can manage scanning at low-power without taxing the CPU. 3. At least for new HW, some of the 5G-NR stuff really isn't well optimized yet, not as bad as LTE originally was... but it's entirely possible the new modems for now are a little power hungry. Turning on wifi makes the cell chipset track less carriers, typically it'll just hug to one low-band carrier for status/push messages instead of as many as 5 or 6 carriers. EDIT: Phones usually only transmit on one channel while receiving anywhere from 1-7 different channels at once, only the recent flagships transmit on 2 or 3 right now.

mNovak 6y ago

Small point, but the idea here is not using additional spectrum, the antenna design lends (in their analysis) up 29dB added link budget. For a more intuitive example, that's roughly the equivalent of pointing a satellite dish at your phone.

jauer 6y ago

> Lost interest when I read: > >The test location had a rocky desert topology with minimal foliage, and tests were conducted using LTE Band 41 (2,500 MHz). Testing was conducted in other locations as well. One use-case being discussed doesn't exclude the others. For example: > The Metcalf location has flat terrain with thick deciduous trees covering the land. Also... > Ignoring all the other social/anticompetitive issues there is with Facebook proposing this, it stinks like a scam to get a tax writeoff or jump onto the same sort of FCC rural internet grant money Starlink is bilking taxpayers out of. Facebook doesn't build and operate this kind of network. This project (and others such as efforts in middle mile fiber construction and funding cable consortiums) are largely intended to help regional carriers outside of the US past hurdles around capacity and density that limit their growth. Since it's not targeted at the US, the FCC's grants, spectrum allocation, and power limits are not relevant. Cui bono? Facebook's learned that just getting people connected to the internet in a content-agnostic way is sufficient for growth. This is why FB funds consortium fiber around and across Africa, funds internet exchanges, and makes free network planning tools available to carriers. https://www.internetsociety.org/issues/ixps/facebook-ixp-partnership/ https://www.internetsociety.org/issues/ixps/facebook-ixp-par... Disclaimer: I'm a Network PE at Facebook, in prod, not in connectivity labs where this project originated, and def not speaking for the company.

thaumasiotes 6y ago
> Testing was conducted in other locations as well. One use-case being discussed doesn't exclude the others. Except the comment you're responding to doesn't seem to take issue with the location. It goes on at some length about the problems with LTE Band 41. How does pointing out that testing occurred in other locations address the problems with Band 41?
spoopyskelly 6y ago
"It doesn't work in my stupidly weird case, so it must be bad."