5 ms·

Ok, so, for one, you're miss-understanding the MIMO designation, or at least miss-representing it's meaning. 128x128 means that both sender and receiver have 12

by namibj 6y ago

Ok, so, for one, you're miss-understanding the MIMO designation, or at least miss-representing it's meaning. 128x128 means that both sender and receiver have 128 antennas. Not that it's an array of 128 * 128 antennas (16384). Also, the 128x128 5G MIMO deployments I could find were distributed deployments, placing remote radio heads very densely at relevant indoor locations. I assume they're referring to places like large train stations or shopping malls. Also, regarding the "massive amounts" part: there is little incentive to transmit more than a few hundred mW per channel, just because the mobile device needs to transmit at a similar level anyways, and there are battery and cooling considerations, even neglecting the cost of power amplifiers for these frequencies. And, the 1 million devices per square kilometer is actually just a dense, standing crowd. It's the average density that can be reached over any sizable area (putting a school class's phones in a box until the end of the lesson would imply some insane density in that box, but there'd be a limit for how many boxes could be arranged into a dense grid).

owenversteeg 6y ago
As the HN guidelines say, "Assume good faith." I understand the MIMO designation, and I am not trying to misrepresent it in my comment. I know that 128x128 is not sixteen thousand (!!!) antennas on one tower, but rather 256, half for rx and half for tx. That said, two hundred and fifty six antennae on one tower is far, far more (orders of magnitude, plural!) than the typical 2x2 or 4x4 4G towers deployed today. And keep in mind that this is certainly not "just" 256 antennae for one mall, because 5G is blocked by anything thicker than a post-it (the article mentions how future plans include deploying massive MIMO to each floor of a building, as drywall and glass both block many 5G frequencies!) The reality is that no matter how you want to slice it, 5G means moving from widely spaced 4G towers transmitting at frequencies we have used for around a century to hyper-dense massive deployments of large numbers of antennae transmitting at new and relatively un-studied frequencies. 4G towers are (mostly) kept away from humans getting too close; 5G towers will be on lampposts and on the same floor of your office where someone can touch them. I'm not saying 5G is inherently bad, or good, I have no idea. I haven't run a longitudinal study, but _neither has anyone else_, and that's what scares me a little. Look, the #1 post on HN right now is how highly trained, expert engineers accidentally made a bridge (one of the oldest human inventions, around for millennia) create an extremely loud eerie noise currently blanketing San Francisco. And sure, transmit power is low. But it's not just about the power. Today I went out and enjoyed a warming 1000 W/m2 of hundreds of-nm EM radiation all over my body. Then I accidentally looked at the source, which hurt my eyes and disoriented me. Later I played with a device of only 0.01W emitting highly temporally coherent EM radiation. I had to put on safety equipment, because it had the possibility to harm me, including permanently damaging my sight.
- mintyc 6y ago
  Lots of work has already been carried out. I think you misunderstand the concept of directional beamforming. The antennas in question in a phased array are 'elements' that cooperate to steer a more focussed beam in a given direction. The phone in your pocket when transmitting (whether 3G/4G/5G) is the biggest contribution to your personal health. Not a base station. I'd be concerned much more about low and mid band that can penetrate much further than high band. I am concerned about high band too (skin surface effects) but know nothing about this and assume work has been done to quantify and assess. My biggest problem both with 5G hype and those that seek to cast doubt on it is that both sides misrepresent the 'facts' to suit their agenda. Sadly that's true in all walks of life.
  - owenversteeg 6y ago
    I've messed around with radio a bit, so I have some idea of beamforming. Basically, you use interference in the wavefront to your advantage. I am not sure what relevance it has here - at the end of the day, you are still dumping lots of power into new and unknown frequencies in every direction, very close to humans. I am going to disagree with you that the phone is always the bigger risk. Apparently Huawei 5G base stations are above 11 kilowatts, and these are being rolled out closer to humans than ever before. Sure, some research has been done, but the vast majority of it has been simply pointing some mm-waves at people for a few hours and checking if they're OK afterwards. I haven't seen anything for babies (baby skin is thin enough that mm-waves can go through the dermis, unlike adults) and not even a hint of any quality longitudinal study. And yes, I agree, the 5G hype/hate is so rabid that it makes it much harder to find any actual science on the internet about the subject. Personally, I don't have any agenda here. I was generally positive on 5G until I read the details in this great and informative article, and thought "wow, that's a lot of antennas, and a lot of new frequencies, and they're closer to us than ever before" If you know of any decent studies on this, I'm all ears - please drop any links.
    - g_p 6y ago
      Do you have a source for 11 kW base stations? Assuming we are talking about RF power output here, that is far higher than anything I've ever dealt with, and I'm not sure that it's at all right. A typical macro cell has 20 Watts of RF power output (for example). The relevant international standards are those from ICNIRP, and they've recently updated and expanded on these in great detail around safety margins of various frequencies. The UK telecoms regulator, Ofcom, recently did a safety study of actual deployed equipment, looking at measuring the RF output from base stations. Therefore I'm not sure where figures like 11 kW are coming from. Maybe there are some very hot (and inefficient) early base stations somewhere using 11 kW of mains power to produce 20 or 40 W of RF energy? But considering Huawei is heavily advertising 5G as being "greener", that wouldn't seem likely either. But even then, this is far higher than even the wall socket consumption of the equipment I've dealt with.

by namibj 6y ago

owenversteeg 6y ago

As the HN guidelines say, "Assume good faith." I understand the MIMO designation, and I am not trying to misrepresent it in my comment. I know that 128x128 is not sixteen thousand (!!!) antennas on one tower, but rather 256, half for rx and half for tx. That said, two hundred and fifty six antennae on one tower is far, far more (orders of magnitude, plural!) than the typical 2x2 or 4x4 4G towers deployed today. And keep in mind that this is certainly not "just" 256 antennae for one mall, because 5G is blocked by anything thicker than a post-it (the article mentions how future plans include deploying massive MIMO to each floor of a building, as drywall and glass both block many 5G frequencies!) The reality is that no matter how you want to slice it, 5G means moving from widely spaced 4G towers transmitting at frequencies we have used for around a century to hyper-dense massive deployments of large numbers of antennae transmitting at new and relatively un-studied frequencies. 4G towers are (mostly) kept away from humans getting too close; 5G towers will be on lampposts and on the same floor of your office where someone can touch them. I'm not saying 5G is inherently bad, or good, I have no idea. I haven't run a longitudinal study, but _neither has anyone else_, and that's what scares me a little. Look, the #1 post on HN right now is how highly trained, expert engineers accidentally made a bridge (one of the oldest human inventions, around for millennia) create an extremely loud eerie noise currently blanketing San Francisco. And sure, transmit power is low. But it's not just about the power. Today I went out and enjoyed a warming 1000 W/m2 of hundreds of-nm EM radiation all over my body. Then I accidentally looked at the source, which hurt my eyes and disoriented me. Later I played with a device of only 0.01W emitting highly temporally coherent EM radiation. I had to put on safety equipment, because it had the possibility to harm me, including permanently damaging my sight.

mintyc 6y ago
Lots of work has already been carried out. I think you misunderstand the concept of directional beamforming. The antennas in question in a phased array are 'elements' that cooperate to steer a more focussed beam in a given direction. The phone in your pocket when transmitting (whether 3G/4G/5G) is the biggest contribution to your personal health. Not a base station. I'd be concerned much more about low and mid band that can penetrate much further than high band. I am concerned about high band too (skin surface effects) but know nothing about this and assume work has been done to quantify and assess. My biggest problem both with 5G hype and those that seek to cast doubt on it is that both sides misrepresent the 'facts' to suit their agenda. Sadly that's true in all walks of life.
- owenversteeg 6y ago
  I've messed around with radio a bit, so I have some idea of beamforming. Basically, you use interference in the wavefront to your advantage. I am not sure what relevance it has here - at the end of the day, you are still dumping lots of power into new and unknown frequencies in every direction, very close to humans. I am going to disagree with you that the phone is always the bigger risk. Apparently Huawei 5G base stations are above 11 kilowatts, and these are being rolled out closer to humans than ever before. Sure, some research has been done, but the vast majority of it has been simply pointing some mm-waves at people for a few hours and checking if they're OK afterwards. I haven't seen anything for babies (baby skin is thin enough that mm-waves can go through the dermis, unlike adults) and not even a hint of any quality longitudinal study. And yes, I agree, the 5G hype/hate is so rabid that it makes it much harder to find any actual science on the internet about the subject. Personally, I don't have any agenda here. I was generally positive on 5G until I read the details in this great and informative article, and thought "wow, that's a lot of antennas, and a lot of new frequencies, and they're closer to us than ever before" If you know of any decent studies on this, I'm all ears - please drop any links.
  - g_p 6y ago
    Do you have a source for 11 kW base stations? Assuming we are talking about RF power output here, that is far higher than anything I've ever dealt with, and I'm not sure that it's at all right. A typical macro cell has 20 Watts of RF power output (for example). The relevant international standards are those from ICNIRP, and they've recently updated and expanded on these in great detail around safety margins of various frequencies. The UK telecoms regulator, Ofcom, recently did a safety study of actual deployed equipment, looking at measuring the RF output from base stations. Therefore I'm not sure where figures like 11 kW are coming from. Maybe there are some very hot (and inefficient) early base stations somewhere using 11 kW of mains power to produce 20 or 40 W of RF energy? But considering Huawei is heavily advertising 5G as being "greener", that wouldn't seem likely either. But even then, this is far higher than even the wall socket consumption of the equipment I've dealt with.