9 ms·

His #1 can not and will not ever happen. The radio spectrum is a shared resource. The total information capacity of the usable spectrum, say from 100 KHz to 100

• Retric 6y ago
  Directional antenna completely break those bandwidth limitations. It’s not currently practical for hand held devices to make significant use of it, but ultimately everything is point to point.
• gumby 6y ago
  Beam forming, phased array antennas, sophisticated coding (CDMA) and "time slots" (TDMA) will provide a lot more availability than purely looking at bandwidth available. I still agree wired/optical is best for most fixed installations both LAN and WAN, but people are getting more out of wireless than I would have predicted. And the "last mile" capacity of today's technology far exceeds what people seem to want even looking forward a decade...which paradoxically suggests that wireless might be adequate in the interim for some use cases.
  • yarcob 6y ago
    None of these technologies allow you to exceed the available bandwidth. They just make use of the shared bandwidth more efficient. It's still a shared medium. Where I live, a lot of people have 3G internet because mobile data is pretty cheap and the companies advertise it as an alternative to cable. And now they all have really crappy internet. In the evening when everyone watches youtube you get a fraction of the advertised bandwidth. With fibre, every customer gets the full spectrum. And since the frequency of light is a lot higher than radio frequency, you also get a lot more bandwidth. At radio frequency we're already hitting the physical bandwidth limits; with optical transmission there's still a lot of bandwidth left. Thinking that radio frequency transmissions are an alternative to cable / fibre is pretty short sighted thinking. Data usage is going to grow, more devices are going to use data, and wireless transmission is going to seriously limit us.
    • michaelmrose 6y ago
      You are dead on. We are still transitioning from HD to 4k with 8k coming eventually. The difference in HD to 8k is 17x the bandwidth.
      • ksec 6y ago
        >The difference in HD to 8k is 17x the bandwidth. The pixel is 17x, not bandwidth. Even Compressed RAW size dont scale linearly with pixel count. I dont have any experience with 8K, but compressing / encoding 4K with HEVC or AV1 tends to easier with fixed VMAF score than a comparatively low pixel count of 2K / 1080P. I would imagine the same if not better for 8K. And that is discounting the use of much better video codec like VVC which brings another 40 to 50% reduction in bitrate.
        • michaelmrose 6y ago
          Good point.
      • AlexandrB 6y ago
        Unless you're displaying on movie theatre sized screens, 8K seems like a waste of space/bandwidth. Even 4K is generally overkill for the typical living room. I think we're hitting the point with video resolution that music CDs hit with audio, where improvements in fidelity are largely outside the range of human perception. It's one of the reasons the music DVDs and SACDs never really caught on.
        • elzbardico 6y ago
          Not sure about that. With large screens 55" at home and over I can see a difference between FHD and 4K, enough to know I am having network problems when the streaming service starts to downscale the resolution in a 4k video.
          • leetcrew 6y ago
            that could be the bitrate more than the resolution. streams are highly compressed. would be interesting to see whether you prefer 1080p bluray over a 4k netflix stream (I suspect yes).
  • paul_f 6y ago
    You can add in quadrature amplitude modulation. Reusing bandwidth is a a fascinating field. It's not as simple as 1 bit per Hz
    • jkelleyrtp 6y ago
      Current laser com systems are getting multiple bits per photon - it seems that the communications field will keep pushing the limits until there is simply no business case, and then push some more. Really, the only limit is Shannon's limit, but that's only concerned with data rate. The modulation schemes that sit on top of the raw data is where all the capacity magic happens.
      • XorNot 6y ago
        I assume you're referring to something like this: https://www.sciencedaily.com/releases/2017/02/170203102740.htm https://www.sciencedaily.com/releases/2017/02/170203102740.h... but this isn't a scalable transmission system since it's based on single photon detection, and single-photon detection is not a high bandwidth communications ability because you have to discriminate the photons. It's a far cry from "current laser communications". AFAIK the fastest IP network speed at the moment if 44.2 Terabits/sec for a single light source (https://www.sciencedaily.com/releases/2020/05/200522095504.htm https://www.sciencedaily.com/releases/2020/05/200522095504.h...).
        • jkelleyrtp 6y ago
          I'm talking about the laser communication satellites that NASA et al have launched into orbit, which are supposedly around 3-4 bits per photon. These are hitting upwards of 10Gbit speeds (not quite 44.2 Terabits) but still impressive nonetheless. https://en.wikipedia.org/wiki/Laser_communication_in_space https://en.wikipedia.org/wiki/Laser_communication_in_space https://en.wikipedia.org/wiki/Optical_PAyload_for_Lasercomm_Science https://en.wikipedia.org/wiki/Optical_PAyload_for_Lasercomm_...
      • henrikeh 6y ago
        > the only limit is Shannon's limit, but that's only concerned with data rate. But that limit, the capacity, is also the maximum possible limit of information transfer on the channel. Modulation schemes don't increase it or change it, they just push the achievable information rate of the system closer to the capacity.
  • tdeck 6y ago
    This comment betrays a lack of understanding of some of these multiplexing technologies. They minimize wasted bandwidth due to signal collisions and interference, but they don't increase the overall bandwidth available. Let's take TDMA as an example. TDMA means that instead of using the available bandwidth continuously, each participant only gets to use that bandwidth for a fraction of the available time. Saying that TDMA helps us increase the available bandwidth is like saying queueing up at the restroom will "provide a lot more availability than purely looking at the number of stalls". CDMA is more complicated but it's still a similar story. Look at this diagram of a CDMA signal: https://en.m.wikipedia.org/wiki/File:Generation_of_CDMA.svg https://en.m.wikipedia.org/wiki/File:Generation_of_CDMA.svg Notice how the "data" actually being transmitted is only a couple of bits, but the CDMA signal includes many more transitions. CDMA is essentially using N bits of transmission bandwidth to send a signal bit of data signal, the benefit being that if multiple signals interfere it's possible to extract one of them using some complicated math. It's like if 10 people were sharing a phone line, and instead of taking turns talking they all spoke at the same time, but repeated themselves 10 times so you could pick up enough snippets from one speaker to understand what they were saying if you concentrate hard enough.
    • Sanzig 6y ago
      TDMA/CDMA don't bypass information theory, though. Shannon always wins in the end. You can improve the situation with spatial beamforming, polarization isolation, mmWave bands, etc, but there eventually comes a point where the added complexity doesn't win over just hiring a few guys with a backhoe to run fibre down the street.
      • tdeck 6y ago
        Not sure why this is responding to my comment, but I was basically making that same point.
        • Sanzig 6y ago
          Oops, I meant to respond to the grandparent post. Sorry!
• kylec 6y ago
  Well wireless won't ever replace wired for every use case, I don't see why we can't get to a point where 90% of households are provided internet service via cellular technologies, either to a MiFi-like device or with cellular built into the computer. If my iPhone, iPad, and Apple Watch have cellular built in, why not my Mac too?
  • deleted 6y ago
    [deleted]
  • michaelmrose 6y ago
    The radio is the most trivial part possible in fact computers with cellular radios have been a thing for a very long time. The little micro cell tower alternative arrangement exists to support devices that expect to communicate with a cell tower where cell service is poor. You normally actually plug them into your wired router so they are actually for areas where relying on wireless would be the worst possible experience. Fiber is able to provide Gbps to for example all homes in a square mile where they each get Gbps and can indeed fairly heavily use it. Cellular internet isn't actually wireless you run fiber to the towers and then everyone in that square mile. Urban areas where 80% of people live have a high density so for example in New York City that 1 sq mile contains 27000 people.
  • eloisant 6y ago
    Wireless makes sense in the country side, because it's expensive to pull optical fiber for just a few houses. In cities however, where most of the population is: - Bringing optical fiber is cost effective because of the population density - Wireless gets clogged very quickly (also because of the population density). Additionally 5G is even worse than 4G at going through walls.
  • dmingod666 6y ago
    Does energy cost come into play here? Quality of Service is definitely one of the metrics ISPs track, wired is a more reliable way to guarantee service than wired in a fixed setting, upto the house.
  • themulticaster 6y ago
• rusk 6y ago
  I think you’re imagining some centralised MMDS type architecture but with cellular architecture this is a reality in many places. Even in modern settings if you have WiFi you need never even be aware that there is a wire there feeding it. Indeed to many of my younger contemporaries it can take a moment to explain the difference ...
  • superkuh 6y ago
    I understand there's a horizon for cells (vhf and up isn't going to be reflecting off the ionosphere) but a whole lot of people can exist within a single cell. My argument is about the informational capacity per cell.
    • rusk 6y ago
      Well cells are getting smaller all the time and currently there is enough capacity available in an optimally configured network to provide all the services one could possibly need. Of course you’ve got physical cable tying it all together but the “experience” is wireless.
• ghaff 6y ago
  Intel was so pushing WiMAX at one point. I really irritated someone there when a wrote something critiquing their efforts. We are seeing wireless technologies (including satellite) starting to handle some use cases where it's hard to wire. But I do expect denser areas to remain mostly wired.
• nemothekid 6y ago
  I'm surprised his #1 is still TBD. To me, ethernet lines have become more important in the last 5 years as competitive gaming/esports has completely taken off. Latency is a far more prevalent in gamers minds today, I'd argue moreso than bandwidth and the first networking related advice a gamer receives to make sure you are on ethernet.
  • majewsky 6y ago
    I see frustrated WiFi users all the time, but I've never seen a frustrated Ethernet user. If I had a dime for every WiFi user in a video call who's "breaking up", I had a whole bunch of dimes.
    • themulticaster 6y ago
      Exactly. I have a suspicion that a large part of people complaining about "Internet issues" are faced with WiFi issues. Apparently many struggle with the concept of separate links that make up a connection (LAN vs WAN). But the reverse mix-up also happens: Hotels, restaurants and the similar businesses like to boast their "included free WiFi" when they really mean complimentary Internet access, provided with an AP.
      • RobertKerans 6y ago
        I'd take that as a given for 99% of cases. As fibre takes over from piggybacking off copper, IME actual internet issues seem to be pretty rare: [UK and] I haven't noticed that kind of service issue for a few years now, whereas used to be relatively common. Happy to keep the pretence up though -- what else is a as neutral and widely understood as "internet issues"? Whoops, seems as if my connection has dropped out! Yes, I was very interested in that discussion over sales targets that's been going on for the past half an hour, please email me a summary! Bloody internet, always dropping out!
      • moftz 6y ago
        I always laugh when I see Comcast commercials for "fastest in-home Wifi". An 802.11ac router isn't going to help anything when you can only get 10/10 bandwidth on a good day.
• elil17 6y ago
  As someone working on 5G, I disagree strongly. 5G supports up to 1 million devices per square kilometer (the most dense city, Manila, in the world has about 50k people per square kilometer). My understanding is that you can have about 100k devices per square kilometer before speeds drop below ideal (20 gigabit). So even if everyone in downtown Manila wanted stream seven movies at once they could all do it. As other commenters have said, that’s because of clever techniques like beamforming and OFDMA. But cities aren’t really the area where 5G home internet provides an advantage. Sure, the protocols more efficient than WiFi - the tower allocated bandwidth and time blocks to coordinate transmissions instead of having everyone’s router blast away on the same hardcoded WiFi channels. But it still achieves those high speeds and great connectivity through having a bunch of small cell towers - hardly much different than wired internet. The real advantage is suburbs, small towns, and rural areas. You solve the last mile problem for cables, eliminate outages, and you do it all with a couple large cell towers. Yeah, people (or more likely businesses) with high throughput needs will still use wired connections. But it will be because the electricity costs of transmitting from a 5G tower are high enough that there’s always a base cost per GB, not because there isn’t enough bandwidth to go around.
  • smt88 6y ago
    > eliminate outages Why do you expect 5G to eliminate outages when we can't eliminate them with existing LTE towers, with home wifi, or even with direct ethernet connections to modems? As of now, my least reliable network is always my cellular network. > you can have about 100k devices per square kilometer before speeds drop below ideal (20 gigabit) When, though? We're far, far from this at the moment. What is going to fix it and when?
• rahimiali 6y ago
  A lot of confusion in the replies below. Here is an illustration of this point: Suppose you’ve saturated your communication bandwidth between two points, sending bits through the entire 500 Thz spectrum. If you have a wired connection, you can lay another set of cables between these points and send more bits. With wireless, there is nothing more you can do. No amount of beam forming helps you.
• brigade 6y ago
  Each cable node shares ~1GHz of bandwidth among all the separate runs to individual houses. Relative to that, 5G has similar local bandwidth, given the low propagation of mmwave. It's not going to completely replace hardwired internet in suburbs/cities, but it might just kill last-mile fiber rollout short of new construction.
• spookthesunset 6y ago
  Yup. I’ve always questioned people who think wireless can replace a wire at scale. It just can’t. That being said I can browse most sites and do 90% of my internet just fine either on my phone or tethered to my phone using my data plan. So maybe I’m wrong!
• syoc 6y ago
  Not trying to prove you wrong, just asking. Can a service like starlink not deal, in some hypothetical configuration, replace cabled internet?
  • henrikeh 6y ago
    Can it exist and provide a usable service to some? Yes, probably. Can it replace cabled internet, period? Can it replace terrestrial cellular? Unlikely: Mobile internet is constrained by the capacity and coverage of the cell. "Capacity" being the practical sort of what the maximum achievable information rate is, given the available receivers and transmitters. Satellite links are a bit complicated, but essentially the Shannon-Hartley theorem holds and you either have to increase bandwidth or increase signal-to-noise ratio to provide better data rates within a cell. Bigger cell, more users, less capacity per user, worse data rate per user. I don't know what the cell sizes Starlink will use are, but I've read numbers around 200 km^2. My hometown of 10000 homes is 21 km^2. If they were to provide 100 Mb/s just to my hometown, they would need a 1 Tb/s capacity in a much smaller cell. Of course, not everybody will use 100 Mb/s all the time, but it illustrates the problem. This is why SpaceX is mainly focusing on low-density areas in places where the infrastructure is less-developed/monopolized. The capacity / coverage problems works much better to their advantage.