back to article Lightbulb moment for visible light networking: 200 Gbps without a fibre

If you think the multi-gigabit per second performance promised by WiFi communications is hot, think again: research out of Oxford University is claiming 100 Gbps and beyond in homes using free-space optics. The research, led by photonics engineer Dominic O'Brien, uses a base station to communicate with computers using light …

  1. Tromos

    I would have thought line of sight considerations would render this technology marginal. People tend to place access points and desks near to walls and, unless they are the same wall, the user's body would tend to block the straight line path. Bouncing off a mirrored ceiling might help, but this would chew into the already very limited range. I don't see this as viable beyond some niche applications.

    1. Anonymous Coward
      Anonymous Coward

      Even in a niche it's not viable, since the field of view would be more restricted than out in the open.

      Aside from that, there will also be problems with passing co-workers, cats, butterflies, what have you. However, these problems might be mitigated by simply increasing the wattage of the laser a tad...

  2. Long John Brass

    IrDA all over again

    My ancient PalmPilot networked using the same technology :)

    1. DropBear

      Re: IrDA all over again

      Well yeah but I suppose it has been dead for long enough now that people forgot how utterly miserable it was compared to any proper RF or cable connection (anything else, really). Guess we're back at "point that bloody IR remote AT THE MEDIA BOX there on the left, idiot, NOT AT THE TV!!!"

  3. Anonymous Coward
    Anonymous Coward


    Why the comparison to WiFi? That is a very different part of the EM spectrum than they are dealing with.

    For starters, this thing isn't going to get through a wall unaided, unlike the technology I am using right now whilst I tap away on my laptop to send this to you.

    Cool hack though.

    1. Danny 14

      Re: WIFI WTF?

      unless the wall had a window :D

  4. Mark 85

    Speed is good

    Until it leaves my router to go to the ISP. :( Now if only they could fix that problem child.

  5. Anonymous Coward
    Anonymous Coward

    In Ceiling

    Contrary to the Debbie Downers above, if occurs to me that a great many wifi APs these days in offices are in the ceiling space for even coverage. 3m to the ceiling with a reasonable angle might be quite workable.

    Won't work without line-of-sight but as an auxiliary option it might be useful.

    1. Anonymous Coward
      Anonymous Coward

      Re: In Ceiling

      I was thinking along the same lines but even at home it would work if you have fairly high ceilings. You could have most of the AP's/hubs/whatever mounted above the doors and below the ceiling fans. The final hop to a PC's receiver might be tricky at times. Of course this is all assuming they could produce fairly inexpensive repeaters to route all this with. The other constraint is power of course. They'll have to beam power via microwave (joking).

      For now it's not all the practical but I can see something like this being useful in the long term if they address the usability as much as possible. In the near term this would be great for rack to rack communications wouldn't it? Rather than have a nest of cables...

      1. Long John Brass

        Re: In Ceiling

        What about a HomePlug <--> LedLighting style adapter

        Visable light for the meatbags

        IR for the iFondleThings

        Mains power for the back-haul to the router

        The downside would be no network connectivity when the lights are off, Which will make night time happy time difficult unless you make it a "smart" light bulb along the lines of the Philips Hue style units.

    2. JamesTQuirk

      Re: In Ceiling

      Li-Fi sounds fine, like the speed, but just a thought, I understand we may be talking about nano/milli-seconds here, but flashing light has been found in fluro's & older screens, causing medical issues, I wonder if they have made any in studies of it's effects in this area ..

      Also, as I am pensioner, & have free time, to go mad with My PC's, they are spread out in flat, so main Internet PC is online 6 months at a time, long time to leave lights on ...

      1. JamesTQuirk

        Re: In Ceiling

        ummm, another thought, what if you had mirrors in room, would/could they cause a ghost signal in light ?

  6. Anonymous Coward
    Anonymous Coward

    What's the use case for 100 Gbps wireless?

    Even a half dozen HEVC compressed 8K streams couldn't add up to a single gigabit. Until we have holographic video or the like we've pretty much reached the limits of the speed required in the home or typical office environment at a gigabit. We need far richer media to go beyond that.

    For content creators (i.e. those editing the 8K videos, for example) they might want more speed so they can load/save files to the cloud faster. Though even that's questionable, since you probably won't have a 100 Gbps link to the internet anytime soon so you'll have to wait anyway. Without the vast horde of content consumers coming along for the ride to drive down the price, higher speeds on this level would remain a Cadillac option.

    I know I'll get a few downvotes from the "640K is enough for anybody, right" folks who think we will always find a way to use faster networking, but just like computers became "fast enough" to the point few think their PC needs more speed, so it will be with networking.

    1. Paul 129

      Re: What's the use case for 100 Gbps wireless?

      Ok I'll down vote you. I typically throw around a couple of hundred gig to a terabyte at a time (disk images), across the network, so the ability to speed it up in any form is appreciated.

      The bottle neck in my work though is the speed of hard drives that i'm sucking the data from. Can't wait till the day SSD's overtake hard disks as the main storage

      1. Ken Hagan Gold badge

        Re: What's the use case for 100 Gbps wireless?

        @Paul129: Two small points: firstly you concede that the network already isn't the bottleneck for your case, and secondly have you tried sneakernet? "Transferring disc images" is quite possibly the one thing that sneakernet is best at.

        1. Philip Lewis

          Re: What's the use case for 100 Gbps wireless?

          never underestimate banwidth of a utility van filled with disk drives

    2. P. Lee

      Re: What's the use case for 100 Gbps wireless?

      Sure its faster than any one PC will need, but if you're looking at networking, you want to share resources.

      Cross-rack traffic has been mentioned. There are security applications where you might want wireless, but you want to confine it geographically. You might want to have some high-speed networking in your bedroom which doesn't involve irradiating your head while you sleep. I might not want to turn it off in the rest of the house, but a simple cover (or sweaty t-shirt) can close it down locally. The 100G engineering might pay-off with smaller capacity consumer networking.

      1. Anonymous Coward
        Anonymous Coward

        Re: What's the use case for 100 Gbps wireless?

        You guys talking about copying terabyte disk images and "cross rack traffic" involving the home mark you pretty clearly as atypical use cases! I specifically said I wasn't saying NO ONE could benefit from 100 Gbps networking, but the typical PC user (high 90s percentage) doesn't and thus if it appears in the marketplace the price would be much higher than previous generations of wireless due to the very small addressable market.

        You might want it, but would you pay $1500 for a wireless router to get it? I suspect at those prices most of you would choose to make due with slower networking.

    3. Charlie Clark Silver badge

      Re: What's the use case for 100 Gbps wireless?

      100 Gbps is just for the headlines. Anything that increases the real throughput in any particular situation will have its uses. 100 Gbps is only 50 Gbps duplex with only two members of a network, in optimal conditions. Real world situations might be closer to 10/20 Gbps or less. Plenty of situations where that would be nice to have.

      WiFi is reaching the limits of its because of the bandwidth available at the frequencies at which it runs and contention with other networks. Research into alternatives is essential. And that is what this is: research.

    4. Filippo Silver badge

      Re: What's the use case for 100 Gbps wireless?

      The use case is when you have several users close to each other.

      1. Danny 14

        Re: What's the use case for 100 Gbps wireless?

        100gb is a fast link but im not sure I'd trust it as a SAN iSCSI (I suppose you could still have a 10gb backup link) even in a light guide (toilet roll tube?)

    5. Return To Sender

      Re: What's the use case for 100 Gbps wireless?

      As a callow youth I used to think on the same lines. Started networking with sub-Mbps networks, where yeah, faster would be nice, through Mbps, then 4, 10, 16Mbps (spot the tech), and by the time 100Mbps appeared it was 'why would you want 100Mbps to the desktop?'. Same sort of question with 1Gbps, of course.

      The answer is generally that most people, to begin with, don't need the higher bandwidth. But eventually, the ability to push high-bandwidth stuff around means apps appear which do exactly that. Then there's a killer (or at least ubiquitous) app that everybody uses and suddenly the big bandwidth connections start making sense.

      Actually, I suspect what makes more of a difference is not so much the bandwidth as the improvements in stuff like latency, which tends to make the 'feel' of things that bit nicer. Kind of an intangible for most end users. Add in rapidly falling cost and a decent bit of backwards compatibility and it's just easier to put the new stuff in. As I think others have pointed out, the headline speed is more of a hook for marketing; fairly pointless unless you also develop the techniques to exploit it fully.

      These days, I try not to think in terms of "what's the current use case?". If I can get the tech at a sensible price, the use case will probably turn up in due course, In the meantime, if all the extra tweaks improve my current usage, then that's a bonus to me.

  7. This post has been deleted by its author

    1. choleric

      Re: I can see it now...

      The thing is, I think that's a good idea and I would consider buying those curtains from you! But how many people do you know who have aluminium foil in their wallpaper and wire mesh on their curtains to keep the WiFi signal from escaping their home?

    2. JamesTQuirk

      Re: I can see it now...

      Wouldn't a blindfold be easier ? Maybe more dangerous, but ...

  8. thexfile

    Sharks with frickin 200 Gbps lasers attached to their heads?

  9. Down not across

    Stop or you'll go blind

    While such efforts often focus on visible wavelengths for data transmission – the “Li-Fi” development effort – O'Brien's team worked at the 1550 nm band familiar to the telco industry.

    Among other things, that provides access to off-the-shelf silicon for key components like the lasers. ® they're using lasers? Isn't that a potential safety issue if considered as Wifi replacement?

    You know someone will look into the transmitter or catch a reflected beam.

    Would work nicely for inter building link tho assuming buildings aren't more than 3 meters apart :-)

    Although heavy rain/snow/fog could cause some issues.

    1. choleric

      Re: Stop or you'll go blind

      Any laser system worth its salt can just up the power and burn through the fog and rain can't it?

      1. Anonymous Coward
        Anonymous Coward

        Re: Stop or you'll go blind

        "Any laser system worth its salt can just up the power and burn through the fog and rain can't it?"

        Certainly, but consider that fog/rain is highly variable. One second you're burning a nice clean hole thru the fog, an the next you're burning a nice clean hole thru the receiver.

        1. choleric

          Re: Stop or you'll go blind

          Sorry, I wasn't trying to make light of the problems.

  10. Neoc

    Biggest Problem with Li-Fi

    is the same reason why Wi-Fi appeared in the first place: all the so-called solutions to Li-Fi seem to require the receiver (laptop/pc/whatever) to be in a pre-arranged location... just like a wired solution. At least with Wi-Fi I can walk, move my laptop, check email on my phone wherever I am, etc... For everything else, I have cables in the wall, thank you (an advantage of being there with a box of blue cable when the house was being built).

    Until I can walk around unimpeded, Li-Fi sounds like the worst of both world.

  11. roger stillick

    my obsolete DirecTV system uses IR...

    from the controller to the NTSC settop box and coax to the hub... the current DirecTV is WiFi HD... will repl the boxes n sets w/ WiFi HD's this summer... the optical free space thingy was hosed from day one as my hard surfaced walls gave freespace multipath to the IR rcvr on the set top box (making sweet spots n dead zones).

    At work we tried IR connected laptops a long time ago n it was a joke, went back to the sneaker net or the Cat-5 test cable... couldn't use WiFi as we were afraid of spoofing a data stream.... ditto cell fones... Cisco, Alcatel, Nortel Networks stuff... metro ring mulispectral transport stuff...base rate oc-3, oc-12, oc-48 fiber cross-connect cabeling between stuff.

    IMHO= reality... a simple city telco comm center uses about 500 fiber cables fiber cables to hook all the stuff together... all at the same optical wavelengths, fiber is needed to avoid cross-talk... the proposed freespace system here might work as a CDMA headset n pad comm system but not much a possible replacement for Bluetooth... it would probably work just fine - for a single room.

    Note= Model railroaders have 2-way IR train controller systems, but, they need repeaters everywhere to keep in contact w/ engine as it travels over the tracks...RS.

POST COMMENT House rules

Not a member of The Register? Create a new account here.

  • Enter your comment

  • Add an icon

Anonymous cowards cannot choose their icon

Other stories you might like