UK Scientists Claim 1Tbps Data Speed Via Experimental 5G Technology

Mark.JUK writes A team of Scientists working at the University of Surrey in England claim to have achieved, via an experimental lab test, performance of 1Tbps (Terabit per second) over their candidate for a future 5G Mobile Broadband technology. Sadly the specifics of the test are somewhat unclear, although it's claimed that the performance was delivered by using 100MHz of radio spectrum bandwidth over a distance of 100 metres. The team, which forms part of the UK Government's 5G Innovation Centre, is supported by most of the country's major mobile operators as well as BT, Samsung, Fujitsu, Huawei, the BBC and various other big names in telecoms, media and mobile infrastructure. Apparently the plan is to take the technology outside of the lab for testing between 2016 and 2017, which would be followed by a public demo in early 2018. In the meantime 5G solutions are still being developed, with most in the early experimental stages, by various different teams around the world. Few anticipate a commercial deployment happening before 2020 and we're still a long way from even defining the necessary standard.

Comments

That's Your 2GB cap in 0.9375 seconds

[Shakrai]

Not counting TCP and other protocol overhead of course.....

Overlooking one small detail...

[__aaclcg7560]

You can deliver more wireless bandwidth to users. Are you willing to pay big bucks to upgrade the backend equipment (i.e., routers and switches) for more bandwidth?

*crickets*

Re:Overlooking one small detail...

[Archangel Michael]

Hell, certain "High Speed Internet" providers aren't even willing to apply a 10GB Fiber from one rack, to another, to help their users get content faster.

http://qz.com/256586/the-insid...

I remember seeing an interview with someone at Netflix, which basically said "Comcast has the bandwidth to carry all Netflix traffic, without issue. Netflix has the bandwidth to carry all the traffic requested by Comcast customers to Comcast, without issue. We have the capacity, they have the capacity, and if they need networking equipment so we can add a 10GB connection from our rack to their rack (at the COLO) we're willing to buy everything needed. They just won't do it"

Re:Overlooking one small detail...

[allquixotic]

Also, 100 MHz is *a lot* of spectrum to allocate to a single client, given the amount of spectrum that's currently available. They'd have to free up a lot of old spectrum that is used for obsolete stuff like 2G voice and 3G data, so that they could repurpose the spectrum for 5G. The only way they'd be able to pull this off, realistically, would be to increase tower density. 100 MHz is just too much to ask. Typical LTE bands have 1.4 MHz to 20 MHz allocated to a given LTE client; this increases that by a factor of 5 for the largest-width LTE deployments today, and by a significantly larger factor for LTE running on narrower widths.

We can't just manufacture more bandwidth. Once the usable spectrum is allocated for something, we have to either wait until that technology goes obsolete and deallocate and repurpose it, or invent newer and better transceivers that can reliably transmit and receive over a previously unused range of frequencies (factoring in problems like building penetration, which gets harder at higher frequencies). Absent such advances in transceiver technology, we are stuck using the finite bandwidth ranges we have today -- at least for long distance cellular.

So, while it's quite plausible to think they could allocate 100 MHz for this technology, maybe even as much as 500 MHz of spectrum for it, there would only be enough spectrum for a lot fewer clients at a time for each tower, compared to what we can do today.

Problem is, there will be people who are perfectly happy with their 3G or 4G devices and resist upgrading, who want to remain customers under their current contract and continue to use the service already available. These folks are going to give carriers the motivation to retain their existing spectrum for the legacy protocols, inhibiting its repurposing for the next generation. It may be 50 years before the regulators officially announce, say, the 700 MHz LTE band to be free for a new auction.

2020 seems to be very aggressive to me, mainly for policy reasons, not so much technical reasons.

Re:Overlooking one small detail...

[BronsCon]

divide that 100Mhz channel into 1000 1ms time slots (or 10000 100 microsecond time slots and allow 1000 users 10 apiece, or keep dividing into smaller slices as the technology allows, to reduce latency) and provide 1gbps to 1000 users. Or 10000 1ms slots, to provide 100mbps to 10000 users.

At the 1gbps per user level, that's a little less capacity (without overselling) than current towers, considerable more if oversold at current rates. At the 100mbps level, that's insanely better coverage in high-population-density areas, as each channel can handle 10000 simultaneous users without overselling, closer to 20k if oversold. At which point, interference becomes an issue and you have 20k users on the channel, each getting 10-20mbps; which is a huge improvement over the current situation during a conference, where the most anyone is lucky to get is a few kbps, due to radio interference, while the hard line running to the tower sits there mostly unused. It's not even a matter of the tower not having a large enough pipe to the network, the radios can't keep up with demand, so the pipe largely goes unused in these instances.

Question! Shouldn't multiplexing be priority?

[goruka]

I'm not an electrical engineer or anything close, but I live in a developing country and notice that the biggest problem here is not 3G or LTE speed (which just works fine everywhere) but that when a zone gets a little crowded, even if the signal strength is high, connectivity drops to E and stops working.

Is this a problem that the specification does not allow more than a certain amount of frequencies per antenna and more are needed? As in, If it's so easy to saturate an antenna, shouldn't the extra frequencies, speed and bandwidth be used for allowing more connections instead first?

Re:Question! Shouldn't multiplexing be priority?

[mlts]

Ideally, it should do both. One device would have an extremely large amount of bandwidth to play with if in range of the tower, but as more devices get handed off to the tower, there is less bandwidth per device, but all devices get some level of service until a threshold is reached where the tower cannot accept any more items, where even EDGE or GPRS speed cannot be maintained. This is especially important at sporting events or SXSW where there are tens to hundreds of thousands of people in one space. Assuming the tower has terabits of bandwidth available, it should at least provide 3G coverage, decent enough for people to pop selfies and upload them or tweet about how badly the band on stage sucks.

Re:Question! Shouldn't multiplexing be priority?

[tlhIngan]

I'm not an electrical engineer or anything close, but I live in a developing country and notice that the biggest problem here is not 3G or LTE speed (which just works fine everywhere) but that when a zone gets a little crowded, even if the signal strength is high, connectivity drops to E and stops working.

  Is this a problem that the specification does not allow more than a certain amount of frequencies per antenna and more are needed? As in, If it's so easy to saturate an antenna, shouldn't the extra frequencies, speed and bandwidth be used for allowing more connections instead first?

Most likely the control channel gets overloaded. It's the problem AT&T had when the iPhone came out - the iPhone was very aggressive with power management which resulted in it basically setting up and tearing down data connections on an almost per-tcp connection basis. This results in control channel overload, and other devices can't access it when they need it - perhaps when doing a handoff. The end result is the call drops because the phone can't establish communications with the next cell in time. And there is no relation to a cell's load level and its control channel load level - AT&T found that while the control channel was overloaded, they still had plenty of data and voice channels available - resulting in the worst performing carrier having the best data speeds.

The control channel is used to set up and tear down links (voice channels, data channels), perform handoffs, handle SMS, etc. In crowded places, this can easily be overloaded - most providers set up additional micro-cells in densely populated areas to prevent this.

Your phone is likewise seeing the same problem - it can't establish a 3G connection with the tower (overloaded control channel), so it falls back to 2G (which uses a different set of bands and thus has its own set of control channels) which are far less crowded where it can obtain service. Hence the "E" (stands for EDGE).

Re:Question! Shouldn't multiplexing be priority?

[kaiser423]

It already is multiplexed, via multiple access schemes. You typically see 3 antenna sets arrayed on a cell phone tower. Each of those typically operates at a different frequency set so that they don't interfere. Then in each of those coverage ares you're typically multiplexed via TDMA, or you're given time slices in which to communicate. There's only so fine that you can dice up time before either your calls get choppy, or not everyone in the cell can get synchronized enough to communicate effectively. Over the last couple of years, you've seen cell providers rolling out more and more stringent timing requirements to their sites, so that they can reduce the guard-time between slices and also ensure that all phones/devices are synced up better so that they make better use of their actual time slice.

There's definitely more to it than that in a typical cell site (including other ways to add more users), but at some point you have to deal with physics. You have a certain amount of bandwidth at your frequency to use, and no matter how clever you get, there are thigns like noise, interferers, limitations on the sophistication of hardware you can put at cells or in phones, the laws of physics, etc. You hit hard limits pretty fast. One of the main reasons Verizon and some of the US networks went to CMDA was that at the time you could pack in more users per channel, because you weren't limited by timeslices, you were limited by SNR (more users effectively increased the noise floor since their codes wouldn't correlate), so you could get some pretty impressive numbers of users per cell, making deploying a network cheaper. Newer 4G and advanced 4G waveforms are kind of an interesting combination of an optimized waveform that's TDMA based, but has some similar features to other networks.

This high speed is relevant, because you usually can use some of the techniques to divide up the bandwidth effectively to get more users per cell -- you can have smaller timeslices to transmit if the amount of data you can transmit in that timeslice is massive. The maximum amount of data passable over a link is kind of an industry standard metric for how much capacity a given channel can handle. It's easier to grok than channel capacity, etc

TLDR: We're trying our damned best to multiplex as many users as possible into a cell site. The more that you can get in one site, the cheaper it is to operate and deploy networks, so tens of millions of dollars annually is spent making it better, and the strides that have been made are pretty darn impressive. But we still have work to do!

or $1.5-2 M in roaming fees in a second

[Anonymous Coward]

or $1.5-2 M in roaming fees in a second but let's say it takes up till 1 hour for you to get cut off you have a 1B+ data bill how are you going to pay that off?

Only 100 meters

[ITRambo]

This will be a breakthrough when they can get their desired 5G speeds at 15 kilometers, or greater distances. Until then it's only PR.

Re:Only 100 meters

[phoenix_rizzen]

Only 100 MHz, and using 100 MHz of spectrum. Most carriers in North America are lucky to have 10-20 MHz of contiguous spectrum, and maybe 40 MHz total usable spectrum in a specific area. Good luck finding 100 MHz of spectrum to use anywhere other than lab conditions.

Would be nice if they worked on increasing the number of bits that can be transferred per MHz of spectrum, instead of increasing the amount of spectrum required to send the bits.

Re:Only 100 meters

[Archangel Michael]

I live in a city, and can go from full bars to no coverage in about 1/2 mile. (1KM). There are notorious dead zones in the middle of the city, because the city regulates cell towers, making cell service unusable in large swaths of town.

Yeah, it is that bad.

Not even close

[fisted]

1 Tbps = 1e12 bit/sec
2 GB = 8*2*2^30 = 2^34 bit
2^34/1e12 ~= 0.017 sec

Re:Not even close

[Shakrai]

Sure, if you're using a burst transmission that doesn't wait for acknowledgments or the TCP window size to be set. My calculation totally took those variables into consideration. It's not as though I misplaced minutes for seconds or anything that stupid, it's not like that at all. :)

Re:Mod Parent Up

[serviscope_minor]

I think this busts the physics, unless I misunderstand completely. Paging Dr. Shannon...

Nope.

Think about baseband for a moment.

Let's say you hae a bandwidth of 100MHz.

You can basically change from 0v to 1v 100e6 times per second, giving 100Mbit/s.

But you can also introduce more symbols. If you have 10 voltage levels between 0 and 1 V you get 1Gbit /s.

What limits the number of symbols is noise. The datarate is symbol rate * bits per symbol. In the absence of noise, you can transmit an infinite amount of data in a 1Hz channel.

For non baseband signals, they generally use QAM to get symbols spanning the whole phase space around the centre frequency.

Re:How do you get 1Tbs in 100MHz of BW?

[kaiser423]

You make multiple measurements, and you get more fine grained measurements. Originally you had on/off keying (AM modulation). On = 1, Off = 0. You had FM modulation, where +freq = 1, -freq = 0. It's easy to see how to make either of those better -- for on/off keying, a simple amplifude modulation. Full power = 11, 2/3rd power = 10, 1/3 power = 01, off = 00. Boom, double the bit rate in the same amount of bandwidth (technically, potentially a little bit less if you do things right). You can see how you can infinitely divide that -- you can track 4, 8, 12, 16 power levels, etc. You can do the same thing with the phase of the carrier -- change phase by half phase intervals, or quarter, etc. Then you can combine the two and end up with a constellation of points, which is basically QAM. You see QAM-16 (16 discrete phase/amplitude points), QAM-64, QAM-128, etc.

Now, if you've been thinking about implementation details, you realize that the fundamental question is: "how do I know that I'm at half power instead of full, or my phase has changed?". Well, there's basically a synchronization period -- you listen to the stream for long enough to kind of know where you are at. Some streams also send synchronization patterns periodically. The next issue then is "what happens when my signal fades, or my signal bounces and the phase gets screwy". The answer then is in algorithms and multi-hypothesis guesses as to how the channel medium is acting. Lots of math there, but no matter how good you get more highly advanced tighter packed schemes are going to be more vulnerable to things like signal fades, etc and then also take more time to get back up to speed because you need more symbols flying by you to sync up to where you are at. But you can push them at a higher rate, so you gain some of that back. You end up wit ha constellation that you synchronize to, and then to make it more complex, Fourier tells us that if the bigger phase/amplitude change you have per bit period, the more bandwidth you occupy. So, actually, sub-dividing the phase/amplitude helps you generally occupy less bandwith, but you can also get tricky where the constellation is adaptive in such a way that you minimize amplitude/phase changes for each bit set transmitted, making you occupy even less bandwidth. But that's one more thing for the receiver/transmitter to keep in sync....

As you can see, this gets incredibly complicated quickly. It's a very math heavy field, with lots of very neat, clever tricks to make it all work seamlessly. These guys just figured out how to maintain coherency, etc at higher frequencies, which is fairly notable, but this march is expected to carry on as we get faster processors, higher performance amplitude/phase modulators, and low noise devices we can keep packing those bits tighter and having more points on the constellation.

Re:Mod Parent Up

[ledow]

Cat5 cables is only aimed at 100MHz signals, but you can put Gigabit Ethernet over it.

The number of bits sent does not have to be less than the frequency of the carrier (or even half that).

Phase, amplitude, frequency-modulation, plus others, all combined allow you to get a lot more out of the signal than merely the carrier frequency rate.

Otherwise your old 56Kb/s modem of old would never have got to that speed, your DSL modems wouldn't come close, your wifi would be nothing more than a radio modem, etc.

Hasn't been true for decades, and with multiple antenna etc. tricks you can do even more.

Re: Mod Parent Up

[ledow]

There are four twisted pairs. Assume they are 100MHz each. That's only 400MHz (800 if you think the other one of a pair does anything (*)). Yet you push 1000Mbits a second over it (and, yes, that's the actual speed) .

How? PAM, QAM, and a bunch of other tricks - because you think you need an entire cycle/wavelength in order to encode a single bit of information, which just isn't true.

(*) it doesn't - the other half of the pair allows you to subtract interference received along the same route by an equal length cable. Much like MIMO antenna differencing.