back to article All those new '5G standards'? Here's the science they rely on

The 5G arms race has commenced, but beneath the duelling “my 5G is faster than your 5G” demos, there's serious work going on – and whatever the future of 5G, that work will change the future of mobility one way or the other. With that in mind, The Register spoke to Professor Eryk Dutkiewicz of Macquarie University. In May, …

  1. frank ly

    re. small antennas

    Doesn't a physically smaller antenna 'extract' a smaller amount of power from the incident field, thus leading to lower S/N ratios etc.? Maybe they use arrays, and other clever techniques. Waits for an expert .......

    1. JeffyPoooh
      Pint

      Re: re. small antennas

      I'm not sure that I qualify as an expert, but...

      A long time ago, there was an April 1st article about bouncing radio signals off the Moon (Earth-Moon-Earth, EME), a sub-hobby (seriously) filed under Ham radio. EME is normally done at UHF and above, using large antennas and high power. The author of the article noted that pathloss went down with lowering the frequency and he thus concluded that Moonbounce should be attempted at the lowest possible Ham frequency, 160m or 1.8 MHz. The punchline was "Fewer wavelengths to the Moon." Funny. Sort-of.

      Same sort of thing really. Yes, there's an element of truth in your point; but there are other factors at work.

      The pathloss equation is informative. Path Loss (dB) = 32.45 + 20log(km) + 20log(MHz).

      LNA Noise also tends to go up with frequency. So, using the upper end of the radio spectrum *is* very challenging in the SNR department, but there's plenty of space for wide signals and Coding gain. Etc.

    2. Anonymous Coward
      Anonymous Coward

      Re: re. small antennas

      Yes, which is why path loss rises with increasing frequency. If you are only interested in small ranges then this actually helps with interference mitigation, but of course you need enough link budget to make your applications work within the serving cell.

  2. A Non e-mouse Silver badge

    Where to put the intelligence

    If memory serves, when they were designing the early mobile phone networks, they put a lot of the control of cell handover into the mobile phone itself. This was because working out which cell was best for the handset was hard for the network to figure out, whereas the handset could tell much easier.

    It seems like they're coming across the same problem with spectrum sharing: It's hard for the network to know what's best for the handset at it's current location.

  3. Dave Ross

    So, 4G is barely available outside major UK cities (and pretty scarce inside some of them) and we are already talking about 5G. Well, good luck on the rollout of that given how well the 4G rollout is going so far.

    1. Anonymous Coward
      Anonymous Coward

      4G?

      On EE I'm sick of seeing G and E icons - 3G would be a luxury!

      1. A Non e-mouse Silver badge

        Re: 4G?

        Even decent 2G GSM coverage would do!

        1. Anonymous Coward
          Anonymous Coward

          Re: 4G?

          Where I live in the US, we got LTE about a year ago, before that it was HSPA+. I thought that was plenty fast enough, and don't really care if I've got that or LTE. HSPA+ is more than fast enough as far as I'm concerned.

          Hopefully 5G is more concerned with increasing the total bandwidth available per tower/cell than it is increasing the bandwidth for an individual user. Talking about getting hundreds of Mbps is all well and good, but what's the use case? I suppose getting 500 Mbps to my phone is good because it takes a slightly smaller fraction of a second to download a 1 MB image on a web page so someone else can have their turn, but increasing per device bandwidth shouldn't be the focus.

          The real limiter in a lot of places will be the network connectivity to the tower. If your cell can serve 500 Mbps to dozens of devices simultaneously it isn't much good unless you have a multi gigabit link to the tower to feed it. Otherwise it is all a rather pointless exercise.

  4. JeffyPoooh
    Pint

    Software Defined Radios will be part of all this...

    SDR technology provides some useful flexibility, but beware. The processing requirements of each new generation of advanced waveform swamp out the hardware capabilities of the previous generation of SDR hardware.

    If someone marketing SDR products promises that your hardware is SDR and "will therefore be future-proof", then just punch them square in the face.

    SDR is no more future-proof than your PC or smartphone.

    1. A Twig

      Re: Software Defined Radios will be part of all this...

      Agreed, what's sold as SDR now is effectively a hybrid, with a good chunk of the "work" done in the software domain, but still a good few hardware components (switched band pass filters etc).

      True SDR (where the receiving antenna is just dumping everything into a software package via an ADC and the converse for the transmitter) will require some serious computing heft and a bloody good ADC / DAC (very high rate and accuracy). The technology isn't anywhere near there yet.

  5. Dan Paul

    The higher the frequency,...

    the lower the range. Doesn't cell phone service suck enough? Sure, maybe you can get blazing speeds but without an effective range, the phone may as well be useless.

    1. Queasy Rider

      Re: The higher the frequency,...

      Being a non-tech type, reading this article made me feel their goals were impossible to achieve, although I expect them to succeed eventually.

      As for range vs. speed, I wish they would give good range spectrum priority to voice

      and whatever spectrum is left over to data. If you want to watch movies, listen to music or work on spreadsheets during your daily commute, download that shit before you walk out the door. And browse Facebook at work like everybody else does. I use my phone as a phone. YMMV

      1. Henry Wertz 1 Gold badge

        Re: The higher the frequency,...

        "As for range vs. speed, I wish they would give good range spectrum priority to voice"

        VZW does this -- if they have 800mhz and 1900mhz spectrum, they run all their CDMA 1x (voice) at 800mhz. They only run any EVDO (3G data) on 800mhz if they have room, otherwise they run it all at 1900mhz. LTE did end up at 700mhz but it doesn't really reach further than 800mhz CDMA (plus, who wants to deploy CDMA on brand new bands in this day and age?)

  6. Henry Wertz 1 Gold badge

    Cognitive radio...

    The big problem cognitive radio, this is another angle at trying to use "whitespace" radio spectrum. This is tricky! Intel and Microsoft went to demo a whitespace radio setup a few years ago that they were assuring everyone would do a great job of picking up signals and not stepping on them. It basically didn't work at all. Why? The relatively small antennas in the base and the mobile devices were not picking up a signal that was in fact there and they stepped all over it. Thus the current solution of expecting all devices to do a database lookup before they can use a particular (potentially licensed) chunk of spectrum. I pick up my stations from about 60 miles away, the last thing I need is some phones not picking these up at all and stepping all over my shows. The mobiles do not have a directional, high-gain UHF antenna in them so I don't expect they could detect there's a signal at all; the base may be able to if it's reception threshold isn't set too low.

  7. DerekCurrie
    Unhappy

    So where's REAL 4G already? Nowhere.

    Thanks to Marketing-Speak, high end 3G (LTE) is called '4G' to the public's face. Meanwhile, referring to the REAL 4G standard, I'm unaware of anywhere in the WORLD offering actual 4G. Once we have what's formally called LTE Advanced, we'll have real 4G.

    Meanwhile, I've been seeing ridiculous references to '4.5G', which of course also doesn't exist IRL. And now we have a proposed 5G standard. Excellent! But first we have to get the Cheap, Lazy, Stupid mobile phone service providers to upgrade to REAL 4G. So what's the hold up?!

    1. Smitty Werbenjaegermanjensen
      Holmes

      So what's the hold up?

      $

      That is all.

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