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back to article LTE-U’s window is closing and bigger 5G disputes may be coming

One of the presumed outcomes of the 5G process is full convergence of licensed and unlicensed spectrum, with one or more air interface standards which can span both, using frequencies entirely flexibly according to requirement. This is a very long way off, if the current quarrels over extending LTE into licence-exempt bands are …

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  1. Mage Silver badge

    Not consumer friendly

    Fuelled by greed to (eventually have no WiFi in Mobes and) use paid Mobile access over WiFi Frequencies.

    ANY convergence (i.e. call / connection handover) between Licensed and Unlicensed spectrum should only be using EXISTING WiFi or BlueTooth. Mobile Pico and Femto cells MUST use licensed spectrum. That was working 8 years ago.

    Unfortunately many regulators (Ofcom, Comreg) are only interested in looking after big Telcos. See Regulatory Capture.

    2 0 Reply
    1. Anonymous Coward
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      Anonymous Coward

      Re: Not consumer friendly

      No, I don't agree.

      This isn't about dropping wifi from phones (carriers sell fewer and fewer phones now that they aren't on contract, so how's that even going to work?) but about not spending more money buying licensed frequencies. Instead of spending tens of billions in the upcoming 600 MHz auction in the US, they want to say "screw that, we'll use all this free spectrum instead".

      There would certainly be a lot of egg on the FCC's face if we went through this whole process to get TV stations to move their frequencies or sell their licenses entirely to clear TV channels 31-51, and then none of the big cellular players showed up because they decided they'd rather save that money and use unlicensed spectrum for free.

      I'm sure we'd see some discount plans / carriers evolve that used the unlicensed spectrum as much as possible, and offered only minimal speeds on licensed spectrum to keep it clear for customers willing to pay more. The unlicensed bands would quickly become so crowded as to be useless, and if they didn't share well with wifi then those bands would be useless for wifi in many places as well!

      2 0 Reply
  2. Frederic Bloggs

    Why use 5Ghz?

    Obviously "because it's free" or at least likely to cost some negligible amount (compared to the $86 billion the FCC thinks it's going to get for its next round of spectrum auctions). And they "need" the spectrum. Bugger the current users. They have no ownership "rights". They have no "economic power", or more accurately "regulatory mindshare".

    There is a distressing tendency for hard pressed civil servants, who are generally intelligent and well meaning but have insufficient domain knowledge, to need to rely on "industry partners" to help them "think". Anyone who has been on one of the DoT wireless related study groups or the TAG will have seen this in action.

    There has to be a real shift in Civil Service recruitment and training to address this. But how it is to be achieved is moot, especially for acquiring comprehensive knowledge without compromising independence. Can't say I am hugely optimistic. Sadly, the way the US equivalent works with its built in political cycles, stands no chance.

    It truly is a pity that the US still seems to succeed in styling itself "leaders of the free world", because "free" in this context means allowing big US money to determine what the rest of the world has to put up with.

    Hands off our WiFi spectrum.

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  3. Down not across

    Fuck off LTE-U

    It is sadly easy to see, in the current 5 GHz rows, glimpses of the likely debates which will risk delaying or derailing full 5G platforms in the 2020s. The latest outbreak of hostility over LTE-U enters on a testing plan, proposed by the Wi-Fi Alliance, and more specifically over signal strength thresholds. LTE-U is, of course, particularly controversial because it does not have to support listen before talk (LBT), which is required for coexistence in the 5 GHz band in many parts of the world, but not in the US. LTE-U uses carrier sensing adaptive transmission (CSAT) instead.

    Not sad at all. Hope it gets derailed lot longer than that.

    Just we got slight improvement to the WiFi situation with 5GHz (whereas in most populated areas 2.4GHz is utterly swamped), here come telcos not being content with their paid for spectrum but want the "free" one too.

    At least in Europe LTE-U has LBT, but that does not mean it wouldn't still have an impact.

    Here is blurb from Qualcomm:

    1. Channel Selection: LTE-U small cells always try to select a clean channel to avoid interference with nearby nodes, based on continuous channel measurements. Considering that multiple 20 MHz channels are available in 5 GHz, channel selection is very effective in low to medium density scenarios.

    2. Time-domain coexistence techniques are needed when there is no clean channel available. Based on unlicensed band regulations in specific markets, there can be multiple techniques to share the channel fairly with Wi-Fi. For non listen-before-talk (LBT) markets such as the US, South Korea, China and India, CSAT (Carrier Sensing Adaptive Transmission) can be used without changing Rel-10 Carrier Aggregation protocols for co-channel coexistence. For LBT markets such as Europe and Japan, Rel-13 LAA will enable channel sharing with Wi-Fi by performing clear channel assessment (CCA) based channel availability sensing and adapting the transmission duration on a fine timescale, ranging from 1ms-10ms. Both solutions achieve co-existence through adaptive on/off transmission based on channel utilization measurements. The choice between the two options will depend on the regulatory requirements in a specific region and time-to-market considerations.

    3. Opportunistic SCell operation: In LTE-U, unlicensed carriers are designed to operate as secondary cells (SCells), with the principle that LTE-U small cells would release the unlicensed carriers and fall back to the anchor carrier in licensed spectrum at low traffic load.

    Coexistence performance has been thoroughly studied by Qualcomm and other companies with numerous simulation results showing that LTE-U can provide higher spectral efficiency and better user experience while maintaining the performance of neighboring Wi-Fi users.

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  4. Fazal Majid

    Carriers trying a spectrum land grab

    Obviously they'd love to enclose the commons for their own benefit. That's why Israel is considering banning the use of unlicensed spectrum by carriers:

    http://disruptivewireless.blogspot.com/2013/06/is-israel-about-to-ban-carrier-wifi.html

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    1. Anonymous Coward
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      Anonymous Coward

      Re: Carriers trying a spectrum land grab

      That's something different, the article you linked is talking about carrier wifi offload - that is, if you are in a coffee shop with AT&T (insert the name of a popular cellular carrier in Israel here) sponsored wifi, carrier wifi offload means your phone will make the call via wifi using that AT&T wifi access point.

      What the Reg article is talking about is using wifi frequencies for cellular traffic. That is, they won't be using wifi protocol to talk to nearby wifi access point, it will use cellular protocol to talk a cellular base station. Exactly like it does now with cellular frequencies, except it will use the same frequencies your home wifi uses.

      Carrier wifi offload has traditionally referred to using these carrier owned wifi access points to offload data. Calls/texts would still go through the traditional mobile network - though now that phones are supporting wifi calling even voice traffic could be offloaded. However, there's little incentive to do so as calls/texts account for such a small percentage of overall usage that this really isn't worth doing if your problem is overloaded networks.

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      1. Anonymous Coward
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        Anonymous Coward

        Re: Carriers trying a spectrum land grab

        >>carrier wifi offload means your phone will make the call via wifi using that AT&T wifi access point.

        I don't know about the Israeli carrier's subscribers or handsets but for the AT&T customer its only true that it will do that if you have a phone that supports wi-fi calling. There are 15 handset models they sell which do, including the iPhone 6 onward, but its still a relatively new thing and something I'd be very careful with anywhere considered overseas because their international roam per minute rates are insane.

        0 0 Reply
        1. Anonymous Coward
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          Anonymous Coward

          Re: Carriers trying a spectrum land grab

          No, wifi calling is something different - as you say support for it is still pretty spotty. Carrier wifi offload works for data only, but has been around for years.

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