back to article Hutchison's 3UK and Google push 3.5 GHz on both sides of the pond

Some are talking about 3.5 GHz as a 5G band, but Hutchison’s deal to acquire UK Broadband to bolster its 3UK arm is all about the good old fight for LTE spectrum. This deal shows that it is not just the US’s opening of its 3.5 GHz band, via its CBRS scheme, that has thrust this spectrum into the limelight. In many parts of the …

  1. Mage Silver badge
    Flame

    3.5GHz

    It's been used by FWALA licence holders for 12+ years in Ireland.

    One company used nomadic indoor terminals instead of outdoor aerials and had the most rubbish service.

    Mobile was tested 10 years ago by Intel, Motorola and various ISps. Rubbish. The frequency is too high. One company went to indoor WiMax to replace the older gear, then LTE. It's still rubbish because the frequency is too high.

    The 3.5GHz band is only good for open plan office Femto cells or fixed outdoor aerials using "nearly" line of sight.

    Basic physics that no "5G" marketing can bypass.

    1. Commswonk Silver badge

      Re: 3.5GHz

      I am equally baffled about the enthusiasm for ever higher frequencies into the GHz regions. Quite apart from the increasing "line of sight" characteristic there is also the point that for a portable transmitter to generate "x" mW of output power at 3.5 GHz requires a lot more primary power than one generating the same x mW at 800 MHz, and for primary power read "current from a small battery". On top of which the path loss over the same route (not the same as being "line of sight") is greater at 3.5 GHz than at 800 MHz and so on; I cannot be bothered to work it out but an additional loss in the region of 10 - 12 dB seems likely. As the result the maximum distance between cell and phone shrinks alarmingly.

      I suppose all this "expansion" is to satisfy the burgeoning demand for mobile data rather than simple phone calls and texts, but I cannot get away from the thought that this "demand" is little more than an addict's craving for their next fix rather than anything really essential.

      1. Ogi

        Re: 3.5GHz

        > but I cannot get away from the thought that this "demand" is little more than an addict's craving for their next fix rather than anything really essential.

        That is most likely exactly what it is. Turns out however, that charging addicts for their fix is really really profitable. Coupled with ever increasing population density in urban areas, it makes sense they would want a shorter range, higher bandwidth spectrum. Just the kind of thing if many people want to get their fix at the same time from the same base station, yet within a small distance of each other.

        Might also be good for point to point backhaul links.

        1. Mage Silver badge
          Flame

          Re: 3.5GHz

          If it was really about demand, then increasing capacity and speed by adding more base stations, having smaller cells etc. But the ROI investment isn't there unless they charge per Mbyte per hour.

          They don't need ANY more spectrum outside 900MHz to 2,600MHz ( 0.9GHz to 2.6GHz).

          It's driven by regulators wanting to sell licences.

          1. Ed_UK

            Re: 3.5GHz

            "If it was really about demand, then increasing capacity and speed by adding more base stations, having smaller cells etc."

            Indeed. That's why the femtocell makers are getting tooled up for 3.5GHz.

            1. ARGO

              Re: 3.5GHz

              Yup, and also why lots of local authorities are busy writing contracts to stick the things on lamp posts.

              The main problems seem to be handling backhaul from such sites (not many street lights being equipped with fibre) and the lack of 3.5GHz support in handsets.

        2. Mage Silver badge

          Re: 3.5GHz

          Higher than 2.2GHz up to 400GHz is ALREADY used for backhaul, in some cases since 1970s! Were fibre can't be justified, which is actually rare. The licence on microwave link is expensive, it's ONLY LOS and very much less than fibre capacity.

          1. Commswonk Silver badge

            Re: 3.5GHz

            it's ONLY LOS and very much less than fibre capacity.

            On top of which as the frequency increases the attenuation due to rain and snow becomes more of a problem, necessitating a rather large fade margin being built in to the links, which can be difficult with the small parabolic reflectors commonly encountered.

            From the original article (AT&T) wants to conduct these tests in suburban and rural environments in the California Central Valley including locations around Fresno and Bakersfield. The aim is to collect continuous wave (CW) data for a propagation modelling study, evaluating path loss characteristics in outdoor environments in these midrange and high bands.

            All well and good (if it didn't rather point towards the cart being in front of the horse regarding the use of ever higher frequencies) but results obtained in the California Central Valley may well not apply in areas of greater precipitation. IIRC California is a pretty dry State (to the point where some parts are positively arid) so any conclusions drawn may not be universally applicable.

            I wonder how many technical staff the MNOs actually employ, or if it's all down to marketeers...

          2. Ed_UK

            Re: 3.5GHz

            "Were fibre can't be justified ..."

            That's people who turn into fibre on a full moon?

    2. Ed_UK

      Re: 3.5GHz

      "The 3.5GHz band is only good for open plan office Femto cells or fixed outdoor aerials using "nearly" line of sight."

      Good points, having the backing of reality. I mentioned femtocells in another post. Nice that Cisco refers to a femtocell access point as a FAP.

      Lucent and Nortel were building wireless local loop (WLL) fixed radio at 3.5GHz back in the late 1990s.

  2. Kay Burley ate my hamster

    Had to look up SaS

    'What’s different about CBRS is that mobile network infrastructure makes a request for spectrum from a Spectrum Allocation System “SAS” that connects to a database that manages overall licensed usage.'

    http://www.spidercloud.com/cbrs

    1. Commswonk Silver badge

      Re: Had to look up SaS

      I found the entire article something of a buzz - word / acronym rich environment, to the point where the will to live was flagging quite significantly. And then I made the mistake of looking at the "CBRS Alliance" front page:

      MISSION

      *Evangelize LTE-based CBRS technology, use cases and business opportunities

      *Drive technology developments necessary to fulfill the mission, including multi-operator LTE capabilities

      *Establish an effective product certification program for LTE equipment in the US 3.5 GHz band ensuring multi-vendor interoperability

      I am now palpitating and breathing into a brown paper bag. To answer my own question from earlier on... "marketeers".

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