5G industry news Technologies | Devices & Sensors

Innovation Briefing Issue 6 | Band 3

  • 2 minute read
  • Published by Crispin Moller on 22 Sep 2021
  • Last modified 16 Sep 2021
On the face of it, band 3 would seem to be the most attractive of the shared-access spectrum bands. The 1800MHz frequency is an anchor band. Pretty much all devices support it.

Peter Gradwell

Article by Peter Gradwell, Chief Commercial Officer, Telet.

Band 3 was the launch band for One2One, which became T-Mobile and now is EE, and for Orange, also now EE. At the time, in 1994, there was concern that the new mobile technology would interfere with DECT, which was a standard spectrum for digital cordless phones at around 1900MHz.

So, a gap was left between the top of the mobile and the bottom of the cordless spectra. This was known as a guard band. Over time, it was found that Ofcom had been a little too cautious, the two technologies didn’t interfere and therefore some of that spectrum could be used. The mobile operators each had 5.6MHz of bandwidth but there was 5MHz between the top of what they used and the bottom of the DECT frequency. It was decided that a 3.3MHz section between the two could be used.

In many ways, this was the first foray into shared-access licence spectrum. Ofcom sold ten licences for ten years at auction. Each successful bidder was told that they had to work with the others to avoid interference. None of the operators that bought these licences have done anything particularly exciting. One, Coffee Telecom, was acquired by Talk Talk; another is used by BT for its OnePhone service. BT bought another of the operators and so had two licences for the same thing.

At the end of the ten years, the guard band morphed into shared-access licence spectrum. Anyone can apply to use it but the biggest challenge is finding equipment that supports 3.3MHz, as the minimum supported in most Qualcomm chips is 5MHz. The narrow spectrum also means that an internet connection will always be too slow for anything but the lightest of users. One person with a cell to themselves might see 6Mbps.

For 5G deployments, the value of band 3 is to have it running alongside other spectrum. Devices will latch onto band 3 and can then be re-directed to band 77 or where-ever. It’s also useful to run band 3 as 2G GSM and to use it to handle voice calls for devices that cannot carry voice over 4G or 5G.