• NeoNachtwaechter@lemmy.world
        link
        fedilink
        English
        arrow-up
        22
        arrow-down
        1
        ·
        edit-2
        1 年前

        2G defines basic mobile services, for example telephone or SMS.

        3G, 4G etc. added internet to it, but there they are interchangeable. Each new one replaces the former if you use only the internet service. But none of them replaces 2G fully.

        • InvertedParallax@lemm.ee
          link
          fedilink
          English
          arrow-up
          2
          ·
          1 年前

          It’s more that all should be backwards compatible, so if you have 5g then you still have 2g and it gives you the bare minimum voice and some scraps of data.

          They can reclaim all the spectrum for 3 and 4g (which is a lot) for 5g, while leaving some of the barest functions working for stuff that doesn’t need real data.

          • grayman@lemmy.world
            link
            fedilink
            English
            arrow-up
            10
            ·
            1 年前

            You can read in the spec why they chose not to be backwards compatible. The cons were too great.

            • InvertedParallax@lemm.ee
              link
              fedilink
              English
              arrow-up
              7
              ·
              1 年前

              5g low band actually does, they have down to 600mhz bands which are crazy low with tons of noise shaping, mimo, beamforming and other stuff to potentially bump the snr.

              They’re looking to add 400mhz bands for even more range, but the low bands have less capacity.