Ten years ago, Bluetooth tethering was a big thing and the only option to wirelessly tether a notebook via a phone to the Internet. How things have changed since then…
As I noted in a blog entry from back in 2007, Bluetooth 2.0 was just about fast enough to support the 3G data rates of the day but would not be near enough once higher data rates with HSPA+ would appear in devices and networks. Fortunately Wi-Fi tethering came around the corner with Android a little while later. But it didn’t take long and even the then prevalent Wifi 802.11g would again become too slow for advanced cellular networks of the day. 802.11n would help again and today’s flagship phones support 802.11ac for even higher data rates. On the other hand, many notebooks in use still do not, making USB connectivity the only connectivity option over which to get the maximum data transfer speeds offered by LTE today.
But once again we are close to hitting a limit of today’s USB-2 technology in smartphones once LTE 3-Carrier Aggregation (3-CA) is being rolled out. With LTE 3-CA and 3x 20 MHz, the maximum theoretical LTE data transfer speed with 64QAM modulation is 450 MBit/s. USB-2 on the other hand transfers around 40 MB per second if everything is optimized which is ‘only’ 320 Mbit/s. Time to move to USB-3 on mobile devices then. It doesn’t only make sense for higher cellular speeds but also to transfer large amounts of pictures, videos and music files faster than today. Fortunately, small USB type C connectors have arrived in the real world in the meantime so USB-3 connector size on smartphones won’t be an issue anymore.
Yes, and only 10 years ago, 2 Mbit/s of Bluetooth was the limit. Incredible…