Bluetooth and LTE: Friends or Foes?

The news about the Bluetooth roadmap for 2016 are officially out so we can discuss them in public now. I've covered the Mesh many times already and the next thrilling (and many even say shocking) feature is the range increase. It will be four times what it is today. Which translates to extra 12dBm link budget (every 6 dBm increase in link budget results in a doubling of the possible distance that is achievable).

Today, which means Bluetooth LE 4.0 A.D. 2015, the Bluetooth Smart modules we've designed at Silvair reach about 2000ft / 700m LoS (line-of-Sight) module-to-module range (using small omnidirectional λ/4 antennas). Our official figure is 1500ft / 500m, which is still shocking to many. The link budget we have is 108dB.

In the near future we will be offering a new Bluetooth Smart module that can go up to 118dB link budget. 1500ft/500m will become 5000ft/1500m - almost a mile. And this is still WITHOUT the 4x range increase that will come later in 2016. Assuming everything goes as planned, a year from now we will have Bluetooth Smart modules with 130dB link budget, capable of reaching the range of 20000ft  / 6km, or 3.5 miles. This matches the size of a typical LTE cell size, which is 1 to 5km (0.6 - 3 miles).

The BOM of a high performance Bluetooth radio in an LTE base station is about $10. All stations are already connected to the Cloud. Bluetooth can do IPv6 already. So what do we get out of that?

A SigFox / LoRa killer. If an LTE base station can also be a Bluetooth Smart base station, all Bluetooth Smart devices within the 3 mile radius can be connected directly to Clouds. Just think of what a game changer it can potentially become!

There is one competitor on the horizon though. It is called NB-LTE (Narrow Band LTE), which can do even more with the 164 dB link budget (certainly it can kill SigFox and LoRa), but it is MUCH slower, with speeds similar to the old analog modems - several hundred bps to single kbps.

So should LTE build yet another narrowband protocol, or should it just adopt Bluetooth Smart as a carrier grade WAN IoT bearer? They will likely opt to push their own technology, but it still means the field of use of Bluetooth Smart is expanding dramatically. The evolution is really shocking, if the last thing you remembered about Bluetooth was it could link your wrist (a smart watch) to your pocket (a smart phone).