WiFi HaLow vs Bluetooth Smart
The WiFi Alliance announced WiFi HaLow (pronounced "halo") in January 2016 as an extension to the IEEE 802.11ah standard. It has been haloed as the WiFi Alliance's answer to Bluetooth Smart (also known as Bluetooth Low Energy) Both are low energy consumption protocols specifically designed for the emergence of the Internet of Things (IoT).
The two technologies target the same use cases but they approach it differently.
First the two technologies operate on different frequencies. The frequencies each technology uses is important because a lower frequency signal will reach further and can penetrate thru obstacles such as concrete walls better. Bluetooth Smart operates at 2.4GHz and WiFi Halow operates at the lower frequency of 900MHz. This means if you were designing an home outdoor motion detector, WiFi Halow would allow for a better and larger coverage area for your device compared to Bluetooth Smart.
The second key difference is connectivity. Bluetooth Smart allows devices to discover and talk to nearby devices by effectively establishing a "local area network". This local area network of devices can then gains access to the Internet using a device such as a router that implements a Bluetooth Internet Gateway. WiFi HaLow is focused on getting devices connected to a router and then directly to the Internet. Both have advantages depending on your device and use case. For example if you have a heart rate sensor and a pedometer Bluetooth Smart has the advantage that each device could discover each other, and all the data can be directly be sent to your smartphone without routing the data thru the Internet. I would speculate a future revisions of WiFi HaLow will add support for adhoc networking capabilities to allow devices to create a "local area networks" where the data between devices are not routed thru the Internet and also the ability to control and limit the signal strength. Even with encryption I would prefer my personal data not be transmitted down the whole block.
WiFi HaLow devices are expected to appear in 2018 and specific power consumption and signal range specifications have not been presented but unless power consumption numbers for WiFi HaLow are at least a 50% decrease compared to that of Bluetooth Smart, neither technology will render the other obsolete from a technical standpoint. Instead in many IoT scenarios the technologies are interchangeable. WiFi HaLow is well suited in situations where an Internet connection is required to transfer small amounts of data and a requires a large coverage area. A perfect example of this is the Nest thermostat. The Nest currently uses standard Wi-Fi to connect to your home router and using the Nest smartphone application you can control the thermostat from anywhere.
Where Bluetooth Smart will shine is in situations requiring device discover and device to device communication. Think scenarios like proximity detection such as Beacons and wearables such as a Fitbit.
The truly exciting part of WiFi HaLow and Bluetooth Smart is the potential to combine both technologies to enable devices that currently require being connected to a power outlet to be battery powered in the future!