HaLow WiFi Standard Brings Its Own Set of Highs and Lows

 
 
By Wayne Rash  |  Posted 2016-01-04 Print this article Print
 
 
 
 
 
 
 
HaLow WiFi

NEWS ANALYSIS: The WiFi Alliance announces a new standard for lower-frequency communications aimed primarily at the Internet of things.

The WiFi Alliance has released a new standard for wireless communications that acknowledges some basic facts about radio communications that have frustrated users for years.

Those basic facts involve the distance and building penetration capabilities of 2.4GHz WiFi and, to an even greater extent, 5GHz WiFi. The bottom line is that WiFi has some pretty short ranges and doesn't go through walls very well.

The new 900MHz standard uses frequencies that eliminate some of those problems, but as you might expect, will introduce some problems of their own. The unlicensed part of the 900MHz frequency band is shared by a number of licensed services, including private land mobile communications, some types of medical equipment and amateur radio, all of which operate in the 902–928 band planned for what the WiFi Alliance is calling HaLow, but which is really called 802.11ah.

In addition to the licensed services, other unlicensed services, including NCR WaveLAN, occupy this section of radio spectrum. WaveLAN is the predecessor of WiFi and was used in much the same way. I first reviewed WaveLAN for Byte magazine long ago, and while you might think it's obsolete to the point of extinction, it's still being used.

The advantage to WiFi users is that 900MHz is such a low frequency that it exhibits propagation characteristics more akin to radio waves than what you find in the microwave regions above 1GHz. While 900MHz is still only suitable for line-of-sight communications, it has excellent range, and it will go through walls far better than WiFi has in the past.

The ability to cover longer distances also translates into the ability to use lower-power transmitters, which is vital to Internet of things (IoT) devices that may have to run for long periods of time on batteries.

In addition to supporting devices that can use lower transmission powers, HaLow devices are assigned channels with less bandwidth than usual. Some of those data channels only provide 1MHz bandwidth allocations, which translates into data rates as low as 150K bps.

Those low data rates aren't going to do you a lot of good for streaming movies from NetFlix, but they are more than adequate for machine-to-machine communications as well as for telemetry and smart devices. For now, the largest channel size that the WiFi Alliance is certifying is 4MHz, which can provide a data rate of 18M bps.

While this might seem like a step back from the WiFi Alliance's previous efforts to get wireless communications above gigabit speeds, in fact, it's a smart step to put lower bandwidth networks into place where high speed isn't needed.

 



 
 
 
 
 
 
 
 
 
 
 
 
 

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