Wireless IoT Networking – Why Data Rates Matter
Have you ever wondered why your Wi-Fi is so slow? Or tried to figure out what determines the speed?
Well then this blogpost about Wi-Fi Data Rates is for you.
How fast digital data can be piped through the radio waves depends on many things. One of which is how far the data has to go. If the distance is short it is possible to transmit data faster than if the distance is long.
A smart mathematician named Claude Shannon worked out the exact physical maximum data speed in the 1940’s.
And he figured, higher data rates are good because:
a) you get your data quicker, which is nice for those impatient souls download large files
b) the device transmitting the data can get it over and done with faster, thus freeing up precious radio spectrum for use by other devices and,
c) they are more power efficient.
When you are on a video streaming site * cough Netflix cough * you’re probably more concerned about point A, which is to get your video fast.
For Internet of Things (IoT) devices and networks point b) and c) are more of concern. A fast data rate enables more devices to transmit more information which is what the IoT is all about! A lower power consumption allows devices to run for longer on smaller batteries.
So, high data rates are good, and are physically possible at short range. The smart folks who developed Wi-Fi realised this, hence they designed Wi-Fi so that devices automatically increase their data rate when they are close to the Wi-Fi Access Point. They called it Dynamic Rate Shifting. Genius.
Wi-Fi HaLow is a new version of Wi-Fi designed specifically for the needs of the IoT. It uses a small fraction of the power required by conventional Wi-Fi, travels through walls and other obstacle better and reaches ten times as far. Like conventional Wi-Fi it also utilises dynamic rate shifting to up the data rates as distance drops.
Wi-Fi HaLow offers great data rates for ranges up to around 1km.
Wi-Fi HaLow scales its data rates from around 150 kilo bits per second to many mega bits per second. Some may say that 150kpbs is excessive for IoT and that 100bps would suffice. However, with only 100bps a basestation would only transport 44kB of data per hour. This is not even enough for 25 sensor nodes uploading one securely encrypted message every minute.
Fast data rates allow high capacity networks. They also allow for lower power consumption, and when it comes to battery power IoT devices, power consumption is king.
The best way to save power it to have the power hungry radio transmitter switched off for as much of the time as possible. Low data rates present a serious impediment to this goal.
A low data rate forces transmitters to be powered on for extended period of time as they slooooowwwwly get their messages out. Wi-Fi’s dynamic rate shifting automatically increasing power efficiency at short distances by increasing the data rate at reduced distances.
For a more comprehensive analysis of network capacity and power consumption download our white papers on the subject which compares six IoT technologies suitability for deployments in five applications.