Wi-Fi, the name that is often used to describe the 802.11 protocol, is a short-range wireless communication standard which utilizes the freely available, unlicensed 2.4 GHz frequency band. It is true that several geeks have tried (and many of them succeeded!) to increase Wi-Fi range tenfold by utilizing combinations of custom-built high gain antennas, a variety of cable adapters and powerful signal amplifiers. While this approach has worked fine, significantly boosting wireless range, it has also increased the required amount of power. Nevertheless, since most network clients were desktop PCs back in 1997, when the first version of the wireless standard was released, power efficiency wasn't a key priority.
So, Wi-Fi can be a great solution for applications where power consumption isn't an issue. An intelligent home security system, which is connected to the mains at all times, can (and should) utilize a wireless network, because it needs to stream large amounts of data. Additionally, Wi-Fi networks are everywhere, and this has the potential to make IoT devices inexpensive and easy to deploy.
Today's devices utilize various sensors and have different sizes, though. Often, some of these Internet of Things gadgets need to utilize the power that's provided by a tiny battery for several months. Not only that, but very few IoT gizmos require a permanent data connection. Just think at an IoT device that serves as a utility meter, for example; it will only need to transmit data for a second, a few times per week. A permanent data connection would be useless in this case. Not only that, but since there are so many Wi-Fi networks around us, signal interference can cause trouble.
The limited signal range can also be a serious issue. A smart watch will only need to send data over a range of 10...20 feet, so any Wi-Fi connection will do a proper job. Still, other portable IoT devices, which are used to send alerts when crops need to be watered, may need to transmit the information several miles away from their location.
So, it is quite clear that smaller sized devices, which can't utilize large batteries, and especially IoT devices that need to operate in the field for several months, and sometimes even years in a row, need to conserve power by utilizing a different data transmission technology. The most promising options so far are Bluetooth, cellular IoT, low power wide area networks, Wi-Fi HaLow (aka 802.11ah) and HEW (aka 802.11ax). Let's see how these technologies can help.
It is estimated that by 2020, a third of the IoT devices will utilize Bluetooth. The last version of Bluetooth has increased the range by 400% in comparison with the previous iteration, and Bluetooth Low Energy, which was designed for devices that need to conserve power, can keep the devices in sleep mode until they are required to send or receive data.
Cellular IoT utilizes the already existing infrastructure, and this means that signal is available everywhere! In addition to this, it has already been proven that cellular networks allow lots of phones to be used at the same time without any problem, so the system should also be able to accommodate the constantly increasing number of IoT devices.
Low power wide area networks, aka LPWANs, connect low-bandwidth devices that transmit small chunks of data (10...1,000 bytes) using low bit rates (less than 200 Kbps). This way, even battery-powered devices can easily send and receive information over tens of miles.
Wi-Fi HaLow utilizes the free 900 MHz band, and can be used for devices that need a signal range of about half a mile. It reduces power consumption by shutting down the equipment and powering it back on at predefined intervals.
The High Efficiency Wireless (HEW) standard is an improved version of Wi-Fi HaLow; it incorporates MIMO (Multiple-Input Multiple-Output) features and uses a narrower communication band, which allow up to 18 devices to send data simultaneously, using the same wireless channel.
As you can see, there are lots of technologies that can help make IoT devices even better. While certain applications, for example the ones that are used for home automation, will continue to use our trusty Wi-Fi networks for a long time, other devices will probably utilize one of these new technologies, which will make their batteries last much longer.