As the IoT market accelerates and becomes more of a reality, the hype surrounding it becomes more intense and more confusing. It is time for a reality check to take inventory of where things really stand, and to make some assessment of where things are going. Some confusion has been cleared, some confusion has exacerbated – but let’s start with what has simplified.
Two years ago there was a lot of discussion about the different radio technologies that would be useful for the IoT. Some companies advocated that WiFi and Bluetooth would be sufficient, while other companies were starting to push IEEE 802.15.4 (the underlying radio technology for ZigBee and Thread). Actually, the majority of today’s networking technology decision makers are now comfortable with and fully understand that the IoT will use all three technologies for different applications.
To address the weakness of WiFi (compared to ZigBee) an activity was started to standardize low-power WiFi (IEEE 802.11ah). Although activities in this area are still proceeding and may lead to a standard, the worldwide acceptance will be very doubtful. This standard is not universal, because we will have different specs and flavors in different regions in the world. Adding to the challenge is the fact that even though this new low-power standard is called WiFi, it does not have any compatibility with “real” WiFi. It is a completely different radio and MAC technology. So why not use IEEE 802.15.4, which is already a universal standard and provides all the features the developers of this new low power WiFi is struggling for? This new flavor of “WiFi” does not make much sense.
Bluetooth, as an IoT standard, has a critical weakness – it was designed as a point-to-point cable replacement technology – not a networking technology. To address this weakness, some companies have started to work on a network layer for Bluetooth (‘Bluetooth Mesh’) but they face serious challenges. Previously, many industry networking engineers have seen similar mesh networking attempts fail. For example, IEEE 802.11s exists but is hardly used, and implemented only a single hop mesh topology (repeater). The key problem is that latency cannot be controlled when supporting multiple hops. So, the skepticism amongst network technology engineers around the new Bluetooth Mesh story is really no surprise.
So, bottom line, the worldwide wireless market has accepted three core IoT radio technologies, IEEE/802.11/WiFi for content distribution as we are all familiar with today, IEEE 802.15.4/ZigBee for sentroller networks like Smart Homes and Bluetooth, including Bluetooth Low Energy, for connectivity, personal area networks (around the smart phone) and wearables. The first two connect devices in your home to the internet, the last one mainly uses the smart phone for internet connection.
A variety of cross-over radio products are already available from multiple suppliers: WiFi/Bluetooth, ZigBee/Bluetooth and WiFi/ZigBee/Bluetooth. They all may not be at the right price point yet, but the underlying message is clear: there are three large open worldwide uniform radio communication standards that are the cornerstones for the IoT. That is the good news.
Figure 1: The world of IoT, short range IoT standards as available or currently announced.