The IoT concept has been around for a while and soon applications and platforms will start hitting the market (whether the market is mature enough for the IoT, could be another debate…). It has never been that easy to build a prototype, make a nice 3D-printed case, deploy a backend application on a Cloud platform (or use one of the numerous existing IoT Web applications) and use crowd funding for getting started.
So, I am quite sure there is a number of people out there investigating potential solutions for M2M communication. In addition, a number of vendors are offering respective solutions trying to address the major IoT communication challenges: cost, power consumption, range.
Lately there have been many debates over low-power WiFi and RF (including ZigBee, 6LoWPAN, etc.) networks in the context of IoT application and sensor devices. In the lack of a succesfull radio communication technology for IoT devices, people (developers, researchers, etc.) seem to have been divided into two groups: Group A that supports that new WiFi implementations (featuring low energy consumption) can be used for IoT internetworking. Group B that opposes and suggests that WiFi is too complicated for sensor and M2M communication.
Was WiFi ever ment to be used for M2M and IoT? Definitely not, so why bother with the comparison and why do vendors care about providing enhanced WiFi modules that can be integrated into devices? There are some benefits for sure:
- Internet gateways (i.e. WiFi access points) are already used so IoT devices could have direct connectivity to the Internet without the need for additional infrastructure (setup cost, maintenance cost, etc.).
- Almost every smartphone is WiFi enabled, so communication with WiFi devices is quite easy and direct without the need for additional hardware.
- It is an established standard, supporting a full TCP/IP stack, meaning that when developing applications you need to focus only on the application level programming for message and information exchange.
- Integrates security
- Cost (even the Electric Imp at 25$ is much more expensive than a pair of RF transceivers)
- Even low power WiFi has more power consumption than RF (and also the communication protocol introduces much unnecessary overhead)
- Low power has poor indoor performance
RF on the other hand has also great benefits over WiFi in the context of M2M:
- Higher transmission range and better indoor performance
- Better price
Standards like ZigBee and 6LoWPAN include security implementations and mechanisms for error corrections/retransmission, etc. so that developers can focus just on the application level as well.
Who is the winner?
I think there can be two answers here: a) depends on the application/use case, b) the hybrid solution.
For instance, if an IoT system relies on a limited number of devices and direct mobile communication, then WiFi currently looks the best solution.
For case a) there are several options. An Arduino with a WiFi shield, or a Flyport WiFi module can be used for quick prototyping (and also used integrated in systems, especially the Flyport). The soon available electric imp is another example of a WiFi integrated device with low power consumption that can interact with the physical world and enable IoT applications.
For the hybrid solution, the idea is that devices are interconnected through RF and then a gateway is used to provide connectivity with the rest infrastructure and/or the Internet.
What’s missing here? Standards for gateway-to-devices communication, address translation (like NAT) for physical devices so that they can be accessed remotely, etc.
Which RF technology is going to win?
Well, ZigBee for a number of reasons has failed to penetrate home market (even Bluetooth 4 seems to compete better) and I am not quite sure it will be given a second chance in the IoT era. 6LoWPAN looks more promising, incorporates IPv6 support (thought I am not sure why every device shall have an IP address) and might have a better chance.
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