Co-Authored by:Mirko Naumann
This will naturally employ all kind of available connectivity channels – including Ethernet, Power-line, satellite, and other wireless solutions. In fact, the lion’s share of IoT networks will use some form of wireless connectivity, be it short range WPAN like RFID/Bluetooth-LE; mid-range WLAN/LPWAN like Wi-Fi/LoRa; or long range cellular networks like 2G/3G/LTE.
The technology selection will be use-case dependent – determined by a set of attributes: the number and types of connected devices, mobility and geographical distribution, direction and volume of data transmission, latency requirements, power consumption and battery lifetime, as well as factors like cost and complexity in both deployment and maintenance.
Previously, the development of new standards followed the paradigms of higher throughput and lower latency. However, IoT necessitates connectivity for an unprecedented number of devices, and battery life– in some scenarios, up to 10 years. In order to achieve this, future technologies need strategies for a more simplified control plane, reduction or even elimination of signaling and synchronization, and the option to switch off communication entities entirely when not in use.
Although IoT is an emerging trend, inter-machine communication has existed for decades and so have the supporting technologies. In the next section, this blog will provide an overview of existing communication technologies and their pros and cons – for an assessment of their IoT suitability.
Radio-Frequency Identification (RFID) is a passive system that uses tags that respond to a reader’s signal and gets processed via RFID middleware. It works in the low to microwave frequency range, within a distance of 10 cm to 200 m. Although the most cost effective IoT solution in existence today, RFID is fundamentally limited in functionality. NFC is a similar solution – by design, these tag based systems are not suitable for mesh networks.
Bluetooth-LE is a technology from Special Interest Group (SIG) initiated by Ericsson 20 years ago, with over 30,000 member companies by 2016. Operating within the ISM band from 2.40 to 2.48 GHz, Bluetooth uses low power short wavelength messages within 10-100 m distance, along with high level security to form a personal area network (PAN). Bluetooth v5.0 boosts existing IoT capabilities, with Transport Discovery Services and a dedicated developer framework.
ZigBee is based on the IEEE 802.15 standard for line-of-sight transmission in a 10-100m distance. Designed for mesh networks, its 2 lower OSI layers are from IEEE, middle 4 layers are from Alliance and the application layer can be vendor proprietary. However, different vendor implementations are not interoperable.
Wi-Fi is an implementation of IEEE 802.11 wireless LAN technology that’s focused primarily on high speed data communication in 2.4 GHz, 3.6 GHz or 5 GHz bands, commonly within a range of 100 m. While it provides greater bandwidth, high power consumption renders it unsuitable for devices without a permanent power source.
Global System for Mobile communications (GSM) is an open cellular technology by ETSI and provides terrestrial coverage for 90% of the global population. It offers both voice and data services, and has been in use for asset tracking and M2M for decades. Due to its long-term market presence, GSM wireless modules are cost effective. However, it functions on a licensed spectrum – continuously eyed by operators for harnessing more efficient technologies like LTE and beyond.
While each technology has its own unique benefits and may play a role in IoT, it also has limitations that will prevent any significant market penetration. The ones with support for ultra-low power consumption are either not ready for mesh network, support a relatively low number of devices, provide limited coverage area, or have no support for mobility. Often low-power end devices have no analysis or decision making capabilities, and data processing must be rerouted/centralized.
Others require larger power sources or a licensed spectrum, or don’t provide expected spectrum efficiency.
The next blog in this series discusses SigFox and LORA – two existing technology candidates with IoT as their main use case, together with 3GPP options already in practice.