In the next five years Internet of Things communications will see unprecedented growth, and cellular connectivity will become even more valuable. Wireless cellular technologies have found enormous potential as key enablers for IoT, and the continuously increasing technology enhancements and innovations in cellular technologies are promising to be the major primary access methodologies to enable a great number of IoT applications.
Cellular technologies are already being used for IoT today in several use cases and are expected to be used even more in the future as these use cases require excellent mobility, strong networks, robust security, economic scale and communications independent of third party access. At the same time, the Internet of Things requires low complexity, low cost devices with long battery life times as well as good coverage for long communication range and penetration to reach the most challenging locations.
The challenge for the cellular industry now is to unlock the value of this interconnected web of devices in a secure, flexible and manageable manner. The goal is to identify a framework of promising solutions and cover a set of innovative approaches and technologies to meet these challenges.
The cellular IoT alphabet
MTC, Cat-0, Cat-1, LTE-M … Some might get confused with all the acronyms related to cellular IoT, so let’s go through it and explain where the different terms come from and what they mean.
As you probably know, 3GPP (3rd Generation Partnership Project) uses the concept of “Releases” to refer to a stable set of specifications which can be used for implementation of features at a given point of time. User Equipment (UE) Category is one important term here. Categories are used to define general UE performance characteristics – for example, maximum supported data rate in uplink and downlink data channels, and to what extent different multi-antenna capabilities and modulation schemes are supported.
The latest stable Release is Release 12, where the categories range from Category 0 up to Category 13. Release 13, which is being finalized at the moment, will include further UE Categories including at least the so-called “Cat-M1” intended for IoT devices.
Cat-1 – Category 1 – was included in the LTE specifications already in the beginning, Release 8. With a Cat-1 UE, it is possible to achieve 10 Mbps downlink and 5 Mbps uplink channel data rates. Cat-1 has not been a relevant UE category for LTE-based mobile broadband services, as its performance is below the best 3G performance. Now it has become an attractive, early alternative for IoT applications over LTE, because it is already standardized.
Cat-0 – Category 0 – is one of the newest standardized categories from Release 12. Cat-0 UEs are intended for IoT use cases, and provide 1 Mbps data rates for both up- and downlink. Cat-0 UEs have reduced complexity by up to 50% compared to Cat-1; requirements include only one receiver antenna and support of half-duplex operation, providing ways for the manufacturers to significantly reduce the modem cost compared to more advanced UE categories.
LTE-Advanced technology, the chief vehicle of 4G cellular connectivity, started to and will continue evolving to provide new features that support a range of high and low performance and cost-optimized IoT device categories. So far, the focus has been on meeting the huge demand for mobile data with highly capable devices that utilize new spectrum.
However, the arrival of LTE-M signifies an important step in addressing MTC (Machine-Type Communications) capabilities over LTE. LTE-M brings new power-saving functionality suitable for serving a variety of IoT applications; Power Saving Mode and eDRX extend battery life for LTE-M to 10 years or more. LTE-M traffic is multiplexed over a full LTE carrier, and it is therefore able to tap into the full capacity of LTE. Additionally, new functionality for substantially reduced device cost and extended coverage for LTE-M are also specified within 3GPP.
The Internet of Things is set to ascend, and operators have a unique opportunity to offer affordable connectivity on a global scale. At the same time, for IoT applications, existing cellular networks offer distinct advantages over alternative WAN technologies, such as unlicensed LPWA.