5G Update Series: Massive Machine-type Communications IoT Update

The goal of facilitating the growing data-centric behaviors of global society has led to new classifications of wireless communications. One of these new classifications defined in the 3GPP Release 13 is massive machine-type communications (mMTC). A new wireless technology, known as narrow-band Internet of things (NB-IoT) was created to enable communication between large numbers of autonomous/semi-autonomous devices. This new standard required a physical layer redesign, resource allocation optimization, and innovation in radio technologies to better suit large numbers of low-power distributed devices that may be running on batteries. There are also other wireless standards designed for wireless networking of IoT devices, including LTE-M, Thread, Cat M, and LoRa (all low power wide area network technologies).

Due to the nature of some mMTC communications, other wireless network performance factors, or key performance indicators (KPI), are also vital, these include reliability, latency, efficiency, scalability, cost, and configurability. The result of this new standard is the expectation that such systems will eventually be able to support a device density of one million IoT devices per square kilometer. These devices could be anything from a remote data logger to a wireless industrial control network.

There have already been launched early MTC-style wireless networks based on pre-5G network technology, mainly 4G-LTE. Though these networks don’t meet the full expectations of mMTC, they do bridge a gap between the user-centric voice, text, and data services of typical 4G-LTE networks and the predicted future requirements of mMTC. The current release of NB-IoT networks are generally software upgrades of existing 4G-LTE assets, possibly with the addition of small cells and distributed antenna systems (DAS) in key areas of intended use. It is unlikely that these early MTC networks won’t be able to handle massive numbers of devices, and may also be lacking the reliability, latency, and coverage expectations of mMTC. Currently, these technologies use the guard bands between the LTE channels, in an attempt to avoid interference with consumer cellular traffic.

There are several predictions that NB-IoT and similar networks will move from just a few million connections currently, to several billion by 2025. This type of large-scale deployment of systems would require extremely low cost and efficient IoT chips, as well as much more reliable coverage to enable mMTC applications. A current major challenge in creating the infrastructure for mMTC is need for antenna and radio technology that can efficiently handle a wide variety of MTC classifications over a wide area. Current cellular radio technology can generally handle hundreds, possibly thousands, of these types of connections in a large-cell tower. However, there will be a growing need for more distributed and capable radio and antenna hardware to enable the density and features of upcoming mMTC IoT devices.