Cellular LPWAN Networks
It’s in our offices, our homes and increasingly in most public areas. IoT technologies are popular and almost ubiquitous.
It’s led to the rise of low-power, wide-area networks (LPWAN) that are a fraction of the cost they were just 5 years ago.
Traditional cellular options such as 4G and LTE networks consume too much power and don’t fit well with applications where only a small amount of data is transmitted infrequently (e.g. meters for reading water levels, gas consumption, or electricity use).
Cellular IoT is meant to meet the requirements of low-power, long-range applications.
Cellular LPWAN networks are inside the licensed spectrum and are offered by mobile network operators. They were developed by the 3rd Generation Partnership Project (3GPP) and GSMA (the GSM Association, launched in 1982 as the Groupe Speciale Mobile).
Cellular IoT technologies are ideally suitable to hospitals, retailers, airports or any businesses that can benefit from a consistent, clear view of shipments.
Two Current Technologies
Cellular telecommunications network technologies operate in the licensed portion of the wireless spectrum. The two leading technologies (at least for the foreseeable future) are CAT-M and NB-IoT.
Cellular IoT protocols provide a means of harnessing IoT data on a regional, country-wide or even transcontinental scale without the need for pre-established gateways to create a coverage area. Instead, existing cell towers transport the data. This means that your LPWAN will have the same blind spots the cellular networks do, and if the network connection is interrupted—for maintenance, subscription-limits, emergencies or some other reason—your network will also go down. Still, ease of deployment and the coverage area often overweigh the costs and limitations of dependence on a cellular provider.
Cat-M and NB-IoT both use cellular towers to communicate data, similar to high speed LTE. The main difference between these connection types is how data from moving devices is communicated when the devices are in motion. If a device moves from point A to a far away point B, crossing several different networks cells, the Cat-M device would never drop the connection because it behaves the same as a cell phone, connecting from tower-to-tower as it moves. NB-IoT devices, on the other hand, do not transfer the connection and instead have to re‑establish a new connection to a new cellular tower each time a tower is lost and a new tower is detected.
CAT-M
CAT-M (officially known at LTE CAT-M1) is a low‑power, wide-area network often viewed as the second generation of LTE.
IoT devices with medium data rate requirements are suitable: 375Kb/s upload and download speeds in half-duplex mode with a maximum message size of 1500 bytes in a 2-way data communication.
It supports longer battery life and offers enhanced in‑building range as compared to earlier cellular technologies (2G, 3G, or LTE CAT 1).
Being compatible with existing LTE networks, CAT-M doesn’t require carriers to build new infrastructure to implement it.
CAT-M allows for high data rates and low-latency communications, which could be crucial if the user needs to collect large files from his or her IoT devices or push large updates down the pipe to IoT endpoints. CAT-M is perfect for mobile use cases, as its handling of hand-over between cell sites is excellent.
Comparison: IoT Network Technology
NB-IoT
A product of existing 3GPP technologies, Narrowband IoT (NB-IoT) is a fairly new radio technology standard that ensures extremely low power consumption (rivalling LoRaWAN). It uses existing network infrastructure which ensures global coverage in LTE networks.
NB-IoT supports ultra-low complexity devices with a very narrow bandwidth of 200 kilohertz and data rate peaks of about 250 Kbps. Compared to CAT-M, NB-IoT improves the power consumption of user devices, system capacity and spectrum efficiency, especially in deep coverage.
NB-IoT is touted as less expensive than Cat-M because of superior battery life, requiring less frequent replacements.
