Nowadays, almost everybody living in an urban city uses cellular networks every day via their smartphones. Cellular or mobile networks link us not only to our loved ones but also to a variety of other services such as our Gmail and Facebook account. Equivocally, more and more devices are being connected in this Internet of Things (IoT) era.
In consequence, the demand for physical devices like your car, television, headphones to be connected along with other devices like power lines and road signals, to a cellular network is on the rise. This is the impetus behind Cellular IoT technology.
Cellular IoT is all about connecting physical devices, such as sensors, to the internet using the same technology as your smartphone. These physical devices piggyback on the same mobile networks as smartphones, which eliminates the need to create a new, private network to house IoT devices.
Different Types of Cellular Network
Ref: Tata Communications
As you can see, there are five different categories of Cellular network. For Cellular IoT, there are two primary types of connections, LTE-M and NB-IoT. They are both categorised as an LPWAN cellular network, meaning a low-power wide-area network. LPWAN is designed to allow long-range communications at a low bit rate. In March of 2019, it was announced that over 100 operators have deployed either NB-IoT or LTE-M networks.
Cellular IoT networks are generally from the LPWAN category as a wider area is more favourable than higher speed in this scenario. LPWAN networks generally have wider area coverage with low power requirements allowing battery-operated devices to run longer. They are best suited for applications that send small and infrequent amounts of data that are not overly time-sensitive.
LPWAN has two variations: Unlicensed and Licensed. Licensed LPWAN generally has higher-quality connectivity, less interference and fewer dropped connections. The cellular networks covered in this article are licensed LP-Wan.
What is LTE Cat.M?
To accommodate our escalating bandwidth, wireless networks evolve to LTE. LTE offers higher speed, bandwidth, and reliability. Nonetheless, most IoT connections don’t require 4G’s level of speed. That is where LTE-M comes in. LTE-M, short for LTE Cat.M, was developed by 3GPP to enable a wide range of devices and services (specifically for machine-to-machine and IoT applications).
LTE CAT-M1 have very low power requirements, allowing devices to be able to spend more time in the field. It limits the amount of time needed to spent updating firmware or replacing batteries, reducing human capital requirements. It also has a built-in power-saving mode that activates automatically when devices are not transmitting or receiving data.
It is a cost-effective solution for IoT projects as it is driven by LTE, eliminating the need for any network infrastructure to support IoT connectivity.
Different Variations of LTE-M
There are different versions of LTE Cat.M. It will be good to understand the difference between the different category. There are several LTE-M categories but the two main ones are LTE Cat.M and Cat.M2. The main difference between them is their data rate.
Data Rate: LTE Cat.M can support uplink and downlink speeds of 375kb/s in half-duplex mode. This makes it suitable for many IoT applications requiring low to medium data rate needs. LTE Cat.M2 increases data throughput to peak rates of 24 Mb/s for downloads and 2.6Mb/s for uploads, allowing it to be more versatile for applications such as video surveillance. This speed will also allow faster remote over-the-air firmware updates.
In this article, we will be focusing on LTE Cat.M as it is the more widely-used and popular one.
What is NB-IoT?
Similarly to LTE CAT-M1, Narrowband Internet of Things (NB-IoT), also known as LTE CAT NB1, was developed to enable a wide range of IoT devices and services. Unlike most other choices (including LTE Cat.M), gateways aren’t required to aggregate data before sending it to the main server. Instead, MB-IoT devices are directly connected to the base station, reducing expenses.
NB-IoT runs on the LTE standard, but with limited bandwidth to a single 200kHz narrow-band. Therefore, NB-IoT devices consume far less power than LTE Cat.M due to the simpler waveforms used. Nevertheless, this also means NB-IoT devices can’t send as much data as LTE Cat.M and unable to interoperate with other cellular devices. NB-IoT also has power-saving capabilities similar to LTE Cat.M.
Similar to LTE-M, there are different variations: LTE Cat-NB1 and LTE Cat-NB2.
Data Rate: LTE Cat-NB1 has a max downlink of 680 bits and an uplink speed of 1000bits while LTE Cat-NB2 has a max downlink and uplink speed of 2536 bits.
Remote Use: LTE Cat-NB2 introduces OTDOA (Observed Time Difference of Arrival) and E-CID (Enhanced Cell ID), allowing for higher location accuracy.
LTE Cat-NB2 also has reconnection in device connected mode, as opposed to idle mode only in Cat-NB1.
In this article, we will be focusing only on LTE Cat-NB1 as it is more widely-used and popular.
Should I choose LTE Cat.M or NB-IoT then?
Both LTE Cat.M and NB-IoT have their advantages and disadvantages. It is crucial to make clear your needs and then choose the one that best suits your requirements.
|Latency||10ms – 15ms||1.6s – 10s|
|Duplex Mode||Full Duplex, Half Duplex||Half Duplex|
Both LTE Cat.M and NB-IoT have wide coverage. However, NB-IoT has seven times the range of LTE technologies like LTE Cat.M. This is due to their simpler waveforms. Due to this, NB-IoT performs better in indoor environments as they have better obstacle penetration. This makes NB-IoT the ideal choice for IoT projects that have sensors deployed underground or in other hard-to-reach areas with a poorer signal.
Different geographic locations have better signals and support for different networks. For example, in the US, the country is predominantly driven by LTE radios. It will be better to deploy LTE Cat.M as compared to NB-IoT.
In Asia countries, more companies are adopting and driving the NB-IoT network, such as Huawei. NB-IoT devices will be better to deploy as compared to LTE Cat.M in Asia countries.
Similarly, LTE Cat.M will be difficult to deploy in parts of Asia, Africa and Eastern Europe where 3G connectivity is still more prevalent as compared to LTE.
Complexity of Usage
As mentioned, how your IoT devices are implemented will be a huge factor in deciding which network to choose.
If your project requires real-time high-speed connectivity, LTE Cat.M will be better due to their lower latency and higher bandwidth. If your project requires an active mobile connection, such as a moving chiller truck tracking the temperature of its chiller, LTE Cat.M will be more ideal as well due to its mobility capability.
LTE Cat.M network can seamlessly switch from one cell tower to another without a loss in connection, similar to a smartphone. NB-IoT network connectivity will be interrupted by moving from a fixed location, or even a loss of signal momentarily.
LTE Cat.M although more versatile, will cost more than NB-IoT. It will therefore make more sense to use NB-IoT instead of LTE Cat.M if NB-IoT suffices your requirements.
LTE-M is designed for more complex devices that require more frequent interaction with the network. NB-IoT is designed for carrying very small packets from small devices infrequently. With both being very similar in features and costing around the same, the main factors to take note of when choosing between LTE Cat.M and NB-IoT are:
- The required range of coverage
- The geographic location of deployment
- Required bandwidth and connection speed
- Mobility requirements
Real-World Applications of Cellular IoT
There are many current applications of the LTE Cat.M and NB-IoT network. Here are some examples.
Utilities Metering (NB-IoT)
Ref: T&D World
Electrical and water usage are measured with IoT implementations. The utilities metered data will be sent to the various departments via cellular IoT. This solves several issues for utility metering.
Manpower costs for checks and maintenance of traditional meters will be greatly reduced. With cellular IoT implementation, issues with meters can be automatically notified to the various management teams. It will also eliminate the possibilities of human errors in reporting utility usage.
Some meters, especially in older buildings, are in areas difficult to access. This will cause delays and inefficiencies in obtaining readings. With this implementation, there will be no need to acquire reading manually, making the process more efficient.
Fleet management (LTE Cat.M)
Fleets can be remotely tracked and managed via cellular IoT. Potential issues with trucks or routes can be detected before they occur, to boost efficiency. Overall maintenance costs can be reduced with such implementation.
With fleet usage data obtained via IoT implementations, businesses can fully utilise vehicles to optimise operations efficiently and maximise returns.
Drivers usage data can also be obtained to detect any potential vehicle wear and tear. This can potentially reduce the hidden cost incurred in fleet maintenance.
Smart Logistics (LTE Cat.M and NB-IoT)
Cellular IoT will enable warehouse operations to gain real-time visibility and status of goods at all stages of the logistics journey. Temperature, humidity, and location will be reported in real-time for goods such as cold food and medicine to ensure quality assurance. With a complete view of where goods are along the supply chain, there will be a decreased chance of theft, misplacement and unauthorised cross-regional sales.
Traditional logistics solutions use GPS + LTE technology to track good which consumes a large amount of power and have a short battery lifespan. With LTE Cat.M and NB-IoT lower power consumption, battery-powered tracking devices can last longer, reducing expenses.
Relevance in the Future
Due to LTE Cat.M and NB-IoT unique functionality, they are considered future-proof and are viewed as 5G technologies. They are claimed to be able to efficiently co-exist with 5G NR and fulfil future requirements for cellular IoT for a very long time.
With the goal of massive IoT in mind, LTE Cat.M and NB-IoT will consistently be an entry-point for businesses to implement IoT connectivity into their functions in the future with 5G technology.
Solutions for DIY Cellular IoT
Fret not if you are looking to implement cellular connectivity to your IoT projects. Here are some solutions.
This Wio tracker is an open-source gateway that enables faster IoT GPS solutions. It is compatible with Arduino and Grove.
- Supports LTE (4G) communication
- Supports 4 different GNSS – GPS, Beidou, GLONSS and Galileo. It also supports QZSS
- Equipped with STM32 MCU making it 5 times faster than the previous version
- 1Mbytes of flash and 192+4k bytes
- Transplantable and expansible AT command library allowing easy updates from previous versions
This is well suited for outdoor projects where devices can connect to cellular to provide real-time location of the attached devices.
This is an easy to deploy, industrial-grade, 4G cellular sensor hub. It uses the Modbus-RTU RS485 protocol to communicate with sensors. It comes with 4G for remote communication.
- Connect up to 32 RS485 sensors
- Industrial-grade build quality – robust and stable
- IP66 rated – waterproof and dustproof
- Supports 2G/3G/4G communication and LTE
- Built-in rechargeable battery
This SenseCAP Sensor Hub is used for smart city, agriculture and environmental monitoring solutions.
This is an expansion board for Arduino to enable NB-IoT connectivity for Arduino.
- Supports 850Mhz NB-IoT bands
- Low power consumption
- Wide area of coverage
- AT command controls
- Supports 3.3v and 5v Arduino
- Compatible with all popular Arduinos
LTE Cat.M and NB-IoT are both performs well in their designed area. They are future-proof, making them very viable for long-term solutions. They are currently very well implemented for many applications