How to choose NB-IoT, Cat.1, and Cat.M for IoT device communication?

1. What is NB-IoT

NB-IoT (Narrow Band Internet of Things) is an emerging technology in the IoT field, supporting cellular data connections of low-power devices in wide area networks, also known as low-power wide area networks (LPWAN). NB-IoT supports efficient connections of devices with long standby time and high network connection requirements. It is said that the battery life of NB-IoT devices can be increased by at least 10 years, while also providing very comprehensive indoor cellular data connection coverage.

The NB-IoT network consists of NB-IoT terminals, NB-IoT base stations, NB-IoT packet core network, IoT connection management platform and industry application servers.

NB-IoT has the following four advantages:

• Low power consumption is an important indicator for IoT applications, especially for devices and occasions where batteries cannot be replaced frequently. NB-IoT focuses on small data volume and low rate applications, so the power consumption of NB-IoT devices can be very low, and the battery life of devices can be greatly improved from several months in the past to several years.
• Wide coverage NB-IoT has strong indoor coverage, with a 20dB gain over LTE, which is equivalent to a 100-fold increase in coverage area. It can not only meet the wide coverage needs in rural areas, but also be applied to applications that require deep coverage, such as factory areas, underground garages, and manhole covers.
• Large connections In the case of the same base station, NB-IoT can provide 50-100 times the number of accesses than existing wireless technologies. In a not too large space, more devices can be placed without interfering with each other. In other words, NB-IoT is enough to easily meet the networking needs of a large number of devices in future smart homes.
• Low cost Compared with LoRa, NB-IoT does not need to rebuild the network, and the radio frequency and antenna are basically reused. Taking China Mobile as an example, there is a relatively wide frequency band in 900MHZ, and only a part of the 2G frequency band needs to be cleared to directly deploy LTE and NB-IoT at the same time; low speed, low power consumption and low bandwidth also bring low cost advantages to NB-IoT chips and modules.

2. What is LTE-Cat.1

LTE (Long-Term Evolution) is a 4G wireless mobile communication technology that provides high-speed data transmission and low-latency network connections. LTE networks can meet different application requirements through different UE (User Equipment) categories, including LTE Cat.1, LTE Cat.2, LTE Cat.3 and LTE Cat.4.

LTE-Cat.1 is a standard for user terminal categories under the 4G communication LTE network, with an uplink peak rate of 5 Mbps and a downlink peak rate of 10 Mbps. It is positioned as a category for the IoT application market.

LTE-Cat.1 takes into account speed, power consumption and cost, and with the help of the wide coverage of LTE network, it can quickly form economies of scale! This has led to the strong development momentum of LTE-Cat.1 in 4G modules, with its penetration rate rising all the way, becoming the "newcomer" of low-speed networks in the Internet of Things.

3. What is LTE-M

LTE-M, or LTE-Machine-to-Machine, is an IoT technology based on the evolution of LTE. It is deployed on cellular networks and supports a maximum peak rate of 1Mbps for both uplink and downlink, which is a medium-speed IoT technology. Its user equipment can directly access the existing LTE network by supporting 1.4MHz RF and baseband bandwidth.

The most critical capabilities of LTE-M are its support for mobility and positioning. Its cost is only 25% of that of Cat1 chips, and its speed is four times higher than that of GPRS.

LTE-M has the following four advantages:

• High speed: LTE-M supports a peak rate of up to 1Mbps for both uplink and downlink, which is much higher than the rates of GPRS, ZigBee and other IoT technologies. It can support more IoT applications, such as low-speed video and voice.
• Mobility: LTE-M supports connected mobility, allowing IoT users to switch seamlessly to ensure user experience.
• Positioning is possible. TDD-based LTE-M can use PRS measurements on the base station side to perform location positioning without adding a GPS chip. Low-cost positioning technology is more conducive to the popularization of LTE-M in logistics tracking, cargo tracking and other scenarios:
• Support voice. LTE-M evolved from the LTE protocol and can support VOLTE voice. It can be widely used in wearable devices in the future.

4. Application scenario comparison

LTE-Cat.1 can be widely used in industrial gateways, retail cabinets, financial payments, Internet of Vehicles, shared power banks, charging piles, video surveillance and other scenarios.

LTE-M supports cellular base station handover and voice functions and is used in wearable devices such as smart bracelets and smart watches, as well as asset tracking, health monitors and alarms.

NB-IoT is used to connect a large number of low-power devices, which usually operate in low-power mode for a long time, so that a battery life of several years can be achieved, such as sensors, smart water meters, smart electricity meters, etc.