A “cat” walking alone on a narrow road: Cat.1 and narrowband communications (I)

Labs Guide

When we talk about narrowband communication, you may think of GSM, GPRS, MODEM dial-up Internet access, etc. But have you heard of Cat.1? What is Cat.1? The first thing that comes to your mind must be a cat. But what we are going to talk about today is something in another dimension. Cat.1 (LTE UE-Category 1) is a special communication technology that plays an important role in fields such as the Internet of Things (IoT).

Part 01,    What is Cat.1

1.1 Evolution of Cat.1

With the rapid development of mobile communications, 4G LTE networks not only meet people's demand for high-speed data transmission, but also provide new opportunities for IoT applications. According to the definition of 3GPP, UE-Category is divided into 15 levels from 1 to 15, among which Cat.1 was defined by Release 8 released by 3GPP in March 2009, and then Cat.1 bis was proposed in Release 13 in 2012 to further strengthen 1Rx (single receiving antenna).

Initially, LTE networks focused on high-speed data transmission, but with the rise of the Internet of Things, the demand for low-power, low-cost, and stable connections has become increasingly urgent. Since 2016, in order to save scarce spectrum resources, the withdrawal of 2G/3G networks in China has gradually accelerated. In this process, migrating medium- and low-speed network applications to LTE Cat.1 is undoubtedly a good choice, and Cat.1 has gradually come to the fore. Cat.1 is designed to provide IoT devices with connections suitable for wide area networks, and is mainly used in IoT and machine communications. It can support massive machine-type (eMTC) communications and has become an indispensable part of the development of the Internet of Things.

1.2 Cat.1 Main Features

Cat.1 has a unique position and characteristics in the field of 4G communications, which are mainly manifested in the following points:

(1) Global coverage and roaming: Cat.1 supports global coverage and can roam on a variety of different operator networks. This means that devices can communicate seamlessly between different regions and countries, providing wide connectivity.

(2) Reliable connection: Cat.1 technology provides stable and reliable connection, ensuring data transmission and communication quality between IoT devices.

(3) Bandwidth limitation: Compared with traditional mobile broadband communications, Cat.1 technology uses a narrower frequency band for communication, thereby reducing power consumption and cost. It is suitable for application scenarios with low data demand, such as IoT devices.

(4) Low latency and fast transmission: Cat.1 has low transmission latency, with uplink and downlink peak rates of 5 Mbit/s and 10 Mbit/s respectively, enabling fast data transmission.

(5) High efficiency energy consumption: Cat.1 is designed for low power consumption applications, able to work in energy saving mode and extend battery life. This allows the device to run continuously for many years without frequent battery replacement.

Part 02, Cat.1 and narrowband communications

As part of IoT applications, Cat.1 has natural commonalities with narrowband communication technology. The goals of the two are very consistent, both emphasizing low power consumption, stable connection, and high coverage, which allows them to be seamlessly combined with each other to jointly optimize data transmission. The characteristics of Cat.1 in terms of connection quality and stability are closely matched with the advantages of narrowband communication in terms of low power consumption and long battery life.

Narrowband audio communication technology refers to audio transmission and communication in a low-bandwidth network environment. In narrowband audio communication, there are two technologies that can be used to reduce the bandwidth required for audio transmission, namely:

• Discontinuous Transmission (DTX) technology
• Multi-Frame Packet (MFP) technology

The combination of DTX technology and MFP can reduce the audio bandwidth usage by about 70%. We will introduce these two technologies in detail in the subsequent article "A Cat's Alone Journey - Cat.1 and Narrowband Communication (Part 2)".

Part 03: Cat.1 combined with narrowband audio and video communication in the IoT field

Cat.1 communication has the characteristics of low power consumption and stable connection, making it an ideal choice for smart IoT devices. Especially in voice communication in the IoT field, the advantages of narrowband communication technology have been significantly demonstrated. Low-power IoT terminals such as smart doorbells and door locks can save a lot of valuable bandwidth resources by adopting narrowband communication while meeting voice communication needs.

In order to better meet the market demand for multimedia interaction of IoT smart terminals, China Mobile Smart Home Operation Center (hereinafter referred to as China Mobile Smart Home) uses the AIoTel system as its foundation and utilizes the combined advantages of DTX and MFP narrowband audio technologies to reduce the data resources required in the audio communication process by more than 70%. For devices using mobile networks, the saved traffic resources are very considerable, which can greatly extend the usage time of users' traffic packages and reduce users' usage costs.

China Mobile has launched for the first time a smart door lock based on Cat.1 narrowband communication, which fully utilizes the connection characteristics of Cat.1 and narrowband audio communication technology. It has the advantages of fast unlocking, long battery life, high security, and flexible remote control. It can meet the needs of users in areas without WiFi coverage for smart IoT devices, and lay the foundation for building a cellular IoT low-power multimedia communication ecosystem.

picture

picture

Part 04, Summary and Outlook

The rapid rise of IoT technology in the digital age is changing our lifestyles and business models, from smart homes to industrial automation, from health monitoring to city management. As a low-power, low-cost connection method, Cat.1, combined with the optimized bandwidth of narrowband communication technology, provides an ideal solution for different application scenarios. China Mobile Smart Home will rely on China Mobile's widely covered mobile 4G network to further explore the application of Cat.1 in the IoT ecosystem.