Cat.1 is popular? Where did it come from?

Cat.1 seems to have suddenly become popular.

Recently, many bigwigs have endorsed it, and there has been a lot of discussion online, with everyone unanimously optimistic about it.

What is Cat.1? How does it relate to NB-IoT and eMTC? We also often talk about Cat.M1 and Cat.NB-1 . Are they the same thing?

Today, Xiaozaojun will sort out the whole story for you.

This Cat is not it:

Nor is it:

It is the abbreviation of the English word Category, which means category or type.

To be precise, "Cat. X " refers to the LTE UE-Category .

LTE needs no explanation, right? UE stands for User Equipment.

Therefore, "Cat. X " refers to the user terminal category under the LTE network.

Why does LTE need to classify terminals?

When 3GPP was developing the LTE standard, it had the original intention of providing different levels of network service capabilities for different users. Therefore, they proposed the important concept of QoS (Quality of Service) in LTE.

For different services and different QoS, the network provides different bandwidths and access priorities.

Definition of QoS levels in 4G standards

In addition to the network, 3GPP also plans to classify user terminals (including mobile phones, wearable devices, IoT devices, etc.).

Therefore, in March 2009, when 3GPP released Release 8 and formally proposed LTE, it simultaneously launched a total of five terminal categories: LTE Cat.1, Cat.2, Cat.3, Cat.4, and Cat.5.

Later, in R10, Cat.6, Cat.7, and Cat.8 were defined. In R11, Cat.9, Cat.10, Cat.11, and Cat.12 were defined. In R12, Cat.13, Cat.14, and Cat.15 were defined.

As shown below:

Different Cat, different rates

No! The sharp-eyed students noticed that there are 16 categories in the table above. How come there is an extra Cat.0?

There is something fishy!

Yes, there is indeed a Cat.0.

When R8 was released, the 3GPP people had a new idea. They thought that it was not enough to use LTE only for mobile phones. The Internet of Things market must be the trend of the future, so they should "keep a hand" and develop a professional Internet of Things terminal level.

As a result, there is a terminal level Cat.1 with an uplink peak rate of only 5Mbit/s, which is specifically designed for the Internet of Things industry.

In the early days of LTE development, Cat.1 was not paid much attention by the industry. With the gradual popularization of wearable devices, Cat.1 has gradually been taken seriously by the industry.

However, Cat.1 terminals require the use of two antennas, which is still "too demanding" for wearable devices that are extremely sensitive to size (generally only equipped with one antenna).

Therefore, in R12/R13, 3GPP has optimized the Internet of Things many times.

First, a new terminal level Cat.0 was added in R12 , which abandoned the support for MIMO (multiple antennas), simplified it to half-duplex, reduced the peak rate to 1Mbit/s, and reduced the terminal complexity to 40% of that of ordinary LTE terminals. In this way, the cost requirements of the Internet of Things were initially met.

However, although the channel bandwidth of the Cat.0 terminal is reduced to 1.4MHz, the receiving bandwidth of the radio is still 20MHz (too large).

Therefore, 3GPP added Cat.M1 level terminals in R13 , with channel bandwidth and RF receiving bandwidth both of which are 1.4MHz, further reducing terminal complexity.

Cat.M1 is what we often called eMTC ( enhanced Machine-Type Communication ).

In addition, 3GPP also added a new Cat.NB-1 in R13 , whose receiving bandwidth is only 180kHz.

This Cat.NB-1 is our NB-IoT (Narrow Band Internet of Things).

eMTC also has another name, LTE-M , LTE-Machine-to-Machine, LTE-machine to machine. In other words, machines communicate with each other using LTE, which is very straightforward and suitable for the LTE network of the Internet of Things.

By the way, Machine-to-Machine is usually abbreviated as M2M, which you may have heard of.

Do you understand? Cat.1, Cat.M1 ( eMTC ) and Cat.NB-1 ( NB-IoT ) are all from the same mother, 3GPP, and are all used for the Internet of Things.

Among the three, NB-IoT has the slowest rate, followed by eMTC, and Cat.1 has the fastest rate (5Mbps). The following figure shows their positioning compared to other Cats:

Why is Cat.1 becoming more and more popular now?

To put it simply, the industry originally planned: applications with extremely low speed requirements, such as smart meter reading, should be on NB-IoT; and cameras or some IoT applications that require higher speeds should be on eMTC.

As a result, the development of eMTC was not satisfactory. Operators were reluctant to invest, the industry ecosystem did not catch up, and there were too few domestic cases. Everyone thought, why not just find a substitute, so the existing Cat.1 was pushed to the forefront.

Cat.1 is based on the existing LTE network and fully reuses existing LTE resources, without the need for additional investment. Moreover, Cat.1 chips and modules are more mature and very cheap, and can form economies of scale in a short period of time.

With the accelerated withdrawal of 2G/3G networks, operators have begun to actively guide industry users to use NB-IoT and Cat.1 terminal modules, which is also one of the reasons why Cat.1 is becoming increasingly popular.

Okay, do you understand the differences between Cat.1 , Cat.M1 and Cat.NB-1 ?