Hytera's CTO Questions Whether 5G will Completely Replace PMR Networks

Rapid development of 5G technology has enabled network slicing, edge computing, and other technologies to achieve PMR communication on the public network. This has led some people to question whether the PMR network is necessary.

2022 will be a year of growing 5G infrastructures, network intelligence (NI), and fiber broadband, as well as a year of booming digital economy, information and communication technology (ICT). It is also a year for the PMR network to determine how and where it will be, thanks to 5G. PMR networks may not be as well-known as public networks, but they were invented much earlier and were used in specific scenarios such as police radio communications.

The public network is more familiar to most people than the PMR network. Indeed, PMR network communication predates public network communication. It was primarily used in specific scenarios, such as the radios used by police officers to perform general duties.

Simply put, PMR networks are typically built to meet the demands of user organization management, safe production, dispatching, and command. Public networks are less reliable and secure than PMR networks. They are primarily used in public safety, public utilities, industry, and commerce. Their serving objects are large in scale, powerful, and have high PMR network communication product requirements.

The development of the telecommunication industry in China in recent years has spurred rapid growth in the market scale of PMR network communication. According to data released by the Qianzhan Industry Research Institute in April 2021, the market scale of China's PMR network communication reached US$ 2.5 billion in 2016 and US$ 5.3 billion in 2020, with an estimated amount of US$ 6.0 billion in 2021. PMR network communication is playing an essential role in the Chinese communication field.

Rapid 5G technology development has enabled network slicing, edge computing, and other technologies to achieve PMR communication on the public network. As a result, some people have questioned whether the PMR network is even necessary.

In this regard, the Forward-The Economist's interview column "Foresight" invited Mr. Sun Pengfei, the CTO of Hytera, to discuss the development direction and future trends of the PMR network under 5G.

Will PMR Networks Be Replaced by 5G Public Networks?

Sun Pengfei responded to the above-mentioned concerns by stating that, regardless of the differences between the PMR network and the public network, the essence of communication is to transmit information to the destination in a timely, accurate, and secure manner. "Timely" has two meanings. The first is the ability to transmit (network controllable), and the second is the ability to deliver within the time frame specified (delay controllable). "Accurate" means that there was no loss or error during transmission (controllable interference for licensed spectrum resource). The term "secure" refers to the fact that information is not stolen or tampered with during transmission.

Different user groups have different needs for the three preceding factors, and different needs have different costs. As a result, two types of networks are used: self-built PMR networks and operator-provided public networks.

The first PMR networks were built and maintained by users, and they primarily used narrowband large-cell coverage. They have a controllable network, secure and reliable information transmission, and controllable transmission delay, and they meet the requirements of voice communication and small data transmission. PMR networks are cost-effective and affordable for users due to low network investment and O&M costs.

With the arrival of the 4G era and the impact of high-speed and high-bandwidth services on the public network, PMR network users may have a need for broadband services. However, when it comes to building large-bandwidth PMR networks, users face a slew of challenges, including a scarcity of licensed spectrum resources and high network construction and O&M costs.

Furthermore, in the 4G era, the public network focuses on the development of mobile Internet and is aimed at the general public rather than industry users. The public network's information transmission timeliness, accuracy, and security cannot meet the needs of public security user groups. As a result, public network transmission is only used for services with low timeliness requirements, such as query and unidirectional uploading, as well as mobile police services with security measures.

With the arrival of the 5G era, the public network now offers a higher rate, shorter latency, and greater capacity, and its target groups have expanded to include industry users and device-to-device communication.

To meet the needs of industry users for the PMR network, 5G supports slicing technology to provide specific PMR network attributes. As a result, someone has suggested that the public network will eventually replace the PMR network. They believe that the public network can meet all of the PMR network's requirements, and that the PMR network is no longer required.

That is actually not the case. The public network struggles to offer the following three features of the PMR network:

• First, a controllable network.
• Second, more secure communication.
• Third, controllable delay.

These three features are fundamental requirements of the PMR network and are essential to industry users who use the PMR network, especially public security users.

Furthermore, PMR communication on the 5G public network has an unresolvable issue. Even though operators offer theoretically feasible L4 slicing for exclusive carrier frequencies, it is prohibitively expensive for operators to establish physically isolated and independent core networks and base stations for each industry user. The vast number of industry users and network investment increased by N times, making profit difficult for operators. Because industry users are unable to invest in or maintain these networks, operators are unable to profit. PMR communication over the 5G public network simply shifts the investment target from industry users to operators.

One idea is to share the physical networks of operators and use logical division to provide low-level fully shared or partially exclusive slicing (L2/L3). This, however, violates the security redline of critical departments such as public safety. It is an unsolvable issue. Operators' 5G slicing, the Open Radio Access Network (O-RAN) with base stations and some core networks established by users, and User Plane Function (UPF) deployment towards the edge can meet some industry users' broadband communication needs. In short, the PMR network does not reject 5G technology and must properly implement it.

Finally, the narrowband PMR network and the public network are mutually beneficial and will coexist for a long time. It is an unavoidable trend in the development of the PMR network to provide more bandwidth. However, the relationship between broadband and narrowband is complementary rather than substitutive.

The narrowband large-cell coverage PMR network has low network construction and O&M costs, making it suitable for users who want to build their own nationwide large networks. The broadband small-cell coverage PMR network, on the other hand, is best suited for small areas or hotspots. While the broadband network can support narrowband services in its coverage area, it is less cost-effective than the narrowband network. The cost-effectiveness of combining broadband and narrowband networks is higher.

As a result, Sun Pengfei believes that the public network will never completely replace the PMR network. Some industry users with low security requirements may be able to replace their PMR network with the public network.