"The 5G mobile communications market, which was aiming for commercialization early this year, has been launched as of April. There has been a lot of talk about service quality, but as a technology engineer, the claim of being the world's first is also a meaningful statement. However, from the perspective of an industry engineer, there are still some technological shortcomings to call it true 5G, so we looked into why it is difficult to call the current 5G true 5G."

3 Reasons Why 5G Can't Be Called 5G, Even Engineers Know It!

“In reality, it seems that low-latency service as perceived by users is not possible.
“The low latency communication between the user and the server attached to the base station seems to be working well and is a good technology, but there are still issues to be resolved before it can become a practical low latency service between the end-to-end.”
2019 KRnet ETRI Dr. Taesik Jeong Presenting

Why can’t we call current 5G true 5G?

To understand why the current 5G service is not a true 5G service, it can be easily understood by comparing it with the services used by 4G mobile communication users, such as 3GPP LTE and LTE-A, which we are familiar with.

Although current 5G mobile terminal users claim to be experiencing speeds of up to 20 Gbps based on data released by telecommunications companies, the actual usage cases by users are not much different from the services used via existing 4G LTE, such as movie downloading, face-to-face communication, and accessing and playing high-speed games. In the industry, it appears to be about the level of test runs of 5G-based autonomous vehicles. Although it is said to provide an actual VR service, it is closer to a VOD server that you watch after downloading rather than a VR service through real-time streaming between end-to-end.

However, the 5G service that we initially heard of requires a large amount of real-time data communication that is difficult to compare with the services we are using now, such as VR/AR, AI Assistant, Auto Vehicle, Smart City, Robot, Disaster, etc. as shown in the figure below. In other words, a service that can comply with a delay of between 1ms and 10ms and handle a speed of 80Mbps to 2Gbps per second end-to-end. This is what we first called 5G.
- Delay issues
First, the most important point that the 5G we use cannot be called 5G in terms of engineering is that it cannot be networked based on low latency between 1ms and 10ms between end-to-end. In order to guarantee natural real-time communication between people and people, and people and objects, a latency of 10 to 15ms must be guaranteed to enable natural communication. In the network, a latency of less than 2ms must be guaranteed because the delay in traffic movement between systems must be taken into account. In the case of wired networks, it is said that current optical cables guarantee 0.5ms per 1km. In this case, real-time performance can be guaranteed up to 400 km, so it can be said that real-time performance on the wire is currently sufficiently guaranteed.

However, in the current 5G, the end-to-end delay time is 39.9ms based on the current H.264 capture image transmission standard when viewed wirelessly, so real-time is not guaranteed between users or in remote locations. Unlike general communications, this can easily lead to loss of life or large asset damage in mission-critical fields.

To solve these problems, telecommunications companies are applying computing services that analyze, process, and store data at the edge, such as MEC (Multi Access Edge Computing). In other words, instead of transmitting all data exchanged by users to a centralized cloud, only the data deemed necessary at the edge is transmitted to the cloud, and most of it is processed at the edge, reducing latency, and this technology is being applied to high-bandwidth applications.
- Issues with inadequate standards
Second, high-precision networking technology for stable provision of remote control-based industrial convergence services has not even been established as a standard yet.

Current industrial networking technology, called TSN, can be considered the fastest and most reliable next-generation industrial networking technology based on Ethernet. The IEEE 802.1 TSN Task Group is establishing standards, and is currently determining various types of environmental requirements for linking 5G communications with TSN technology and developing them by dividing them into branches.
“5G is wireless communication. It transmits information to numerous nodes wirelessly. Because it is wireless, the real-time and time determinism of 5G cannot satisfy the precision of machines. Also, it is not possible to use 5G for internal machine communication. “Therefore, to bring 5G data down to the OT domain, it must be used in conjunction with TSN.”
This is the industrial world's view on 5G from B&R Vice President Sa Jae-hoon's interview with our magazine in April.

In order for the 5G communications currently in use to be integrated into industrial fields such as smart factories, the standardization work on TSN technology for 5G support in IEEE must be completed.

Currently, IEEE has been conducting standardization on TSN since 2012, and IETF has also been conducting standardization work on IP/MPLS-based DetNet technology to expand the functions of TSN since 2014.

According to ETRI, which is developing technology for TSN in Korea, there are currently no products (chipsets, endpoints, switches) that fully support TSN as TSN is currently in the process of international standardization.

Looking at the current IEEE standard status of TSN, time synchronization, traffic losslessness, and packet scheduling have been completed, but control and profiling for actual field use are in the initial stages, and it is impossible to implement the part of connecting 5G and TSN in industrial fields by linking with actual 5G.

- Infrastructure issues
Third, high-availability networking technology for real-time interactive, high-precision remote control services is still lacking.

No matter how much the delay time is reduced in the network, if a fault occurs on the line and packet loss occurs, the service must retransmit the packet again, and in this case, delay may occur due to the retransmission. Additionally, data collected in real time may be in a critical situation where it cannot be resent if lost.
In this way, it is not only important to reduce delay time, but technologies such as data survivability, which is availability in the network, must also be developed in parallel.

Existing survivability technologies are traditionally used to protect voice services, providing a quality that ensures that users do not experience any disconnection when making a call within 50ms in the event of a call interruption.

At this level of survivability technology, practical data recovery can be considered difficult for mission-critical services.
In some cases, there are mission-critical situations that require a recovery speed of 2ms or lossless operation, so existing protection switching technologies cannot help but have difficulties in real-time interactive and high-precision remote control.

Dr. Taesik Jeong of ETRI, who presented a 5G solution for ultra-low latency at KRnet 2019, said, "If data protection and switching technology so far has only transmitted data when a lot of traffic is collected, in the future, protection and switching technology suitable for real-time critical services between end-to-end should be developed, and a network should be built to secure as many backup resources as possible to ensure high data survivability, and a corresponding technology mechanism should be prepared." He added, "In addition, it is necessary to study efficient survivability mechanisms or methods in terms of actual construction costs."

Which media in the pastIn the past, he said, “What is 5G?” and “5G is both a technical term and a marketing phrase.” In order for South Korea’s telecommunications technology, which launched the world’s first 5G service in 2019, to become “5G that engineers can call 5G,” the three basic elements of ultra-high-speed communications, “low latency, communication standards, and infrastructure,” must come together to establish itself as a 5G with a high degree of technological perfection.