Telecommunications and broadcasting are part of daily life. Behind them, unseen technology competition and industrial change continue. "Shintongbangtong" is a series that explains telecommunications and broadcasting technology and market trends in an easy and interesting way. It looks at the latest technology, policy and market changes with added on-the-ground context.

[DigitalToday reporter Jin-ho Lee (이진호)] Imagine World Cup street cheering or a large concert venue. Tens of thousands of users pull out their smartphones at once. They film the match and post it on social networking services, make video calls or watch live streams. As traffic concentrates in a specific area and time, internet access can become slower than usual or call connections can be delayed.

The problem is that event staff and safety personnel use the same network at that time. Videos uploaded by spectators and communications by safety personnel sharing on-site conditions compete for the same network resources. If an emergency occurs, even a simple slowdown could lead to delays in on-site response.

◆One 5G network implemented as multiple virtual networks

Network slicing is a technology that can stably maintain communications quality for specific purposes when users crowd in. It divides a single physical mobile network into multiple independent virtual networks. Like the English word "slice", it can be understood as cutting one network by use and providing different services for each.

Using a road analogy, it is similar to assigning different lanes depending on purpose even as regular cars, buses and emergency vehicles use the same road. It can provide general users with bandwidth needed to watch high-definition video, and give safety personnel a communications environment with higher stability and connection continuity.

It does not physically install multiple networks. It uses shared infrastructure such as base stations, backhaul and the core network, while logically separating network resources and functions through software. Each slice can be set with different bandwidth, latency, reliability and security levels, and the overall communications path is configured and managed to fit the service purpose.

The need for network slicing grows as more services use telecommunications networks. That is because each service requires different communications conditions. For high-definition video streaming, uninterrupted transmission of large volumes of data is important. Autonomous driving and remote control place more importance on response speed and stability than on data volume. In areas that send small data, such as water and power meters, connecting many devices simultaneously and reducing power consumption take priority over speed.

◆'5G SA' is key to implementing network slicing

That is also why network slicing is considered a core 5G technology. It supports ultra-fast communications for transmitting large volumes of data, ultra-low-latency communications needed for factory equipment and cars, and massive machine-type communications connecting numerous sensors, all on a single network to improve network utilization. A shift to 5G standalone mode, or SA, is also important to properly implement network slicing. Early commercial 5G networks, including in South Korea, were built mainly around non-standalone mode, or NSA, which uses existing 4G core networks. While it uses 5G base stations, much of the network control functions depend on 4G systems.

By contrast, 5G SA builds not only base stations but also the core network, which handles data processing, device authentication and communications path control, using 5G-only technology. That makes it easier to configure network functions in software and flexibly adjust resources depending on service needs. It also makes it possible to manage usage and quality by slice in real time and to isolate slices so that disruptions do not spread to others when failures occur.

In a smart factory, for example, communications controlling production equipment and employees' general internet use can be separated into different slices. A slice for equipment control can be given low latency and high reliability, while office communications are provided general data quality. At disaster sites, communications for rescue teams and firefighting and police personnel can be separated from general user traffic.

Actual use cases have also emerged. Recently, the Ministry of Science and ICT confirmed that an "emergency rescue communications priority transmission service" proposed by the National Fire Agency and three carriers meets the special service requirements under net neutrality guidelines and began the service in earnest. Emergency rescue communications priority transmission is a service that prioritizes transmission of calls between on-site National Fire Agency personnel and general users.

After LG Uplus first proposed it to the National Fire Agency, SK Telecom and KT also decided to participate, expanding the scope of application. KT, which has about 60 percent of the National Fire Agency's work devices in South Korea, or about 8,400 units, completed a demonstration of enterprise-only 5G SA using only 5G throughout the process for the Jeonnam Fire Headquarters, minimizing data latency.

Future uses are also wide-ranging. It is also highly useful in broadcasting. To transmit high-definition video filmed by broadcasters at sports games or performances over wireless networks, stable upload quality is needed. Applying a separate slice to broadcast cameras can provide a certain level of uplink quality even if data usage by nearby spectators surges.

The spread of AI services also increases the potential use of network slicing. Robots, smart glasses and vehicles need stable uplinks and low latency to send video and voice information they collect to AI servers and receive analysis results in real time. The need to subdivide communications conditions required by each AI service is also bound to grow.

◆Could it become a new revenue model for carriers

For carriers, network slicing could become a new business model. Until now, mobile products have mainly been differentiated by data allowances and speed. If network slicing is commercialized, it would become possible for companies or institutions to contract for the communications quality they want and pay costs accordingly. Carriers are expected to configure slices to meet required conditions and guarantee quality through service level agreements, or SLAs.

KT recently reviewed new commercialization potential through demonstrations. On June 25, it carried out a demonstration test of 5G SA-based network slicing technology at a World Cup street cheering site in the Gwanghwamun area of Seoul. Kim Young-geol (김영걸), head of KT's Customer Business Division, said, "This demonstration is a starting point that shows 5G SA network slicing can develop into a new business model that designs and provides communications tailored to the customer's purpose and situation."

There are also many challenges to resolve. Because network slicing shares one physical infrastructure, if overall network capacity is insufficient, there is also a limit to the resources that can be allocated to each slice. If resources are allocated with priority to a specific slice, there is a need to examine the possibility that communications quality for general users could be affected.

That makes it essential for carriers to have advanced management technology that grasps overall network conditions in real time and automatically adjusts resources by service. Support from devices, network equipment and operating systems is also needed. Splitting only part of base stations is not enough. The same policy must be applied across the radio section, backhaul and core network to guarantee the quality users expect to the end. The process of creating and changing slices and checking for failures also needs to be automated.

There are also security issues. Logical separation of slices does not eliminate attack risks. Because multiple slices share some network functions and physical equipment, the level of isolation and access privileges must be designed in detail so that failures or attacks in one area do not affect other services. A system is also needed for carriers to objectively measure speed, latency and stability by slice and verify whether they actually provided the contracted level of quality. If they fail to provide the promised quality, responsibility and compensation standards must be clearly set.

In particular, the debate over net neutrality is ongoing. Net neutrality refers to carriers treating internet traffic equally regardless of content or provider. The ministry's recognition of the special service requirements for the emergency rescue priority transmission service reflected the special nature of disaster safety situations involving firefighting. It is the first case in 15 years since the system was established in which a service has proceeded after meeting the special service requirements.

Protecting socially necessary communications, such as disaster safety or industrial equipment control, is different in nature from providing better quality to services that pay additional fees. Advice has emerged that standards are needed on which services can be given priority and to what level quality for general users must be guaranteed.