After the arrival of 5G, it has brought huge changes to the development of the global communication industry.

This change is not only reflected in the evolution and upgrading of communication technologies, but also in the changes in communication application scenarios. People no longer only pay attention to the consumer Internet represented by mobile phones, but pay more attention to the booming industrial Internet.

Hundreds of industries, represented by industrial manufacturing, energy and power, transportation and logistics, medical education, etc., have begun to introduce advanced communication technologies, carry out digital and intelligent transformation, and move towards the road of digital transformation.

The traditional private network communication technology has been unable to meet the needs of the development of the times. Enterprises need to comprehensively upgrade their internal communication networks to meet the needs of rapid business development.

In fact, in addition to 5G, many communication and IT technologies are being accepted by enterprises and integrated into this once-in-a-century revolution, including campus optical network (PON), Wi-Fi 6/7, Cat.1 , NB-IoT, eMTC, etc.

These technologies basically belong to the underlying connection technology.

Today, what Xiaozaojun wants to introduce to you is an upper-level communication technology, a technology that revolves around business and services. Yes, this technology is the famous IMS.

What is IMS

IMS, the full English name is IP Multimedia Subsystem, IP Multimedia Subsystem. Many readers' understanding of it comes from the previously popular VoLTE business. In addition, 5G messaging (RCS) and 5G new calls (VoNR), which were very popular last year and this year, are also closely related to IMS.

IMS was first proposed in the late 1990s. At the time, it was considered internationally recognized as the next-generation core network communication technology. The 3GPP R5 version, which was frozen in June 2022, completed the early standard definition of IMS, thus pushing it to the commercial stage.

Under the wave of comprehensive IP transformation of major operators in the world, IMS is an indispensable and important system, a unified standard for realizing the integration of fixed communication networks and mobile communication networks, and the cornerstone of the evolution of communication networks from TDM to IP.

Is IMS really that strong? What exactly can it bring?

In fact, the name of IMS (IP Multimedia Subsystem) itself has already revealed part of the answer to us.

First of all, IP, on behalf of IMS is based on IP bearer, and completely adopts IP technology.

The core protocol of the IMS is SIP (Session Initiation Protocol, session initiation protocol). This is an application layer control protocol tailored by the IETF based on the Internet. It is independent of the underlying protocol, is very open and flexible, has strong expansibility, and is especially suitable for multimedia communications.

Secondly, Multimedia (multimedia) means that IMS can implement multimedia services.

Traditionally understood multimedia services are voice, image, audio, video, and so on. The IMS standard divides multimedia services in more detail, including IP telephony services, multimedia conference services, collaborative office services, and communication assistant services.

Finally, Subsystem (subsystem), indicating that IMS is an important component of the entire communication system. It can cooperate with other network systems to realize business functions. For example, IMS cooperates with LTE to implement VoLTE. IMS and 5G cooperate to realize VoNR services. IMS cooperates with instant messaging to realize RCS. ...

Simply put, IMS is a "multimedia server" deployed on an IP network. Through its control and coordination, users on the IP network can carry out multimedia services such as video telephony with each other.

The core goal of IMS is to build a converged platform that has nothing to do with access and supports a wide range of multimedia services, empowers IP networks, and serves customer needs.

IMS was born in 3G and matured in 4G. Its technical standards have been gradually improved, and it has been widely recognized by major mainstream operators, and is widely used around the world.

 IMS and Digital Electric Power Private Network

The power communication private network is the most representative type of private network for domestic enterprise private network communications.

In recent years, under the vigorous promotion of the State Grid Corporation of China (hereinafter referred to as "State Grid"), the digital transformation of the power grid is also in full swing.

The private power network is the basic platform for realizing the digital transformation of power, and an important support for ensuring the smooth flow of power grid dispatching instructions. State Grid's network resources and informatization level are at the leading level in the country on the basis that State Grid has achieved full coverage of factories and stations with all-fiber resources of 35kV and above, as well as self-owned property offices/business offices.

However, there are so many information systems within the State Grid that it is difficult to coordinate efficiently, which has become a key research topic in China's current digital transformation. The integration of information and communication technologies has accelerated the digitization of the power grid, the scale of the network has expanded rapidly, and the "nerve endings" of the power grid have rapidly expanded in the form of explosions. In the information and communication network system that supports power grid security, there are thousands of terminals and devices.

The traditional voice-based program-controlled switching technology faces problems such as shutdown of production and service, high energy consumption, and weak emergency repair capabilities. The softswitch technology has problems such as inconsistent standards, difficult business expansion, and weak collaborative interaction capabilities. They cannot adapt to the needs of the digital development of the power grid.

The networking structure of the State Grid adopts the two-level tandem system of State Grid and provincial companies. With the passage of time, the network structure has become more intricate, the boundaries have become more blurred, the network security, various terminal and system maintenance volumes have increased dramatically, and the problems of weak coordination ability, low emergency support efficiency, poor multimedia communication ability, and insufficient openness have gradually expanded. . All of these have greatly restricted the realization of the State Grid's "digital smart grid" construction goal.

With the development of the new generation of 5G communication technology, State Grid urgently needs to build a new information and communication fusion network based on zero-trust network security and guided by advanced communication technology standards to support the digital transformation of enterprises. A series of problems involving the last mile of access terminal trusted access control, multi-system and application collaborative integration, and cross-network security interoperability need to be resolved as soon as possible.

Therefore, the introduction of IMS into the construction of the power communication private network is the general trend and the necessity of the times.

 The Significance of Introducing IMS into Electric Power Network

State Grid began to introduce IMS technology before 2018. At present, the power administrative switching network of the State Grid has gradually evolved into the IMS switching technology system.

What is the significance of State Grid's continuous embrace of IMS technology?

1. IMS is an internationally established "standard" for a new generation of communication switching technology.

IMS is an internationally recognized standard for fixed-mobile converged networks, and it is also a 3GPP standard that is rooted in Miaohong. Not only 3G/4G/5G will continue to be used, but also 6G in the future. In the process of 6G standard formulation, it is also necessary to optimize and supplement IMS technical standards synchronously.

Therefore, the introduction of IMS technology by State Grid not only promotes the research on the transformation of energy and power enterprises, but also explores and breaks through the key technical problems that restrict the implementation of applications.

Strengthening the research and exploration of IMS in the field of domestic private power network plays an important and key role in enhancing China's right to speak in IMS international standards.

2. It has a standard-leading research value for the construction of a zero-trust information communication network.

Cybersecurity is related to national security. To build a zero-trust network and coordinate various resources in the power grid and information communication network to achieve digital transformation, there must be a "uniform standard" to lead.

The introduction of IMS by State Grid, and based on practical applications, to solve the key technical barriers that restrict the implementation, has the significance of standard guidance for the construction of a zero-trust information communication network for the power grid, and also has important research value.

3. Explore leading solutions for the implementation of 5G applications and digital transformation in the power grid.

As a 5G core exchange and bearer platform, IMS also involves a series of problems such as network security, last-mile access, multi-system collaboration and application interoperability in the exploration of 5G applications in the power grid.

Therefore, in the strategic planning and construction of a zero-trust network with "security" as the red line, exploring and developing key technologies that restrict the application and implementation of the IMS standard can not only help the power grid administrative office communication network and dispatching communication network standardization and standardization, but also help Explore a leading solution for the implementation of 5G applications in power grids and digital transformation.

Main Difficulties Faced by Power Grid Introducing IMS Technology

In the process of introducing IMS technology to the power grid, some difficulties are generally encountered, which are embodied in:

1. Differences in cognition of IMS technology positioning

In the early days of IMS's implementation, many people's cognition of IMS technology positioning was biased.

These people believe that IMS is only based on "calling" needs, and is "similar" to traditional softswitch technology. There are even some manufacturers of softswitch equipment in order to "mislead" users and try to delay the popularization of IMS.

This view and practice hinders and restricts the key technological breakthroughs and research of IMS technology in the digital transformation of power grids.

2. Insufficient awareness of the advantages of IMS technology

As an international communication technology standard, IMS is less well-known among ordinary users. In fact, the technical advantages of IMS are very obvious. Compared with softswitch, it is more "soft", more standardized and rigorous in business definition, and higher in security and reliability. The main advantages are:

(1) Multimedia communication exchange capability

Multimedia switching is the key that distinguishes IMS from soft switching. IMS not only supports SIP protocol video calls, but also supports VoLTE/VoNR video communications, and has the ability to interact with different RTCs and monitor media streams in multiple fields of view.

In addition, IMS also has full-service call transfer capability involving emergency communication support.

The evolution of the IMS underlying technical architecture and the optimization and supplementation of key technical standards will greatly promote the implementation of business models and applications.

(2) The important role of standards in leading multi-system integration

IMS can not only realize the VoIP service of softswitch, but more importantly, it will effectively manage network resources, user resources and application resources, and improve the intelligence of the network.

The IMS standard leads the integration of multiple systems (subsystems), so that users can use multiple terminals across the network and experience a converged communication experience.

3. The lack of openness of IMS technology leads to difficulties in standard formulation and application implementation

The application speed of IMS is not ideal, which is related to the fact that the application of IMS in the world is still in the exploratory stage. The more critical reason is that the openness of the manufacturers is insufficient.

Although IMS is a technical standard, the application needs to be developed in combination with the user's own needs. In view of the lack of openness of equipment manufacturers, even if State Grid has strong professional development capabilities, it cannot effectively participate in the development of IMS standards and the research on key technologies for application and implementation.

As a result, the security of building a zero-trust information communication network, last-mile access, multi-system collaboration and application interoperability, etc., directly restrict the further integration of AI, big data, cloud computing and other advanced technologies to digital transformation research and development. explore.

 The role of IMS in the exploration of 5G applications in power grids

As early as 2019, before the official commercial use of 5G by domestic operators, about 2017, the electric power network started the application research for 5G.

Since then, for various application scenarios of "electricity + 5G", the group headquarters and local power grid companies have cooperated with different communication operators to carry out pilot tests of different depths.

For example, Shaanxi Electric Power Co., Ltd. has launched the first power application pilot of 700Mhz low-band 5G in radio and television.

The pilot is mainly based on the current business status of the electric power supply service commander who is unable to command specific staff, cannot supervise and control the work situation and progress on site, cannot accurately control the command, and the command loses contact. The application of 5G in individual command and emergency repair is carried out. In-depth testing and validation.

First of all, based on the IMS technical standard, under the guidance of the electric power expert team, the world's first 5G physical isolation multimedia communication gateway was developed to solve the intercommunication obstacle of ultra-low-latency video services between the electric power IMS private network and the operator's IMS core network.

Secondly, through the development of the two-way four-factor terminal KEY encryption technology, the security isolation audit of the terminal that communicates with the IMS private network video services is further strengthened, and a security-based zero-trust information communication network system is built. In this way, a two-way command system with no scope of use and scene restrictions is built to realize the access of individual soldiers and complete the command and supervision of individual soldiers.

After the verification and development of the 5G pilot application, a number of key technical obstacles that restrict the application of the application were finally solved.

Epilogue

The IMS technology itself is mature enough. Since the domestic operator's 4G network has fully introduced IMS, the application of IMS has achieved many achievements and experiences. However, due to key technical obstacles, professional cognition, business model and openness, etc., which have been in the exploratory stage, there is still a lot of room for the application of IMS.

In September 2021, the three major domestic operators will realize the interconnection between IMS networks, indicating that the construction of a new communication network ecosystem led by IMS standards has begun.

Following the trend of the integration of the energy revolution and the digital revolution, State Grid Corporation creatively proposed the strategic goal of building a world-class energy Internet enterprise with "three types and two networks". Shaanxi Electric Power actively responded to the spirit of the dual carbon and digital transformation exploration document proposed by the State Grid, and took the lead in carrying out the pilot application of IMS technology in the power grid, and achieved national leading results.

It is believed that with the passage of time, the integration of IMS and power private network communication will become more closely. IMS will germinate in more private network scenarios, and incubate a wide variety of digital multimedia applications, helping enterprises improve production efficiency, improve business processes, and ultimately help enterprises successfully achieve digital transformation.