To liberate the distance between people and equipment, how to complete remote control in the 5G era

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5G has brought new features such as high bandwidth, low latency, and local offloading. As the forerunner of 5G technology, remote control has important value for the intelligent era. 5G can meet the synchronization needs of more information in remote control applications. The article will systematically introduce the theory and use skills of remote control in the 5G era.

The concept of the Internet of Things has been proposed more than ten years ago, and it mainly relies on the mobile communication network to realize the transmission of its functions. In some device control scenarios in the field of Internet of Things in the past, we have more or less seen remote control technology, but limited by the network conditions and technical scenarios at the time, most applications are simple operations on devices. It will not synchronize too much real-time information on the spot. With the continuous development of communication technology and the emergence of 5G technology, intelligent life is getting closer and closer to everyone.

The emergence of 5G brings new features such as high bandwidth, low latency, and local offload to mobile networks. At the same time, as the leader of 5G technology, remote control has important value for the intelligent era. 5G can meet the synchronization needs of more information in remote control applications. It can be said that the maturity of 5G technology has promoted the acceleration and landing of remote control.

At present, the typical application scenarios of 5G remote real-time control are mainly: remote takeover of closed areas such as ports, open-pit mines and autonomous vehicles under open roads in accidents, and high-risk or harsh environments such as cranes, cranes, chemicals, and underground mines. Remote operations in the environment. The former is used as a necessary emergency intervention method to better assist the local intelligent work of equipment such as automatic driving; the latter is used as a normal operation method to enhance the operation experience of front-line personnel.

With the digital development of the industry, unmanned and remote operations will gradually become industry trends in scenarios such as mines, ports, and logistics in the future, and C-end applications such as cloud taxis and cloud-based driving will gradually rise. It is expected that 5G remote real-time control will open up a market space of tens of billions or more and penetrate into various fields to promote social development.

The main pain points and related technologies of 5G remote real-time control

5G remote real-time control is mainly aimed at solving the remote control of complex equipment such as vehicles, and needs to support human-computer interaction based on real-time scenarios.

In order to better restore the real operating scene at the remote end and facilitate more detailed real-time control by personnel, in addition to traditional status data, real-time synchronization of on-site video, audio and other media data will be introduced in the 5G remote real-time control. In order to ensure the safety and smoothness of remote control, the synchronization of these rich field data and meticulous remote operation has very high requirements for real-time perception, reliability and timeliness of operation.

Taking a very representative vehicle remote control scenario in the 5G remote control field as an example, it has strict time delay requirements for the timely return of information such as car-side video pictures. The following table is a simple analysis based on the real-time requirements of vehicle remote control in mobile scenarios. It can be seen that for remote vehicle driving at low speeds, it is recommended to achieve a delay of 200ms, and the ideal indicator is to achieve a time of 150ms. Extension. At present, the remote control delay based on traditional video surveillance is often around 300-400ms. This puts high demands on the network delay, the delay of audio and video communication, and the delay and reliability of control signaling.

In order to reduce the end-to-end delay of audio and video in 5G remote control and ensure the reliability and timeliness of control, it is necessary to introduce technologies such as real-time audio and video communication, control signaling synchronization, and 5G network optimization to jointly improve the control experience.

• Real-time audio and video communication: mainly solves the real-time nature of audio and video communication; in the end-to-end delay of remote control, the proportion of audio and video communication delay often reaches about 80%; therefore, the delay of audio, video and frequency communication for remote control The optimization is very important; in addition, in remote control scenarios, multiple video streams are often used to restore the scene. A single device may involve simultaneous transmission of 4-8 channels of high-definition video streams, which will occupy higher network bandwidth. The optimization of bit rate and freeze rate is also a factor that the remote control is very concerned about.

• Control signaling synchronization: mainly solves the transmission reliability and delay of control signaling; control signaling will ultimately affect the actions of field devices, so the reliability requirements are very high. On the basis of ensuring the delay as much as possible, it needs to be achieved Extreme reliability, and consider the detection and handling of various unexpected situations.

• 5G network optimization: Mainly solve the low-latency transmission of uplink audio and video data, and ensure the downlink transmission of control signaling. The basis for the synchronization of audio and video communication and control signaling is the network. Under severe delay and reliability requirements, the application and the network need to be coordinated and optimized to improve end-to-end performance.

It can be seen that these three technologies are optimized and improved around the pain points such as the delay and reliability of 5G remote control. Among them, 5G network optimization is the base, real-time audio and video communication is the core of delay optimization, and control signaling is synchronized. It is the key to ensure control reliability and safety. In addition to these technical optimizations, in the large-scale application of 5G remote control, the system architecture is also very important, which will directly affect the flexibility and scalability of 5G remote control.

Four mainstream architectures of 5G remote control system

The 5G remote control system mainly includes necessary elements such as controlled terminal, control terminal, 5G network, and optional elements such as remote control server. The following are some common system architectures in current 5G remote control applications:

1) Architecture A: Direct bicycle connection + separation of video and control

This architecture is based on simple expansion of traditional video surveillance + traditional CAN bus control to realize remote control in a simple one-to-one scenario.

• Video link: Multiple cameras are connected to a video gateway like NVR and connected to a 5G private network. The control end will use the pre-configured IP of the video gateway to pull the stream to obtain the remote audio and video stream;

• Control link: Based on the CAN bus, the CAN bus data is transmitted over the IP network provided by the 5G private network through CAN to Ethernet and then CAN, completing the controller CAN interface of the controlled end and the controller CAN of the control end Interface docking;

Although this architecture can easily achieve the basic functions of remote control, the connection between the controlled end and the control end relies on the advance configuration of the IP at both ends and the planning of the network channel. The flexibility is insufficient and it is difficult to apply to the multi-vehicle scenario of large-scale deployment. ; In addition, limited by the delay of traditional video surveillance, its end-to-end delay is also relatively large.

2) Architecture B: direct bicycle connection + video and control integration

The difference of architecture A is that the controlled end gateway incorporates the control capability of the CAN interface and is upgraded to a remote control gateway instead of a pure video gateway such as a conventional NVR. In this way, the collection and control of video, audio, and other sensor data such as vibration, attitude, and vehicle working conditions can be integrated in the gateway, making the scalability of remote control and the richness of on-site content stronger, and compared to traditional video The video delay of the surveillance solution can also be further optimized; in addition, the gateway side can also define the protection strategy of control commands to deal with network fluctuations and unexpected situations, which has better reliability and security.

Also due to the direct connection of bicycles, this kind of architecture still has great flexibility issues in the multi-vehicle scenarios deployed on a large scale.

3) Architecture C: Unified forwarding

Due to the limitations of the deployment of the bicycle direct connection architecture, a unified forwarding architecture has emerged; multiple controlled terminals and control terminals are all connected to a unified remote control server. The remote control server plays the role of connection forwarding to ensure the connectivity between the controlled end and the control end.
Based on this architecture, the control end and the controlled end can transfer through the remote control server, and directly establish a connection according to their respective IDs, without knowing the other's IP in advance, and without relying on the IP reachability of the networks at both ends.
Although this architecture greatly simplifies the complexity of large-scale scenario deployment, due to the introduction of intermediate servers, higher requirements are placed on the forwarding capability and reliability of the servers, and intermediate forwarding delays are also introduced for remote control services.

4) Architecture D: Converged Architecture

The integrated architecture was proposed by the Tencent Cloud 5G team and used for its 5G remote control products. It has been applied in multiple scenarios such as mining areas, ports, and terminal logistics.

In this architecture, the remote control server is mainly responsible for the control plane, unified management of the controlled end remote control gateway and the control end control PC, so the control PC can still apply to the remote control server for connection establishment based on the controlled end ID. The IP of the controlled end needs to be pre-configured.

During the transmission of audio, video, control commands, and sensors, the data plane still uses the traditional direct network communication method as far as possible. In the case that the direct network is unreachable, the media relay server is used for relay.

This architecture combines the advantages of the bicycle direct connection architecture and the unified forwarding architecture. It can greatly simplify the complexity of large-scale deployment scenarios while maintaining the advantages of low latency in the bicycle direct connection architecture. The requirements for remote control servers are also great. reduce.

In the long run, the converged architecture is the future development trend of 5G remote control. Because there are many 5G remote control application scenarios, the network scenarios are also more complicated. There are private network scenarios (such as remote control of mines and ports) and public network scenarios (such as terminal logistics, trunk logistics, and cloud taxis). 5G MEC combines edge distribution and calculation to further reduce network delay. Therefore, in the system architecture, it is a very good choice to separate the control plane and the data plane, which can deploy the media data plane more flexibly, adapt to multiple network environments, and give play to the advantages of 5G MEC.

In the future, with the continuous development of 5G remote control applications, in addition to the continuous evolution and upgrading of technology and architecture, it is believed that the standardization of the audio, video and control interface protocols of the controlled end and the control end will also continue to improve, so that different vehicles and cockpits can be realized. Interoperability.

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