In today's digital and intelligent era, voice service is developing and evolving at an astonishing speed. From intelligent assistants to customer service, from voice translation to navigation guidelines, a variety of scene-based voice services are widely used in a variety of industries.
Imagine a tourist using a voice navigation application to get accurate route guidance through simple voice commands, eliminating all tedious operations. And now when we are in the car, we no longer use buttons to adjust the seats, we only need to say a voice command to control the opening of the air conditioner, the closing of the windows, and so on. These scenes show that the communication voice service greatly facilitates our lives.
Voice service can be said to be the most basic and important service in mobile communication, so is there any change in the transmission of voice service from the earliest 2G to the present 5G?
The development of voice service in 2G/3G2G and 3G era, our voice service uses CS (Circuited Swiched- Circuit switching) technology.
That is, the mobile phone needs to establish a separate and resource-intensive line when making a call, and the line will not be released until the end of the call. To put it simply, when we make a call, the network of our phone will be directly disconnected until we open the web page for a period of time after the end of the call.
In the era of 4G4G, voice service is mainly realized through two technologies: CSFB (Circuit Swiched FallBack-CS voice drop) and VoLTE (Voice Over LTE-LTE voice).
The former is the voice service technology used in the early days of 4G. When the user carries on the voice service, the device will fall back from the 4G LTE data network to the 2G / 3G network.
In order to solve this phenomenon, VoLTE technology was introduced in the later stage of 4G, and IMS (IP Multimedia Subsystem, IP multimedia system) architecture was introduced. VoLTE technology is a control platform for transmitting voice on the packet domain (Packet Switch) in the form of IP packets. That is, voice data and video data are transmitted through PS in the form of IP packets.
VoLTE makes voice service and data service run on LTE network. It is an IP data transmission technology that all services are carried in LTE network. Compared with 2G / 3G digital communication mode, 4G has higher bandwidth, clearer video and voice, and higher network speed. Therefore, no matter from the technical level or from the user experience point of view, the emergence of VoLTE in the history of mobile voice service development is a milestone in technological innovation.
In the 5G era, will our voice business make a qualitative leap as it did in the 4G era? Although there is no completely subversive technological change like VoLTE, the voice service in the 5G era also has its new mission-VoNR.
What exactly is VoNR in the 5G era?
What is the era of VoNR5G, voice service is mainly realized through two technologies: EPS FB (EPS FallBack-EPS voice drop) and VoNR (Voice Over NR-NR voice).
In the early days of 5G, the coverage of 5G devices was not perfect, and operators did not directly upgrade their voice business to 5G voice, but let the voice fall back to 4G voice with complete functions in areas where there was no 5G coverage, which is called EPS FB. The adoption of this method will inevitably lead to call delay, and the biggest disadvantage of EPS FB will lead to temporary disconnection of voice service, which will be more easily detected by users than call delay and make the user experience worse. Therefore, with the innovation of technology and the development of 5G, a new voice service VoNR has emerged.
Because the wireless access technology of 4G is LTE, the voice carried on 4G is called VoLTE. In 5G, voice service is provided on the new radio interface technology (NR), so this voice technology is called VoNR in 5G. The 5G network architecture basically continues the 4G architecture, and also uses IMS in VoLTE.
However, with the 5G IMS upgrade, VoNR can support more concurrent calls and higher data transfer rates, which makes it possible to support a richer communication experience.
Making use of the characteristics of high bandwidth and low delay of 5G network, it can achieve the purpose of connecting in seconds and parallel to the Internet, achieve both voice games, and provide high-definition voice communication and data services. This makes the experience of voice communication better, especially in a noisy environment where users can still hear the conversation clearly.
Secondly, the low latency of VoNR gives it an advantage in real-time communication. In traditional telephone calls, the delay of the network will lead to incoherence and interruption of the conversation. The low delay performance of VoNR can solve this problem and make the voice communication more fluent.
In the aspect of voice, it can not only achieve high-quality voice and video calls, but also achieve real-time translation, voice-to-text and other functions. It is equivalent to the original call interface, which strengthens the interaction between the user and the device.
The birth of VoNR indicates that we are moving from traditional voice communication technology to a new generation of digital voice communication technology.
Principle and key Technology of VoNR
The phonetic principle is as follows:
Initialization: after the user terminal equipment (UE) is connected to the 5G network, the initialization is completed through the authentication and registration process with the core network.
Call establishment: the user initiates a voice call request, invokes the call control function, and establishes a communication connection with the other party's UE. In the process of call establishment, operations such as resource reservation, media stream setting, encoding and decoding are involved.
Encoding and decoding: VoNR uses scalable codecs to support different audio quality and bit rate settings. The goal of the encoding and decoding process is to minimize bandwidth and data transmission requirements while ensuring voice quality.
RTP encapsulation: VoNR is encapsulated by Real-time Transport Protocol (RTP:Real-time Transport Protocol), slicing the audio stream and adding relevant synchronization, timing and header information.
Data transmission: VoNR uses 5G's new air port protocol (N1 interface) to transmit voice data. Unlike VoLTE, VoNR no longer uses the LTE network to carry voice communications. But all the data is carried on the 5G network.
Voice service: VoNR can realize services such as teleconference, call transfer and so on through IMS server.
The key technologies of VoNR implementation are as follows:
5G new air port technology 5G NR (New Radio): 5G NR is the wireless access technology standard of 5G network, which achieves higher spectrum efficiency and lower delay.
5G NR contains a large number of new technologies and functions, which provides a good wireless access environment for VoNR.
NR band: 5G NR supports higher spectrum bandwidth and higher carrier aggregation ability, provides larger transmission capacity, and can support a large number of voice users.
The beamforming technology in Beamforming:5G enables the speech signal to be transmitted through the specified beam, which improves the transmission quality and coverage.
Network slicing technology: 5G network slicing technology enables the network to be divided into different virtual slices, each of which is optimized according to its specific business needs. Voice communication can be given priority as an independent network slice to ensure low delay and high reliability of voice.
QoS (Quality of Service- quality of Service) guarantee VoNR ensures the real-time and stability of voice communication by realizing strict QoS guarantee in 5G network.
QoS mechanism can schedule and guarantee network resources to meet the environmental conditions needed for voice communication.
Multi-decoder technology VoNR's multi-decoder technology can adaptively select appropriate audio codecs according to network quality and user needs to provide the best voice quality and resource utilization efficiency.
Through the above principles, we can clearly see its advantages:
HD voice quality: VoNR supports HD voice calls, providing a clearer and more natural call experience.
Low latency: the low delay characteristic of 5G network makes the delay of VoNR voice communication even lower, achieving almost real-time call experience.
Large capacity: 5G network provides higher bandwidth and transmission capacity, and can support more voice communication users at the same time.
Enhanced service: VoNR can realize services such as teleconference and call transfer by integrating IMS service and network slicing technology.
Data service and voice service are parallel.
The future of VoNR generally speaking, VoNR is a new voice service technology in the 5G era, which represents a trend of the future development of voice communication technology. The emergence of VoNR can not only provide a high-quality voice call experience, but also open up new communication application scenarios (such as virtual reality (VR) and augmented reality (AR) communication, remote monitoring, etc.), bringing more convenience to people's life and work.
The development of VoNR faces some challenges. Because VoNR is based on 5G technology, users must use devices that support 5G and can only use VoNR services in areas covered by 5G networks. Although the coverage of 5G network is gradually expanding, the coverage of 5G network is still limited in some areas.
Secondly, the implementation of VoNR requires a lot of investment from operators. Operators need to upgrade their network equipment to support VoNR services. This may cause operators to face high investment costs in the short term.
Therefore, these problems and challenges require the joint efforts of all parties in the communications industry to promote the progress of its technology and the promotion of its application.
Although the widespread use of VoNR will take time. But we can foresee that with the continuous development and maturity of 5G network, VoNR will play a more and more important role in the future communication market.
This article comes from the official account of Wechat: ZTE documents (ID:ztedoc)
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