As the key infrastructure of the digital society, 5G could not only serve individuals but also accelerate the digital transformation in all walks of life. 5G networks will be ubiquitous to meet diverse demands for man-to-man, man-to-machine, and machine-to-machine communications.
Network Slicing: To Meet Diverse Service Demands of 5G
While 4G has only to meet the traffic demands of individual users, 5G has diverse application scenarios, which pose different demands on the network. For example, in an industrial control scenario where a service interruption may cause property loss, the network needs to provide a low latency of 1 ms, high availability, and effective isolation between different services. For internet-connected self-driving cars, its anti-collision systems concerns human safety and the network needs to provide an ultra-low latency and 99.999% network reliability. For VR/AR applications, the network needs to provide more than 1 Gbps bandwidth. For the IoT data collection service, there are low requirements for network bandwidth and latency, but the network needs to provide up to 1 million connections per square kilometer. Other scenarios such as smart factory, telemedicine, and smart grid have all posed strict requirements on 5G networks. Building a new network for each type of service will lead to great network construction costs and hamper business development; however, carrying all the services over a single network could not simultaneously fulfill the requirements for ultra-high bandwidth, ultra-low latency, and ultra-high reliability, and also has potential risks in service isolation.
To resolve the conflicts between differentiated SLAs and network construction costs, network slicing becomes an inevitable choice. Network slicing enables flexible slicing of 5G network resources into multiple virtual networks to meet specific customers’ requirements. In addition, network resources can be fully shared, dynamically balancing on-demand services and network construction costs. Network slicing by offering flexibility and openness will have a direct influence on operators’ capabilities for service innovations and capturing business opportunities, and thus has become a basic 5G network requirement.
ZTE's End-to-End Network Slicing Solution
An end-to-end 5G network slice is composed of RAN, core network, and bearer sub-slices, and supports the lifecycle management of network slices through its upper-layer E2E management system (Fig. 1). Focusing on 5G E2E solutions, ZTE takes the lead in releasing an E2E slicing solution, facilitating operators to build sliced networks.
Service-Oriented Core Builds On-Demand Slices
Traditional core networks based on dedicated hardware are rigid and closed, and cannot meet diverse 5G requirements. The 5G core networks based on NFV further introduce a service-based architecture, which decouples network functions from hardware, implements components-based functions, and adopts a stateless design, and lightweight, open interfaces, and are thus more agile, easily scalable, flexible, and open. The service-oriented virtualized core networks for 5G can realize on-demand orchestration and rapid deployment of network functions and slices while meeting the elasticity and high availability requirements, laying a solid foundation for network slicing.
RAN Slicing, Unified NR to Support Diverse Scenarios
5G RAN supports slicing and flexible deployment of AAUs, CUs, and DUs, meeting networking requirements in different scenarios. The cloud-based deployment of CUs facilitates centralized management of radio resources, while the co-location of DUs and CUs and the deployment of service anchors close to users can reduce latency in transmission.
5G NR with a flexible frame structure design can meet the service requirements in different scenarios. In addition, differentiated key 5G technologies can fulfill the SLA requirements in different scenarios, for example, Massive MIMO technology doubles data rates for users, the MUSA technology developed by ZTE increases the number of connected terminals, and the mini-slot greatly reduces the latency in communications. With flexible parameter configurations, RAN can support different frame structures and key technologies to adapt to various scenarios, meeting different network slices' requirements based on a unified NR.
Multi-Layer Slicing for SDN-Based Bearer Network Flexibly Creates Slices
Bearer network slices are created by physical network virtualization, and the SDN architecture with unified management and control can achieve IP and optical layer synergy. This allows a physical network to become open and programmable and support innovation in network architecture and service in the future. The degree of intra-slice isolation depends on the slicing technology used, for example, FlexE and FlexO technologies can be used to build rigid pipes, ensure strict isolation between slices while implementing rapid forwarding at the underlying layer. The technologies can be selected flexibly to address different service requirements on bearer networks.
Compared with constructing multiple physical planes, implementing virtual bearer network slices greatly reduces network construction costs, and flexibly schedules resource on demand, meeting rapidly changing 5G service requirements.
E2E Slicing Orchestration & Management Enables Creation of Intent-Driven Slices
The application of new technologies brings about flexible network slicing as well as complicated management, and there are various types and a great number of network slices, which necessitates unified E2E slicing orchestration and management.
ZTE network slicing, based on the carrier-grade DevOps platform, supports the life-cycle management of E2E network slices, achieves “closed-loop” automated design, automated development, automated deployment and automated operations and maintenance (O&M), and also provides wizard-based Dev design to implement E2E orchestration and minute-level deployment (Fig. 2). Based on AI-driven O&M, it can also achieve network self-healing, elasticity, and self-optimization. Driven by model-based workflows, the E2E slicing orchestration and management system flexibly matches network resources with service requirements, enabling rapid customization and deployment of slices based on specific customer requirements.
Building an Ecosystem for Slicing
Network slicing brings about new business models. 5G network slicing based on SDN/NFV technologies matches resources to applications and supports rapid customization for industry-specific customers. Network slices that are customizable, deliverable, measurable, and chargeable can be sold by operators as a product to industry customers. In addition, slicing-related capabilities can be opened to enable network slice as a service (NSaaS) model to better meet the needs of different industrial services. With open interfaces, industry customers can combine network slices with their own applications, and flexibly use and manage a network slice as with a self-built dedicated network, thereby providing convenient services.
For vertical industry customers, they can cooperate with operators to gain access to 5G networks, which helps them save initial network construction costs and rapidly achieve digital transformation. For example, the internet of vehicles (IoV) slices can provide high-availability and low-latency services with the security of IoV platforms guaranteed through slice isolation. Open interfaces can be used to meet the requirements for vehicle positioning, and edge computing nodes to guarantee better user experience. Take a future smart factory for another example. Massive sensors need to be deployed to monitor the production environment, with each sensor requiring a low bandwidth. Low latency and 99.9999% high availability are needed for efficient collaboration between smart robots. HD video surveillance used for workshop area inspections, and VR/AR technologies used for image processing in industrial design require ultra-high access bandwidth. These network requirements can be met by using the slicing technology to slice a single 5G network into three virtual network slices. In addition, physical network resources can be fully shared to facilitate enterprises to achieve digitalization of manufacturing at the lowest network construction costs.
5G has extensive application prospects in the fields such as internet of things, smart city, automatic pilot, smart manufacturing and remote control. These scenarios have different requirements for networks, which represents great opportunities for network slicing. With the close integration of slices and industrial applications and the development of an ecosystem, it is believed that network slicing will give full play to the leading role of 5G in the construction of a digital community, promote application innovation and achieve a win-win future for verticals and operators.
[Keywords] End-to-end network slicing, 5G E2E, VR/AR, RAN slicing, E2E slicing, slice lifecycle management, intent-driven slices