Common Core facilitates rapid deployment of 5G

Problems to 5G Network Deployment
As the demand for high-speed bandwidth of services such as AR/VR/HD video/3D video, the demand for mass terminal accesses of services such as smart city and smart meter reading, as well as the demand for low latency and high reliability of services like Internet of Vehicles, industrial control, and telemedicine, are becoming more and more urgent, and the pace of 5G network deployment is getting closer and closer, various industries are full of expectations for operators’ 5G networks.

At the same time, operators also have a big problem in how to deploy the 5G Core. On the one hand, they have to consider whether the traditional EPC network can meet the ever-changing needs of 5G vertical services. On the other hand, the 5G Core using the service-based architecture (SBA) has brought a big impact on the traditional telecommunication network, such as the integration transformation of existing equipment and the change of operation and maintenance (O&M) mode.

Main problems that operators have to face for deploying the 5G Core is including how to meet industry users, how to coexist with the existing network, how to smoothly cut over users and how to operate and maintain.

5G Core Deployment Solution

1、Directly deploying 5GC vs. Upgrading EPC

In order to meet the needs of users using 5G Internet access, there are two main paths to deploy the core network:

Path 1: Upgrade EPC to support 5G wireless access (5G deployment Option 3)
Path 2: Directly deploy 5G core network (5G deployment Option 2)

Upgrading EPC to 5G faces a big problem: it does not support network slice which is required by 5G vertical industry. In addition, the solution is a transitional solution for evolution to 5G. After the 5G core network is deployed, the cost of retrofitting the original EPC network will be wasted. The direct deployment of the 5G core network can maximally meet service demands and will not cause unnecessary investment waste, so it is the preferred solution for the current 5G network deployment.

In addition, whether the industrial chain can meet requirements of commercial time is also one of the important factors for deployment path selection. In current 3GPP specifications, the 5G Core R15 specification has been officially released, and system equipment and terminal devices complying with the specification can meet the time requirements for commercial use in the fourth quarter of 2019.

Therefore, the core network deployment solution using 5G Option2 is the best 5G evolution deployment path.

2、Reuse legacy interfaces to reduce network transformation

To deploy a new network, the key questions are what are the transformation requirements for existing network equipment, and how to coexist with existing network equipment.

In order to make full use of the legacy network, the network construction principle is usually the new network for new users and the legacy network for legacy users. The existing EPC provides access services for original 2/3/4G users, and the newly built 5G Core provides 5G users with access services.

In order to realize the service continuity between the newly-built 5G Core and the existing EPC, operators need to upgrade the existing network equipment to support necessary inter-working interfaces, to identify the 5G terminal and connect the 5G terminal to the newly built 5G Core. The N26 interface is introduced to achieve smooth and fast 4/5G switching. However, there are two problems in the transformation of existing network equipment: one is waste of investment; and the other is that the development cycle caused by the transformation may affect the commercial deployment time. Therefore, the maximum reuse of legacy network interfaces becomes the best solution for the initial 5G deployment.

The 3GPP 5G standard also has a large change to the billing system, and has a large transformation requirement for the operator’s billing system: online billing and offline billing are unified, and a service-based interface is adopted. However, the offline billing system of the existing network is generally undertaken by the BOSS, and the online billing is undertaken by the OCS, which makes the transformation difficult. Therefore, the newly-built 5G core network expands a small number of fields with 5G features based on the original EPC charging architecture and interfaces, and minimizes the transformation of the existing network charging system. This is the best charging deployment solution.

ZTE Common Core solution is converged with EPC and 5G Core capabilities. No need to upgrade the existing EPC, it can achieve convergent access and smooth handover in the 4/5G overlapping coverage area, maximally guaranteeing service continuity and requiring minimum transformation of existing billing system. Therefore, it is the best choice for the initial 5G deployment.

3、Smoothly hand over to 5G network with the same card and number

After the deployment of the new network, the headache for operators is how to migrate users of the legacy network to the new network.

When transitioning from 2/3G to 4G network, the user needs to replace a new SIM card, and the operator has to invest a lot of money to provide users with free card replacement service. The 5G network is compatible with the original 4G SIM card, that is, the user only needs to replace a 5G mobile phone but not to change the card and number to enjoy the 5G high-speed data service, which is very popular.

In order to realize the conversion of original 2/3/4G users to 5G users, it is necessary to sign such users in the 5G system. Usually, the migration of the user number segment to the 5G network can be implemented in the following ways:

Single user migration: The user can choose whether to enable 5G services. The solution is beneficial for operators to carry out independent billing, special packages and other 5G services; and they can still maximally make use of the existing 4G network signing system.
Batch number segment migration: The system directly migrates the existing number segments to the newly created 5GC. The solution does not require users to modify the subscription network, but it is not conducive to the development of differentiated 5G packages.

4、One-key deployment opens the road of intelligent O&M

The 5G Core adopts a slice network architecture based on NFV technology. The software and hardware integration of traditional NE becomes an architecture with hardware resource pool, virtualized resource pool and separated network functions (NF). The traditional installation and O&M cannot meet the O&M management under the NFV architecture.

ZTE network slice management system CloudStudio supports E2E network slicing and life-cycle management. Combined with AI technology and automated software framework, it enables slice-based automation design, orchestration and deployment, and intelligent slice selection, achieving complete network autonomy without human intervention.

ZTE CloudStudio introduces DevOps to facilitate agile development and deployment of innovative services with on-demand design, automated deployment, SLA assurance, intelligent analysis and forecasting, security isolation and tenant management capabilities. Operators can develop appropriate network slicing SLA according to industry, region, virtual operators and other scenarios, and then use the CloudStudio system to implement all-round automated management from resource pool construction to network function deployment, daily monitoring, fault O&M, and upgrade and expansion, reducing the requirements for operating staffs.

Suggestions for the evolution of 5G Core

For the evolution of the existing network to the 5G network, ZTE recommends that it can be carried out in the following three phases:

Phase 1: Now~2019, the 4/5G convergent core network will be introduced to carry out 5G trials. At the same time, vEPC in the convergent core is used to expand the existing EPC. In this stage, the existing network does not need to be upgraded.

Phase 2: 2020~2021, large-scale commercialization of 5GC is realized. The 2/3/4G users gradually migrate to the 5G network. In this phase, vEPC in the convergent core is implemented to achieve the interoperability with the 5GC, to realize smooth cross-network switching of 4/5G users in hot-spots. If service continuity is required in the whole region , it is needed to upgrade the existing EPC to support the inter-working with the 5GC.

Phase 3: From 2022 to the future, traditional devices gradually exist from the network. Slice-based O&M management is leveraged to provide multi-system end-to-end network slicing, meeting the needs of different service scenarios such as eMBB/mMTC/uRLLC.