5G: System and Core Aspects - ATIS LTE Legacy Cellular RATs Wireline / Others LTE Core with ... • The packet core forms a critical component of an end to end 5G system. To fulfill

5G: System and Core Aspects

Farooq Bari

AT&T

© 2015 AT&T Intellectual Property. All rights reserved. AT&T and the AT&T logo are trademarks of AT&T Intellectual Property.

Evolution of Cellular Networks

• Cellular industry has historically been introducing a new generation of cellular networks every decade or less

• Each generation represents a significant leap in technological advances as well as in what the network has been able to deliver to a consumer

– 1G (AMPS)

– 2G (TDMA and GSM/GPRS/E-GPRS)

– 3G (UMTS/HSDPA/HSPA+)

– 4G (LTE/LTE-Advanced)


How is next generation of cellular networks defined?

• Within a given generation we see several incremental enhancements where backwards compatibility is preserved

• Next generation typically requires major new technology steps that

• May not be evolutionary but associated with a break in backwards compatibility

• Require a potentially expensive infrastructure upgrade


Next Generation of Cellular Networks

• Breaking of backwards compatibility usually comes with significant deployment and developmental hurdles

• the industry will accept it only in the case where significant improvement can be achieved as a result of breaking this backwards compatibility

• It is commonly believed that the term “5G” will be reserved for a fundamental change in technology such as the one that comes with a new air interface definition where backwards compatibility is sacrificed in the interest of truly significant gains


5G Ecosystem

• This technology step of a new air interface will be accompanied with a number of other changes in the end to end system

• In the radio access network as well as the core network

• These changes can be

• evolutionary / incremental in nature or

• they can introduce a completely new concept

• Together with a new air interface they form what we can refer to as a “5G Ecosystem”

• “5G Ecosystem” will introduce many new technical enhancements both in the radio access network as well as the core network

• It is likely that these enhancements will come about in multiple 3GPP releases over multiple years rather than over a single release


5G System and Packet Core

NGMN whitepaper lists several 5G related requirements. Key requirements relevant to 5G System and Packet Core include the following • A functional decoupling of Core and RAN network domains

• A RAN technology agnostic architecture where introduction and connection of new radio technology will be possible in a plug and play manner

• Changes and enhancements to one equipment/network domain should not mandate changes/enhancements to the other

• A decoupling of Hardware and Software functions of network elements in all network domains

• Cost and effort efficient upgrade path so that Operators can leverage significant investments into existing operational infrastructure and maximize its utilization

• Real-time and on demand network configuration and automated optimization

• Flexible and cost efficient network operation

• Maximize utilization efficiency of available network resources

• Dynamic relocation of network resources depending on current and local needs, fully controlled by operator


5G System and Packet Core

4G Americas also lists several 5G requirements that are relevant to development of a next generation of packet core

• The 5G network architecture should be such that the air interface and the core network can evolve and scale independently of each other

• Changes/enhancements to one should not mandate changes/enhancements to the other

• 5G networks must also support multi-RAT connectivity efficiently and effectively

• Provide access agnostic packet core across multiple Radio Technologies (e.g. cellular, Wi-Fi, etc.) to support uniform Authentication, Session Continuity, and Security across radio technologies.

• Provide Plug and Play capability where a new access technology may be attached to the packet core without any modifications.


Redefining of current architecture

Simplifying the network

• Flattening of the network and reducing access specific nodes

• Separation of user and control plane

Mobility

• Mobility on Demand

Operator Policies

• Use of SDNs for enforcing operator policies

QoS

• Access agnostic QoS in the packet core

Service specific core

• Network virtualization and service specific network slicing


Core Network Transformation

From To

Physical Network Function (PNF) Virtual Network Function

Nodal boundaries Composition and decomposition of VNFs

Hierarchical network deployment Flexible network deployment

Nodes with combined control and user plane

functions

Complete separation of control and user planes for

independent scaling and distribution

One Mobile Packet Core (MPC) to suit all use cases Instantiation of a virtualized MPC optimized for each use case

Mobility invoked for every subscriber Mobility on demand

Designed specifically for 3GPP defined RAN.

Interworking with non-3GPP access (e.g., WiFi) as an

afterthought.

Designed for a multi-access environment from the beginning.

Plug and play for non-3GPP access types

Manual service creation via EMS Automatic service creation in concert with VNF-M and EMS.


Example of Network Slicing in a 5G Network

From 5G White Paper By NGMN Alliance


5G Architecture From 5G White Paper By NGMN Alliance


5G Architecture

5G RATs

Evolved LTE

Legacy Cellular RATs

Wireline / Others

LTE Core with LTE Capabilities

Legacy Core with Legacy Capabilities

Wireline / Other Core with their Capabilities

Services (e.g. IMS) Services

(e.g. IMS) Services (e.g. IMS)

Access Agnostic Interface



Legacy Interface

Legacy Interface

Legacy Interface

Network Capabilities Exposed to the Outside World via APIs

Databases 5G, LTE, Legacy, Wireline/Others

Access Agnostic Functions Authentication Authorization

Accounting/Charging Quality of Service

Security Mobility on Demand

Data Analytics Policy Enforcement

Content Optimization Others…


Conclusions

• In order to achieve the level of scalability and flexibility required by industry drivers and significantly reduce the cost per Gigabyte and the cost per connection, 5G networks must utilize concepts such as SDN, Cloud Computing and Network Function Virtualization (NfV)

• The packet core forms a critical component of an end to end 5G system. To fulfill operational needs of operators an access agnostic packet core that is largely decoupled from radio access technology dependencies is required

Documents

5G: System and Core Aspects - ATIS LTE Legacy Cellular RATs Wireline / Others LTE Core with ... • The packet core forms a critical component of an end to end 5G system. To fulfill