1. 5G ENABLERS FOR NEW NETWORK
A Compact Overview from High Level Perspective
ver.1.0
July 27, 2017
Ertan ÖZTÜRK

2. Contents
 Objective
 5G Vision
 5G Requirements
 5G Technologies
 Paradigm Shift
 Could-RAN
 Fronthaul and Backhaul Considerations
 5G Core Network
 Conclusions
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3. OBJECTIVE
Emerging Radio Technologies that are mmWave communications,
Massive MIMO, Novel Waveforms and Multiple Access techniques etc.
will provide ultra high data rate trafficper user. However, only new
Radio techniques implemented in lower layers of legacy networks
could not guarantee the all 5G requirements, consequently the new
network architecture along with new Radio technologies will emerge
to fulfill all 5G requirements.
The purpose of this presentation is to give a compact overview of 5G
enablers for new network architecture mainly to researchers in radio
technologies to better understand how the whole system will evolve to
satisfy challenging requirements.
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4. 5G Vision
 5G with new spectrums, new technologies will target new services and new
business models than those in legacy systems.
 These have been developed in collaboration with vertical industries and imply
new requirements and new ways of thinking, building and managing the
network.
 There is already a wide consensus to consider the following three main 5G
service types:
1) Enhanced Mobile Broadband ( e.g., UHD video streaming, Virtual Reality, etc.)
2) Massive Machine Communication (e.g., Smart city, smart farming, etc.)
3) Mission Critical Machine Communication (e.g., Autonomous driving, remote
surgery, etc.)
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5. 5G Vision
The above defined services will require some of the below Key Performance
Indicators (KPI) depends on their traffic characteristics. The relationship between the
three main service types and KPIs are given in well known diagram in Figure 1.
 Ultra high data rate per user
 High Reliability
 High Mobility
 Low Latency
 Massive Number of Devices
 Energy Efficiency
In addition to the above KPIs, 5G networks are required to provide
 Backward Compability
 Low Capex and Opex
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6. 5G Requirements
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Figure 1 5G Requirements (from METIS)

7. 5G Radio and Network Technologies
Efficient and
Adaptive
Coding and
Modulation
Techniques
Novel
Waveforms
Novel Multiple
Access
Techniques
mmWave
Communication
Massive MIMO
Sofware
Defined Air
Interface
Solutions
• Massive Connections
• Gbps per User traffic • Spectral efficiency
• Energy efficiency
• High Mobility• 100 Mbps
Guaranteed data rate • Very Low Latency
Key
Performance
Indicators (KPIs)
• Flexibility
• Scalebility
• Backward
Compability
• Self monitering, healing,
and optimization
Cloud Based
RAN &Core
Network
Network Slicing
New Network Architecture
Emerging Radio Technologies
Distributed
Network
New Fronthaul
and Backhaul
Solutions
Softwarization
and
Programability
Heteregenous
Radio Access
(RAN) Networks
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8. A PARADIGM SHIFT
 The 5G mobile network architecture would include both physical and
virtual network functions, as well as distributed-cloud and central-cloud
deployments.
 A crucial enabler of 5G is the use of softwarization and programmability
that are expected to provide appropriate level of flexibility in 5G networks.
 The use of Software Defined Network (SDN) and Network Function
Virtualization (NFV) will play an important role.
 Self-organized Network (SON) capabilities enable the network to efficiently
predict demand and to provide resources, so that it can heal, configure
and optimize accordingly.
 Network functions in 5G will be more decoupled from physical architecture
than in legacy systems.
 In addition to those, Network Slicing is also an important part of the overall
5G architecture that could be composed of a collection of 5G resources
such as NFV and RAN, computing, storage, transport that are combined
together for a specific use case and/or business model.
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9. SOFTWARIZATION AND PROGRAMMABILITY
 Network softwarization is an approach to use software programming to
design, implement, deploy, manage and maintain network
equipment/components/services.
 Softwarization of networks includes the implementation of network
functions in software, the virtualization of these functions, and the
programmability by establishing the appropriate interfaces.
 It takes advantage of programmability, flexibility and re-usability of
software for rapid re-design of network and service architectures.
 The goal of network softwarization is to optimize processes in networks,
reduce their costs, and bring added value to network infrastructures.
 5G network segments include radio access networks, core networks,
transport networks, network clouds, mobile edge networks and Internet.
Certainly, each segment has its own technical characteristics, and thus
different requirements of softwarization.
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10. CLOUD RADIO ACCESS NETWORK (C-RAN)
 Traditional Radio Access Networks, where Base Band Units (BBUs) and radio
units are co-located, suffer several limitations.
 New services require support more sophisticated mechanisms for traffic
differentiation with more stringent Quality of Service (QoS) requirements than
those in legacy systems.
 It is expected that many 5G services can be economically supported only if
infrastructure resources (e.g. radio resources, hardware and software
platforms) are extensively reused among different services.
 Aiming to address these limitations and to support new services, Cloud Radio
Access Networks (C-RANs), with the option of flexible processing splits and
taking advantage of pooling and coordination gains, have been proposed
for advanced 5G network.
 In C-RAN, distributed access points, referred to as remote radio heads (RRHs),
are connected to a Base Band Unit (BBU) pool, through high bandwidth
transport links known as Fronthaul (FH).
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11. CLOUD RADIO ACCESS NETWORK (C-RAN)
 One of the advantages offered by Cloud RAN is that the centralized BBU
resources are shared among a large number of RRHs, which means that a much
higher BBU utilization rate and lower power consumption can be potentially
achieved.
 The cloud computing based radio access infrastructures will provide on-demand
resource processing, delay-aware storage, and high network capacity wherever
needed.
 Another challenge in the 5G mobile radio access network is the efficient
integration of an additional layer of small cells into the existing macro-cell
network. C-RAN are considered as an innovative approach in which small cells
are deployed as remote radio heads connected to a centralized macro-cell via
a fronthaul interface
 On the other hand, the remote processing requirements for operational network
purposes together with the need to support a wide variety of compute and
storage end user services, introduce the need of high bandwidth transport
connectivity, with stringent delay and synchronization requirements between the
radio units and the remote compute and storage resources.
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12. BBU
Figure 1 Illustration for basic segments of Cloud based 5G Network
5G
Core
Fronthaul Backhaul
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Cloud-RAN Cloud-CoreRRH

13. Fronthaul Considerations
 The physical fronthaul interfaces are standardized through the
Common Public Radio Interface (CPRI), the Open Base Architecture
Initiative (OBSAI) and the Open Radio Interface (ORI), with CPRI
currently being the most frequently used standard.
 Once massive MIMO is applied, CPRI capacity between BBU and
each RRH will be enhanced substantially. Moreover, when a
bandwidth more than 20 MHz (even up to 400 MHz) is used in 5G,
CPRI capacity per RRH will require tens or hundreds of Gbps, which
can not be handled with current fronthaul solutions.
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14. Fronthaul Solutions
 The solution would redefine the functions of BBU and RRH, differently
from the way they are defined in legacy system, and change the
interface between BBU and RRH from Circuit fronthaul (CPRI) to
Packet fronthaul (Ethernet).
 If ideal fronthaul is available and a high degree of centralization is
desired, it will be better to have an centralized MAC functionality,
whereas PHY functions are performed at the remote radio units.
 This will allow an entire cloud RAN to be considered as a giant base
station having many distributed antennas, but without the high
bandwidth requirements on the fronthaul interface that the legacy
solutions pose.
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15.  If low latency connectivity between centralized processing and RRH
cannot be guaranteed, the solution could be spliting radio
functions between synchronous and asynchronous functions. PHY,
MAC and RLC related functions are typically synchronous with the
radio, wheras PDCP and RRC functions are asynchronous and less
tightly to the radio.
 The synchronous functions could then be virtualized and centralized
over many RRH, and run on a edge cloud along with BBU; while the
asynchronous functions would be distributed and run on the RRHs.
.
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16. Figure 2 Function split in CRAN
IP
Ideal Fronthaul
BackhaulRRH
RLC
MAC
PHY
RF
BBU
(RRC
PDCP)
5G
Core
PHY
RF
BBU
(RRC
PDCP
RLC
MAC)
Non ideal Fronthaul
Cloud RAN Cloud Core
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17. Backhaul Considerations
 In 5G, radio IP capacity will become as large as 20Gbps with ultra-
large content traffic (e.g. UHD Video Streaming, and Virtual Reality
etc.). All mobile communication traffic have to travel via packet
core network.
 If the current architecture is kept, massive backhaul between BBU
Pools located across a country and packet core in a few
centralized sites is inevitable, hence a substantial backhaul
investment has to be made. In addition, 5G core in centralized sites
should have ultra high processing capacity as well.
 On the other hand, Mission-critical (Ultra-reliable and low latency
communications) applications require radio latency of less than
1ms, and end-to-end latency of less than a few ms.
 The solution for backhaul limitation will be distributed Core Network
and will be discussed next.
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18. 5G CORE
 The 5G core will be cloud-based, with a high degree of Network Functions
Virtualization for scalability, SDN for flexible networking, dynamic orchestration of
network resources, and a modular and highly resilient base architecture.
 The majority of the Core Network functions are will be deployed as VNFs, thus
running in virtual machines over standard servers, potentially on cloud
computing infrastructures.
 The design of these functions will to some extent explore SDN principles, such as
data plane/control plane split, fulfilling the envisioned SDN/NFV native
architecture.
 These VNFs can be flexibly deployed in different sites in the operator’s network,
depending on the requirements with regards to latency, available transport,
processing and storage capacity, etc.
 Network slicing is one of the key capabilities that will enable flexibility, as it allows
multiple logical networks to be created on top of a common shared physical
infrastructure.
 Virtualization and SDN are the key technologies that make network slicing
possible.
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19. Control- and User-plane Separation
 Supporting the separation of the control- and user-plane functions is
one of the most significant principles of the 5G core-network
architecture.
 Separation of the control plane and the user plane is enabled by
concept of SDN.
 Typical control-plane functionality includes capabilities like the
maintenance of location information, policy negotiation, and session
authentication.
 User-plane functionality can be deployed to suit a specific service.
Given that the connectivity needs of each service varies, the most
cost-efficient unique deployment can be created for each scenario.
 Separation allows control- and user-plane resources to be scaled
independently, and it supports migration to cloud-based deployments.
 By separating user- and control-plane resources, the planes can also
be established in different locations based on the service requirement.
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20. Distributed Network
 Evolved virtualization, network programmability, and new 5G services will
change everything about network design, from planning and construction
through deployment.
 Cloud technology together with advanced analytics capabilities, NFV, and
SDN provide a common distributed platform on which networks can be
instantiated.
 If 5G core nodes are distributed closer to cell sites and content servers can
be placed on the distributed 5G core. This can help significantly reduce
backhaul traffic by having mobile devices download content immediately
from the content server without having to pass the backhaul to reach 5G
core.
 Distributed 5G Core (User Plane), New BBU and Applications will run on
virtualized servers at the local cloud RAN sites.
 Hence, boundaries between the core network and the RAN will be
redefined, and may not be physically separated as in the legacy networks.
 On the other hand, one way to achieve minimal end-to-end latency in
terms of network architecture would be to eliminate backhaul delay by
distribution core closest to mobile devices, and placing application servers
right next to it. In such structure, the control plane can be placed in a
central core, which makes management and operation less complex.
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21. Figure 3 Distributed Network
IP
Fronthaul Backhaul
RRH
5G
Central
Core
Cloud-RAN
BBU
Distributed
Core (UP)
RRH
Cloud Core
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22. Network Slicing
 In 5G networks, network slicing will be significant for service
provisioning, in order to accommodate different vertical sectors
under a unified network infrastructure view.
 Network slicing may provide horizontally planned network
architectures in telecommunications; and the business model that
decouples physical access to the network resources from the
actual provisioning and delivery of services on top of these network
resources.
 Network slicing can be used as a dedicated network for a specific
service. Thereafter, a newly created slice can be locally managed
by the tenant who will perceive the network slice as his/her own
network complete with transport nodes, processing and storage.
 These will be disruptive architectures to serve the purpose of giving
an optimal performance for a specific use case.
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23. Network Orchestration and
Management Functions
 The role of the network management functions/orchestrator is to
describe the interrelation of network functions, and ultimately for
allowing the orchestrator to communicate with the data and control
planes in the network.
 In this process, the orchestrator has to consider service specific
requirements, e.g. latency, physical locations of specialized hardware,
etc. This is done through the entire lifecycle of a function/service, i.e.
deployment, operation, monitoring and termination.
 Resource orchestration is responsible for the integration and
coordination of physical or virtual network, computing and storage
components available in networks to realize different services, to
support network slicing, and/or to achieve certain performance goals.
 Service orchestration is built on top of resource orchestration to
provision services cross multiple network segments and/or different
network domains.
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24. CONCLUSIONS
 5G networks will fulfill very diverse requirements for new services and models
developed in close collaboration with vertical industries.
 In one perspective, 5G era will be the time of machine type
communications for both massive and mission critical applications.
 These will be possible by not only emerging Radio Technologies, also by
new Network Architecture.
 New architecture will have central and distributed cloud deployments with
high degree of computing, storage, transport capability.
 Boundaries between the core network and the RAN will be redefined.
 The use of softwarization and programmability with SDN and NFV as well as
cloud deployments will provide scalability and flexibility for 5G network.
 Finally, network slicing is also an important part of the overall 5G
architecture that could be composed of a collection of 5G resources such
as NFV and specific RAN, computing, storage, transport that are
combined together for a specific service.
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25. REFERENCES
[1] 5GPPP “View on 5G Architecture”, Ver. 1.0, July 2016.
[2] NGMN “5G White Paper”, Ver. 1.0, Feb. 2015.
[3] A Vision of the 5g Core: Flexibility For New Business Opportunities, Review,
Ericsson Technology, Vol. 93, 2016.
[4] 5G RAN Architecture and Functional Design, White Paper, 5GPP, METIS II,
March 2016.
[5] Mamta Agiwal, et. al., Next Generation 5G Wireless Networks: A
Comprehensive Survey IEEE Communications Surveys & Tutorials, Vol. 18, No. 3,
Third Quarter 2016.
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26. For comments, please write to oztuert@yahoo.com
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