Objective is to include the brief insight on 5G network architecture and standard progress, Accumulated it from different paper/journal, vendor’s white paper and different blog.

1. 5G network: Architecture &
3GPP standards progress
Complete standard of 5G by 2020 in 2 phases.
Rel-15 by Q2’2018, Rel-16 by Q1’2020.

2. 5G Target, used cases and design principle
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Flexibility
Flexible design is the key for addressing wide range of carrier frequencies (sub 1 GHz to 100 GHz), different deployment types (macro, micro, pico
cells), and diverse use cases with extreme and sometimes contradictory requirements.
Forward compatibility
5G Radio will continue to evolve beyond 2020, with a sequence of releases including additional features and functionalities. Since 5G radio must
support a wide range of use cases (many of which are not yet defined) forward compatibility is of utmost importance.
Ultra- lean design
Cellular networks transmit certain signals at regular intervals even when there is no data to transmit to user. Ultra-design refers to minimizing
these “always on” transmissions. Network should transmit signals only when necessary which improves energy efficiency, reducing OPEX.
5G wireless access is being developed with three broad use case
Enhanced mobile broadband (eMBB)
Extreme Throughput.
Enhanced spectral efficiency.
Extended coverage.
HD video,
VR services,
Wireless broadband
Massive machine-type
communications (mMTC)
High connection density.
Energy efficiency.
Low complexity.
Extended coverage.
Remote Sensors,
Utility metering, Wearables,
Object tracking
Ultra-reliable low-latency
communications (URLLC)
Low latency.
Ultra Reliability.
Location precision.
Autonomous car,
Industrial automation,
Robotics
High data rates 10~20Gbps
Low latency < 1 ms
1000 times the capacity (Capacity/km2)
100 times of connected devices
90% reduction in network energy usage
5G Performance Targets

3. 5G Components
3
Millimeter Wave
The number of network-connected wireless devices will reach 100 times or more. One of the most crucial challenges is the scarcity of frequency.
So providers are experimenting with mm Waves. There is one drawback to mm Waves — they can’t easily travel through buildings/obstacles and
can be absorbed by foliage/rain. That’s why 5G networks will likely augment traditional cellular towers with small cells.
Small Cells
Small cells are portable miniature base stations that require minimal power and can be placed every 250 meters or so. To prevent signals from
being dropped, carriers could install thousands of these stations in a city to form a dense network that acts like a relay team, receiving signals
from other base stations and sending data to users at any location.
Massive MIMO
Today’s LTE’s base stations have a dozen ports for antennas: 8 for Tx and 4 for Rx. But 5G BS can support about a hundred ports, means many
antennas can fit on a single array. So a BS could send and receive signals from many users at once, increasing the capacity by a factor of 22 or
greater. However, installing so many antennas to causes more interference. That’s why 5G stations must incorporate beamforming.
Beamforming
From massive MIMO BS, Beam forming help to reduce interference while transmitting from many antennas at once, signal-processing algorithms
plot the best Tx route through air to each user. So they can send individual packets in many different directions, bouncing them off
buildings/objects in a precisely coordinated pattern. By choreographing the packets’ movements and arrival time, beamforming allows many
users and antennas on a massive MIMO array to exchange much more information at once.
For millimeter waves: As signals are easily blocked by objects and tend to weaken over long distances. Beamforming can help by focusing a signal
in a concentrated beam that points only in the direction of a user, rather than broadcasting in many directions at once. This approach can
strengthen the signal’s chances of arriving intact and reduce interference for everyone else.

4. 5G Components
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Flexible/Full duplex
FDD will remain the main duplex scheme for lower frequency bands.
TDD for higher frequency bands (>10GHz) – targeting very dense deployments, as dynamic traffic variations expected, the ability to dynamically
assign Tx resources (time slots) to different Tx directions- allow more efficient utilization of the available spectrum.
Full Duplex: Tx and Rx at the same time and on the same frequency, double the system capacity and reduce the system delay.
Access/Backhaul Integration
Using common Spectrum pool, integrate wireless- access link and wireless backhaul, use same basic technology for efficient spectrum utilization.
Direct Device to Device communication
The use of mobile devices as relays to extend network coverage.
Multi-Antenna Transmission
5G radio will employ hundreds of antenna elements to increase antenna aperture beyond what may be possible with current cellular technology.
Tx and Rx will use beamforming to track each other to improve energy transfer, reduce interference, extent coverage and provide higher data
rates at lower frequency in specific sparse deployments.
User/Control Separation
Decouple user data and control functionality to allow separate scaling of user-plane and system control functionality. User data may be delivered
by a dense layer of access nodes, while system information is provided via an overlaid macro layer on which a device initially accesses network.
Also extend the separation of user data and system control functionality over multiple frequency bands and RATs. e.g, system control
functionality for a dense layer based on new high-frequency radio access could be provided by means of an overlaid LTE layer.

5. 5G Components
5

6. Network Architecture from LTE to 5G
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UE EUTRAN
MME
HSS
S-GW P-GW Internet/DN
UE NR
AMF
UDM
UPF DN AF
SMF PCF
AUSFCCNF UDR NEF SDSF UDSFNRF
Flexible Interconnect
LTENetwork5GNetwork
Two options of 5G network architecture representation 1) service based 2) reference point based
5G Radio network is called New Radio (NR), Core functionality is described in following slides
N1
N2
N3 N6
N5
N4

7. What is new about 5G New Radio
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Radio User plane protocol Stack
Protocol Brief reflection on the anatomy of a 4G radio Changes in 5G
SDAP
May be New layer: Service Data Adaptation Protocol (SDAP).
To support complex QoS functionality.
PDCP
Process IP packets and provides services like
compression, ciphering and integrity protection.
Duplication feature added to increase reliability.
Same PDCP Data Units to be sent over different carriers (CA scenario) reducing the
retransmissions.
RLC
Segmentation/concatenation and error controls
[Automatic Repeat Request (ARQ)].
Disable concatenation to reduce processing time .
MAC
Scheduling,
Multiplexing,
Hybrid ARQ process and
Manage transport blocks transferred with PHY layer.
New enhancements are being introduced to the HARQ procedure to speed up retransmissions
PHY
Channel coding: Turbo codes.
Modulation (QPSK and up to 256QAM),
MIMO.
Multiple access procedures (SC-FDMA, OFDMA).
LTE defines only one sub carrier spacing of 15KHz.
In LTE, a slot is defined as seven OFDM symbols.
Main Spectrum ranging from 1GHz to 100GHzbands.
Channel coding: LDPC (low density parity check) for user plane; Polar coding for control plane.
QPSK to 256 QAM+ may be up to 1024 QAM + л/2-BPSK in UL.
Massive MIMO with array of Antenna.
Multiple access: will be OFDMA with DFT-S-OFDM in uplink
Flexible sub carrier spacing: 2n of 15KHz, reduce symbol duration thus reduce latency.
5G NR introduces a new “mini-slot” occupy two symbols to enable URLCC.

8. Core Network from LTE to 5G
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Core functions in 5G In LTE Functionalities
Authentication Server Function (AUSF) AUC/HSS AUSF stores data for authentication of UE
Unified Data Management (UDM) HSS
Store subscribers data and profiles. Similar to an HSS in 4G but used for both
fixed and mobile access in NG core
Unified Data Repository (UDR) Single SDB/UCDB
All the user data is stored in a single UDR allowing access from core and
service network entities
Access and Mobility Management Function (AMF) MME
UE-based authentication, authorization, registration, reachability, mobility
management and connection management.
Policy Control function (PCF) PCRF Policy control of the user based on services/access.
Session Management Function (SMF)
MME/
S-GW/P-GW
Session establishment and management and allocates IP addresses to UEs.
It also selects and controls the UPF for data transfer.
If a UE has multiple sessions, different SMFs may be allocated to each session
to manage them individually and possibly provide different functionalities per
session
User plane Function (UPF) S-GW/P-GW
Packet routing and forwarding functions, currently performed by the SGW and
PGW in 4G

9. Core Network from LTE to 5G (cont..)
9
Core functions in 5G In LTE Functionalities
Data network (DN) DN operator services, Internet access or 3rd party services
Common Control Network Function (CCNF)
NA
Common Control Network Function (CCNF) is used for Network slicing, which is common
to all or several slices.
It includes the Access and mobility Management Function (AMF) as well as the Network
Slice Selection Function (NSSF), which is in charge of selecting core network slice
instances.
Structured Data Storage network function
(SDSF)
Allows the NEF to store structured data in the SDSF intended for network external and
network internal exposure by the NEF.
Unstructured Data Storage network
function (UDSF)
Allows any NF to store and retrieve its data into/from a UDSF (e.g. LI data)
Network Exposure Function (NEF) Expose and publish network data.
NF Repository Function (NRF)
Provides registration and discovery functionality so that Network functions (NFs) can
discover each other and communicate via API.
Application Function (AF)
Application/
Service
e.g OTT/Service/IMS

10. 5G Architecture Options
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New RadioLTE
EPC
New RadioLTE
EPC
New RadioLTE
EPC
New RadioLTE
EPC
New RadioLTE
EPC
New RadioLTE
EPC
5G Core 5G Core 5G Core
5G Core5G Core5G Core
UE UE UE
UE UE UE
1. Standalone LTE, EPC connected
2. Standalone LTE Rel-15, 5GC connected
3. Standalone NR, 5GC connected
4. Standalone 5G NR, EPC connected
5. Non Standalone, LTE assisted, EPC connected
6. Non Standalone, NR assisted, 5GC connected 8. Non Standalone, LTE assisted, 5GC connected7. Non Standalone, NR assisted, EPC connected
Also non 3GPP access is considered to be integrated with 5G core

11. Early 5G deployment with CUPS in LTE
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UE EUTRAN+NR
MME
HSS
S/P-GW-U Internet/DN
LTENetwork
PCRF
S/P-GW-C
Gx
Sx
Rx
SGiS1-U
S11
S6a
S1-MME
EPC NAS
UE anchored to Network over LTE/UPC control plane.
Wide area coverage through LTE with NR as capacity boost as secondary RAT.
*CUPS (Rel-14): Control user plane separation in EPC, control plane and user plane decouple in S-GW/P-GW
LTE RRC
LTE PDCP
LTE Uu

12. Early 5G deployment with <6 GHz
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The main spectrum options for 5G in its early phases are around 3.5 GHz and 4.5 GHz and millimeter waves at 24-28 GHz and 39 GHz with
Time Division Duplex (TDD) technology. The initial phase aims to use existing base station sites for 3.5/4.5 GHz to simplify 5G introduction.
The spectrum around 3.5 GHz is attractive for 5G because it is available globally and offers a high amount of spectrum – potentially more
than 100 MHz of contiguous spectrum per CSP. 3.5 GHz provides less coverage than the 2 GHz used by 4G networks. However, deploying
massive MIMO beamforming antennas at 3.5 GHz can match the coverage of existing LTE1800/2100 with throughput 2Gbps using 100 MHz
of bandwidth, providing a capacity up to 10 times greater than 4G.
But uplink is limited because the 0.2W maximum output power of devices is much lower than the base station power which can be in
excess of 100W. Therefore, a 3.5GHz uplink falls short of LTE2100 or LTE1800 coverage.
One solution is to deploy 5G at low bands which are then
aggregated with the 3.5 GHz band.
Another option is to share the uplink frequency between
5G and LTE, for example, at 1800 MHz or 800 MHz

13. Key capabilities of 5G: Network slicing (Motivation)
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Traditional case operators provide all types of services to various kinds of customers via single network.
With Network slicing, operators can divide entire same physical network into different slices - each with its own configuration and specific QoS
e.g. speed, capacity, coverage, latency etc can be allocated in logical slices to meet the specific demands of each use case.
Each slice will be considered separate logical network to support variety of vertical industries which we can say a Personalized Network.
Network slicing will use virtualization technology i.e. NFV or SDN in order to design, partition, organize and optimize communication and
computation resources of a physical infrastructure into multi logical networks for enabling of variety of services.
Examples of network slices can be:
a slice to serve remote control function of a factory where lower latency is the critical requirement
a slice serving for a utility company where coverage and capacity will be critical requirement.
a slice dedicated to provide emergency health services where speed and latency will be critical requirement, and so on
There are two different concepts of using network slicing in communication networks
Slicing for QoS/Vertical slicing:
This is primary focus. Create slices in order to offer different types of services to the end users, to assure specific types of QoS within specific
slice. E.g. live video streaming, broadband connection to medical emergency response operation, autonomous car and so on.
Slicing for Infrastructure Sharing/Horizontal slicing:
The idea is to virtualize RAN domain and share it among operators. The owner will give a slice to a tenant based on an agreement. The tenant
will have overall control on both functions and infrastructure of that slice which leads to optimize network cost and network scalability.

14. Key capabilities of 5G: Network slicing Architecture
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The architecture consists of
• CN slices
• RAN slices,
• Radio slices.
Each slice in CN is built from a set of Network Functions (NFs), some NFs can be used
across multiple slices while some are tailored to a specific slice.
There are at least two slice pairing functions, which connect all of these slices together.
• The first pairing function is between CN slices and RAN slices, and
• the second pairing function is between RAN slices and radio slices.
The mapping among radio, RAN and CN slices can be 1:1:1 or 1:M:N, it specifically
means that a radio could use multiple RAN slices, and a RAN slice could connect to
multiple CN slices.
Network slicing standardization process is still in its initial phase and is mostly focused
on vertical slicing.

15. Key capabilities of 5G: Network slicing Management Architecture
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From the operational perspective network slicing concept is
consisted of three layers:
• Service Instance Layer:
It represents end user and business services, which are expected to
be supported by the network. These services can either be
provided by the network operator or by a third party.
• Network Slice Instance Layer: The network slice instance provides the network characteristics required by a service instance. The
network slice instance may be shared across multiple service instance, or separate NSI for separate service which are decided by a
network operator.
• Resource Layer: The actual physical and virtual network functions are used to implement a slice instance. At this layer, network slice
management function is performed by the resource orchestrator, which is composed of NFV Orchestrator (NFVO), and of application
resource configurators.

16. Key capabilities of 5G: Network slicing (Working principle)
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AN-CCNF CN-CCNF
CP Functions
UP Functions
AN Slice
CP Functions
UP Functions
CN Slice
UDR
AF
DN
Network Slice
Management
To/from all Network Slices
UE
Option 1. UE provides NSI (Network Slice
Instance) ID to the network and the
network selects the corresponding NSI at
the interface with UE, i.e. RAN, and then
Core Network checks if the selected
network slice is acceptable and continues
the operation if it is acceptable.
Option 2. Core Network selects a network
slice based on the service request sent
from UE. To enable control message
delivery from UE to CN before allocating a
NSI, it defines a common control path and
CCNF (Common Control Network Function)
outside of the network slice.
• CN-CCNF (Core Network – CCNF) is the core network part of CCNF. CN CCNF includes, NSI selection, MM (mobility), and AA (Authentication).
• ANCCNF (Access Network-CCNF) is access network part of CCNF, which includes CN-CCNF selection and AN Slice Control.
• AN Slice and CN Slice are bound to each other to complete an end-to-end NSI during the deployment of the NSI by Network Slice Management.
• UE has slice independent signaling paths to AN-CCNF and CN-CCNF.
• UE also establishes a slice specific signaling paths both to AN CP functions and CN CP functions (CP: control plane; UP: User plane).

17. Key capabilities of 5G: Network slicing (Challenges)
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Business case: telecom regulatory framework has to be conducted. New innovative ways of pricing, cost of infrastructure sharing, service level
agreement between the owner and tenant of slice, and expected generating revenue should be addressed and standardized.
CAPEX/OPEX estimation: In traditional networks CAPEX and OPEX are estimated according to the number of BTS, transmission power and
traffic volume. For sliced networks, each resource can be shared by several network slices, and slicing scheme varies from one resource to
another. Cost cannot be generally estimated for entire physical network. A novel slice-oriented cost model may require.
Security: Existing and some of proposed open interfaces in network slicing, which support network programmability lead to bring new potential
attacks to softwarized networks (dynamic threat detection, user authentication, accounting management, and remote attestation.)
Management: In order to dynamically assign network resources to different slices, the optimization policy that manages resource orchestrator
should deal where resources demands vary. Network management and orchestration in multi-tenant scenarios will be major concerns.
Performance: When network slices are deployed, network performance analysis and QoS measurement can become more challenging. An
intensive study is required to provide solutions for dynamic performance measurement and network analysis considering both time and cost.
Standardization: Network slicing standardization process is in its initial phase and is mostly focused on vertical slicing. There are wide range of
studies being conducted on network slicing by various research projects (NGMN, 5G NORMA, Co-Funded framework, WWRF, 3GPP, and 5GPPP.)
Access Network Virtualization: Core network slicing has been already investigated. However, as 5G network is composed of multiple access
technologies, it is vital for RAN virtualization solutions to be able to accommodate these various technologies. It is unclear so far, whether
multiple access technologies can be multiplexed over the same hardware or each will need its own dedicated hardware.

18. Development towards 5G across the world
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SK Telecom with Nokia Moves Closer to 5G with 2 ms (between the handset and base station) Low Latency LTE Technology by applying
Uplink Pre-Scheduling, a technology that enables the handset to immediately transmit data to the base station,
Short Transmission Time Interval (TTI), a technology that reduces data transmission time between base station and handset to about 1/7.
Ericsson introduces a new radio product, AIR 3246, for Massive
Multiple Input Multiple Output (Massive MIMO). AIR 3246 supports
both 4G/LTE and 5G NR (New Radio) technologies and is Ericsson’s
first 5G NR radio for frequency division duplex (FDD). This launch will
enable operators – especially in metropolitan areas – to bring 5G to
subscribers using today’s mid-band spectrum and boost capacity in
their LTE networks. Commercially available in Q2’2018.
ZTE and China Unicorn conducted 5G NR field test using 3.5GHz
and 100 MHz BW.
Phase 2 of China’s National 5G tests, organized by IMT-2020 (5G)
promotion group, were conducted in Beijing. ZTE tests for
continuous wide coverage, eMBB at sub 6GHz, eMBB at
mmWave frequencies, uRLLC, eMTC.
[Tokyo, Japan, June 27, 2017] Recently, at the 3rd Global 5G Tokyo Bay Summit, Huawei successfully showed 39 GHz mmWave technology
based on 3GPP standard 5G New Radio (NR) current agreements in cooperation with NTT DOCOMO, INC. The cell coverage reached up to
2.0 kilometers with Gbps peak throughput for a single user in the mmWave. With this system, a real-time 3-way 4K video conference was
demonstrated.
The field test was performed in 21 District of Japan. The test system was made up of one base station that works in the 39 GHz band with
1.4 GHz bandwidth, and 2 UEs (User Equipment). According to the test, 1.3 Gbps (MAC Layer) peak throughput for a single user in the high
band was achieved at a distance of 1.5 kilometers. The test employed key 5G technologies, such as the MMFA (Meta-Material Focal Array)
and Polar Code.

19. 5G Network standard timeline
• The plan is now to deliver the whole Network as a Service. The approach to this being taken in 3GPP is to re-architect the whole core based
on a service-oriented architecture approach.
• 3GPP is well progressed on the Phase I of this new service based architecture system design (TS 23.501 and TS 23.502), and it is expected to
be complete by December 2017, Roadmap for Release (Rel -15) June 2018.
• Phase I will include a basic system solution and basic network slicing capabilities.
• Phase 2 (Rel‐16) to be completed by March 2020. IMT 2020 submission, addresses all identified use cases & requirements, advanced
features and capabilities.
References: https://www.computerworld.com/article/3219828/mobile-wireless/the-5g-core-network-3gpp-standards-progress.html
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