epc dimensioning

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Core network and Core network and

transmission studytransmission study

Sami TABBANE

ITU ASP COE Training on

“Wireless Broadband”

5-8 November 2013 – Nadi (Fiji Islands)

Session 7

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CONTENTSCONTENTS

I. Introduction

II. Evolved Packet Core

III. Core network Dimensioning

IV. Summary

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CONTENTSCONTENTS

I. Introduction

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� LTE Commercialization

• 351 Operators in 104 Countries are investing in LTE

• 105 LTE Commercial LTE Networks Launched in 48 Countries

IntroductionIntroduction

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� LTE: Fast Market Growth

• 100 LTE Commercial Launches within 3 years of the first launch

• WCDMA took longer than 4 year for 100 commercial launches

• 100M LTE Subscribers within 3.3 year expected


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� World evolution of mobile data traffic


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� 3GPP technologies are based on CDMA and OFDMA technologies

• WCDMA and HDPA are based on CDMA

• LTE is based on OFDMA

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� Provide low latency

� Higher network throughput

� Increased data transfer speed

� More cost effectiveness

� Improvements over 3G network

Advantages

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CONTENTSCONTENTS

II. Evolved Packet Core

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Evolved Evolved Packet Core Packet Core

� 3GPP Core Network Evolution

� 3GPP Network has evolved from 4 tier architecture to 3 tier architecture

2G /3G

LTE

CDMA/EV-DO

GSM/GPRS

EDGE

UMTS

HSPA IP channel

Voice

channels

eNodeB

BSC/RNC

Packet swirched

core data

Circuit swirched

core voice

BTS

NodeB

PTSN

Other

Mobile

networks

Internet

VPN

Transport (backhaul and backbone)

Evolved packet core

(all–IP)

eNodeB

IP channel

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Evolved Packet Core Evolved Packet Core

eNodeB

IP channel

MME PCRFS-GW P-GW

Service delivery platforms

IP communications

(VoiP, video)

• Messaging SMS/MMS

• Internet, Web 2.0

Advanced location based services

• Mobile Tv, IP mULimedia

• Mobile office

Evolved core network

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� Radical changes in the network

� End of circuit-switched voice:

• LTE uses a new paradigm for voice traffic — VoIP.

� Evolved wireless broadband

� Mobility as a part of the core network:

• In LTE, all mobility management is moved into the mobile

core and becomes the responsibility of the MME.


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� End-to-end QoS becomes essential:

• LTE must provide superior end-to-end QoS management and

enforcement in order to deliver new media-rich, low-latency and

real-time services.

� Policy management and enforcement:• Service control is provided via the Policy and Charging Rules

Function (PCRF)

• PCRF dynamically controls and manages all data sessions and

provides appropriate interfaces towards charging and billing

systems.

• LTE requires significantly more capacity in both the data plane and

control plane.

� Radical changes in the network


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SGWSGW P-GWP-GW

HSS

PCRFPCRFS1-C

S11

S5/S8

S6a

S7 (Gx)

S1-U

eNode B

� 4G (LTE) architecture

MMEMME

2G2G

3G3G

RNCRNC SGSNSGSNSAE GW

eNode B

X2


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� The EPC is realized through four new elements:

• Serving Gateway (SG-W)

• Packet Data Network (PDN) Gateway (P-GW)

• Mobility Management Entity (MME)

• Policy and Charging Rules Function (PCRF)

� SGW, PGW and MME are introduced in 3GPP Release 8,

� PCRF was introduced in 3GPP Release 7


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� SGW is the termination point of the packet data network interface towards

E-UTRAN.


eNodeB

IP channel

MME PCRFS-GW P-GW

Evolved core network

Serving Gateway (S-GW)

Manage user-plane mobility � acts as an interface between the RAN and

core networks.

Maintains data paths between eNodeBs and the PDN Gateway (PGW).

eNodeB

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The termination point of the packet data interface towards the Packet Data Network(s).

the PDN GW supports:

• Policy enforcement features

• Packet filtering (for example, deep packet inspection for application type detection)

• Charging support (for example, per-URL charging)

In LTE, data plane traffic is carried over virtual connections called service data flows

(SDFs).

One or more SDFs are aggregated and carried over one bearer.

� Packet Data Network (PDN) Gateway (P-GW)

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• It performs the signaling and control functions to manage the User

Equipment (UE) access to network connections, the assignment of network

resources, and the management of the mobility states to support tracking,

paging, roaming and handovers

The MME supports:

• Security procedures: End-user authentication as well as initiation and

negotiation of ciphering and integrity protection algorithms.

• Terminal-to-network session handling

• Idle terminal location management


� Mobility Management Entity (MME)

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• A concatenation of Policy Decision Function (PDF) and Charging Rules Function

(CRF)

• A control plane element that is not strictly speaking, an EPC element, but is

required to give dynamic control over bandwidth, charging, and network usage

� Policy and Charging Enforcement Function (PCEF):

supports service data flow detection, policy

enforcement and flow-based charging.� Application Function (AF):

supports applications that require

dynamic policy and/or charging

control.

� shows how PCRF interfaces with other EPC elements..


� Policy and charging rules function (PCRF)

AF

PCRF

SGW PGW

Online

charging

Offline

charging

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EPC deployment model


Deployment architecture Centralised Function Distributed Function

Completely centralised SGSN+GGSN+MME+SGW

+PGW

Completely distributedMME+SGSN+GGSN+SGW

+PGW

Centralised bearer/

Distributed control SGW+PGW+GGSN MME+SGSN

Centralised control/

Distributed bearerMME PGW+SGW

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CONTENTSCONTENTS

III. Core network Dimensioning

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� General wireless network planning process

Core network DimensioningCore network Dimensioning

Dimensioning:Requirements and

Strategy for coverage,

capacity and quality

Coverage planning

Capacity equipment

Parameters planning

Optimization Optimization Performance analysis in

terms of quality and

interference

Pre-planning • Collect area parameters .

• Detailed information of EPC core

network

• Superficies

• Subscribers information

Output

• Equipment capacity

• Offered services

• Number of subscribers

Coverage and capacity constraints

� Minimize exploited resources

Output:

• Necessary capacity

• User Traffic rate

• Signaling traffic

Geographical site position

� Maximize the coverage

KPI (Key performance indicator)

� QoS requirements

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1. Dimensioning Phases

CORE NETWORK DIMENSIONINGCORE NETWORK DIMENSIONING

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Dimensioning Phases Dimensioning Phases

Equipment

dimensioning

Dimensioning Traffic

Signaling Traffic

Data Traffic

Number of

equipment needed

Subscribers

demands

� Traffic Dimensioning

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� Dimensioning preliminary phases

Initial parameters

configuration

Signaling Traffic

Handsets profiles

configuration

Traffic at Busy hour

• Number of subscribers, N

• Number of smartphone

• Number of data card

• Session size

• Number of sessions during the busy hour

• Traffic percentage in DL

• Data traffic carried in VPNs or for Internet services

• Network attach and detach

• Bearer activation

• HO procedures

• Tracking area update

Dimensioning Phases Dimensioning Phases

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2. Traffic dimensioning at BH


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Nc= NA* PC

NS =NA* Ps

Where:

Nc: Number of data cards

NA: Total subscribers number

PC: Data card percentage

NS: Total smartphones number

Ps: Smartphones percentage

� Initial parameters (Number of smartphones and data cards)

Traffic dimensioning Traffic dimensioning at at BHBH

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With smartphones we can access to:

• Streaming

• Interactive video games

• Download

• Internet

�� Traffic at busy hour:

ρSBH-DL/UL = (Tsession*Nsession)

Where

ρSBH-DL/UL: Traffic volume in UL/ DL at Busy hour

Tsession : Exchanged data volume per session

Nsession: Number of sessions at BH

� Smartphone profile in Busy hour


Service characteristics:• Session size

• Number of possible sessions at

busy hour

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ρSBH-DL = (ρS

BH-DL/UL ) * ρ DL

Where:

• ρSBH-DL/UL: Traffic volume at Busy hour

• ρSBH-DL: Traffic volume on the DL

• ρ DL : Percentage of DL traffic

�� Traffic on DL:

Traffic dimensioning Traffic dimensioning at BHat BH

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� Smartphones Total traffic

ρSDL/UL= ρS

BH-DL/UL *Ns

ρSDL/UL: Smartphone total traffic at Busy hour

�� Data card total traffic

ρCDDL/UL= ρCD

Internet-BH-DL/UL *NCD

ρSDL/UL: Smartphone total traffic at Busy hour

� Traffic during BH


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�� Total traffic Internet services

ρInternet DL/UL = ρSDL/UL + ρCD

DL/UL

�� Throughput of Internet services

THInternet BH-DL/UL = (ρInternet DL/UL *8) / 3600

Where

THInternet BH-DL/UL: Internet services throughput at busy hour

� Internet services Throughput at BH


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Number of cards supporting this services:

NCD_VPN = NCD*PCD_VPN

NCD_VPN: Number of cards using VPN

PCD_VPN: Percentage of cards using VPN

ρ VPN DL/UL = (ρ CDVPN BH-DL/UL ) * NCD_VPN

THVPN DL/UL = (ρVPN DL/UL *8) / 3600

Where

THVPN DL/UL: Throughput VPN services at busy hour

� VPN services Throughput during BH


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ρSDL = (ρS

BH-DL) * Ns

ρSDL = Smartphones total traffic in DL

ρCDDL = (ρCD

Internet BH-DL) * NCD

ρCDDL = Data cards total traffic in DL

(ρInternet BH-DL)= ρSDL + ρCD

DL

(ρInternet BH-DL)T: Total traffic in DL ( Internet services)

THInternet BH-DL = ((ρInternet DL) *8/3600)

� Traffic in DL


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� Number of active users at Busy hour

NAU= NA*P AU

NAU: Number of active user at busy hour

PAU: Percentage of active user at busy hour

� Number of operations made at busy hour

NAttach= NAttach/sub/BH*N AU

Nattach: Total number attachment

NAttach/sub/BH: Number of attachment at busy hour

NDetach= NDetach/sub/BH*N AU

NDetach: Total number of detach

NDetach/sub/BH: Number of detach at busy hour


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NIDLE/ACTIVE= NIDLE/ACTIVE/sub/BH*N AU

• NIDLE/ACTIVE: Total number of transitions idle to active

• NIDLE/ACTIVE/sub/BH: Number of transitions idle to active at busy hour

NPDN= NPDN/sub/BH*N AU

• NPDN: Total number of PDN connections

• NPDN/sub/BH: Number of PDN connections at busy hour


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NBEARERS= NBEARERS/sub/BH*N AU

NBEARERS: Total number of bearer activation and deactivation

NBEARERS/sub/BH: Number of bearer activation and deactivation per user at busy hour

NTAU_INTER_MME = NTAU_INTER_MME/sub/BH*N AU

NTAU_INTER_MME: Total number of tracking area update inter MME

NTAU_INTER_MME/sub/BH: Number of tracking area update inter MME per user

at busy hour

NTAU_INTER_MME_SGW = NTAU_INTER_MME_SGW/sub/BH*N AU

NTAU_INTER_MME_SGW: Total number of tracking area update inter MME /SGW

NTAU_INTER_MME_SGW/sub/BH: Number of tracking area update inter MME/SGW per user

at busy hour


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NX2_HO= NX2_HO/sub/BH*N AU

NX2_HO: Total number of handover via X2 interface

NX2_HO/sub/BH: Number of handover via X2 interface per user at busy hour

NS1_HO = NS1_HO /sub/BH*N AU

NS1_HO: Total number of handover via S1 interface

NS1_HO/sub/BH:Number of handover via S1 interface per user at busy hour

NHO_INTER_MME = NHO_INTER_MME/sub/BH*N AU

NHO_INTER_MME: Total number of handover inter MME

NHO_INTER_MME/sub/BH: Number of handover inter MME per user at busy hour


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N proc = NAttach+ NDetach + NIDLE/ACTIVE + NPDN + NBEARERS + NTAU_INTER_MME + NX2_HO

+ NS1_HO + NHO_INTER_MME

N proc: Total Number of procedures

� Total number of procedures at busy hour


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3. Equipment dimensioning


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Equipment dimensioningEquipment dimensioning

a) MME dimensioning

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N MME = E[ Nattach / OC SAU]

N MME: Required number of MME

OC SAU: Capacity MME in simultaneous users attached

N MME= E[NIDLE/ACTIVE /3600)/ OC IDLE/ACTIVE]

OC IDLE/ACTIVE: Capacity MME in Idle to active transactions (in seconds)

N MME= E[NPROC /3600)/ OC TRANS_MME]

OC TRANS_MME: Capacity MME in transactions (in seconds)

MME dimensioningMME dimensioning

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b) SGW dimensioning


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N SGW = E[ NBEARERS / OC BEARERS]

N SGW: Required number of SGW

OC BEARERS: Capacity MME in bearers activation and deactivation

N MME= E[NIDLE/ACTIVE /3600)/ OC IDLE/ACTIVE]

� For internet and VPN services:

N SGW = E[ THBH-DL-INTERNET / OC DATA-PROCESSING]

N SGW = E[ THBH-DL-VPN/ OC DATA-PROCESSING]

OC DATA-PROCESSING: Capacity data treatment

SGW dimensioningSGW dimensioning

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c) PGW dimensioning


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N PGW = E[ NBEARERS / OC BEARERS]

N PGW: Required number of PGW

N PGW = E[ THBh-DL-INTERNET / OC DATA-PROCESSING]

N PGW = E[ THBh-DL-VPN/ OC DATA-PROCESSING]

PGW dimensioningPGW dimensioning

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d) HSS dimensioning


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N HSS = E[ NA / OC A]

N HSS: Required number of HSS

OC A: Maximum capacity of HSS in term of subscribers

HSS dimensioningHSS dimensioning

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d) PCRF dimensioning


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N PCRF = E[ NPROC/3600) / OC TANS_PCRF]

N PCRF: Required number of PCRF

OC TANS_PCRF: Capacity of PCRF in term of transactions ( in seconds)

PCRF dimensioningPCRF dimensioning

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e) Dimensioning of signaling procedures


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0.2 T ≤ NMSG*Duration= Tsignal = TMSG /Throughput ≤ 0.4T

• TMSG: Request signaling size ( in bit)

• Throughput: Transmission throughput

• Tsignal: Time transmission

• NMSG: Number of signaling messages between network elements

TH INT_C = [TMSG * NMSG * NPROC/3600]

• C INT_C= ∑ TH INT_C

• NPROC_x: Number of operations

• TH INT_C: Throughput per interface in the control plane

• C INT_C: Capacity per interface

Dimensioning of signaling proceduresDimensioning of signaling procedures

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IV. Case Study

CONTENTSCONTENTS

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Subscribers Subscribers InformationInformation

Population 1 003 700

Market Evaluation 52,6 %

Data Card Percentage 42 %

Smartphones (% ) 27 %

� Area Information

Total Subscribers Data cards Number Smartphones Number

527 947221 738

142 546

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Traffic

topology

Number of

session at BH Session size

DL Percentage

(%)

Web

Browsing1 2 85

Email 4 0.5 80

Video

streaming1 10 95

VPN 0.25 1 60

Gaming 1 0.04 60

� Smart-Phone Configuration Profile UL/DL

Subscribers Subscribers InformationInformation

Service Active subscribers

Internet access ALL

VPN 30% of data cards

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1. Traffic dimensioning at BH

CASE STUDYCASE STUDY

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Traffic

topology

Number of

session

Session

Size(Mb)

Traffic Volume at busy

hour UL/DL

(Mb)

Traffic Volume at

busy hour DL

(Mb)

Web

Browsing1 2 2 1.7

Email 4 0.5 21.6

Video

streamin

g

1 10 10 9.5

VPN 0.25 1 0.25 0.15

Gaming 1 0.04 0.04 0.02

Total Traffic Volume (Internet) 14.04 12.82

Traffic Traffic Volume ULVolume UL--DLDL

� Data session profile for a Smartphone

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Traffic

topology

Number of

session

Session

Size(Mb)

Traffic Volume at busy

hour UL/DL

(Mb)

Traffic Volume at

busy hour DL

(Mb)

Internet 1 2 2 1.7

Internet 2 2 43.2

Internet 1 10 10 9.5

VPN 0.5 2 1 0.6

Internet 1 0.04 0.04 0.02

Total Traffic Volume (Internet) 16.04 14.42

Total Traffic Volume (VPN) 1 0.6


� Data session profile for a Data card

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ItemTotal traffic at BH for Internet

(Mb)

Total traffic volume for all smartphones 1.99

Total traffic volume for all data cards 3.54

Total traffic (Mb) 5.54

BH throughput for intent DL&UL (Gb) 12.31

Data cards using VPN 30%

Total traffic VPN (MB) 0.06

BH throughput for office VPN (GB) 0.14


� Total traffic for office VPN and internet at BH (DL and UL)

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ItemTotal traffic at BH for

Internet(Mb)

Total traffic volume for all smartphones 1.827.439

Total traffic volume for all data cards 2.005.513

Total traffic ( Mb) 3.882.952

BH throughput for internet DL&UL ( Gb) 8.62

Data cards using VPN 30%

Total traffic VPN (MB) 39 913

BH throughput for office VPN 0.08

� Total traffic for office VPN and internet at BH (DL)


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2. Dimensioning of signaling procedures


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Procedure

Subscriber/BHNumber

Active user at BH 90%

N attach 1 475153

N detach 1 475153

N Idle to active 50 23 757 600

N PDN 0,5 237 576

N Bearers activ/deactiv 0.5 237 576

N TAUs inter MME 0,01 4752

N TAUs 0,1 47 516

N X2- HO 0,25 118788

N S1- HO 0,25 118788

N HO inter MME 0,01 4752

N Procedure 25 477 654

• Busy Hour Active Subscriber

= 527 947 x 90%

= 475 153

Dimensioning of signaling proceduresDimensioning of signaling procedures

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3. Equipment dimensioning


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Equipment dimensioning Equipment dimensioning

Components Metrics Unit Value Percentage Operating capacity

MME

SimULaneous attached users

(SAU)Subscribers 400 000 85% 340000

Idle to active

transition/secondTrans/sec 2600 85% 2210

Transactions/second Trans/sec 3000 85% 2550

SGWNumber of active bearers bearers 1000000 85% 850000

Data processing capacity Gbps 10 85% 8.5

PGW

Number of active bearers bearers 1000000 85% 850000

Data processing capacity Gbps 10 85% 8.5

Combines

GW/P-GW

Number of active bearers bearers 600000 85% 510000

Data c processing capacity Gbps 5 85% 4.25

HSS Number of users supportedSubscribers

3000000 85% 2550000

PCRF Transactions/secondTrans/sec

1600 85% 1360

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Component Required number

N MME-OC SAU 1

N MME-IDLE/ACTIVE 3

N MME-Proc 3

N SGW-Bearers 1

N SGW-Data Proc 2

N SGW-VPN 1

N PDNGW-Bearers 1

N PDNGW-DL Internet 2

N PDNGW-VPN 1

N SGW-PDNGW Bearers 1

N SGW-PDNGW DL Internet 3

N SGW-PDNGW DL VPN 1

N HSS 1

N PCRF 5

� Required nodes

Equipment dimensioning Equipment dimensioning

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VI. Summary

CONTENTSCONTENTS

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SummarySummary

� Main Challenges for the Future

• User QoE decrease and operator cost increase due to mobile traffic growth

• Operator revenue growth slows

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SummarySummary

• Many promising technologies have been identified in 3GPP

• Operator and consumer benefit should be carefully considered when

new technologies are introduced for beyond 4G

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Thank you Thank you

epc dimensioning

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