epc dimensioning
DESCRIPTION
epcTRANSCRIPT
05/11/2013
1
1
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
2
CONTENTSCONTENTS
I. Introduction
II. Evolved Packet Core
III. Core network Dimensioning
IV. Summary
05/11/2013
2
3
CONTENTSCONTENTS
I. Introduction
4
� LTE Commercialization
• 351 Operators in 104 Countries are investing in LTE
• 105 LTE Commercial LTE Networks Launched in 48 Countries
IntroductionIntroduction
05/11/2013
3
5
� 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
IntroductionIntroduction
6
� World evolution of mobile data traffic
IntroductionIntroduction
05/11/2013
4
7
IntroductionIntroduction
� 3GPP technologies are based on CDMA and OFDMA technologies
• WCDMA and HDPA are based on CDMA
• LTE is based on OFDMA
8
IntroductionIntroduction
� Provide low latency
� Higher network throughput
� Increased data transfer speed
� More cost effectiveness
� Improvements over 3G network
Advantages
05/11/2013
5
9
CONTENTSCONTENTS
II. Evolved Packet Core
10
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
05/11/2013
6
11
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
12
� 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.
Evolved Packet Core Evolved Packet Core
05/11/2013
7
13
� 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
Evolved Packet Core Evolved Packet Core
14
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
Evolved Packet Core Evolved Packet Core
05/11/2013
8
15
� 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
Evolved Packet Core Evolved Packet Core
16
� SGW is the termination point of the packet data network interface towards
E-UTRAN.
Evolved Packet Core Evolved Packet Core
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
05/11/2013
9
17
Evolved Packet Core Evolved Packet Core
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)
18
• 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
Evolved Packet Core Evolved Packet Core
� Mobility Management Entity (MME)
05/11/2013
10
19
• 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..
Evolved Packet Core Evolved Packet Core
� Policy and charging rules function (PCRF)
AF
PCRF
SGW PGW
Online
charging
Offline
charging
20
EPC deployment model
Evolved Packet Core Evolved Packet Core
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
05/11/2013
11
21
CONTENTSCONTENTS
III. Core network Dimensioning
22
� 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
05/11/2013
12
23
1. Dimensioning Phases
CORE NETWORK DIMENSIONINGCORE NETWORK DIMENSIONING
24
Dimensioning Phases Dimensioning Phases
Equipment
dimensioning
Dimensioning Traffic
Signaling Traffic
Data Traffic
Number of
equipment needed
Subscribers
demands
� Traffic Dimensioning
05/11/2013
13
25
� 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
26
2. Traffic dimensioning at BH
CORE NETWORK DIMENSIONINGCORE NETWORK DIMENSIONING
05/11/2013
14
27
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
28
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
Traffic dimensioning Traffic dimensioning at at BHBH
Service characteristics:• Session size
• Number of possible sessions at
busy hour
05/11/2013
15
29
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
30
� 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
Traffic dimensioning Traffic dimensioning at BHat BH
05/11/2013
16
31
���� 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
Traffic dimensioning Traffic dimensioning at BHat BH
32
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
Traffic dimensioning Traffic dimensioning at BHat BH
05/11/2013
17
33
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
Traffic dimensioning Traffic dimensioning at at BHBH
34
� 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
Traffic dimensioning Traffic dimensioning at at BHBH
05/11/2013
18
35
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
Traffic dimensioning Traffic dimensioning at at BHBH
36
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
Traffic dimensioning Traffic dimensioning at at BHBH
05/11/2013
19
37
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
Traffic dimensioning Traffic dimensioning at BHat BH
38
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
Traffic dimensioning Traffic dimensioning at at BHBH
05/11/2013
20
39
3. Equipment dimensioning
CORE NETWORK DIMENSIONINGCORE NETWORK DIMENSIONING
40
Equipment dimensioningEquipment dimensioning
a) MME dimensioning
05/11/2013
21
41
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
42
b) SGW dimensioning
Equipment dimensioningEquipment dimensioning
05/11/2013
22
43
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
44
c) PGW dimensioning
Equipment dimensioningEquipment dimensioning
05/11/2013
23
45
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
46
d) HSS dimensioning
Equipment dimensioningEquipment dimensioning
05/11/2013
24
47
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
48
d) PCRF dimensioning
Equipment dimensioningEquipment dimensioning
05/11/2013
25
49
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
50
e) Dimensioning of signaling procedures
Equipment dimensioningEquipment dimensioning
05/11/2013
26
51
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
52
IV. Case Study
CONTENTSCONTENTS
05/11/2013
27
53
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
54
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
05/11/2013
28
55
1. Traffic dimensioning at BH
CASE STUDYCASE STUDY
56
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
05/11/2013
29
57
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
Traffic Traffic Volume ULVolume UL--DLDL
� Data session profile for a Data card
58
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
Traffic Traffic Volume ULVolume UL--DLDL
� Total traffic for office VPN and internet at BH (DL and UL)
05/11/2013
30
59
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)
Traffic Traffic Volume ULVolume UL--DLDL
60
2. Dimensioning of signaling procedures
CASE STUDYCASE STUDY
05/11/2013
31
61
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
62
3. Equipment dimensioning
CASE STUDYCASE STUDY
05/11/2013
32
63
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
64
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
05/11/2013
33
65
VI. Summary
CONTENTSCONTENTS
66
SummarySummary
� Main Challenges for the Future
• User QoE decrease and operator cost increase due to mobile traffic growth
• Operator revenue growth slows
05/11/2013
34
67
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
68
Thank you Thank you