Download - Modeling and Simulation of 3G UMTS in OPNET
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Modeling and Simulation of 3G UMTS in OPNETXi Li, Carmelita GörgTZI, Institute of Communication NetworksUniversity of Bremen, [email protected]
27. Treffen der VDE/ITG-Fachgruppe 5.2.4, Stuttgart June 19, 2008
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OutlineIntroduction and motivation
Introduction to UMTS networksGoal of simulationsOPNET Simulator
Modeling FrameworkModeling scope Requirements and challenges
Modeling of UMTS and its evolution in OPNETRel99 ATM-based UTRANRel5 IP-based UTRAN
Performance EvaluationFuture Work
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External network(Internet, PSTN)
Node B
UTRAN
Core Network
Node B
RNC
Node BNode B
Node B
RNC
Node B
IntroductionIub Interface- Transmission resources is limited and costly- Economic factor of UMTS network design
Performance Evaluation- Delay and jitter-Connection reject ratio- Packet discarding due to congestion and excessive delay
Uu Air Interface:- WCDMA (Wideband Code Division Multiple
Access)- Data sent at every TTI- Invokes strict delay requirements of transport
of radio frames on Iub interface
UE
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Performance Evaluation by simulationsNew feature modeling and testingParameter and network optimizationTraffic generation and characterization Network capacity planning and dimensioning
Derive the dimensioning rules from the simulationsValidate the analytical dimensioning models
Focused on the UTRAN Iub interfaceTransport resources management Dimensioning of the Iub interface
Why Simulations?
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OPNET Simulator
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OutlineIntroduction and motivation
Introduction to UMTS networksGoal of simulationsOPNET Simulator
Modeling FrameworkModeling scope Requirements and challenges
Modeling of UMTS and its evolution in OPNETRel99 ATM-based UTRANRel5 IP-based UTRAN
Performance EvaluationFuture Work
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Modeling ScopeUE UE
Air Interface
NodeB RNC
Core Network
CorrespondingNode
CorrespondingNode
Iub
Groups of UEs and their corresponding nodes as traffic source and sinkAir interface: WCDMA UTRAN: NodeBs, RNC, Iub interface, underlying transport technology (e.g. ATM, IP/Ethernet)Core network: Packet Switched (PS) and Circuit Switched (CS) domains
UTRAN
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Modeling Requirements (1)
Physical LayerWCDMA
Traffic QoS classes in UMTS networkBackgroundConversationalInteractiveStreaming
Network ArchitectureUE: User EquipmentNodeB: Base stationsRNC: control and serve multiple base stationsCore network: provide gateways to UTRAN
Transport TechnologyATMIP
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Modeling Requirements (2)Logical Channels
Dedicated channel (DCH)Common channel (RACH, FACH)
Protocol modelingRadio Link Control (RLC)Medium Access Control (MAC)Frame Protocol (FP)Transport network layer, e.g. AAL/ATM, IP/Ethernet
Resource managementRadio Access Bearer (RAB) setup/releaseCall Admission Control (CAC)Channel Type Switching (CTS)Bit Rate Adaptation (BRA)
Traffic managementPacket classification Buffer managementSchedulingShaping
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Challenges for modeling
Quality of Service (QoS) provision and differentiationATM defines five QoS classes: CBR, UBR, VBR-rt, VBR-nrt, ABRIP: e.g. DiffServ, IntServ, RSVP
Traffic EngineeringCongestion control, flow control
Traffic SeparationRel99 with HSPA (HSDPA/HSUPA)
UMTS EvolutionHSDPA/HSUPALTE (Long Term Evolution)
Mobility ModelingSoft/Softer HOHard HO
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OutlineIntroduction and motivation
Introduction to UMTS networksGoal of simulationsOPNET Simulator
Modeling FrameworkModeling scope Requirements and challenges
Modeling of UMTS and its evolution in OPNETRel99 ATM-based UTRANRel5 IP-based UTRAN
Performance Evaluation Future Work
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UTRAN Model Concept
UE Traffic
Iub
RLCRLC
Applications
TCP/UDP
IP
MACMAC
PDCPPDCP
FP
AAL2
ATM
PHYPHY
PDCPPDCP
RLCRLC
MACMAC
FP
AAL2
ATM
PHYPHY
Applications
TCP/UDP
IP
Traffic from the remote servers or terminals via core network
Traffic from the remote servers or terminals via core network
NodeB
RNC
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Modeling of UMTS Rel99 in OPNET
TNL
RNL
Based on the OPNET ATM library (workstation/server)
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Main Functions App. layer:Each user is represented by one app. instancedefine Traffic modelse.g. web, voice, ftp
UE UEUEUE
RRM(CAC, CTS, BRA)
RAB
Channel assignment DCH (DTCH/DCCH), FACH/RACH
Transport Layer
TCP, UDP/IP
Radio Network Layer (RNL)
RLC/MAC/FP
Transport Network Layer (AAL/ATM)AAL2 QoS prioritization (BE and RT)AAL2 shaping based on PCR rate
(VP/VC shaping)limited waiting time at the AAL2 buffer of RNC
ATM VC, VP setup (CBR, UBR, etc.)
Air interface modelling, e.g. propagation delay, radio frame loss due to bad channel conditions, etc.Core network and Internet delayEach NodeB serves up to three cells
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ATM → IP based UTRAN
RNC
NodeB
NodeB
ATM RNC
NodeB
NodeB
IP
3G Release 99 3G Release 5
Based on AAL2 / ATM Based on UDP / IP
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Rel5 IP-based UTRAN
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Modeling of Rel5 IP-based UMTS
• Multiplexing, e.g. LIPE, CIP, to enhance the transport efficiency
• QoS provisioning and differentiation, e.g. DiffServ, IntServ
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OutlineIntroduction and motivation
Introduction to UMTS networksGoal of simulationsOPNET Simulator
Modeling FrameworkModeling scope Requirements and challenges
Modeling of UMTS and its evolution in OPNETRel99 ATM-based UTRANRel5 IP-based UTRAN
Performance EvaluationFuture Work
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The properly dimensioned Iub has to achieve two main targets:Ensure a given level of application performance (guarantee a maximum end-to-end transfer delay) Allow only a certain percentage of discarded radio frames or FP PDUs, referred to as “delayed FP PDU ratio”, the FP PDU is discarded due to excessive delays
SimulationsSimulations
End-to-end Transfer Delay
Delayed FP PDU ratio
Dimensioning Targets
Analytical ModelsAnalytical Models
The maximum acceptable utilization of the Iub capacity
Dimensioning Results
traffic load
QoS
With given Iub bandwidth/configuration
E2E delay
Load 1
delayed FP PDU ratio
Load 2
Dimensioning Task
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Simulation ModelModeling of RLC (Radio Link Control), MAC (Medium Access Control), FP (Frame protocol) for UMTSEach user session is assigned to a specific RAB typeAAL/ATM as the transport layer
103842064RAB 3
201282064RAB 2
20642064RAB 1
TTI(ms)
bit rate (kbps)
TTI(ms)
bit rate (kbps)
DownlinkUplinkDedicated channels - DCHs
Application: FTP
Iub link: e.g. 1 E1 line (2Mbps ATM link)
TTI: Time Transmit Interval
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Dimensioning for Elastic Traffic – w./w.o. CAC
0.80.9
11.11.21.31.41.51.61.71.81.9
22.12.22.32.4
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Load
Aver
age
File
Tra
nsfe
r Del
ay(s
)
0%
10%
20%
30%
40%
50%
60%
70%
80%
Del
ayed
FP
PDU
Rat
io
file transfer delay (with CAC) file transfer delay (No CAC)
delayed FP PDU ratio (with CAC) delayed FP PDU ratio (No CAC)
When employing the admission control in the system, the application performance is stabilized by limiting the number of active user connections simultaneously on the link.But due to the bursty Internet traffic, the performance of the FP layer is only slightly improved.FP layer performance is the more critical restriction.
Scenario: RAB 128kbps, Iub = 1 E1 line (2Mbps), FTP ( file size: constant 12kbyte)
Source: X. Li, R. Schelb, C. Görg and A. Timm-Giel, "Dimensioning of UTRAN Iub Links for Elastic Internet Traffic." in Proc. 19th International Teletraffic Congress, Beijing, Aug/Sept. 2005, 2005.
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Validate analytical model via Simulations (I)
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 13
3.2
3.4
3.6
3.8
4
4.2
4.4
4.6
4.8
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offered load
file
trans
fer d
elay
(s)
M/G/R/N-PSSimulation with CAC (50kbyte)
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.1
0.11
0.12
offered loadbl
ocki
ng ra
tio
M/G/R/N-PSSimulation with CAC (50kbyte)
file transfer delay blocking probability
Scenario: RAB 128kbps, Iub = 1 E1 line (2Mbps), FTP ( file size: constant 50kbyte)
Source: X. Li, R. Schelb, C. Görg and A. Timm-Giel, "Dimensioning of UTRAN Iub Links for Elastic Internet Traffic." in Proc. 19th International Teletraffic Congress, Beijing, Aug/Sept. 2005, 2005.
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Multiple RAB Types
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.90
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3
loadfil
e tra
nsfe
r del
ay (s
)
Constant File Size 12kbyte
M/G/R-PS (RAB 128)Simulation (RAB 128)M/G/R-PS (RAB 64)Simulation (RAB 64)M/G/R-PS (RAB 384)Simulation (RAB 384)
The transfer delay dependent on the bearer typeAnalytical results matches the simulaitons in the low loadIn high load, the flows with the small peak rates achieve longer transaction times than calculated with the M/G/R-PS model, while the high-peak-rate flows experience a somewhat higher QoS than calculatedThe delay for a common file size among the different traffic classes tends to converge in the high load as none of them can utilize its peak rate and thus a fair share of the available resources is available among different RAB types
Validate analytical model via Simulations (II)
Source: X. Li, R. Schelb, C. Görg and A. Timm-Giel, "Dimensioning of UTRAN Iub Links for Elastic Internet Traffic with Multiple Radio Bearers," in Proc. 13th GI/ITG Conference Measuring, Modelling and Evaluation of Computer and Communication Systems, Nürnberg, March 2006, 2006
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Main Research
Dimensioning for Iub link for supporting various traffic scenarios for different UMTS releases (Rel99, IP-based UTRAN, HSDPA, HSUPA)
Derive the dimensioning rules from the simulationsValidate the analytical dimensioning models
Iub Overbooking in multi-NodeBs scenarioCombine HSPA and Rel99 traffic with traffic separation
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Future WorkUMTS Evolution
Internet HSPA or I-HSPA, a flat architecture that provides the first step towards Long Term Evolution (LTE)
3GPP Long Term Evolution (Evolved UTRA and UTRAN) accompanied by 3GPP System Architecture Evolution (SAE)
New Services, e.g. VoIP, IPTV, etc.
Validate with real word scenario
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References
X. Li, R. Schelb, C. Görg and A. Timm-Giel, "Dimensioning of UTRAN IubLinks for Elastic Internet Traffic." in Proc. 19th International TeletrafficCongress, Beijing, Aug/Sept. 2005, 2005.
X. Li, R. Schelb, C. Görg and A. Timm-Giel, "Dimensioning of UTRAN IubLinks for Elastic Internet Traffic with Multiple Radio Bearers," in Proc. 13th GI/ITG Conference Measuring, Modelling and Evaluation of Computer and Communication Systems, Nürnberg, March 2006, 2006
T. L. Weerawardane, X. Li, A. Timm-Giel and C. Görg, "Modeling and Simulation of UMTS HSDPA in OPNET," in Proc. OPNETWORK 2006, September, 2006, Washington DC, USA, 2006
X.Li, W. Cheng, A.Timm-Giel, and C. Görg, "Modeling IP-based UTRAN for UMTS in OPNET", distinguished paper award, in Proc. OPNETWORK 2007, September, 2007, Washington DC, USA, 2007
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Thanks for attentions!Questions?