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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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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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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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

5

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?

modeling and simulation of 3g umts in opnet

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