3G Network Dimension Ing

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Treffen/Workshop der ITG Fachgruppe 5.2.1

Radio Access Network Dimensioning for 3G UMTS

Xi [email protected]

November 13, 2009

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OutlineIntroduction and MotivationUMTS Network Dimensioning Framework Developed Simulation Models Developed Analytical ModelsDimensioning Models and ResultsConclusions and Outlook

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Universal Mobile Telecommunication System (UMTS)

UE User EquipmentNode B Base StationRNC Radio Network Controller

UTRAN UMTS Terrestrial Radio Access NetworkPSTN Public Switched Telephone Network

UE

PSTN ...

Core Network

Node B

UE

UE

UE

InternetX.25 ...

UTRAN External Networks

Iub

Node B

UE

UE

UE

UE

Iub

RNC

Circuit SwitchedDomain

Packet SwitchedDomain

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Motivation of UMTS Network Dimensioning

Dimensioning: determine appropriate bandwidths for transport linksmaximizing utilization of transport resourcesguarantee QoS (Quality of Service) requirements

The transport resource within the UTRAN is considerably costly

UTRAN Costly interface Strict delay QoS

Costly interface Strict delay QoSIub Interface

Dimensioning of Iubis important to design a high cost- efficient UMTS network

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Goal of This Thesis

UMTS network is developing fastEvolutions of UMTS

Radio Access Network (RAN) evolution: Rel99, HSDPA, HSUPA, HSPA+, LTEEvolved UMTS terminals and emerging new servicesSignificant increase of the traffic volumeRemarkable changes in traffic pattern and characteristics

Transport Technologies for UTRAN, e.g. migration from ATM to IPQuality of Service Schemes, e.g. QoS differentiation and prioritization

Goal of this ThesisInvestigate important aspects related to the Iub dimensioning Develop dimensioning approaches for different UMTS Networks

simulation modelsanalytical models

Derive important dimensioning guidelines and rules

Goal of this ThesisInvestigate important aspects related to the Iub dimensioning Develop dimensioning approaches for different UMTS Networks

simulation modelsanalytical models

Derive important dimensioning guidelines and rules

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OutlineIntroduction and MotivationUMTS Network Dimensioning FrameworkDeveloped Simulation Models Developed Analytical ModelsDimensioning Models and ResultsConclusions and Outlook

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Objectives of UMTS Network Dimensioning

Network Costs: the costs correlated with the expenditures necessary for leasing transport link bandwidths

Quality of Serviceuser-relevant QoS: refers to the QoS related to the individual users

Application delay or throughput, connection reject ratio due to admission control function

network-relevant QoS: network-specific QoS to evaluate the quality of a network, measured on the packet level

Packet delay, packet loss ratio

The goal of network dimensioning is to minimize costs while maximizing QoSThe goal of network dimensioning is to minimize costs while maximizing QoS

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Framework of UMTS Network Dimensioning

Bandwidth

QoS

Analytical Approach

Input Traffic Demand

traffic classtraffic loadtraffic distribution

QoS Targetsuser-relevant QoSnetwork-relevant QoS

DimensioningProcess

NetworkConfigurations

network topology

traffic control functions

resource control functions

transport technology

QoS mechanisms

Output

Network Costminimum required link

capacities (Mbit/s)

Simulation Approach

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OutlineIntroduction and MotivationUMTS Network Dimensioning Framework Developed Simulation ModelsDeveloped Analytical ModelsDimensioning Models and ResultsConclusions and Outlook

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Simulation Models

Model a complete UMTS system following 3GPP specificationsFocused on a detailed modeling of the Iub interface (i.e. protocol stack, transport network, resource and QoS management)Modeling of air interface and core network are simplifiedReduce complexity and improve simulation efficiency

ATM TransportATM TransportIP Transport IP Transport

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Services and QoS Measures

Voice VideoConferencing Applications/Services

Circuit-Switched Traffic

Traffic Classes

Web FTP

Elastic Traffic

Real Time (RT)low delaylow loss

require Admission Control

Non Real Time (NRT)

carried by TCP/IPdelay tolerant

QoS Measuresat flow/call level

Blocking probability(CAC reject ratio)

Application Throughput(Application Delay)

Packet DelayPacket Loss ratio

QoS Measuresat packet levelover the Iub

Packet DelayPacket Loss ratio

Network-relevant QoS

User-relevant QoS

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Overview of Analytical Models

Queuing Models with non-Markovian Arrival Process

Non-preemptive priorityqueuing model

Modeling Packet Level

MMPP(2)/D/1

or BMAP/D/1

MMPP(2)/D/1 - Priority

or BMAP/D/1-Priority

Erlang LossModel

ProcessorSharing (PS)

Model

ProcessorSharing Model+ Erlang Model

ProposedAnalyticalModels

Modeling Call or Flow Level

Erlang-BMD Erlang-B

M/G/R-PSqueuing model

Traffic Policy- BW sharing- BW separation

Dimensioning Tool Analytical Models

User-Relevant QoS Network-Relevant QoS

Circuit-SwitchedTraffic

Mixed TrafficElastic Traffic Elastic Traffic Mixed TrafficCircuit-switched traffic

blocking QoS application delayor throughput

packet delay, packet loss ratioover the Iub interface

both QoS needto be met

TrafficScenario

QoSMeasure

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OutlineIntroduction and MotivationUMTS Network Dimensioning Framework Developed Simulation Models Developed Analytical ModelsDimensioning Models and Results

Processor Sharing Model (Application Performance)Packet level Queuing Model (Transport Network Performance)

Conclusions and Outlook

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Processor Sharing (PS) Model for Elastic Traffic- for User-Relevant QoS (Application Performance)

Iub (C)

UE

UE

UE

UE

UE

NodeB RNC

R = C / rpeak

Radio Network Cont

Radio Access Bearer (RAB) rpeak

rpeak

rpeak

rpeak

rpeak

rpeakIub (C)

UEUE

UEUE

UEUE

UEUE

UEUE

NodeB RNCRNC

R = C / rpeak

Radio Network Cont

Radio Access Bearer (RAB) rpeak

rpeak

rpeak

rpeak

rpeak

rpeak

Flow arrival follows Poisson ProcessGeneral file lengthdistribution

Assumptions

M/G/R-PS Model

K. Lindberger (1999)Peak data rate

File length

{ } Rpeakpeak

RGM fr

xR

RREr

xxTE ⋅=⎟⎟⎠

⎞⎜⎜⎝

⎛−

+=)1(),(1)( 2

// ρρ

Link utilization Delay factor

Number of servers R = C / rpeak

Expected Sojourn Time (average transfer delay)

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Proposed Extensions on M/G/R-PS Model

Case Extensions Analytical Realizations

2. Single RAB With CAC

3. Multiple RABsNo CAC

General M/G/R-PS model - R is bearer specific - consider total traffic

ii r

CR = ∑=bearers

iρρ

{ } Rii

i

i

ii

i

iiRGM f

rx

RRRE

rxxTE =⎟⎟

⎠

⎞⎜⎜⎝

⎛−

+=)1(

),(1)( 2// ρ

ρ

4. Rate Adaptation- BRA j

K

jjavgpeak qrr ⋅=∑

=1_ avgpeakavg rCR _/=

Reuse single rate M/G/R-PSCalculate an average ratefrom different rpeak to derive R

1. Single RAB No CAC

Radjust f RTT RTT ⋅=

{ } { } adjustRTTratiorttULxTExTE )__2 ()(*)( ++=

New parameter UL_rtt_ratio

Seven Extensions are proposed in this thesis to incorporate UMTS networks

RAB Radio Access BearerCAC Call Admission Control

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Proposed Extensions on M/G/R-PS Model (cont’)

5. Mixing with CS Traffic

CSelasticIub LCC +=

M/G/R-PS

CSelasticIub CCC +=

M/G/R-PS Erlang

(a)

(b)

Case Extensions Analytical Realizations

7. IP DiffServ { } kkpeak

k

kk

kkk

kpeak

kkRGM f

rx

RRRE

rxxTE

_

2

_// )1(

),(1)( =⎟⎟⎠

⎞⎜⎜⎝

⎛−

+=ρρ

6. Multi-Iub RAN Cbb

Node B

Node B

Node B

IP Router

Cac_1

RNC

Cac_n

Cac_2

Backbone Link

Last mile links

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IP-based UTRAN with DiffServ QoS Structure

EF Expedited ForwardingAF Assured ForwardingPHB Per Hop Behavior

UMTS Core Network

UMTS Core NetworkNode B RNC

SP Strict PriorityWFQ Weighted Fair QueuingDiffServ Differentiated Services

Per Hop Behavior (PHB)

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Validation of Application Delay Estimation

BE

AF41

AF31

AF21

AF11

EF

EF

PHB

10NRT HSPA 2Mbps

50NRT RAB 384kbps

40NRT RAB 256kbps

30NRT RAB 128kbps

20NRT RAB 64kbps

RT video

RT voice

WFQ weightService class

Single Link Scenario

The relative errors of obtained analytical results are withinthe agreed level for network dimensioning of industry

The relative errors of obtained analytical results are withinthe agreed level for network dimensioning of industry

0.5 0.6 0.7 0.8 0.9 10

2

4

6

8

10

12

Iub link utilization

AF1

1 ap

p. d

elay

(s)

AF11 PHB - NRT RAB 64kbps

M/G/R/N-PSSimulations

0.5 0.6 0.7 0.8 0.9 10

2

4

6

8

10

12


AF4

1 ap

p. d

elay

(s)


M/G/R/N-PS Simulations

0.5 0.6 0.7 0.8 0.9 10

2

4

6

8

10

12


AF2

1 ap

p. d

elay

(s)



0.5 0.6 0.7 0.8 0.9 10

2

4

6

8

10

12


BE

app

. del

ay (s

)

BE PHB HSPA


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Queuing Models for Network-Relevant QoS

Arrival process model (shall capture bursty and self-similarity of the aggregated arrival traffic and Bulk Arrival of packets)

2-state Markov Modulated Poisson Process (MMPP) model, where the inter-arrival time distribution is based on 2-Phase Hyper-exponential distributionBatch Markovian Arrival Process (BMAP)

TTI

TTI

TTI

AAL2Queue

ATMQueue

Deterministicservice rate

Deterministicservice rate

Link

DCH 1

DCH 2

DCH n

Segmentation

FP PDUs

RT or NRTArrivals

Server process(deterministic service rate)

Depatures

(a) Single-service system

DepartureRT

NRT

H

L

Packet scheduling:Non-preemptive priority

Server process(deterministic service rate)

DepaturesArrivals

(b) Priority system

Departure

queuing delay

Delay distribution

0.99

30ms

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MMPP Model for Estimation of the Iub delay

Capture of the Characteristic of the Arrival Traffic

Traffic demand

Mean traffic Variance Correlation

Add network / protocol overhead

Measure arrival traffic

MMPP arrival process model parameters

Capture the arrival traffic characteristics

MMPPD/1 queuingMMPP/D/1 – priority queuing

Queuing delay distribution

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Validation of the Iub Delay Estimation

0 1000 2000 3000 40000

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

voice traffic demand [kbps]

requ

ired

Iub

band

wid

th [k

bps]

voice only scenario - Rel99 ATM-based Iub

system simulationM/D/1H2/D/1MMPP/D/1

0 1000 2000 3000 40000

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

voice traffic demand [kbps]

rela

tive

erro

r of t

he a

naly

tical

mod

el

voice only scenario - Rel99 ATM-based Iub

M/D/1H2/D/1MMPP/D/1

Scenario I: 100% voice traffic (single Iub)Traffic model: Adaptive Multi Rate (AMR) 12.2kbps

Speech/silence period: exponential distribution, mean = 3 secondsCall duration: exponential distribution, mean = 120 seconds

Dimension QoS target: 99% of packets experience less than 10ms Iub delay

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Validation of the Iub Delay Estimation

1000 2000 3000 4000 50001000

2000

3000

4000

5000

6000

7000

8000

UTRAN traffic demand [kbps]

requ

ired

Iub

band

wid

th [k

bps]

packet switched traffic (BRA) only

System simulationQueueing simulation (Opnet)Analytical calculation

0 1000 2000 3000 4000 50000

1000

2000

3000

4000

5000

6000

7000

8000

UTRAN traffic demand [kbps]

requ

ired

Iub

band

wid

th [k

bps]

packet switched traffic (BRA) with 10% voice

System simulationQueueing simulation (Opnet)Analytical calculation

Dimension QoS target:99% of voice packets experience less than 10ms Iub delay99% of data packets experience less than 30ms Iub delay

Scenario III: 90% web traffic (low priority) & 10% voice traffic (high priority)

Scenario II: 100% web traffic

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Conclusions and OutlookPropose a general UMTS network dimensioning frameworkDevelop several detailed simulation models with OPNETInvestigate important aspects related to Iub dimensioningDevelop novel analytical models for dimensioning of the Iub interface and validated by simulations

Develop a dimensioning tool (in Matlab)Summarize all proposed analytical models Apply to derive dimensioning rules

MMPP/D/1-non-preemptive priority

Packet delay & loss QoS

MMPP/D/1 orBMAP/D/1

Packet delay & loss QoSMMPP: Markov Modulated Poisson ProcessBMAP: Batch Markovian Arrival Process

MMPP/D/1 or BMAP/D/1

Network QoS

Consider applied traffic policy and its Mux. gain

Application QoSProcessor Sharing (PS)Extensions of M/G/R-PS

Blocking QoSErlang-B (single stream)MD-Erlang B (multi-stream)

User QoS

Mixed trafficElastic trafficCircuit-switched Traffic

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Conclusions and Outlook (cont’)

Dimensioning and Comparing of ATM- and IP-based UTRANSingle Iub link scenarioMulti-Iub RAN scenario

Dimensioning HSPA traffic in ATM-based UTRANHSDPAHSUPAHSPA+Rel99 (Traffic Separation)

Further Work: Long Term Evolution (LTE)Expect a much higher demand on transport bandwidth in access networksDimensioning for LTE transport access network

Investigating applicability of current dimensioning modelsExtensions of analytical models are desired

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Thank for your Attention

3G Network Dimension Ing

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