The Composite Radio Environment Conceptappropriate radio segment (short-term optimisation). •...

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THE COMPOSITE RADIO ENVIRONMENT

CONCEPT∆ρ. ΧΑΡΑΛΑΜΠΟΣ ΣΚΙΑΝΗΣ

ΙΝΣΤΙΤΟΥΤΟ ΠΛΗΛΟΡΟΡΙΚΗΣ & ΤΗΛΕΠΙΚΟΙΝΩΝΙΩΝΕΚΕΦΕ ‘∆ΗΜΟΚΡΙΤΟΣ’

Μεταπτυχιακό Πρόγραµµα Σπουδών «Έλεγχος και ∆ιαχείριση ∆ικτύων»

Τµήµα Μηχανικών Πληροφοριακών & Επικοινωνιακών ΣυστηµάτωνΣχολή Θετικών Επιστηµών

Πανεπιστήµιο Αιγαίου

ΣΑΜΟΣ 7-8/04/2003

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The Composite Radio Environment Concept

• A composite radio platform is comprised of heterogeneous wireless access components, such as WLAN, GPRS, UMTS, HIPERLAN, DVB-T, offering wideband wireless access to broadband-IP based services, and ‘co-operating’ with each other.

• A terminal as part of such a platform supports at least one wireless access technology. To take full advantage of such a composite environment the terminal should be able to perform vertical handover among the various heterogeneous wireless segments. An enhancement to this could be a terminal using traffic and environment conditions for selecting the appropriate radio segment (short-term optimisation).

• Mid-term network-level composite radio resources optimisation could be achieved via the efficient joint utilisation of resources of heterogeneous radio segments through a suitable centralised composite radio management system.

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Core Composite Radio Environment Components

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Core Composite Radio Environment Components

• A composite radio infrastructure comprising commercial GPRS segments, a WLAN testbed that is compatible to the IEEE802.11b standard, a DVB-T testbed, and an interconnecting IP backbone.

• Multimode terminals, capable of operating in the composite radio environment and comprising functionality (provided through a Terminal Station Management System -TSMS) for conducting (or participating in) decisions regarding the most appropriate radio technologies, through which IP-based services can be obtained efficiently, in terms of cost andQoS.

• A Network and Service Management System - NSMS for the control and management of the composite radio infrastructure. This system will enable the joint optimisation of the alternate radio network segments, so as to deliver services efficiently, in terms of cost and QoS.

• Web-based applications, services and multimedia content.

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Functional and Architectural Framework

PolicyRepositoryDatabase

User sDatabase

DVB

WLAN

GPRS

Sessions &Communication

Manager

NetworkManager

ServiceManager

ServiceDatabase

Monitor

QoS

Req

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Serv

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clas

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efin

ition

s

RA

TD

ecis

ion

ServiceManager

QoSRequiremnentsService class definitions

NSMS area

MS area

NetworkManager

NSMS /TSMS

Measurement & Decisions

CommunicationManager

Logical ManagementRegistration /

Authentication"Generic Event

Specifier"Session Description

QoS

Req

uire

mne

nts

Serv

ice

clas

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finiti

ons

TSMS area

App

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Video RequestCREDO Application

Other NSMSCommunication path

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Functional and Architectural FrameworkNSMS modules description

• Session & Communication Manager:– Performs all operations concerning communication with TSMS and

other NSMS entities. – Contains a local or a distributed database containing users profile data

(authentication data, service contract etc).• Network Manager:

– The main module of NSMS. – Communicates with Session & Communication Manager module to

receive/send data towards TSMS and – Interacts with Service Manager to retrieve all data needed for

services profile and QoS levels.• Service Manager:

– Retrieve service profiles from a database. – Collaborates with Network Manager in order to provide all necessary

data about application profiles.

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Functional and Architectural FrameworkTSMS modules description

• Session & Communication Manager:– Implements the communication with other composite radio environment

components. – For the communication between TSMS and composite radio environment

tailor-made applications there is a different module (i.e., Application Interface module).

– The combination of these two modules performs the authorization request towards NSMS.

• Network Manager:– Similar to NSMS module, – Monitor network parameters as they are provided by network adapters

(attached in the MS), – handle all configuration issues (i.e. IP assignment) and – select/re-select network interface.

• Service Manager:– Responsible to contact NSMS or a service profile database to retrieve all

the necessary info

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Network and Service Management System (NSMS)

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Presentation Overview

• General NSMS structure – System overview– Session manager

• Role• Functionality

– Network managers (GPRS, WLAN, DVB-T)• General Role• Components

– Role– Functionality

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NSMS Full Component Overview

RBMS (G)

GPRS NSMSarea

MSPM (G) RMS - RATDP (G)

RMS - RATIP (G)

VE

Service Requester ServiceManagerService

Database

User sDatabase

Session Manager

Service Analyzer

NSMS Comm Manager

Session &Communication Manager

NetworkManagerPolicy

RepositoryDatabase

GPRS

RBMS (W)

WLAN NSMSarea

MSPM (W) RMS - RATDP (W)

RMS - RATIP (W)

VE


Database

User sDatabase

Session Manager

Service Analyzer

NSMS Comm Manager



RepositoryDatabase

WLAN

RBMS (D)

DVB NSMSarea

MSPM (D) RMS - RATDP (D)

RMS - RATIP (D)

VE


Database

User sDatabase

Session Manager

Service Analyzer

NSMS Comm Manager



RepositoryDatabase

DVB

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NSMS Full Component OverviewNetwork Manager modules (1)

• Managed System Performance Monitoring (MSPM):– Capture the (changing with time) conditions that originate from the environment

(service area) of the managed GPRS, WLAN, and DVB infrastructure.• Resource Brokerage and Service Management (RBSM):

– Brokerage between the network resources and the service providers (SPs), so as to enable the latter to request the reservation of resources (establishment of virtual networks) over the managed network infrastructure.

• Resource Management Strategies (RMS):– Dynamically find and impose the appropriate GPRS, WLAN, and DVB network

infrastructure reconfigurations, through which the service provider requests, and/or the (new) service area conditions, will be handled in the most cost-efficient manner. RMS is partitioned into two parts,

– RMS-RATIP (RMS - Radio Access Technology Independent Part) - independent to the Radio Access Technology that the NSMS belongs to - and

– RMS-RATDP (RMS - Radio Access Technology Dependent Part) - dependent to the Radio Access Technology that the NSMS belongs to.

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NSMS Full Component OverviewNetwork Manager modules (2)

• Validation Engine (VE):– Enables off-line testing and validation of the management decisions.

• NSMS Communication Manager:– Provide a communication interface with other NSMS entities, used by RBMS in

order to provide a distribute optimization algorithm for the allocation of MS in the three network segments.

• Session Manager:– Provide a communication interface between TSMS entities and NSMS.

• Service Analyzer & Service Requester:– Components that format TSMS requests for services (as they arrive through

Session Manager), with the help of Service DB, into proper requests for RBMS.

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System Overview – NSMS Structure

TSMS Managed Networks(GPRS, WLAN, DVB-T)

NSMS Structure

Session Manager

Network Manager

RMS-RATDPRMS-RATDP

MonitoringMonitoring

RMS-RATIPRMS-RATIPResource Brokerage Service Management

(RBSM)

Resource Brokerage Service Management

(RBSM)

Resource Management Strategies

Technology Independent

Technology Dependent

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Software Architecture

IP Backbone Network

GPRS

Session Manager

Network Manager W

LAN

Session Manager

Network Manager D

VB-T

Session Manager

Network Manager

Service Area Region

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Session Manager Role

• Exploits the interface with the TSMS

• Issues recommendations to the TSMS– Best network, QoS level

per application– Look up operations– Types of “light”

optimisation problems• Receives requests and

reports


NSMS Structure

Session Manager

Network Manager

RMS-RATDPRMS-RATDP



(RBSM)


(RBSM)

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Session Manager FunctionalityCommunication with TSMS (CTNP)

• Service Contract Information Request issued by the TSMS• Service Contract Information Reply issued by the Session

Manager– Service Contract Information Reply = (Service Definition 1,…,

Service Definition N)• Service Definition

– Service Identifier– Service QoS parameters– Cost Related Parameters– Candidate network list

• Service Request issued by the TSMS– Application– Quality of Service Levels– Cost related information– Network availability

• Service Reply issued by the Session Manager– indicates the appropriate radio technology

• Quality Report Request issued by Session Manager• Quality Report Reply issued by TSMS

– measurements reflecting the quality level at which each service is provided to the particular terminal

• Handover Notification

Service Configuration

Service Request

Session ManagerSession

ManagerTSMSTSMS

Assignment of applications to quality levels and network(s)

Quality Report Reply

Quality Report Request

Session ManagerSession

Manager

Formulation of Quality Report containing

measurements reflecting the perceived

quality levels.

TSMSTSMS

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Status and policies of underlying networks

OptimisationProcess

Allocation of applications to network

Allocation ofapplications to quality levels

Session-level optimisation

User class profile

• Short-term problem selecting radio network technologies and QoS levels• Objective function associated with

– Utility deriving from the assignment to QoS levels • utility volume = user benefit

– Cost deriving from the assignment to QoS levels and networks • Constraints the assignment to acceptable QoS and cost levels

Session Manager Core Functionality

Service Request (Applications, QoS

levels, etc.)

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Interface Session and Network Manager

• From session manager– Load, performance and

QoS information for the service area region

– Alarms on degradations• From network manager

– New solutions– Allocations to networks

and QoS levels


NSMS Structure

Session Manager

Network Manager

RMS-RATDPRMS-RATDP



(RBSM)


(RBSM)

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Network Managers

• Monitor managed network infrastructure

• Assess network and service level performance

• Decide (mid-term process)– Application

configuration– Traffic distribution– Network configuration


NSMS Structure

Session Manager

Network Manager

RMS-RATDPRMS-RATDP



(RBSM)


(RBSM)

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Network Manager – RBSM

• Resource Brokerage– Enables cooperation of

NPs of the composite radio infrastructure

– Exchange and negotiationon a set of offers

• Service Management– Proactive behavior

• Invoked when new applications introduced

– Description of situation to be addressed

• Applications• User Class profiles• Terminal profiles• Demand volume


NSMS Structure

Session Manager

Network Manager

RMS-RATDPRMS-RATDP



(RBSM)


(RBSM)

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Network Manager – Monitoring – GPRS

• Parameters– Dedicated Time Slots

(TSs) for GPRS traffic– Average available TSs– Load for GPRS traffic

(Requested data channels for GPRS usage - Average used downlink TS)

– Circuit switched traffic load

– Downlink throughput per TS (Data throughput per TS – TS throughput value)

– Successful packet channel allocation

• Alarm generationTSMS Managed Networks(GPRS, WLAN, DVB-T)

NSMS Structure

Session Manager

Network Manager

RMS-RATDPRMS-RATDP



(RBSM)


(RBSM)

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Network Manager – Monitoring – WLAN

• Parameters– Total Received

Counter (bytes)– Total Transmitted

Counter (bytes)– Error count– Failed count (Loss)– Retry count– Polling interval

• Processing of SNMP MIBs

Network Manager


NSMS Structure

Session Manager

RMS-RATDPRMS-RATDP



(RBSM)


(RBSM)

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Network Manager – Monitoring – DVB

• Indicative parameters– Total Bit Rate

• 24 Mbps– Useful Bit Rate

• TV services and IP data

– Residual Bit Rate per PID

• Available bit rate• Processing of SNMP MIB


NSMS Structure

Session Manager

Network Manager

RMS-RATDPRMS-RATDP



(RBSM)


(RBSM)

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Network Manager – RMS

• Output of optimisation process– Application configuration– Traffic distribution to the

composite radio infrastructure

– Network configuration• RMS-RATIP functionality

– Mid-term process– Optimisation problem targets

• Assignment of applications to quality levels

• Assignment of traffic to networks of the composite radio infrastructure (Traffic distribution)TSMS Managed Networks

(GPRS, WLAN, DVB-T)

NSMS Structure

Session Manager

Network Manager

RMS-RATDPRMS-RATDP



(RBSM)


(RBSM)

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Trigger(Applications, QoS levels,

profiles, demand, etc.)

Status and policies of originating NP

Offers of cooperating NPs

OptimisationProcess

Allocation of demand to networks

Allocationto quality levels

RMS-RATIP functionalityConstraints

Network Manager - RMS-RATIP functionality – (1)

• Trigger– describes the situation to be resolved – provides information on applications, QoS levels, profiles, etc.

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OptimisationProcess





• Constraints derive from– Status and policies of the originating network, e.g., capacity of

originating network, etc.– Offers, e.g., capacity that can be provided by the cooperating network,

etc.– Trigger, e.g., candidate QoS levels, cost levels, available networks, etc.

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OptimisationProcess





• Optimisation maximises objective function consisting of two terms:– Utility deriving from the assignment to QoS levels

• utility volume = user benefit and NP benefit– Costs from the assignment to QoS levels and NPs

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High-level NSMS OperationWLAN Radio and

Fixed Network Manager

WLAN Radio and Fixed Network

Manager

DVB Radio and Fixed Network

Manager

DVB Radio and Fixed Network

Manager

Session Manager

(G)

Session Manager

(G)RBSM

(G)RBSM

(G)RMS-RATIP

(G)RMS-RATIP

(G)MSPSM

(G)MSPSM

(G)RMS-RATDP

(G)RMS-RATDP

(G)

GPRS Radio and Fixed Network Manager

TSMSTSMS

4.Offer exchange phase

3.Network status acquisition phase (monitoring) and load evaluation

2.User related information collection

1.Identification of new environment condition

5.Assignment of applications to QoSlevels and traffic to

networks

6.Acceptance phase

7.Session Manager Notification phase

8.Traffic distribution phase

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Terminal Station Management System (TSMS)

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Objectives

• Definition of hardware and software architecture for IP based services on a composite radio environment

• Development of terminal functionality for inter-system handover– Mobile IP

• Development of TSMS– Conducts decisions regarding the most appropriate network at

each moment.– Interface to applications.– Interface to NSMS.– Terminal monitoring.

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Terminal Architecture

CREDO NSMS

CREDO TerminalCREDO application

TSMS

CREDO application

Legacy serv. support

TCP/IP stack

WLANdriver

GPRSdriver

DVB-Tdriver

Session Manager

CTNP:TSMS - NSMS

protocol

TSMS User Interface

CATP: Applications -

TSMS API

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Terminal Hardware – a paradigm -

• Choices: – Linux based laptop, PDA, desktop.

• Network interfaces– IEEE802.11b PC Card– GPRS phone over serial line or GPRS PC Card– USB DVB-T receiver

• Issues:– No support for USB DVB-T devices on Linux: only PCI DVB-T

receivers are supported• Two test terminals for developments:

– Desktop computer with IEEE802.11b, GPRS and DVB-T support.– Laptop computer with IEEE802.11b and GPRS support.

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Terminal Hardware – a paradigm -

• Foreseen CREDO Terminal– Desktop-based with WLAN (PCMCIA),

DVB (PCI), GPRS (Phone)• Reduced-size terminal (ex.: m-ToGuide) would

be more interesting– External DVB Rx connected with central

processor (with GPRS / WLAN) • ‘Converting’ part of capital expenditures onto

services– TSMS porting on Windows Portable

Computer (PDA)Pocket PC 2002 OS (Windows possible)240x320 color LCD displayIntegrated radios:

802.11bGSM/GPRSClass 2 Bluetooth

Internal AntennasUSB Support possible:

Connecting external DVB

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TSMS Software ArchitectureCREDO TerminalCREDO

NSMS

TSMS

Network Selector.Decision mechanism

Handover middleware

Mobile IP

Network interface support

WLANsupport

GPRSsupport

DVB-Tsupport

Mobile IP NAT traversal

WLANdriver

GPRSdriver

DVB-Tdriver

CREDO applications

Legacy services(Generic ISP services)

Legacy service support

Session Manager Interaction

Service interface

User interface

Session Manager Quality monitor

TCP/IP stack

CATP: Applications -

TSMS

CTNP:TSMS - NSMS

protocol

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TSMS Interfaces

• Interface with the NSMS: CTNP– Service Contract Information Request/Reply– Service Request/Reply– Quality Report Request/Reply– Handover Required Notification– Error messages

• Interface with the applications: CATP– Application Service Request– Network Ready– Application Keep Alive– Application Termination– Error messages

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Network Selector (1)CREDO TerminalCREDO

NSMS

TSMS


Handover middleware

Mobile IP


WLANsupport

GPRSsupport

DVB-Tsupport


WLANdriver

GPRSdriver

DVB-Tdriver

CREDO applications




Service interface

User interface


TCP/IP stack

Network Selector• Core TSMS module.• Stores TSMS data shared

by all modules.• Takes handover decisions.

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Network Selector (2)

• Stores TSMS data shared by all modules:– Networks information:

• Available network list.• Preferred network list.• Currently selected network.

– Services information:• Service definition list.• Service instance list.

– Quality information:• IP parameters.• Link layer parameters.

• Receives events from the other modules– Application service requests and termination messages.– Service Replies from the Session Manager.– Network availability/unavailability notifications.– Handover status.– Quality information.

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Handover Middleware (1)CREDO TerminalCREDO

NSMS

TSMS


Handover middleware

Mobile IP


WLANsupport

GPRSsupport

DVB-Tsupport


WLANdriver

GPRSdriver

DVB-Tdriver

CREDO applications




Already available. Not CREDOProvided by Motorola

Developed in other WPsDeveloped in WP3

Service interface

User interface


TCP/IP stack

Handover Middleware• Network availability detection• Mobile IP• MIP NAT Traversal• Network driver configuration

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Handover Middleware (2)

• Based on MNM libraries:– Mobile IPv4 Mobile Node implementation.– DHCP and Agent Discovery.– IEEE802.11b support

• Sub-modules:– Mobile IP NAT Traversal

• Implementation according to draft-ietf-mobileip-nat-traversal-07 (approved as Proposed Standard, RFC edition pending)

– GPRS and DVB-T support.

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Quality Monitor (1)CREDO TerminalCREDO

NSMS

TSMS


Handover middleware

Mobile IP


WLANsupport

GPRSsupport

DVB-Tsupport


WLANdriver

GPRSdriver

DVB-Tdriver

CREDO applications




Service interface

User interface


TCP/IP stack

Quality Monitor• IP parameters• Link layer parameters

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Requirements for Quality Monitor (2)

• Monitor quality related parameters from the radio to the application level.

• Aggregate this information by creating a transparent, composite-radio wireless monitoring interface.

• Process the information in order to:– Indicate services actual perceived quality.– Indicate the cause of possible perceived quality problems.

• Provide interfaces in order to optimally configure network stackand application, based on the current radio conditions. I.e. specific WLAN, GPRS, DVB-T vertical (from radio to application level) configuration

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Quality Monitor (3)

• IP parameters– Downstream and upstream data rates

• GPRS parameters– MSCoT (MultiSlot Class of Terminal)– Receiver power

• IEEE802.11b parameters– Nominal bit rate– Signal level– Noise level

• DVB-T parameters– Bit error rate– Signal strength– Receiver flags

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Quality Monitor (4)

Input: parameters (network + application level)

WLAN DVB-T GPRS

CREDO applications

IP

TCP UDP

Parameters monitoring sub-moduleParameters monitoring sub-module

Parameters processing sub-moduleParameters processing sub-module

Output:Radio/TCP-IP/Apps re-configuration commands

TSMS Quality monitoring module

TSMS Network Selector: Decision mechanism

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Quality Monitor (5)

• Parameters monitoring mechanism sub-module:– Implements the interface between the Quality Monitoring module

and the network and application. – Collects information vertically from all layers, in a polled or interface

driven manner. – The interfaces it implements are different, depending on the layer it

is communicating with.• Parameters processing sub-module:

– Process the collected monitored parameters in order to provide meaningful results about the perceived quality, the overall network status and the causes of possible problems.

– Issue reconfiguration commands in order for each of the network layers to be optimally configured for the current conditions.

• TSMS network selector module:– Decide about handover actions.

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User InterfaceCREDO TerminalCREDO

NSMS

TSMS


Handover middleware

Mobile IP


WLANsupport

GPRSsupport

DVB-Tsupport


WLANdriver

GPRSdriver

DVB-Tdriver

CREDO applications




Service interface

User interface


TCP/IP stack

User Interface• TSMS configuration• TSMS status:

• Available networks• Current network• Current services

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Operational Scenario-Terminal Initiated Optimisation-

Service and ContentProvider

Service and ContentProvider

IP-basedFixed Network

IP-basedFixed Network

Radio Networks(GPRS, WLAN, DVB)

Radio Networks(GPRS, WLAN, DVB) N S M SN S M S TSMSTSMS

2. Information Request

2a. Information Provision

1. Identification of condition that can

require change of the radio access technolodgy

3. Information Acquisition PhaseThe NSMS prepares a reply to the TSMS, potentially by cooperating with the managed radio and fixed network

4. The TSMS selects the best radio access

technolodgy based on quality and cost criteria

5. Reconfiguration PhaseThe TSMS and NSMS cooperate and reconfigure the terminal, the radio network, the IP-based fixed network and the service and content provider servers

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Application Aspects- A Test Case -

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Service framework

Services based on both• multimode-specific applications interfacing to the rest of the system

1. The Sports Events information retrieval application2. The Video Streaming application

• Important existing Internet (‘legacy’) applications3. Through a collective ‘umbrella’ called Generic Internet Services

Each of 1-3 yields two services (of different QoS): low & high– high: greater average data rate, smaller delays (than low)

Simultaneous service reception at a terminal is possible– Following Internet paradigm

Association of services to users: through Service Contracts

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Service contracts

Formal definition: a vector of service descriptorsService_Contract = (Service_1, …, Service_N)

Service contract examples:• (Sports Events High, Video Streaming High, Generic ISP High)

– ‘premium’ contract, with all services registered as high quality• (Sports Events High, Video Streaming Low, Generic ISP High)

– ‘fast Internet’ contract, with all services except Video Streaming registered as high quality

• (Sports Events Low, Generic ISP Low)– ‘basic Internet access’ contract, with Sports Event and ISP

registered as low quality (and the Video Streaming not registered at all)

Tailor-made protocols (CTNP,CATP) provide facilities compliant with the notion of service contracts

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Service Definition in Composite Radio Environment

: (IP src, IP port) | (OWD, ipdv) Extra parameters(Currently not used)

Optional parameters

: QoS Level AQ1: (Average Bandwidth, burst size), …QoS Level List

: (Application, network1, network2, …), …Candidate Network (Technology) List

: (Application, QoS level, Cost ), …Cost Related Parameters

:(Application A1, QoS Level AQ1), … , (Application An, QoS Level AQm) QoS Related Parameters

: Application or a Set of applicationsSet of applications

Service Identifier

ParametersSERVICE

DEFINITION

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Indicative list of Services

WLAN, GPRS(642, high)Generic ISP

-Low Quality

WLAN, GPRS, (DVB-T?)(512, high)

Set of legacy applications

Generic ISP-

High Quality

WLAN, GPRS,(642, high)Sports Event

-Low Quality

WLAN, (DVB-T?), GPRS,(256, high)

Sports events application

Sports Event-

High Quality

WLAN, (DVB-T?), GPRS(64, moderate)Video Streaming

-Low Quality

WLAN, DVB-T, GPRS(256, moderate)Video streaming

application

Video Streaming-

High Quality

Available networks(GPRS | WLAN | DVB-T)

QoS parameters(Average Bandwidth, burst size)

(kpbs,low/moderate/high)

Application/

Set of applicationsService

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Overall Architecture

• RS 6000 system running AIX version 5.1 • Database content stored in IBM DB2 version 7.2• Application server version 4.0 and Video Charger Server 8.1• Java enabled WWW Client, using HTTP, RTP to retrieve

content• Video streaming performed using RTP protocol

Sports eventsSports events& &

Video ContentVideo Content

SQL request

XML reply

Content Generation

Pool of beans

ServerTransforms

Request interpretation

CREDO CREDO NetworkNetworkClientClient

HTTP Request

Sports eventsSports events& &

Video ContentVideo Content

SQL request

XML reply

Content Generation

Pool of beans

ServerTransforms

Request interpretation

CREDO CREDO NetworkNetworkCREDO CREDO NetworkNetworkClientClientClientClient

HTTP Request

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Applications –TSMS interface

• Application and TSMS exchange through CATP:– Information transparent from the specific network technology currently

used.– TSMS is applications mediator to NSMS, hiding composite radio system

details.• Information exchanged:

– Application Service request: initialisation message that indicates the required by the application resources

– Network ready: indicates successful or unsuccessful resource allocation– Application keep alive: indicates the status of the application (still running,

enjoyed QoS)– Application service termination: indicates normal exit of the application and

leads to correct de-allocation of the resources– Error message

ApplicationsTSMS NSMS

CATP CTNP

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Interaction

CATP CTNPAppl. Client

App. Server

Video AVH

TSMS NSMS

VL………

Appl. Service Req. (VH).

Network Ready (negative)

Appl. Service Req. (VL).

Network Ready (positive)

TSMS Service Req.(VL,networks,…)

Service Reply(networks,cost,…)

Video BVL

Scenario B

Scenario A

Content

System ViewVideoVH/L

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Mobility Issues- paradigm -

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Composite Radio Network Architecturein an IP Environment

Home Agent

NSMS

IP network (private and public segments)

SP IPbackbone

Application server

SP IPbackbone

Application server

Local IP infrastructure

Local NSMS

Foreign Agent

Access Router

NAT

WLAN APsand DHCP servers


NAT

GGSN

GPRSNetwork

Local NSMS


Local NSMS

Access Router

IP/DVB Gateway

DVB-T transmitter

WLAN SegmentWLAN Segment GPRS SegmentGPRS Segment DVBDVB--T SegmentT Segment

Smart Terminal

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Composite Radio Network Architecturein an IP Environment

DVB return path (tunneling method) for IP protocol (Return path from WLAN / GPRS , NAT compatibility)

DVB IP space and assignment mechanism in a MS. (NSMS usage or DHCP in DVB segment)

DVB-T segment

Network deployment – AP placing, network naming (ESSID) and frequency assignment.

WLAN IP space and assignment mechanism (DHCP server or relay, NAT etc.)

WLAN segment

GGSN: element that provides the interface to external PDNsPDP (Packet Data Protocol) context creation procedureIP address of a MS & NAT mechanism

GPRS segment

IP architecture main componentsNetwork Segment

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Network issues• Inter-system handover

– Mobile IPv4– A specific IP micro-mobility protocol is not necessary,

since Mobile IPv4 is only used for inter-system handovers

• NAT (Network Address Translator)– Most wireless operators (GPRS & WLAN) use NAT to

enlarge the available address space– “Plain” Mobile IPv4 incompatible with NAT– Solution: Mobile IP NAT Traversal IETF standard

• Unidirectional link– DVB-T links are unidirectional– UDLR or a similar solution will be used for automatic

configuration of a return path

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NSMS-TSMS Interaction

• NSMS– Monitors the network state, and each terminal– Decides which terminal should use which network

• TSMS– Management software on the terminal

• NSMS-TSMS interaction is based mainly on two messages:– Service Request

• Sent from the terminal to the network to report available networks and running services

– Service Reply• Sent from the network to the terminal to tell the terminal which

network it should use.

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Smart TerminalHome Address: H@. Key: ABC.

Home Agent

NSMS


NSMS-TSMS Interaction (1)

SP IPbackbone

Application server

SP IPbackbone

Application server


Local NSMS

Access Router

NAT



NAT

GGSN

GPRSNetwork

Local NSMS


Local NSMS

Access Router

IP/DVB Gateway

DVB-T transmitter


1. Starting point:

• The terminal has two available networks: WLAN and GPRS.• The currently selected network is WLAN. • The terminal is running one application. All application traffic is routed through the WLAN network.

Foreign Agent

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61


Home Agent

NSMS



SP IPbackbone

Application server

SP IPbackbone

Application server


Local NSMS

Access Router

NAT



NAT

GGSN

GPRSNetwork

Local NSMS


Local NSMS

Access Router

IP/DVB Gateway

DVB-T transmitter


2. The TSMS sends a Service Request to the NSMS. The Service Request contains:

• The list available networks: GPRS and WLAN• The currently selected network: WLAN• The list of running services in the terminal

Foreign Agent

62


Home Agent

NSMS



SP IPbackbone

Application server

SP IPbackbone

Application server


Local NSMS

Access Router

NAT



NAT

GGSN

GPRSNetwork

Local NSMS


Local NSMS

Access Router

IP/DVB Gateway

DVB-T transmitter


3. The NSMS analyses the Service Request, and runs the optimisation algorithms taking into account the load of each access network and the services that each terminal is running. As a result the NSMS decides, for example, that this terminal should be switched to GPRS. The switch decision is notified using a Service Request message

Foreign Agent

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63


Home Agent

NSMS



SP IPbackbone

Application server

SP IPbackbone

Application server


Local NSMS

Access Router

NAT



NAT

GGSN

GPRSNetwork

Local NSMS


Local NSMS

Access Router

IP/DVB Gateway

DVB-T transmitter

WLAN SegmentWLAN Segment GPRS SegmentGPRS Segment DVBDVB--T SegmentT SegmentGPRS

interfaceIP@: B

PDP context creation

Foreign Agent

4. The terminal opens a PDP context on the GPRS link and obtains an IP address for the GPRS interface.

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Home Agent

NSMS



SP IPbackbone

Application server

SP IPbackbone

Application server


Local NSMS

Access Router

NAT



NAT

GGSN

GPRSNetwork

Local NSMS


Local NSMS

Access Router

IP/DVB Gateway

DVB-T transmitter


interfaceIP@: B

5. The terminal performs Mobile IP registration (Registration Request/Registration Reply) using the GPRS IP address as new CoA.

Foreign Agent

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65


Home Agent

NSMS



SP IPbackbone

Application server

SP IPbackbone

Application server


Local NSMS

Access Router

NAT



NAT

GGSN

GPRSNetwork

Local NSMS


Local NSMS

Access Router

IP/DVB Gateway

DVB-T transmitter


interfaceIP@: B

Foreign Agent

6. When the Mobile IP registration completes the traffic from the application is handed over to the new selected network.

FRAMEWORK FOR THE SYSTEM AND PERFORMANCE EVALUATION OF A COMPOSITE RADIO ENVIRONMENT

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Presentation Overview

• A generic framework for defining basic experiment templates in composite radio platforms– Terminal-centric– Network-centric

• Components for experiment analysis and validation– Performance metrics for assessing congestion– Traffic models– High-level network segment models (DVB-T, GPRS,

WLAN)• Tools for traffic generation and analysis

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Key Actions for short-term (terminal-centric) optimisation processes

• an intelligent multimode tagged terminal indicates to management a potential reason for short-term optimisation

– loss of coverage, or – increased congestion in the current radio segment, or – increased resource requirements due to initialisation of new

services, etc.• Management runs the appropriate radio optimisation

algorithm and identifies the suitable radio segment for serving the tagged terminal.

• Management notifies its suggestion to the tagged terminal. • Based on the information received from management, the

terminal decides on the most appropriate radio segment, which satisfies specific quality and cost criteria.

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Key Actions for mid-term (network-centric) optimisation processes

• Management identifies that a radio segment has been congested and determines the appropriate redistribution of terminals (and the corresponding traffic load) over the segments.

• Management issues instructions for the execution of the decided redistribution.

• The involved intelligent multimode terminals follow the instructions.

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Key Generic Items• Triggering event: The reason behind the invocation of short- or mid-term

optimisation processes. The triggering event defines the target/topic of an experiment.

• Environment conditions (in both pre- and post-experiment phase):– In the pre-experiment phase, they refer to the experiment setup (e.g., number of

terminals participating in the experiment, active services in these terminals, form and magnitude of background traffic, examined QoS parameters/metrics, etc.).

– The environment conditions in the post-experiment phase refer to a subset of the pre-experiment conditions depending in the nature of the experiment (usually, these conditions concern QoS parameters/metrics).

• Analysis of the experiment’s scenario: An analysis procedure for estimating/predicting the experiment’s dynamics, in both qualitative and quantitative terms (employs traffic and network modelling).

• Experiment realisation and data collection (key system actions): The set of key events associated with the specific experiment. This set includes internal TSMS/NSMS actions, exchanged messages and the output of optimisation algorithms.

• Analysis of the collected results (experiment analysis): The data collected during the experiment (as discussed in the previous item) are compared to:

– the estimates obtained from the qualitative analysis procedure with the objective of checking the correctness of system’s functionality and operations and

– the requested QoS levels (specified in the pre-experiment phase).

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Experiment Templates – terminal centric

Move Terminal outside of coverage area

Terminal indicates modificationof its status

CRMS Runs OptimisationAlgorithms

Composite radio platformReconfiguration

Experiment SETUP

Log distribution of Terminals(and active services therein)

Log Applications Quality ParametersLog BG traffic

Log Applications QualityParameters

Key SystemActions

EnvironmentConditions


(Pre-experimentphase)

TriggeringEvent

ExperimentAnalysis

Logmessage

Logactions

Log messagesNew distribution of

Terminals

Check for the correctness of system operationsValidation of algorithm’s potential for

achieving QoS(Analyser involved)

Prediction of systemoperations

Increase BG Traffic(quantitative specification)

in radio segment used by theterminal

Open/Close a Service

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Experiment Templates – network centric

Increase BG Traffic(quantitative specification)

in a specific segment

CRMS sensesQoS degradation

Composite radio platformReconfiguration

Experiment SETUP

Log distribution of Terminals and activeservices therein

Log Network Quality ParametersLog BG traffic

Log Network QualityParameters

Key SystemActions



(Pre-experimentphase)

TriggeringEvent

ExperimentAnalysis

Logactions

Log messagesNew distribution of

Terminals

Check for the correctness of system operationsValidation of algorithm’s potential for

achieving QoS(Analyser involved)

Prediction of systemoperations

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A high-level terminal centric experiment• Triggering event

– A tagged terminal (TA) served by WLAN segment of a composite radio platform runs a high-quality video-streaming application (requiring a bandwidth of 768Kbps). According to two different experiment scenarios, alternatively:

• the terminal moves outside the coverage of WLAN, or • using appropriate traffic generators, the background traffic over the WLAN radio segment is increased (to become

1Mbps.). – In both cases TA senses QoS degradation.

• Environment conditions– Pre-experiment phase logs

• A composite radio platform with a WLAN and DVB-T segment.• WLAN_BgTraffic=0.5Mbps• The WLAN segment serves two multimode intelligent terminals: called TA and TB.• TA runs high-quality video-streaming service (Bandwidth =768Kbps).• TB runs low-quality video-streaming service (Bandwidth =128Kbps).• Application quality parameter = minimum throughput.

– Post-experiment phase logs• WLAN_BgTraffic=1Mbps• WLAN segment will serve CTB.• DVB-T segment will serve CTA.• Bit Rate for CTA.

• Prediction of system operations– The tagged terminal sends appropriate message to management indicating QoS degradation. – Based on the terminal’s message and the current traffic load in radio segments, management decides

that the DVB-T is the appropriate radio segment for the tagged terminal.– It answers to the tagged terminal with the appropriate reply message.– The tagged terminal switches to DVB-T.

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Experiment analysis and validation

• traffic models to describe the load imposed on the segments of the composite network;

• network models to represent the mechanisms through which the network resources in each segment serve the traffic load; and

• performance metrics, obtained as output from analysis on the abovementioned models, for assessing network performance and quantifying congestion.

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Performance metrics for use in models

A large number of elaborate metrics exist.HOW TO CHOOSE?

Requirement: Metrics must be simple (otherwise, very difficult to compute using tractable modelling techniques).Approach: Adopt simple service metrics such as the throughput and the delay.Effects: 1) Analytic solutions and cost-effective approximations based on measurable data,

2) Metrics relate directly to service-level QoS

Note that in all cases congestion is modelled by queueing phenomena

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Performance metrics

In line with the QoS specification– A queueing delay percentile, specifying that

delay is not exceeded with probability >p– The long–term average-rate requirement

(matching the source’s mean rate) is guaranteed (statistically) through the stability condition of the queueing model, namely iff (traffic intensity < capacity)

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Traffic Models

• Various types of data traffic loading the segments of the composite environment

• Circuit-switched (voice) traffic that shares network resources with data traffic over the GSM/GPRS cells

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Traffic Models

• Circuit-switched services– A traditional birth-death process, with – speech and non-real time services arriving to the system

according to a Poisson process,– the service time (holding time) exponentially distributed.

• Packet traffic– Possible framework UMTS modelling framework where traffic at

packet level is bursty with silence durations corresponding to reading or silence periods and burst of packets at a variable size.

– Drawback: UMTS model can prove overly complex.– 1st Approach: Simplify using an MMPP process to describe bursty

packet traffic.– 2nd Approach: Use GE (still captures burstiness when first two

moments are known) as a further approximation/simplification in the absence of traffic data to map to all the parameters of an MMPP process

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Traffic models – Data traffic•Capture burstiness(performance impact)•Use MM processes•Interest in ‘burst-level’ region

– Beneficial to employ fluid-flow simplification

•Upper left (low occupancy) – no apparent correlations•Lower right (burst level) –behaves as a continuous fluid with the same burst-level rate fluctuations and and constant rate values between fluctuations occurences

Buffer occupancy threshold x

log(

Pr

buffe

r oc

cupa

ncy

> x

)

burst scale

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The Generalised Exponential (GE) distribution

The GE distributional model is• robust and • versatile • widely implemented in development of

analytical solution techniques for general (QNMs)

For C2>1 the GE model a mixed probability distribution interpreted as either

• extremal case of two-phase exponential distributions; or

• bulk type distribution with underlying counting process equivalent to CPP with geometrically distributed batch size

Note that GE distribution is versatile, possessing pseudo-memoryless properties making solution of GE-type queueing systems/networks analytically tractable.

M

αν ν = +

2 2 1 C

1 2 1 2 1

− = − +

α C C

α = +

2 2 1 C

2 2

2 2( ) 1 exp , 01 1

tF t tC C

ν = − − ≥ + +

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The MMPP distribution

The Markov-modulated Poisson process (MMPP)

• qualitatively models the time-varying arrival rate,

• captures important correlation futures between interarrival times while still remaining analytically tractable.

The MMPP is the doubly stochastic Poisson process with the arrival rate given by [ ]* ( )J tλ , where ( )J t , 0t ≥ , is an m -state irreducible Markov process. By varying the arrival rate of a Poisson process according to an m -state irreducible continuous time Markov chain which is independent of the arrival process an MMPP can be constructed. When the Markov chain is in state i , arrivals occur according to a Poisson process of rate iλ . In general the model is described by the infinitesimal generator Q

1 12 1

21 2 2

1 2

m

m

m m m

Q

σ σ σσ σ σ

σ σ σ

− − = −

,

1

m

i ijjj i

σ σ=≠

=∑ ,

and the diagonal matrix with m Poisson arrival rates.

1 2( , , , )mdiag λ λ λΛ= … .

The steady-state vector of the Markov chain is π such that

0Q=π , 1π =e ,

where (1,1, ,1)T= …e is the column vector length m .

An interesting future of the MMPP is that the superposition of MMPPs is again an MMPP with

1 2 mQ Q Q Q= ⊕ ⊕ ⊕… ,

1 2 mΛ=Λ ⊕Λ ⊕ ⊕Λ… ,

where ⊕ represents the Kronecker-sum.

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c

Network segment models

• Resources in each segment described in generic terms through a queueing model with M.M. fluid-flow input.

• In GPRS, additional complication due to varying CS traffic.– Separation of timescales (NCD

structure of model) exploited through decomposition/aggregation.

– Model yields simpler ‘submodels’ whose solutions are combined to yield the global one.

• Tail functions of queueing delay obtained from solutions of models (for GPRS under a mix of PS and CS load).

cV(t)r(t)

blockedGSM calls

Bursty arrivalprocess

NV GSM/GPRS Shared

(N-NV) GPRS dedicated

N Time Slots in cell

Packets queuedfor GPRS access

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The GPRS model – approach 1

• Capacity for data modulated by presence of voice calls.– When J calls present, (N-J)c available to

serve data (c=capacity/TS)• For buffer occupancy, equivalent to

assume that each call contributes CBR data traffic of rate c.

• Input is superposition of ‘virtual’ voice traffic + data traffic.

• Time dynamics of voice traffic veryslower than those of data traffic. Decomposition possible (based on NCD theory).

• Split state space in ‘macroblocks’, each identifying activity under a constant number of voice calls J.– Frequent transitions within macroblock– Infrequent transition between

macroblocks

blockedGSM calls

Bursty arrivalprocess

NV GSM/GPRS Shared

(NV-N) GPRS dedicated

N Time Slots in cell

Packets queuedfor GPRS access

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The GPRS model – approach 2

Transfer QueueAccess Queue

GSM voice traffic

GPRS

GPRS data traffic

GSM

GSM/GPRS cell modelled as• Two queueing sub-systems,

– one dedicated to voice traffic and – the other to data traffic

• Under partial sharing scheme (PSS) with – certain amount of channels dedicated for data traffic

and– remaining shared amongst voice and data traffic.

The cell partitions modelled as• The GSM Partition (a classical M/M/c/c loss system)

– Poissonian arrival process for voice traffic, – exponential call durations.

• The GPRS partition (GE/GE/1/N/FCFS GE/M/1/K/PS) – GE interarrival distributions for both external and

internal traffic. – Finite Capacity– FCFS access queue– PS (Processor Sharing) transfer queue (air interface)– GE is a versatile and tractable traffic model.

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The DVB-T model – approach 1

• Dedicated PID for composite radio traffic.

• Constant fixed amount C of capacity guaranteed for this PID.

• The ‘generic’ FF queueingmodel applies directly:– MC rates describe

superposition of input traffic.

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The DVB-T model – approach 2

µ=C/VBursty arrival process

G/G/1µ=service rateC=constant capacityV=packet size

DVB-T traffic futures

• Traffic is segmented in a number of groups.

• Each group is allocated some bandwidth.

• Each group operates independently.

DVB-T traffic model

• Focus on one group,• Adopt simple queueing model with

– general type of arrival process– service period with constant

capacity, C– variable packet size, V

• under FCFS service policy.

Note that queueing is kept back to the router when congestion

occurs

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The WLAN model – approach 1

Complex EnvironmentDifficult to analyse directly

ApproachUse detailed model to derive throughput

metrics as values of virtual capacity which is state dependent on the number

of users and model

Note that queueing occurs at the entry buffers of the access point or a

router just before

CArrival processfor WLAN users

Access point

State dependent link Capacity, C(modeling WLAN congestion)

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The WLAN model – approach 2

• Original capacity available, C• Fixed probability of packet

retransmissions (due to collissions/timeouts) (determined by detailed modeling/measurement of AP)

• In fluid setting, this results in a constant output capacity

• Use generic FF queueing model (as with DVB) with capacity

Access Point

Probability of retransmission, pR

C

M.M. bursty packetarrival process

C~

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Tools for traffic generation and analysis

•traffic generator: load the network or inject monitoring test traffic•traffic analysers: capture the effect of congestion on selected traffic streams and provide through it measurements of performance metrics.

•Assist on dimensioning and on parameterization decision/optimisationalgorithms within network manager

N S M S

Ser v er

Tr affic

G en er ato r

IE E E 8 0 2 .1 1

D V B - T

G P R S

C redo Te rm i nal s

ho stin g T S M S

Analyzer

IP B ac k bo n e

A p plic atio n

Ser v er

O the r Te rm i nal s

Analyzer

N S M S

Ser v er

Tr affic

G en er ato r

IE E E 8 0 2 .1 1

D V B - T

G P R S

C redo Te rm i nal s

ho stin g T S M S

Analyzer

IP B ac k bo n e

A p plic atio n

Ser v er

O the r Te rm i nal s

Analyzer

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BG traffic generators & analysers – simple examples

TG tools specifications:• TG should flexibly produce

very general traffic profiles,– based on built-in ‘canonical’

models– or (in ‘playback’ mode) read off

of a ‘log-file’ of stored traffic event descriptions (packet size & interarrival time traces)

• Thus may recreate traffic captured-processed by a traffic analyser

– may generate ‘test traffic’• TG could be combined (in

playback mode) with simulator, towards generating complex BG traffic effects

NetworkSimulator

Log file

Generator

Network

Analyzer

Traffic analysis/processing tools:• Standard Unix/Linux TCPdump

– may be hosted (as an external process) on top of (Linux-based) CREDO terminals

The Composite Radio Environment Conceptappropriate radio segment (short-term optimisation). •...

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