WiMax Overview Alcatel

Introduction - Page 1

3FL38224AAAAZZZZA Edition 1

All rights reserved 2006, Alcatel

WiMAX Overview

WiMAX Overview

Introduction

3FL38224AAAAZZZZA Edition 1.01

Welcome to this web-based overview training session on WiMAX



Introduction

All rights reserved 2006, AlcatelWiMAX Overview

Target Audience & Objectives

All persons who need an introduction toWiMAX technology

Characterize WiMAX technology as opposed toother radio access systems

Explain benefits and limitations of WiMAX

Understand IEEE 802.16 standards incl. IEEE 802.16e

Describe the main WiMAX features

Distinguish different layers and protocols used by WiMAX

Explain benefits of QoS, services, service flows and security features

Understand the Alcatel solution

EstimatedDuration:

6 hours

Continue with

This web-based training is designed for all persons who need an introduction to WiMAX technology. This applies especially to all persons who will be in charge of operating and maintaining the Alcatel WiMAX Solution. A basic knowledge of telecommunication protocols and of air interfaces or radio access systems will be assumed

By then end of this training, you will be able to:

Characterize WiMAX technology as opposed to other radio access systems

Explain benefits and limitations of WiMAX

Understand IEEE 802.16 standards

Describe the main WiMAX features

Distinguish different layers and protocols used by WiMAX

Explain benefits of QoS, services, service flows and security features

Understand the Alcatel Solution

You will need about six hours to work through this web-based training

To continue please click on the Continue button at the bottom of this window



Introduction


Getting Started

Split into 7 modules

Consult moduleswhenever you wish

Learn at your own pace

Narrators notes

Useful attachments(Printable version of this training,links etc.)

Quiz for self-assessmentat the end of each module

Continue with

This web-based training is split into 7 modules which you are invited to consult whenever it suits your schedule

As well as being able to consult the modules at your own convenience, you will be pleased to learn that you are able to run the training session at your own pace. You can take a break at any time. You can also go back to a particular page to look again at a specific point. For navigation inside a module, browse the Outline tab on the left-hand side or use the Previous and Next buttons in the navigation controls at the bottom of this window

You may also see the spoken text by selecting the Notes tab which will display the page content at the same time

By clicking the Attachment tab at the top right-hand side of this window, you will be able to access some very useful supplementary documents and further links. It will also interest you to know that this training material can be downloaded in PDF format and printed

Finally and in order to assess the knowledge you have taken in from this training session, you are invited to participate in a short quiz at the end of each module

To continue please click on the Continue button at the bottom of this window



Introduction


Contents

Alcatel WiMAX Products7

Technical OverviewWiMAX System Overview and Main Features

6

Technical OverviewMedium Access Layer (MAC)

5

Technical OverviewAir Interface and Radio Performances

4

Why WMAN IEEE 802.16?3

WiMAX Standard Status2

Broadband Wireless Access and WiMAX1

Alcatel WiMAX Products

Broadband Wireless Access and WiMAX

WiMAX Standard Status

Why WMAN IEEE 802.16e?

Technical OverviewAir Interface and Radio Performances


Technical OverviewWiMAX System Overview and Main Features

Exit with

Before we start lets have a look at the structure of this web-based training:

1) Module one gives a short introduction to what WiMAX can be used for

2) In module two you find information about the evolution of the WiMAX standards and which organizations support the development and the deployment of WiMAX

3) In module 3 you can get an impression of what forces drive the evolution and deployment of WiMAX

4) Physical and mathematical basics of WiMAX are presented in visual form in module 4. Acronyms such as OFDM and AAS are explained

5) How do WiMAX devices get access to the network and what types of services are available? This is explained in module 5

6) Mobility and security in WiMAX technology are the most important aspects in module 6

7) The web-based training ends with an overview of Alcatel WiMAX products and their features

To leave this introductory module click on the Close button (which is the red X) in the upper right-hand corner of this window. You will then be returned to the table of contents from where you can start any other module at your convenience. So, take your time and take the first steps into the world of WiMAX

Module 1 - Page 1


(1) Broadband Wireless Access and WiMAX



Module 1

Broadband Wireless Access and WiMAX

Module 1 - Page 2




Our Vision : Seamless Services

Connected Everywhere Anytime

In the officeIn the officeAt homeAt home

On the moveOn the moveDuring the breakDuring the break

Connected everywhere anytime to a powerful network, which is able to transport all types of services with the requested Quality

Wireless Metropolitan Area Network: WMAN or WiMAX adds to the existing wire line and wireless transport networks another wireless technology based on modern radio transmission technology

WMAN has been standardized by IEEE according to the 802.16 specification. It provides full Quality of Service (QoS) for any kind of real-time, near real time or non-real-time application

Module 1 - Page 3




New devices are getting smart

Mobile broadband access is the name of the powerful transmission technique which supports Next Generation Network technologies and new kinds of user devices

Wireless Metropolitan Area Network allows for new devices having small form factors to communicate using modern internet based methods. A large range of applications from home entertainment, gaming, to business applications are supported by this wireless broadband transmission method

Module 1 - Page 4




Universal Broadband Wireless Access & Mobility

Speed/user

Phone

UMTS/FDDEDGE/GPRS

WiFiWireless DSL

Fibre

xDSLWiredSatellite

High-end PDAPDA with phone

Laptop

Fixed On the moveDuringa break

Medium

High

Very High

Global coverageHot spots

TDDTD-SCDMA*Mobile DSL

Hot zones

HSDPA

In the zone

WiMAX

Complementary access solutions for different mobility and nomadic needs

Mobility

Full Mobility

This picture shows complementary access solutions for different mobility and nomadic, or fixed mobile needs

Today for all kinds of applications the appropriate access technology exists

The figure shows the typical access solutions for different mobility and nomadic needs

For fixed network access DSL-based systems deliver broadband data rates depending only on the type of access technology used: copper line or optical fibre

WiMAX is the synonym for Worldwide Interoperability for Microwave Access which stands for support and promotion of WMAN or IEEE 802.16 technology

This technology preserves Quality of Service through the air interface supporting genuine real-time applications

Small, non-QoS sensitive access methods use WLAN available in so called hot spot areas

User traffic generated with this method may be transported into powerful core networks over flexible wireless access

WMAN hot zones may support urban mobility as well

Full mobility preserving QoS requirements is realized using UMTS and EDGE/GPRS technology

Module 1 - Page 5




High Speed Data Solutions

Note: Comparative ranking with other technologies in performance per cell Global cost per end user including spectrum fee

Source: Alcatel

012345

Spectral ef ficiency

Global cost

CPE cost

Mobility

Security

Reach

Number ofsimultaneous subs /

cell

Spectrum w idth

Hotspot coverage

during a break

Wi-FiWi-Fi

012345

Spectral efficiency

Global cost

CPE cost

Mobility

Security

Reach

Number ofsimultaneous subs

/ cell

Spectrum width

Data Intensive Broadband in the zone

WiMAXWiMAX

012345

Spectraleff iciency

Global cost

CPE cost

Mobility

Security

Reach

Number ofsimultaneous

subs / cell

Spectrum w idth

cc

Combined Voice, Data & multimediaon the move

UMTS+HSPDAUMTS+HSPDA

These three diagrams compare various system parameters of WLAN (WIFI), WMAN (WiMAX) and the mobile network technologies UMTS with High speed Packed Downlink Access (HSPDA). The parameters have the following meaning:

Spectral efficiency: is the exploitation of the radio frequenciesSpectrum width: means the exploitation of radio channelsNumber of simultaneous subscribers/cell: is the support of multiple access to one networkReach: is the reachability of subscribers within radio areasSecurity: means Authentication, authorisation and cipheringMobility: is the change of location at full or reduced speedCPE cost: is the customer premises equipment costGlobal cost: is the cost for network operator and service user

This kind of visualisation is called a spider diagram. It can be used highlight differences between the compared systems. The shape of the spider net displays the different parameters and their associated values

Spider net diagrams are used also with complex applications, which show different thresholds for normal and critical system behaviour at a glance

Module 1 - Page 6




User Terminals

2007

2008

2006

2005 IEEE 802.16e

IEEE 802.16-2004

Outdoor CPE

Smartphones

Integrated in laptops & PDA

Indoor CPE

PCMCIA

WMAN technology will be integrated in standard user equipment

But at first there will be dedicated indoor and outdoor customer premises equipment solutions, which support WIMAX functionality only. The next step will be the integration into laptop by PCMCIA cards

There will be multi-services cards available on the market, supporting WLAN for short distance wireless applications, WIMAX for longer distance, QoS sensitive applications, with a limited mobility support (802.16e) and UMTS for the support of full mobility and QoS preservation provided by a UMTS Wide Area Network

Further chip integration will integrate WiMAX connectivity into smaller user terminals such as PDAs and smart mobile phones

In any hardware environment, we will find a variety of wireless access techniques, ranging from WLAN and WiMAX to UMTS

Module 1 - Page 7




Application: Wireless Fixed Broadband Access

For urban and suburban areas where access via copper or fiber is not available

Provides similar kind of service to ADSL with similar limitations

The user has a Subscriber Station on his premises (Customer Premises Equipment CPE). CPE may be provided by the network operator

CPE connected to the same Base Station

Simple AuthenticationTypically CPE authentication/authorization is enough

Bridging the so called digital divide by delivering broadband to low density areas

This page shows some typical applications and application scenarios for WiMAX

One important WiMAX application is the Wireless Fixed Broadband Access

This plays an important role for flexible service delivery to urban or suburban areas, which are expensive to provide with wired connectivity. Wireless Fixed Broadband Access technology provides a kind of service similar to wired ADSL, for example the same internet based services, similar quality of service etc.

WiMAX subscriber stations will be located at customers, similar to DSL splitters used with wireline access methods. Such Customer Premises Equipment will be connected permanently to the same base station. Therefore the CPE can work with simple authentication procedures, based on CPE authentication only

WiMAX technology can also overcome the lack of broadband services in low density areas. This is especially the case in emerging countries. The underdevelopment of broadband services leads to the so-called digital divide, the lack of world-wide access digital information networks

Module 1 - Page 8




Application: Nomadicity - Internet in the Pocket

Provides user terminal nomadicityi.e. a step beyond fixed access and basic fixed DSL type operation

The user is able to get broadband wireless access from differentlocations within an operators IEEE 802.16 network

No handovers are specified or supported between network access points (Base Stations). Connections are not retained

Global network authentication and charging

Connections and contexts are not necessarily retained between two network (re-)entry actions

Allows inter-operator roaming

The availability of 802.16 interfaces for laptop computers creates the need for terminal nomadicity, which is the possibility of moving a portable WiMAX device to various locations within the same network access area

The user may change to various network access points, but any existing service connection will be interrupted and not handed over to the next radio network access point

The network access procedures, such as authentication and authorisation are globally stored within the network, so that after the re-entry to the network, the previous authentication and access security data are still available, but no previous data connections

Different network access options are supported, including roaming within different networks operated by different WiMAX service providers. WiMAX networks will provide the technical basis for inter-operator roaming

Module 1 - Page 9




Application: Portability

Portability is the next step towards mobility with the support of handover

Same network access procedures as Fixed Access or Nomadicity

Handover is best effort

User may experience a glitch during change of network point of attachment

Latency-tolerant applications maintain IP connectivity during change of network point of attachment

Handover latency is a few seconds (worst case)

Packet loss is best effort

Portability and handover are two requirements which lead towards unrestricted mobility. These features are provided by the IEEE 802.16e extension of the WMAN standard

The IEEE 802.16e extension covers mobility including handover and thus allows continuous connectivity, e.g. in public transportation such as trains

The extension to the standard supports the same network access procedures used by IEEE 802.16 for wireless fixed broadband access and for nomadic applications

During handover there will be a short delay due to synchronisation with the next base station. This may cause buffer underrun for real-time applications and may result in a short glitch in real-time applications, which are not latency-time tolerant

Depending on the actual speed of the subscriber station and the present radio network coverage, transmission degradation such as packet loss and packet error rate may increase significantly during the handover process

In worst-case situations, the handover latency-time will be as long as a few seconds, if the number of base stations in a geographical area is too low and if adjacent base stations do not overlap. In this case packet loss will be best effort

Optimized network configuration provides full mobility at a max. speed of 120 km/h (with degraded transmission) and 60 km/h with the support of all Quality of Service classes maintained during handover. This means real-time applications such as VoIP are maintained during handover

Handover latency will be less than a few tenths of a millisecond

Additional features for mobile performance such as low-power operation are provided

Module 1 - Page 10




WiMAX Network Architecture

WiMAX Access Network

DSL, Cable

3GPP, 3GPP2

Private networks

WiMAX accessWiMAX accessWiMAX accessWiMAX access

Core NetworkCore NetworkCore NetworkCore Network

WLAN accessWLAN accessWLAN accessWLAN access

Operator value-added content

Partners value-added content

Internet

3GPP/3GPP2 radio access3GPP/3GPP2 radio access3GPP/3GPP2 radio access3GPP/3GPP2 radio accessFixed accessFixed accessFixed accessFixed access

Easy Integration of WiMAX RAN

One generic WiMAX Accessarchitecture that can be integrated into a multitude of networks

End-to-End features and solution for Nomadic network

Nomadic network with limited mobility

Multi Radio Access

WLAN, Mobile, WiMAX In synchronisation withNGN and IMSnetworks evolution

This picture shows the general IEEE 802.16 network architecture

The IEEE 802.16 network architecture can be integrated into a large number of different fixed or mobile networks. The reason of this lies mainly in the following IEEE 802.16 features:

1) The transmission technology used is based on IP technology , only IP packets are transmitted over the air interface. This makes it well suited to be the Next Generation Network access technology

2) The IEEE 802.16 protocol provides an adoption sub-layer as part of the MediumAccess Control (MAC) layer, which can be used to transport different types of layer-2 packets over the air interface such as Ethernet packets or ATM cells

The support of mobility creates the basis for new mobile and nomadic service concepts which comprise VoIP, high speed internet access, mobile TV, mobile gaming. Mobile Triple Play applications which comprise TV, internet access and VoIP, will use WiMAX transmission technology

Module 1 - Page 11




Alcatel Vision of WiMAX Applications & Architecture

Fixed Wireless DSL

Main Features

NLOSIndoor ApplicationPlug & Play CPE

NomadicityPortabilityService access

Across multiple BS

Simple Mobility

Full MobilitySession continuityAcross multiple BSAcross multiple RAN

Internet In the PocketReduced end-user devices

PCMCIA, USB Key, Embedded

Network Architecture

Integration in Fixed & Mobile Networks

Applications

Architecture

Beyond3G

FullIP RAN Approach

Fixed Operators

Mobile Operators

As to the future development of fixed and mobile networks, Alcatels view is driven by its knowledge and broad experience with legacy and next generation network concepts

One important development direction will be enabled by the convergence of fixed and mobile networks. Future applications will be transported through one type of network only, whether mobile or fixed, based on IP technology

Network operators will offer a wide range of different applications requiring various fixed and mobile access methods. IEEE 802.16 will be the major wireless access technology supporting fixed access, nomadicity, simple and full mobility

Alcatels business will mainly focus on the development of powerful WiMAX Base Stations (BS) and the connected backbone network based on NGN concepts. Such products need to offer a seamless connectivity between all types of networks

Module 2 - Page 1


(2) WiMAX Standard Status



Module 2

WiMAX Standard Status

Module 2 - Page 2




IEEE 802.16 Standardisation

IEEE 802.16(December 2001)

IEEE 802.16a(April 2003)

IEEE 802.16-2004(July 2004)

IEEE 802.16e(on-going)

FWA > 11 GHz FWA 2

Module 2 - Page 3




WW Frequency Bands for WiMAX

3.5 GHz

Europe

Evolution towards Simple Mobility

Lobbying actions e.g. access to Digital Dividend

3.6-3.8 GHz in Europe

China: 3.3 GHz

2.5-2.7 GHz in Europe

IMT2000 allocated

Convergence efforts between WiMAX & 3GPP

Mid Term Available Bands Evolutions

Sub-1 GHz band: 700 MHz USA, India

For better low-density areas coverage

Lobbying in India and further World-Wide

Unlicensed Band: 5 GHz

Unlicensed or Light Licensed

Vertical Markets Usage

Pico Cell Deployments

The table shows the main frequency bands used in different geographic locations of the world. In the short term there are frequency resources available in the 3.5 GHz band

Depending on the geographic region different radio bands and access technologies are specified by local government authorities. In Europe, Latin America, North America, Middle East, India and in the Americas and Pacific region. The available duplex technologies are:

Frequency Division Duplex & Time Division Duplex

For fixed network usage

3.3 GHz in India

The unlicensed bands are located at 5 GHz

These bands can be characterized by the following list items:

They are unlicensed or light-licensed, showing a low license restriction

They target for vertical markets usage, which means for specific segments or niches of a special market

They support pico-cell deployment, used in special areas with dense population as well as services requesting high bandwidth

Module 2 - Page 4




WiMAX Deployments

Suburban

Urban RURAL

Capacity Driven Network

Coverage Driven Network

Main Concern :Sufficient Spectrum ResourcesFor capacity & multiple operators

Main Concern :Frequency Band

Rural

Answer :700 MHz Band

Answer :2.5 and 3.5 GHz bands

The different WMAN frequency bands are deployed in different urban, suburban and rural environments

The lower the frequency band the larger the cell area but the smaller the available total bandwidth per cell. Therefore such frequency bands are most appropriate for low population density and big cell area

Of course rural areas can also be provided with 2.5 GHz and 3.5 GHz bandwidth

Urban and suburban areas need higher bandwidth and because of physical side effects such as multipath propagation and other fading effects the 2.5 and 3.5 GHz bands seem to be most appropriate

Module 2 - Page 5




Competing Technologies

No standard

Proprietary Solutionsmoved to 802.16d/e

WiMAX Solutions Dormant SolutionsMobile Solutions

CDMA (Navini, IP wireless/2.5-3.5 GHz)OFDM &/or Pre-WiMAX (Alvarion, Redline, Nextnet, BeamReach)Single Carrier (Aperto, Proxim)

IEEE 802.20 standardNot existingMobile Broadband Wireless Access (MBWA)

Flash OFDM (Flarion)

802.16d ->802.16 2005

802.16e-2005Nomadicity will bring IOT and full standard

UMTS-HSDPAUMTS TDD(IP wireless)

TD-SCDMA (China)CDMA2000 EV-DV

Standard Standard Dormant

Proprietary solutions will disappear from the market in time. There were some pre-WIMAX solutions on the market but have now been moved to the 802.16-2004 standard

The successor to 802.16d is now 802.16-2004 (802.16-2005) which is in effect the same standard. 802.16d was the draft standard name

Urban mobility is supported by 802.16e

Mobile solutions cover all broadband mobile network technologies such as Wideband-CDMA and CDMA-2000. This means that it will be a development goal to create inter-system connectivity between the different mobile networks supporting various mobile network standards

The 802.20 working group is expected to develop a WMAN standard supporting high velocity such as common mobile networks but with higher user-data-rates available

Module 2 - Page 6




WMAN System Profiles (IEEE)

28 MHz channel PHY profileprofP228 MHz channel PHY profile - FDDprofP2f28 MHz channel PHY profile - TDDprofP2t

25 MHz channel PHY profile - TDDprofP1t25 MHz channel PHY profile - FDDprofP1f25 MHz channel PHY profileprofP1Basic packet MAC profileprofM2Basic ATM MAC profileprofM1DescriptionIdentifier

In order to provide a basic manufacturer independent functionality in all WIMAX implementations, the 802.16 standard describes a set of standard features, which are mandatory for all implementations of the Physical and MAC Layer

Equipment which does not support mandatory features will not receive certification labels

The list above shows the profiles specified in 802.16-2004. There are additional profiles defined by the WiMAX forum and by the Mobile Technical Group, which recently completed the 802.16e profile

The profiles profM1 and profM2 specify the MAC Convergence Sub-layer and MAC layer features if connectivity to ATM transport networks and other packet networks is requested

The other profiles specify the Physical Layer as to different radio channel bandwidth characteristics and different duplex techniques (Time Division Duplex TDD and Frequency Division Duplex FDD)

Each profile specifies general layer features and functions plus all protocol messages and mandatory message parameters

Further details of the Physical and MAC layer functions will be explained at a later stage of this training

Module 2 - Page 7




WIMAX Profile Selection

The following initial profiles have been selected by WiMAX:

Future profiles will cover the following frequency bands:

5725-5850

3400-3600

Freq Band[MHz]

10TDD

7.0

3.5FDD

7.0

3.5TDD

Canalisation[MHz]

Duplexing

5.0 / 5.5TDD2500-2690

5.0 / 5.5FDD

Freq Band[MHz]

Canalisation[MHz]

Duplexing

The following Key Profile Characteristics are defined:

All the current profiles under consideration operate using Orthogonal Frequency Division Multiplex multiple carrier schemes and a Fast Fourier Transformation size of 256 points has been selected

Time Division Multiple Access (TDMA) is currently anticipated as the multiple access mechanism with an option for OFDMA uplink sub-channelisation

OFDM can be scaled to operate within a variety of channel widths. Widths of 3.5 MHz, 7 MHz and 10 MHz have initially been selected as these are consistent with allocations and assignments in many regions around the world

Both FDD and TDD techniques are included. Both techniques offer specific characteristics that can be advantageous for service providers and are supported by the standards

Module 2 - Page 8




WiMAX Forum http://www.wimaxforum.org

Industry organization for promotion of IEEE 802.16

Based on IEEE 802.16-2004 and IEEE 802.16e standards

Propose and Promote Access Profiles Certify Interoperability of Microwave Access Products Achieve a global acceptance of this new technology Promote the use of broadband wireless access in general

IEEE and WiMAX Forum

IEEE 802.16 http://www.ieee.org

Dedicated to PHY & MAC Tasks also to cover MIB & Management Plan

Two organizations specify standards for WiMAX:

First, IEEE - the Institute for Electrical and Electronics Engineers - and

Second, the WiMAX forum.

IEEE sets up general specifications dedicated for instance to layer one and two of the OSI model, the physical layer and the MAC layer. They also specify the MIB structure and management plan

The WiMAX forum is an industry-led, non-profit corporation formed to promote and certify compatibility and interoperability of broadband wireless products.

The main objectives of the WiMAX forum are

to support the IEEE 802.16 standard and its evolution

to propose and promote access profiles for the IEEE 802.16 standard

to certify interoperability both in the network and at the air interface

to achieve a global acceptance of this new technology and

to promote the use of broadband wireless access in general

Up to April 2006 more than 350 companies have joined the WiMAX forum among which are:

Operators for fixed and mobile networks and Internet Service Providers

Nearly all major telecommunications system suppliers as well as

Equipment, Components and System Suppliers

Module 3 - Page 1


(3) Why WIMAX IEE 802.16?


(3) Why WiMAX IEEE 802.16?

Module 3

Why WiMAX IEEE 802.16?

Module 3 - Page 2




Light install CPEsOutdoor NLOS* antenna

Zero install CPEsIndoor

> 10 m

4 m > 10 m

1.5 m

1km

Around 3km

1.5 km

Around 4 km

Maximum user data rate : 22 Mbit/s (80% probability)

Minimum user data rate :4.5 Mbit/s (99.9% probability)

Sectorized BS10 MHz

40 m

* NLOS= Non Line Of Sight

W-DSL Performance - Urban environment

One important WiMAX driving force is the increasing need for high bandwidth in urban and suburban environments. The bandwidth requirements lie close to or beyond DSL capacity

Network operators and/or service providers can bridge the last mile to the customer with this wireless transmission technology

The illustration shows some physical configuration parameters as they are expected in urban environments together with some targeted data rates

Module 3 - Page 3




Dense Urban indoor wDSL scenario

Full indoor (20 dB penetration)

22 Mbps 20 Mbps

Dense Urban Area

Frequency: 3.5 GHzAntenna height: 30 m

AAS: 4 elements

Service: 1024 kb/sNo of sub: 225 (10 MHz)

Average throughput per sector in TDD

24 Mbps

10 MHz

Dense Urban Environment

W-DSL Performance - Urban environment

The figure shows the targeted data rates for dense urban environment under certain conditions, for specific CPE and optimised distance to BTS:

The parameter conditions are: The frequency band used is 3.5 GHz Antenna height is 30 m and Adaptive Antenna System with 4 sectors

The internet based service offered for max. 225 subscriber stations requires a channel bandwidth of 10 MHz

The peak bandwidth for each subscriber station can be up to 1024 kbit/s

The sectorisation of the WiMAX cells creates an efficient deployment of base stations and a high total cell throughput

Module 3 - Page 4




W-DSL Performance - Rural and Suburban environment

3.5 GHzIndoor

3.5 GHzOutdoor

5.2 14

Typical Values

ConditionsIndoor Penetration 15dBAnte. Height 35 mAAS 4 Ante.BS OP 35 dBm

SS : 27 dBm W-DSLA.Gain : W-DSLTDD 3:1

1024 kbps DL128 kbs UL at cell range for

WiMAX

41.45

RuralConditions5 MHz ChannelAgriculture Model90% Probability

3.5GHzIndoor

3.5 GHzOutdoor

Suburban

Rural

SuburbanConditions5 MHz ChannelSuburban Model95% Probability

Similar estimations lead to data rates for suburban and rural environments

The physical and technical parameters are:

The indoor penetration of radio power is 15 dB The Antenna Height is 35 m The Adaptive Antenna System used consists of 4 sectors. The Base Station operates at a radio power of 35 dBm The Subscriber Stations operate at a radio power of 27 dBm The TDD Uplink to Downlink ratio is 3:1 The maximum data rate in downlink direction is 1024 kbit/s The maximum data rate in uplink direction at cell range is 128 kbit/s

Module 3 - Page 5




3G/3G LTE

WiMAX

IMS

DirectPayment

Service DeliveryPlatform

HSSMediaServer

xDSL

Other networks & contents

Internet Protocol: The Corner Stone

IMS USER-CENTRIC

ENABLER

IP Backbone

Ethernet

Ethernet

Multi-standardRadio Access Point

Media Gateways

CallServers

WiMAXMobile

2G/3G/3GLTE

WiMAX The First Full IP Standard Radio Access System

IP

SOURCE OF

RATIONALIZATION

As this picture shows, Internet Protocol (IP) plays an important role as a service enabling technology, as a service delivery platform and a global network technology

With Internet-based Multimedia Services (IMS) new multimedia applications are offered by network operators and independent service providers (such as Instant messaging, Location service etc. )

The combination of multimedia applications with multi-modal applications (such as voice input, voice control, voice output etc.) will support new markets and user behaviour

IMS offers a new kinds of user-specific and user-centric services, for example:

ONE Number: The routing of a call across multiple accesses (mobile and fixed)

ONE BILL: The centralized charging of all services to one bill

ONE MAILBOX, ONE ADDRESSBOOK and ONE PROFILE:Which stand for one type of service available in all networks, hand-over across multiple access networks and seamless and transparent authentication in every network

Module 4 - Page 1


(4) Technical Overview - Air Interface and Radio Performances


(4) Technical OverviewAir Interface and Radio Performances

Module 4

Technical OverviewAir Interface and Radio Performance

Module 4 - Page 2




OFDM is a key multiplexing scheme for broadband wireless network transmission:

FDM sub-carriers with overlapping spectra

prevention of interferences by orthogonality

sub-carrier peak at minimum of all other sub-carriers

application of Fast Fourier Transformation (FFT/IFFT)

highly efficient spectrum exploitation

Data Sub-carriers Pilot Sub-carriersDC Sub-carrier

Guard band Guard band

Orthogonal Frequency Division Multiplex OFDM

Orthogonal Frequency Division Multiplex (OFDM) is the key radio transmission technology for the WIMAX multi carrier radio interface

A large number (256 to 2048) of sub-carrier frequencies, which have a low bandwidth and thus do not show severe physical impairments such as multipath fading are used at the air interface. This can be achieved under the following conditions:

Sub-carrier frequencies are orthogonal which means they do not overlap: sub-carrier peak at minimum of all other sub-carriersThis configuration creates a very efficient exploitation of the available frequency spectrum.

Serial to parallel transformation is used to multiplex input data onto the different sub-carriers

The number of Fast Fourier Transformation (FFT) points is adapted to the number of orthogonal sub-carrier frequencies

FFT and inverse FFT methods are integrated in the air interfaces transmission process. With IFFT OFDM symbols are created (calculated in the time domain) and used to transmit data streams over the air interface

Applying FFT the received symbols are transformed into the frequency domain to create the orthogonal sub-carrier frequencies, which transport the multiplexed data streams

Module 4 - Page 3




WithCyclic Prefix

t

WithoutCyclic Prefix

t

CP removes ISI CP used for synchronisation CP reduces Inter Channel Interference (sub-carriers orthogonality maintained)

copypaste

CP

No ISI

ISI No ISI

Cyclic Prefix

This picture shows the influence of multi-path propagation effects and reflections of radio waves at the air interface. Due to reflection each OFDM symbol reaches the receiver with lower amplitude, with some delay and several times

This is displayed in the picture for three reflected parts of a single symbol. These three parts interfere with the original symbol and cause signal degradation

In order to overcome this effect, the overlapping part of the symbols is marked as security period which is not evaluated. This period is created by copying a known part of the symbol to this overlapping region called Cyclic Prefix (CP)

The total symbol size is of course reduced by this CP and the goal is to reduce the CP part of the total symbol time. The higher the frequency the shorter the symbol duration and vice versa. So the influence of CP is reduced by lower frequencies

Because a CP is a known copy of a part of a symbol it can also be used for synchronisation purposes

Module 4 - Page 4




Time Domain

Ts

TbTg

Tg: Cyclic Prefix (CP)Tb: usable symbol timeTs: symbol time

The OFDM symbol is the result of applying the Inverse Fast Fourier Transformation to the FDM sub-carrier frequencies

OFDM Symbol Structure

The picture shows the structure of an OFDM symbol

Inverse-Fourier-transformation creates the OFDM symbols, which are represented by multi-carrier signals. Its time duration is referred to as the total symbol time Ts and the time which can be used for transport of user data is the usable symbol time Tb

A copy of the last Tg micro seconds of the usable symbol period, termed Cyclic Prefix (CP), is used to collect multipath delayed signals, while maintaining the orthogonality of the frequencies

On initialization, a SS searches all possible values of CP until it finds the CP being used by the BS

The SS uses the same CP on the UL. Once a specific CP duration has been selected by the BS for operation on the DL it should not be changed. Otherwise all subscriber stations would have to resynchronize to the BS

Module 4 - Page 5




Serial to

parallel

Modulator

~ f1

Modulator

~ f2

Modulator

~ f3

+

Higher data rate

Shorter symbol duration

Lower data rate

Longer symbol duration Orthogonal sub-carrier frequencies

Ts = 1/BW

Ts_FDM = N / BW

Ts = Ts_FDM / N

OFDM Principle

The picture shows the process which takes place while sending a user data packet:

A high bandwidth input data stream is split into several different lower bandwidth streams

The high input bit rate Ts is split up. These data streams are then modulated onto the different orthogonal sub-carrier frequencies using efficient modulation techniques, which increase the data capacity (bit/sec). Then inverse-FFT (IFFT) operation is applied to calculate OFDM symbols

Each sub-carrier frequency transports a lower data rate and thus contributes to longer symbol duration

The symbols contain user data in a mathematically converted format in order to maximize bandwidth utilisation. There is no direct relationship between the OFDM symbols, the single sub-carriers and the transmitted user data

Finally the safety area Cyclic Prefix (CP) is created to reduce signal degradation (multipath fading) due to multi-path propagation effects

OFDM symbols are constructed by IFFT application. FDM-frequencies are reconstructed by FFT application

Module 4 - Page 6




Downlin

k (DL)

longPreamble

longPreamble

FrameControlHeader

FrameControlHeader

DLBurst(MAC)

DLBurst(MAC)

burst profiles: DIUC

DL-MAPDL-MAP

1 OFDM Symbol(QPSK 1/2)

Integer number of OFDM Symbols

DLBurst(MAC)

DLBurst(MAC)

DIUC: Downlink Interval Usage Code

DL-PHY Frame Structure

This page shows the general 802.16 physical frame structure in downlink direction

It starts with a long preamble of defined sequence, which can be used by the subscriber stations for synchronisation and alignment purposes

The following part is the Frame Control Header (FCH). It must be decoded by all stations, so the length and the modulation of this field is fixed (1 symbol, QPSK, code rate = 1/2). It contains the following parameters:

The Downlink - Frame Prefix: containing Rate-Id, Length and Header Check Sequence

The Downlink Channel Descriptor (DCD) is a MAC layer message that describes the physical layer characteristics of a downlink channel

The following parts of the physical frame are the Downlink -Bursts which contain MAC-layer messages for signalling or for user data transport

DL-Bursts may be modulated differently because they are sent to different subscriber stations at different physical locations. Therefore each DL-Burst needs to be characterized individually by a Downlink Interval Usage Code parameter

Module 4 - Page 7




Uplin

k (U

L) shortPre-amble

shortPre-amble

ULBurst(MAC)

ULBurst(MAC)

Integer number of OFDM SymbolsUL-Sub-frame

RNGRNGBWReq

BWReq

UL-PH-PDUUL-PH-PDUContention Slots

shortPre-amble

shortPre-amble

ULBurst(MAC)

ULBurst(MAC)

RNG: RangingBW-Req: Bandwidth Request

UL-PH-PDU: Uplink Physical Layer Protocol Data UnitDL-PH-PDU: Downlink Physical Layer Protocol Data Unit

UL-PHY Frame Structure

This page shows the uplink physical frame structure

In this direction the physical header has a different structure

Stations which access the network (called initial ranging) use the Ranging access slots

Stations which are already connected to the network, maintaining active connections, provide bandwidth request opportunities in the header

These two options are displayed as contention slots in the figure above

All uplink payload bursts start with a short preamble followed by an integer number of OFDM symbols carrying the MAC layer PDUs, MAC signalling messages or user data

Module 4 - Page 8




SOFDMA: SOFDM for Multiple Access

Additional flexibility in resource allocation

Especially small packets (VoIP) Range extension in DL and UL

Sub-Channeling is a given

FCH

FCH

Preamble

Preamble

FCH

FCH

DL part UL part

Preamble DL

Preamble DL

Preamble UL

Preamble UL

Preamble UL

Preamble UL

FCH

FCH

Preamble

Preamble

FCH

FCH

DL part UL part

Preamble DL

Preamble DL

Preamble UL

Preamble UL

Preamble UL

Preamble UL

Preamble

Preamble

FCH

FCH

Preamble

Preamble

FCH

FCH

DL part UL part

Preamble

Preamble

FCH

FCH

Preamble

Preamble

FCH

FCH

DL part UL part

OFDM

SOFDMA

WiMAX: 802.16-2004 vs. 802.16e

OFDM vs. SOFDM [1/2]

With 802.16e the more advanced version of OFDM is introduced: the scalable OFDM (SOFDM)

OFDMA and SOFDMA is an access method based on OFDM technique: the subscriber is assigned a number of OFDM sub-channels for transmission of user data. OFDMA means the assignment of OFDM resources used for individual subscribers by the network

SOFDM uses a very high number of sub-carriers (up to 2048). This leads to a reduction of the sub-carrierbandwidth which affects the physical air interface performance positively

Due to this high number of sub-carrier frequencies, the FFT/IFFT calculation is more complex (2048 FFT points). This requires high processing power and there is a need to provide for of a high number of orthogonal carrier frequencies

SOFDMA offers a higher granularity of bandwidth assignable to individual subscriber stations

The result is an optimized exploitation of the air interface especially for small user data packets created by real-time applications such as Voice and Video over IP

Module 4 - Page 9




SOFDM: Scalable OFDM

Higher number of sub-carrier frequencies provides higher capacity

Number of FFT points is adapted to channel bandwidth

Robustness similar to multipath for higher bandwidth Same range when bandwidth is increased

x2

BW

2xBW 2xBW

=

BW

OFDM SOFDM

Sites: + 35%Tg: / 2

Sites: =Tg: =

WiMAX: 802.16-2004 vs. 802.16e

OFDM vs. SOFDM [2/2]

This figure shows the major advantage of SOFDM compared to OFDM

The higher number of sub-carrier frequencies allows a very good granularity of bandwidth assignment to user services

Secondly the advantages of SOFDM lie in a better exploitation of the available bandwidth for user data. The reason is that the SOFDM cyclic prefix duration (Tg) takes a smaller part of the total symbol length and the SOFDM symbol duration is longer compared with OFDM

Module 4 - Page 10




Smart Antennas, Data booster for WiMAX nomadic systems Up to 12 dB gain in DL, 6 dB in UL (4 antenna system)

Increased indoor penetration

Increased data throughput

Alcatel : years of expertise in AAS technologies Contribution of Alcatel R&I Stuttgart

Broad knowledge from projects AAS in GSM and UMTS

Field Trial GSM in 1994 and Field Trial UMTS in 2003 First application in GSM diversity receiver

Generalized with BSS B6 on Alcatel 9100 TRX (1998) R&I for AAS in WiMAX

WiMAX OFDM 256 and SOFDMAAlcatel WiMAX solution includes AAS technology

Alcatel Smart Antenna Technology

Smart antenna systems or Adaptive Array Systems (AAS) can extend cell coverage by improving the system link budget. Link budget gain is realized by an AAS through the coherent combining of signals received or transmitted from multiple antenna elements, as well as by the increase in diversity order offered by the antenna array

At the same time, AAS can increase base station capacity by enabling the use of higher order modulation through interference reduction and by enabling spectral reuse within the cell

For this purpose new AAS-Physical layer signalling messages are introduced. These have an influence on the beam-forming capability of the antenna

Alcatel has as a great deal of experience with this technology. AAS systems were introduced in GSM and UMTS networks to increase radio cell capacity. Alcatel WiMAX base stations will also include smart antenna technology

Module 4 - Page 11




Deployment assumptions

BS antenna height: 35 mBW: 10 MHz

Frequency reuse = 3Morpho: dense urban

Indoor penetration: 18 dBCoverage: probably 95%

Shadowing: 8 dB std64 kbps min @ cell edge

0.60 km 1.05 km Typical cellular range300 - 500 m0.75 km 1.25 km

Capacity (TDD 2:1)DL: 14.6 Mbps average; 4 Mbps peak @ cell edgeUL: 7.4 Mbps average

Dense Urban indoor scenario

3.5 GHz:

2.5 GHz:

WiMAX Performance

Urban Environment

The picture shows a dense urban scenario:

Depending on the equipment and the frequency band used the base station distance varies from 0.6 km to 1.25 km

Without Adaptive array antenna systems the base station distance would be only 360 m

For a Time Division Duplex (TDD) cell with an DL- to - UL time slot ratio of 2:1 the transmission bandwidth of the cell is:

In downlink direction 14.6 Mbps average; with a 4 Mbps peak rate at cell edge position and In uplink direction 7.4 Mbps average value

Module 4 - Page 12




Indoor Outdoor LOS*

SUBURBAN

RURAL

6.75 km 16.75 km

8.30 km 17.00 km

3.5 GHz:

2.5 GHz:

2.20 km 5.80 km

2.70 km 6.75 km

3.5 GHz:

2.5 GHz:

Deployment assumptionsBW: 5 MHz

Frequency reuse = 3Morpho: rural

Indoor penetration: 12 dBCoverage: probably 90 % (indoor)

Availability: 99.99 % (outdoor)Shadowing: 6 dB std

64 kbps min @ cell edge

Deployment assumptionsMorpho: suburban

Indoor penetration: 15 dBOutdoor wall-mountedProb coverage: 95 %Shadowing: 7 dB std64 kbps @ cell edge* LOS: Line Of Sight

* NLOS: Non-LOS

IndoorOutdoor NLOS*

Wall mounted

WiMAX Performance

Rural and Suburban Environment

As rural and suburban cells will cover a larger area the transmission parameters need to be adopted to the transmission requirements

The picture shows some example parameters:

Generally a big cell size has an impact on the cell capacity and the cell bandwidth is reduced by large transmission distances due to physical transmission effects

Module 5 - Page 1


(5) Technical Overview - Medium Access Layer (MAC)


(5) Technical OverviewMedium Access Layer (MAC)

Module 5


Module 5 - Page 2




Medium Access Control (MAC)

A network that utilizes a shared medium requires a mechanism to share it efficiently

MAC layer is connection-oriented. All data communications are in the context of a connection defined by the Connection ID (CID)

The downlink direction, from the base station (BS) to the user, operates on a point-to-multipoint basis

In the uplink direction, the user stations share the uplink to the BS on a demand basis

Network service access is controlled by contention mechanisms between users and enables the service to be tailored to requirements of each user application

The Medium Access Control layer is used to provide efficient multiple access to a shared medium, which is the physical radio interface

All subscriber stations are physically connected to a base station. All data communication between the base station and the subscriber stations are connection oriented. During connection establishment, the subscriber station specifies the type of service and other service parameters needed for this connection

In the downlink direction the communication behaves as a point-to-multipoint operation between the base station and all subscriber stations

In the uplink direction all subscriber stations share the uplink resources. The mechanisms used depend on the service type

For real time-data delivery services the bandwidth is periodically allocated by the base station

For non-real-time data delivery services the subscriber stations compete for network service access in uplink direction using a contention slot mechanism provided by MAC layer signalling. The distribution of uplink and downlink bandwidth is controlled by MAC protocol messages, which are broadcasted over the air interface

Module 5 - Page 3




BS SS

Connection Establishment/ReleaseConnection Establishment/Release

Service Flow ProvisioningService Flow Provisioning

Connection MaintenanceConnection Maintenance

Network AccessNetwork Access

MAC Layer Services

MAC layer services comprise:

Network access, Connection establishment and connection release, connection maintenance and Service flow provisioning

Network Access provides access to physical resources as well as MAC-layer services, such as data transfer and security services, such as authentication and encryption of user data

Connection orientation guarantees QoS. All data exchange over the air interface is based on connections. For each connection the requested QoS is negotiated at connection set-up time

Connection maintenance, e.g. change of connection parametersQuality of service requirements may change during the connection. Bandwidth may be changed using specific MAC layer procedures. This requires sophisticated connection maintenance mechanisms

User data streams which belong to MAC layer connections transport a requested services characterized by QoS parameters. These data streams are called service flows

Module 5 - Page 4




Bandwidth Allocation Method [1/3]

Current bandwidth grants to CIDs are executed by BS through the allocation of time slots for transmission to the selected CIDs

Network time is divided into frames of 5 ms duration

Every frame opens with a DL MAP followed by a UL MAPtransmitted by BS to all SS. The MAPs indicate the activity to be executed by BS and SS during the frame.

DL MAP indicates:

CIDs to which BS will transmit (downlink) during the following frame

The exact moment in time when the transmission will occur.

The physical parameters to be used by BS for each CID (modulation type, FEC coding rate, etc. DL Channel Descriptor-DCD)

One important MAC function is allocation or grant of bandwidth to subscriber stations. This is accomplished by assignment of frames to the Connection Id belonging to a subscriber connection

Every frame starts with a frame header, which contains Downlink-MAP and Uplink-MAP messages. These messages organize the mapping of uplink and downlink payload to and from the subscriber stations

Downlink-MAP indicates the physical payload and its time location within the frame, so that each subscriber station can identify its payload

The Downlink MAP message indicates the Connection IDs to which Base Station will transmit in downlink direction during the following frame, the exact moment in time when the transmission will occur and the physical parameters to be used by the Base Station for each Connection-ID, e.g. the modulation type, Forward Error Correction, coding rate, etc.

The Downlink Channel Descriptor parameter is used to decode the payload contents, because physical transmission parameters may depend on the position of each subscriber station

Module 5 - Page 5





UL MAP indicates:

CIDs that have to transmit during the next frame (uplink)

The exact moment in time when the transmission has to occur

The type of information to be transmitted during the allocated interval (data, management, requests to transmit in the next frame, etc.)

The physical parameters to be used by each CID when transmitting to BS (modulation type, FEC coding rate, etc. UL Channel Descriptor - UCD)

The Uplink MAP information indicates uplink transmission capacity to the subscriber stations

This information is based on the active Connection-Id which belongs to user data connections

Transmission time allocations are based on requests received by the base station during previous frames. In uplink direction resource allocations are made per user, identified by the basic connection ID value

The Uplink-MAP message also contains the type of information, which is to be transmitted (data, management, requests to transmit in the next frame, etc.) and the physical parameters to be used by each Connection-ID when transmitting to BS (modulation type, FEC coding rate, etc.

The uplink mapping information is transmitted in downlink direction to indicate the reserved uplink resources to the subscriber station. These resources are available for the subscriber station in the next frame period. This is shown in detail on the next page

Module 5 - Page 6




DL-MAP

UL-MAP

DL-MAP

UL-MAP

DL UL

DL UL

frame { i }

frame {i+1}

Time Division Duplex (TDD)


The Downlink-MAP information shows the payload position for any subscriber station within the current frame

The Uplink-MAP information refers to the next frame and shows the locations where subscriber stations can position their uplink transmission data

This Bandwidth allocation mechanism is deduced from the Data over Cable Service Interface Specification developed by Cablelabs

Module 5 - Page 7




Channel Description Messages

Downlink Channel Descriptor (DCD)

The BS transmits DCD messages at a periodic interval to define the characteristics of a downlink physical channel (Downlink Burst Profile)

Uplink Channel Descriptor (UCD)

The BS transmits UCD messages at a periodic interval to define the characteristics of an uplink physical channel

A separate UCD Message is transmitted for each active uplink channel associated with the downlink channel

In downlink direction the Downlink Burst Profile defines the physical layer characteristics and associates it with a particular Downlink Interval Usage Code

Each Downlink Burst Profile contains a list of layer-1 attributes

The downlink-MAP message uses the Downlink Interval Usage Code and the Downlink Burst Profile to describe the characteristics of a downlink physical channel

In uplink direction the Uplink Burst Profile defines the physical layer characteristics and associates it with a particular Uplink Interval Usage Code

Each Uplink Burst Profile contains a list of layer-1 attributes

The uplink-MAP message uses the Uplink Interval Usage Code and the Uplink Burst Profile to describe the characteristics of an uplink physical channel

Module 5 - Page 8




Network Entry and Initialization

Subscriber Station Network Entry &Initialization Procedure Steps

1. Scan for downlink channel and establish synchronization with the BS

2. Obtain DL and UL transmit parameters

3. Initial ranging - Transmit Range-Request to set correct power level, accurate frequency and correct transmission timing

4. Authentication, Authorization and key exchange

5. Perform registration SS gets CIDs for its management messages

6. Establish IP connectivity (e.g. via DHCP)

This part explains the different steps a subscriber station has to go through during network entry and initialization

It is important to understand these procedures, because they are basis for the MAC layer function. The following questions are addressed:

Establishment of a physical connection

Setting of physical layer parameters

Network access security functions: Authentication and authorisation

Registration and assignment of signalling connection. (CID allows for manageability.) And

IP layer activation (needed if DHCP is required)

When these procedure steps are completed, the subscriber station can establish user connections for user applications and user data transport

Module 5 - Page 9




MAP

t

Air Frame

MAP

t

Air Frame

MAP

t

Air Frame

MAP

t

Air Frame

Network Entry Process : Synchronization [1/2]

The Subscriber Station (SS) listens to the frequency it is configured for and waits to hear MAPs

The SS will synchronize only if it has received 4 consecutive MAPs from the same Base Station (which match its configured BS-ID) in the same cycle time (t)

Each physical layer frame starts with a header. The part which contains MAP information always has the same modulation, so all stations can read and evaluate it

Before being able to receive MAP information, the subscriber station has to listen to the frequency bands it is configured for and try to synchronize via one physical frequency

If this is successful, the station evaluates four consecutive MAP messages, which were sent by the same base station

Module 5 - Page 10




BS SS

MAPsSend MAPs

SearchMode

Coarse frequency fixschedule recv modeMAP decode start

Adjust Txparameters

MAP with UCDSend MAPswith UCD

5 sec.

Network Entry Process : Synchronization [2/2]

The process is displayed here

Within five seconds the base station transmits one Uplink Channel Descriptor Message. This information must be evaluated by the subscriber station, because it contains important information for the physical parameter setting

Before the subscriber station can only set the physical parameters such as exact frequency framing schedule etc. on a coarse base

The more precise adjustment of these physical layer parameters requires additional information from the UCD message

Module 5 - Page 11




MAP DL - DATA

UL - DATA

Ranging Area

Maintenance Period

T.O. Transmission Opportunity -> new SS send Initial Range Request

BS

T.O

.T.O

.T.O

.T.O

.

DL

UL

Tx

Rx

Network Entry Process: Initial Ranging [1/2]

As a next step the subscriber stations must find a way to contact the base station actively by sending MAC messages

Other mobile radio systems like GSM and UMTS use specific signalling channels, called Random Access Channels, to create a first network access

Because many subscriber stations compete for the limited number of such uplink access channels, this access method has to solve this contention

WiMAX PHY/MAC protocol layers specify a certain time period within a physical header, called Maintenance Period, which is split into multiple so called Transmission Opportunities (TO). The TOs play a similar role, like the Random Access Channels in a GSM system. Any subscriber station may select one TO as a ranging interval to send Initial Ranging information to the base station.

If by chance two or more subscriber stations try to send at the same time using the same TO, a collision occurs and the subscriber stations have to resolve this in a statistical manner (which is achieved using random number controlled time delays)

The message type sent in a TO is the Initial Ranging Request message

Module 5 - Page 12




BS SS

RNG REQ Send Initial Ranging packet in contentionMode with CID = 0

MAPsSend MAP withInitial Maintenance-IEusing broadcast CID

Allocate Mgmt CIDs+ CID to multicastpolling, send RSP

RNG RES

Adjust Tx parametersstore CIDs

Network Entry Process: Initial Ranging [2/2]

The Initial Maintenance Messages have to be sent by the base station using broadcast addresses in order to be received by all new subscriber stations. Broadcast addresses are specific connection IDs

The Ranging Request messages sent by the subscriber stations contain Connection ID = 0.

With this connection address the base station cannot differentiate between all the subscriber stations trying to get network access at the same time. This ambiguity is resolved by each subscriber station, in that they identify themselves during this phase with the (unique) 48-bit MAC address

The base station can now answer to the Ranging Request message received with the Ranging Response, which contains the unique management CIDs for each subscriber station and the requested Initial Ranging parameters

Now the terminal can perform the exact parameter settings

Module 5 - Page 13




Radio Signal Propagation Delay [1/2]

Delay depends on distance between subscriber and base station

Distant subscriber has to transmit frames in advance thus ensuring reception at base station in time

Time length for the Transmission Opportunities has to be set in such a way that even the Initial Range Request of the remotest subscriber station will be received during the Transmission Opportunities length

Taking into consideration the remotest subscriber station propagation delay (using the Cell Radius parameter) the correct TO length should be:

TO = TO (initial) at UL basic rate + 2 x (Propagation delay)

Propagation delay limits the radius of a WiMAX cell. This is similar to GSM

Radio signal propagation may be significant depending on the distance from subscriber station to base station

Because physical frames have a well defined structure consisting of header and type of payload information, the proper decoding requires exact timing. A distant subscriber station has to transmit the physical frames in advance so that it arrives at the base station just in time

Time length for the Transmission Opportunities has to be set in such a way that even the Initial Range Requestof the remotest subscriber station will be received during the Transmission Opportunities length. If the subscriber station is too far away from the base station, the network entry process, i.e. the accessing of Transmission Opportunities, will not be successful because of the time delay due to wave propagation delay. For that reason it is required to define a Cell Radius in the base station which together with the up link basic rate defines the Transmission Opportunities length

Taking into consideration the remotest subscriber station propagation delay (using the Cell Radius parameter) the correct TO length should be:

TO = TO (initial) at up link basic rate + 2 times (Propagation delay)

Propagation delay limits the radius of a WIMAX cell. This is similar to GSM

Module 5 - Page 14




MAP

IRQ-Tx

BS

SS

PropagationDelay (Tx)

PropagationDelay (Rx)

IRQ-Rx

IRQ: Initial Ranging Request

Radio Signal Propagation Delay [2/2]

This animation shows the effect of radio signal delay during the initial ranging phase

The BS sends a MAP message arriving with a delay at the subscriber station. Now the subscriber station knows the MAP fields which contain Transmission Opportunity information

The subscriber station uses one Transmission Opportunity to transmit initial ranging request

This packet arrives, again with a delay, at the base station. If the delay lies within the transmission delay variation time, the BS can evaluate it and in return send physical-layer and MAC-Layer parameters

Module 5 - Page 15




Network Entry Process: Ranging Response

The BS answers the SS with a Range Response message which contains:

1. Propagation delay correction from now on after receiving the correction, each time that the SS will get a MAP with timing for its next transmission, the SS will adjust/correct its transmission time accordingly

2. Power correction

3. Frequency correction in case of frequency deviation(up to +/- 40 ppm or +/- 140 kHz)

4. Subscriber Station ID (SSID)

If needed RNG-REQ & RNG-RSP messages can be used multiple times

The Ranging Response message is sent by the base station as a response to Ranging Request from the subscriber station

The propagation delay value (in GSM it is called Timing Advance) is important to synchronize physical framing between base station and subscriber station

Depending on the distance from the base station and on the radio quality measured, the base station also has to adjust radio transmission power (ATPC)

Finally the physical air interface quality is very sensitive to the setting of the orthogonal sub-carrier frequencies. Frequency deviation may cause inter-carrier interference. Thus the base station can request the subscriber station to fine-tune the frequency within the range of +/- 40 ppm (Parts Per Million)

Finally the subscriber station receives from the base station a unique station ID, which is used for station identification purposes

A Subscriber station may repeat the ranging request procedure at any time if it detects a degradation of transmission quality which may be caused by incorrect setting of the initial ranging parameters

Module 5 - Page 16




High Speed Internet Access For several MBs / user service Through existing network architecture

Taking benefits of deployed services & charging features GGSN or SGSN for Mobile 3GPP & 3GPP2 DSLAM for ADSL

Direct internet access

Video & Audio Streaming based services

Voice Over IP through NGN & IMS implementation Based on SIP signaling plan For fix services (No SS terminating call, No paging, No mobility) Integration in Fix NGN, Alcatel 5020 CSC Integration in Mobile NGN, Alcatel 5020 Atrium

Main Services

All services provided by WMAN are IP based, which means they use as a layer 3 the Internet Protocol and internet based upper layers, like TCP or UDP as transport layers and e.g. HTTP, SIP, etc. as application layers

The main services addressed here relate to the use of bandwidth and to the characteristics of the service as to QoS, which includes parameters such as delay, error rates and effective bit rates

High Speed Internet Access

May require data rates of several MBs per user service

Is provided through existing network architecture in fixed and mobile networks

WIMAX may also offer direct internet access for wireless fixed broadband access

Real time or near-real time based services of audio and video streaming

Real time Voice Over IP through next generation network functionality

Based on SIP signaling plan

Provided for fixed services

Integrated in fixed network NGN architecture

Integrated in Mobile NGN architecture

WMAN base stations can be integrated into different existing network:

In fixed networks they can be attached to DSLAMs to provide ADSL bandwidthIn mobile networks they can be attached to GGSN

VoIP is the only speech service provided by WiMAX. That is why it can be integrated easily into next generation networks, which are based on IP transport technology. Other IP based services, which may be transported over WiMAX interfaces can be included in IP-based Multimedia Service concepts, which will be implemented in UMTS networks (of release 6)

Module 5 - Page 17




Unsolicited Grant (UGS)

For real time services like E1, VOIP (without silence suppression)

Fixed size data packets on a periodic basis

Service parameters: unsolicited grant size, normal grant interval, normal grant jitter

Real Time Variable Rate(RT-VR)

For real time services like MPEG video.

Variable bit rates.

Guaranteed rate and delay requirement.

Service parameters: committed burst, committed time

Delivery Services

Non Real Time Variable Rate (NRT-VR) Variable bit rate services.

Guaranteed rate required, guaranteed delay not required.

Service may expand to occupy full bandwidth rate limit required.

Service parameters: committed burst, committed time excess burst

Best Effort (BE) For service with no rate or delay

requirements.

The requested bandwidth always refers to one of the following service classes:

Real-time service: for connection oriented services

Streaming service: for encoded audio and video streams

Non real-time service variable bit rate service and

Best effort or background service

The service class preserving real-time transmission over the air interface as nearly as possible is the Continuous grant service. This class of service transports (nearly) synchronous packet streams e.g. VoIP without silence suppression and using a fixed encoder output packet size during a connection or the transport of other synchronous information such as E1 frames

Absolute synchronicity cannot be granted, packet streams show a little jitter

Real-time variable bit rate is created by MPEG encoders (MPEG video or audio) or VoIP with silence suppression

VoIP applications need to be monitored with appropriate Voice Quality Analysis (VQA) equipment in order to prove high voice quality and to optimize transmission parameters

Non real-time services often put an emphasis on low bit error rates instead on high data rates and low delay time

This means they may run in the background using low data rates but high data quality, such as e.g. slow file transfer or e-mail services

Module 5 - Page 18




Services High Speed Internet Access Voice Over IP Video Streaming

Main Features Fix and Mobility Nomadicity and Portability Quality of Service

Innovative RAN Architecture

For Broadband Wireless Services

WiMAX

Non Real Time

Real TimeVoice

Real TimeVideo

IP Based RAN

Alcatel WiMAX Solution Services and Architecture

If a subscriber station has access to the network it has received signalling connection IDs which are used to establish a user connection

Each user connection requests a quality of service specific to this connection

The services are generally grouped into real-time voice and video and non real-time applications

Real-time applications also comprise near real-time services like uni-directional or bi-directional streaming

Non real-time applications comprise the request-response type of applications, using TCP as IP transport layer which uses acknowledgement methods. These ACK-messages should not be delayed too much, as this reduces the performance of the TCP dynamic behaviour

Services which do not request fast responses (if any) are called background services, e.g. e-mail or slow file transfer

Module 6 - Page 1


(6) Technical Overview - WiMAX Mobility


(6) Technical OverviewWiMAX Mobility

Module 6

Technical OverviewWiMAX Mobility

Module 6 - Page 2




Multilayer IP Based Mobility Micro mobility

Macro mobility

Inter technologymobility

Simple MobilityService access

Across multiple BSNon-RT applications

Full MobilityAcross multiple BSAcross multiple RAN

RT applications

NomadicityService access

Across multiple BSNo handover

Usages Models

802.16e

AC

(proxy MIP)

WiMAX RAN

Micro mobility

Macro mobility

WiFi hot spots

Mobile RAN

BSCRNC

HA

Inter technology mobility

CorporateCorporateCorporateCorporate

IMSIMSIMSIMS

Internet Internet Internet Internet

AC

(proxy MIP)

Core Network802.16e

AC

(proxy MIP)

WiMAX RAN

Micro mobility

Macro mobility

WiFi hot spots

Mobile RAN

BSCRNCBSCRNC

HA

Inter technology mobility

CorporateCorporateCorporateCorporate

IMSIMSIMSIMS

Internet Internet Internet Internet

AC

(proxy MIP)

Core Network

Alcatel WiMAX Mobility Solutions

Alcatel provides a number of mobility solutions ranging from nomadicity up to full mobility. The difference between the three is the availability of continuous service while being connected with several base stations

The process in which an MSS migrates from the air-interface provided by one Base Station to the air-interface provided by another base station is called Handover

Two hand over variants are defined: Break-before-make and make before break

Break-before-make handover starts the service with the target base station after a disconnection of service with the previous serving base station

Make-before-break handover starts the service with the target base station before disconnection of the service with the previous serving base station

Nomadic services do not allow handovers between base stations. We call this micro-mobility because it is restricted to the area of one base station

Simple mobility is defined as follows: The user device can continue with an operating network data service session as it moves at vehicular speeds within the network coverage area. Handovers between cells, sectors, and base stations provide session continuity. Application performance during handover is guaranteed for all non real-time applications, but not guaranteed for real-time applications. Up to 60 km/h with no performance degradation, 60 to 120 km/h with client-friendly performance degradation

Full mobility is defined as: The user device can continue with an operating network data service session as it moves at vehicular speeds within the network coverage area. Handovers between cells, sectors, and base stations provide session continuity. Application performance during handover is guaranteed for all real-time and non-real-time applications. Up to 120 km/h with no performance degradation Handover latency is less than a few tenths of a millisecond

Module 6 - Page 3




IEEE 802.16e Standard specifies roles to the Base Stations

Serving Base StationBS with which the MSS has most recently completed registrationNeighbour Base StationBS whose downlink transmission can be demodulated by the MSS (other than the serving BS)Target Base StationBS that an MSS will be registered with at the end of a hand overAnchor Base StationBS which assigns resources to the MSS and which it will be connected to all the time

Base Station Roles

In a mobile network a base station may play different roles depending on the current movement of the subscriber station. Thus the BS role refers to one specific subscriber station. IEEE 802.16e Standard specifies roles of the Base Stations:

First of all a base station may be the serving base station. In this case all connections are established with this base station and data is sent to and transmitted from this base station

While being served by one base station the subscriber station may synchronize already to other base stations, which are called the neighbours

The one it approaches will be selected as the Target Base Station, because it provides the best radio signal quality

If we assume that the actual base station also manages the resources (QoS requests etc.) then the serving base station is also the Anchor Base Station

The introduction of an anchor base station role may be taken by other network elements, e.g. the WiMAX Access Controller

When the serving base station changes, the old base station still may be responsible for assignment of resources to the mobile subscriber station. In this case the old base station is the anchor base station and the anchor and serving roles are separated

The definition of base station roles requires communication between the bas stations over the core network

Module 6 - Page 4




Network Reference Model showing interfaces between Subscriber station/Mobile Subscriber Station, Radio Access Network Elements andRadio Access Network interconnection with the Core Service Network

Reference Configuration

SS/MS

SS/MS

BS

BS

ASN-GW(WAC)

R1 R8

R6R3

CSN

ASN-GW(WAC)

SS/MSS

BS

R8R4

R3R1

R6

This page shows the network reference configuration 802.16e network elements as defined by the WiMAX Forum

The Radio Access Network connects the clients equipped with Subscriber Stations (SS) or Mobile (Subscriber) Stations (MS or MSS) to a Core Services Network (CSN) via the Radio Access Network (RAN) Network Elements

Radio Access Network Elements are Base Stations and Access Service Network Gateway (ASN-GW)

In our Alcatel 9100 WiMAX solution, the Access Service Network Gateway is named WiMAX Access Controller (WAC)

The R1 interface is the air interface between subscriber system or mobile subscriber system and base station

The R3 interface is located between the Radio Access Network and the Core Services Network

The R6 interface is located between base station and Access Service Network Gateway

The R4 interface is located between Access Service Network Gateway

The R8 interface is located between base stations. It is not implemented in Alcatel devices

R1, R4 and R6 interfaces carry data and control messages

Control messages belong to user administration (entry, authentication, service flows establishment, mobility handling, etc.)

Control messages on R1 interface are standardized by the Institute of Electrical and Electronics Engineers

Control messages on the other interfaces are specified from the WiMAX forum

Alcatel is currently using proprietary control messages on R6 and R4 interfaces.

Module 6 - Page 5




SERVING+

ANCHOR

BaseStation

BaseStation

Provider Backbone

WAC

WAC: WiMAX Access Control Server

MSS: Mobile Subscriber StationMSS

TARGET

802.16e: MSS Connectivity

The BS broadcasts information about the network topology using special MAC messages. These messages provide channel information of neighbouring base stations. Availability of this information facilitates Mobile Subscriber Stations (MSS) synchronization with neighbouring BS

These messages also define a logical assignment of handover priorities or preferences as determined and set by the serving base station. These preferences can be:

normal neighbour

preferred neighbour and

non-preferred neighbour

With this information the serving BS can control the traffic distribution from one BS to the fo

WiMax Overview Alcatel

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