Brief Introduction of WiMAX Technology

Submitted to: Professors Shun Ping Chen

Prepared by: AKM Faisal Islam

Md Tamim Haider

Outline

What is WiMAX

WiMAX Applications

Traditional Ways to get Internet access

Goal of WiMAX

Available Wireless Technologies

Different Types of Data Networks

LOS and Near LOS Propagation

Licensed and Unlicensed Spectrum

Interoperability in a WiMAX network

WiMAX architecture

WiMAX Reference Network Model

Wi-Fi: The Predecessor of WiMAX

WiMAX Positioning

WiMAX Security

WiMAX RF Performance Indicator

Conclusion

Worldwide Interoperability for Microwave Access (WiMAX) is thecommon name associated to the IEEE 802.16a/REVd/estandards.

These standards are issued by the IEEE 802.16 subgroup thatoriginally covered the Wireless Local Loop technologies withradio spectrum from 10 to 66 GHz.

What is WiMAX?

Connecting Wi-Fi hotspots.

Providing Broadband Access.

Providing a wireless alternative to cable and DSL.

Providing high-speed mobile data and telecommunications services (4G).

Providing a diverse source of Internet connectivity as part of a business continuity plan.

Providing Nomadic connectivity.

WiMAX Applications

Traditional Ways to get Internet access

Internet Cloud

CableDSL

T1

Goal of WiMAX

• Provide high-speed Internet access to home and business subscribers, without wires.

• We need high speed Data, Video, Voice and Streaming media.

Available Wireless Technologies

Source: WiMAX, making ubiquitous high-speed data services a reality, White Paper, Alcatel.

Available Wireless Technologies

Different Types of Data Networks

WLAN WMAN WWAN

WPAN WBAN

Source: Understanding WiMAX and 3G for Portable/Mobile Broadband Wireless, Technical White Paper, Intel.

LOS and NLOS Propagation

• LOS and Near LOS Propagation

Line-of-Sight (LoS) and Near Line-of-Sight (NLoS) propagations may happen whenthe BS and the MS are deployed outdoor, above the average height of theenvironment. This may be the case of the deployment of a fixed WiMAX solution ina rural environment with the BS located on a high altitude point and the SSdeployed on the rooftop of the customer’s house. LOS requires the obstacle freepropagation. In that case, the propagation losses are proportional to the square ofthe distance between the BS and the SS.

• NLOS Propagation

NLOS (Non-Line-of-Sight) propagation occurs when the terminal is located indoorand/or at ground level. In this situation, there is in most cases no direct pathbetween the BS and the terminal, there is a high number of obstacles on the BS toMS path (buildings, trees, cars, etc.) and the receiver may receive several copies ofsignal that experienced several reflections/diffractions on different obstacles.

LOS and NLOS Propagation

Licensed and Unlicensed WiMAX Spectrum

As with any other spectrum based technology, successful WiMAX deployment willdepend largely on the availability and suitability of spectrum resources.

Licensed spectrum

Licensed spectrum offers that individual user an exclusive right to operate on aspecific frequency at a particular location or within a defined geographic area. 2.3,2.5, 3.3 & 3.5 GHz, are the most widely announced WiMAX frequency band.

Unlicensed spectrum

Unlicensed spectrum permits any user to access specific frequencies within therange of WiMAX spectrum. 5 GHz spectrum is the License-exempt bands. In thefuture, various bands between 5 GHz and 6 GHz can be used for unlicensedWiMAX, depending on the country involved. There must follow some rules.

Benefits of Licensed and Unlicensed Solutions

Licensed Solution License-Exempt Solution

Better QoS Fast Rollout

Better NLOS reception at low frequencies

Lower Costs

Higher barriers for entrance More worldwide options

WiMAX Standards: Spectrum Allocation Issues

2.5GHz , 2.3GHz and 3.5GHz are selected by WiMAX forum.

Most WiMAX licenses are on 2.5GHz or 2.3GHz.

Interoperability in a WiMAX network

Technology for wireless networks with interoperability developsthe concept of "communications anytime anywhere".

Within the WiMAX industry there is a strong commitment toensure full interoperability, both through certification and ad-hoctesting between vendors. It is important for network operators torealize how interoperability is established and what it covers sothat they understand how different products, solutions andapplications from different vendors can coexist in the same WiMAXnetwork. The WiMAX Forum Certification program verifiesinteroperability at the PHY and MAC layers.

WiMAX Architecture End-to-End Reference Model

2005-09-16 Page 23

SS/MS: the Subscriber Station/Mobile StationASN: Access Service NetworkBS: Base station, part of the ASNASN-GW: ASN Gateway, part of the ASNCSN: Connectivity Service NetworkHA: Home Agent, part of the CSNAAA: Authentication, Authorization & Accounting ServerNAP: Network Access ProviderNSP: Network Service Provider

The WiMAX network reference model consists of three components interconnected by standardizedinterfaces or reference points R1 to R5.

MS (Mobile Station) ASN (Access Service Network) CSN (Connectivity Service Network)

ASNCo-ordinates traffic across multiple Base Transceiver Stations (BTS)Supports security, Handoffs, Power control and Quality of Service (QoS)

CSNManages core network operations through Internet Protocol (IP) serversAuthorization, Authentication and Accounting (AAA) servicesVoice over Internet Protocol (VoIP)Public Switched Telephone Network (PSTN) gatewaysInterface to legacy core networks and other operators’ networks

WiMAX Architecture

WiMAX Reference Network Model

Interface Functionality

R1 Air interface

R2AAA, IP host configuration,

mobility management

R3AAA, policy enforcement,

mobility management

R4 Mobility management

R5 Internetworking, roaming

R6

IP tunnel management to

establish and release MS

connection

R8 Handoffs

Wi-Fi: The Predecessor of WiMAX

• Wi-Fi (Wireless Fidelity) is a set of technologies that are basedon the IEEE 802.11a,b, and g standards.

• Wi-Fi is considered to be one of the first widely deployed fixedbroadband wireless networks.

• As long as the users remain within 300 feet of the fixedwireless access point, they can maintain broadband wirelessconnectivity.

• Wi-Fi is working on a 2.4 GHz frequency spectrum.

Wi-Fi vs. WiMAX

• WiMAX eliminates the constraints of Wi-Fi.

• Mobility is limited in Wi-Fi. Users can able to be mobile for up to 300 feetand unlike Wi-Fi, WiMAX is intended to work outdoors over longdistances.

• Simplicity and ease of deployment given that it uses unlicensed radiospectrum which does not require regulatory approval. WiMAX is a morecomplex technology than Wi-Fi.

• WiMAX is not intended to replace Wi-Fi. Instead, the two technologiescomplement each other.

WiMAX vs. 3G

Cost

• Lower equipment cost for WiMAX due to certified products (compare with Wi-Fi)

• WiMAX require new infrastructure while HSPA rides on UMTS

Coverage

• Roughly the same coverage (average ~5 km)

Performance

• Roughly the same performance (average ~2 Mb/s per user)

Acceptance

• HSPA has a higher acceptance with mobile operator

2005-09-16 Page 28

User Data Rate

Residential SOHO Small

Business Medium

Business

Multi-tenant

Building Cellular

Backhaul

Large

Business

50 Mbps

20 Mbps

10 Mbps

2 Mbps

500 kbps

56 kbps

5 Mbps

128 kbps

3G / WLAN

Large HS

3G / WLAN

Small HS

WiMAX Positioning: Capacity and User type

WiMAX Positioning: Capacity and Mobility

Wireless Technology Positioning

Mobility / Range

Data rates

10 Mbps0.1

IEEE802.16d

1 100

IEEE802.16e

WLAN(IEEE 802.11x)

GSM

GPRS

DECT

Bluetooth

EDGE

Fix

ed

Walk

Veh

icle

Indoor

Pedestrian

High Speed

Vehicular

Rural

Personal Area

Vehicular

Urban

Fixed urban

Nomadic

WiMAX for wireless-DSL

with limited mobility

Flash-OFDM

UMTS

HSDPA

3G /HSDPA

WiFi

WiMAX

Large

Coverage

Network

Simplicity

Broad

Band

QoSFull

MobilitySecurity

WiMAX Positioning: Wireless Technology Comparison

High

Speed

WiMAX Positioning: The Trade Off Between Mobility & Bandwidth

Price Elasticity of BWA Market

Data Volume Usage

Market Price of 1GB

1 Dimensional Market:

Mobile Data 1 Dimensional Market:

Fixed Broadband

BWA = Selling on Bandwidth and Mobility (Roaming, Coverage, Hand over)

Tomorrow

Price GAP to be filled!

New market

Opportunity!

Some Applications

WiMAX Security Architecture

1. Security Associations

A context to maintain the security state relevant to a connectionbetween a base station (BS) and a subscriber station (SS).

2. Certificate Profile

The standard uses X.509v3 certificates to identify communicatingparties. The standard defines two certificate types: manufacturecertificates and subscriber station (SS) certificates.

3. PKM Authorization

PKM stands for Privacy and Key Management. The PKMauthorization protocol is used to distribute an authorization token orkey to an authorized SS. Correct use of the AK demonstratesauthorization to access the network.

4. Privacy and key management

It is the protocol to rekey the SA. Once authorized to the network, the SS can now establish a data SA between it and the BS, for that it again uses the PKM protocol.

5. Encryption

In 802.16d 802.16e e standard supports DES-CBC and AESencryption protocol to secure the data stream.

WiMAX Security Architecture

WiMAX Performance Indicator

To evaluate and optimize the performance of WiMAX systems two parameter is used.

• RSSI (Received Signal Strength Indicator)

• CINR (Carrier-to-Interference-and-Noise Ratio)

Cluster CINR distributionnCluster RSSI distributionn

Cost of Mobile Systems

Note: cost = PV(CAPEX) + PV(OPEX)