A study on IEEE 802.16e /Mobile WiMAX
Networks
Prepared For
:
Prepared by
:
Mohammad Mamun Elahi , Khorshed Alam ID 012112018
Assistant Professor, Asaduzzman ID 012112001
Department of Computer Science and Engineering Nasir Uddin ID 012 112 006
United International University Md.Shahariar kabir ID 012 112 012


Introduction

Motivation

Objectives and purposes of the study

Over View of Mobile WiMAX & Features

WiMAX & Other Broadband Wireless Technologies
 How WiMax Works
 WiMAX systems
 WiMAX MAC Layer
 WiMAX PHY Layer

WiMax Network Reference Model
 WiMAX Applications, Services & Deployment
 Conclusion

WiMAX is to promote deployment of broadband wireless access networks by using a global standard and certifying interoperability of products and technologies and to provide a cost effective wireless connection with high data rate and coverage which will be the best alternative to DSL,Wifi or cellular data services.

Mobile WiMAX is based on IEEE-802.16e specification and it is expected to deliver high quality wireless broadband service. Recently, wireless technologies research and trends hold the attentions of academicians, technology professionals and expert. Due to tremendous advancement of wireless technology researcher, academician has put significant effort and study on it. Hence, in this term paper has concentrated on IEEE 802.16e-2005 standard where aim to advanced study and discuss about Mobile WiMAX PHY, MAC layers, end to end Architecture .

The objectives of this term report is to study in dept about WiMAX technology. Hence , we emphasized on following aspect of this technology.
q Wireless broadband technology q WiMAX PHY and MAC layer q WiMAX Network reference model
& WiMAX Applications, Deployment

WIMAX stands for W orldwide I nteroperability for M icrowave
A ccess

WiMAX refers to broadband wireless networks that are based on the IEEE 802.16 industry standards.

WiMax is intended for wireless" metropolitan area network". wimax can provide broadband wireless access up to 30 miles for fixed station and 3-10 miles for mobile station. WiMax operates on both licensed and non-licensed frequencies providing a regulated environment and viable economic model for wireless carrier.

• OFDMA: The mobile WiMax air interface uses orthogonal frequency division multiple access.
• High data rates: WiMax technology support both peak downlink and uplink high data rates.
• Quality of service: The fundamental premise of WiMax medium access control (MAC) architecture.
• Scalability: The mobile WiMax technology utilize scalable
OFDMA(S-OFDMA) and has the capability to operate scalable bandwidths from 1.25 to 20 MHz .
• Security: The mobile WiMax incorporates the most advanced security features such as Extensible Authentication Protocol (EAP) ,
Advanced Encryption Standard (AES) , and cipher based authentication code(CMAC) .
• Mobility: The mobile WiMax supports optimized handover schemes with latencies less than 50 ms to ensure real time applications such as Voice over Internet Protocol. (VoIP)

• WiMax operates on the same general principles as WiFi -- it sends data from one computer to another via radio signals. A computer
(either a desktop or a laptop) equipped with WiMax would receive data from the WiMax transmitting station, probably using encrypted data keys to prevent unauthorized users from stealing access.
• A WiMax system consists of two parts:
A WiMax tower-A single WiMax tower can provide coverage to a very large area -- as big as 3,000 square miles (~8,000 square km).
A WiMax tower station can connect directly to the Internet using a high-bandwidth, wired connection. It can also connect to another
WiMax tower using a line-of-sight, microwave link
A WiMax receiver - The receiver and antenna could be a small box or PCMCIA card.

There are wireless technologies other than WiMAX, each has its Pros and Cons where the tradeoff is between MOBILITY and SPEED.

WiMAX Positioning:
Wireless Technology Comparison
WiMAX
Large
Coverage
Network
Simplicity
WiFi
Broad
Band
Full
Mobility
3G /HSDPA
Security QoS

Standard
HSPA+
WiMAX
LTE
Wi-Fi
UMTS W-CDMA
HSDPA+HSUPA
Comparison of wireless technologies
Family
3GPP
IEEE 802.16
UMTS/4GSM
802.11 (11n)
UMTS/3GSM
Radio Tech Downlink (Mbit/s) Uplink (Mbit/s
CDMA/FDD
MIMO
MIMO-SOFDMA
OFDMA/MIMO/SC-
FDMA
21
84
672
128 (in 20MHz bandwidth
FDD)
100 (in 20MHz bandwidth
FDD) Cat3
5.8
22
168
56 (in 20MHz bandwidth
FDD)
50 (in 20 MHz bandwidth
FDD) Cat3/4
150 (in 20MHz bandwidth
FDD) Cat4
75 (in 20 MHz bandwidth
FDD) Cat5
OFDM/MIMO
CDMA/FDD
CDMA/FDD/MIMO
300 (in 20MHz bandwidth
FDD) Cat5
300 (using 4x4 configuration in 20MHz bandwidth) or 600 (using 4x4 configuration in 40MHz bandwidth).
0.384
0.384
14.4
5.76

Mobile WiMax is based on the IEEE 802.16e standard for portable and mobile applications in NLOS environment.
However, Mobile WiMax systems also can provide fixed and nomadic access.
Mobile WiMax incorporates additional features crucial to mobile applications: handoff, flexible power management
(sleep mode and idle mode), channel bandwidth scalability (SOFDMA),and better NLOS performance and indoor penetration. Mobile WiMax is the technology that best meets the demand for personal broadband services.

A WiMax system consists of two parts:
WiMax MAC layer
WiMAX PHY layer

 Convergence sublayer
Handle the higher-layer protocols
 Common part sublayer
Channel access, connection establishment and maintenance, and QoS
 Security sublayer
-Authentication, secure key exchange, and
Encryption
-Privacy key management (PKM) for MAC layer security. PKM version 2 incorporates support for extensible authentication protocol (EAP).
Ethernet /IP
Protocol/ATM TDM
Voice,
Packeting /
Fragmentation/
QoS/ ARQ
Encryption

• Multiple access is achieved in OFDMA by assigning subsets of subcarriers to individual users
• 802.16e uses Scalable OFDMA to carry data, supporting channel bandwidths of between 1.25 MHz and 20 MHz, with up to 2048 sub-carriers.
• It supports adaptive modulation and coding, so that in conditions of good signal, a highly efficient 64 QAM coding scheme is used , whereas when the signal is poorer , a more robust BPSK coding mechanism is used.
• In intermediate conditions, 16 QAM and QPSK can also be employed. Other PHY features include support for Multiplein Multiple-out (MIMO) antennas in order to provide good NLOS (Non-line-of-sight) characteristics (or higher bandwidth) and Hybrid automatic repeat request (HARQ) for good error correction performance
Duplexing Scheme in WiMax :
WiMax implementations either on licensed or unlicensed bands most use TDD.
The reasons are TDD uses half of FDD spectrum and saving the bandwidth. And TDD system is preferable to handle asymmetric data.
Modulation
/Power
Control

•It is 802.16e uses scalable orthogonal frequency-division multiple access (SOFDMA).
Scalable channel bandwiths from 1.25 to 20
MHz.
•Also bring Multiple Antenna
Support through Multiple-input multiple-output communications (MIMO).
•This brings potential benefits in coverage:
– power consumption
– frequency re-use.
– Bandwidth efficiency.

NAP
Network Access Provider
Fig: end-to-end WiMAX architecture
NSP

• Private Networks
– Cellular backhaul
– Wireless service provider backhaul
– Education networks (university campus)
– Public safety (police, defense)
– Offshore communications (oil rigs)
• Public Networks
– Wireless service provider access network
– Rural connectivity
• Triple Play

• Appearance of VoIP made it possible for
Voice over WiMAX 
services
• Appearance of IPTV made it possible for
TV over WiMAX 
services
• Integrated network: Data, Voice and Video

• Connecting Wi-Fi hotspots with each other and to other parts of the Internet.
• Providing a wireless alternative to cable and DSL for last mile broadband access.
• Providing high-speed data and telecommunications services.
• Providing a diverse source of Internet connectivity as part of a business continuity plan.
• Providing nomadic connectivity.
WiFi enabled Device
802.11a/b/g

WiMAX winners
Banglalion Communications LTD
Authority/Agency: Bangladesh Telecommunication Regulatory
Commission (BTRC)
2.3GHz and 2.5GHz WiMAX
Banglalion obtained license to operate WiMAX in Bangladesh through an open bid process at a cost of about 31 million USD. Banglalion was the highest bidder in obtaining the access frequency in 2.5 GHz band, the license allows using WiMAX standard 802.16e.

•There are two versions:
– Indoor SU.
– Outdoor SU.
•Indoor units are comparable in size to a cable modem or DSL modem.
•Outdoor units are roughly the size of a laptop PC, and their installation is comparable to a residential satellite dish.
• There is an increasing focus on portable units including handsets and PC peripherals.
Outdoor subscriber unit nomadic, single-box WiMAX device
Indoor subscriber unit
Mobile devices
USB
Dongle

Example of System Components (Con’d)

• BTS
– Integrated 90-degree antenna
– 4 Sectors
– 11 dBi Gain
• Outdoor CPE
– Integrated multi-element 30-degree antenna
– Ethernet LAN
– 12 dBi Gain
• Indoor CPE
– Four integrated 90-degree antennas
– Switched directional antenna diversity
– Ethernet LAN
– 7 dBi Gain

Mobile WiMax is based on a very flexible and robust air interface. it is an excellent complement to other wireless technologies that are offer wider coverage and high throughput.
Mobile WiMax provides superior throughput and spectral efficiency compared to planned 3G CDMA-based enhancements, EVDO and HSPA.
Lessons Learned
Comprise various wireless technology, WiMAX Physical, MAC layer , end to end reference model and WiMAX applications, services & Deployment.
Future work simulate WiMAX System Performance and link-level simulation in any modeling platform such as Simulink, Network Simulator 2 (NS2), CoWare,
OPNET, OMNET++, and Qualnet. Further study can also be made for a more suitable and optimal propagation model and scheduler for WiMAX networks.

Next version of the mobile WiMAX standard to follow IEEE 802.16e
IEEE plans to published a draft of the next version of the mobile
WiMAX standard to follow IEEE 802.16e
IEEE Approved
The ITU accepted the IEEE’s proposal, designating 802.16m as IMT-
Advanced, 4G technologies. Systems based upon IEEE 802.16m have already been demonstrated to be capable of delivering peak throughputs in excess of 300 Mbps in a mere 20 MHz of spectrum.