1. WiMAX
By:
Ankit Rakha
MSE, CS
JHU-'07

2. What is WiMAX ??

3. Think about how you access the Internet today….

4. 3 options !!

5. Broadband access
Wi-Fi access
Dial-up access

6. WiMAX or Worldwide Interoperability of Microwave Access, is a wireless Internet service designed to cover wide geographical areas serving large number of users at low cost.
WiMAX is the synonym given to the IEEE standard defining wide area wireless data networking .

7. Typical Network Ranges
WAN
IEEE e
IMT-2000(3G)
(Nationwide)
Wide Area Network
MAN
IEEE
ETSI HiperMAN/WiMAX
(50 Km)
Metropolitan Area Network
LAN
IEEE (a,b,g)
(150 m)
Local Area Network
PAN
IEEE
Bluetooth
(10m)
Personal Area Network

8. A WiMAX system consists of two parts :
A Transmitter
A single WiMAX tower can provide coverage to a very large area – as big as 3,000 sq. miles
A Receiver
The receiver and antenna could be a small box or PCMCIA card or they could built into a laptop as the way Wi-Fi access is today.

9. WiMAX
WiMAX
WiMAX

10. HOW DOES IT WORK ?
WiMAX uses microwave radio technology to connect computers to the internet in place of wired connections such as DSL or cable modems.
It works very much like cell phone technology in that reasonable proximity to a base station is required to establish a data link to the Internet.
Users within 3 to 5 miles of the base station will be able to establish a link using NLOS technology with data rates as high as 75 Mbps.
Users up to 30 miles away from the base staion with an antenna mounted for LOS to the base station will be able to connect at data rates approaching 280 Mbps.

11. Forms of Wireless Service NLOS (Non Line of Sight)
Wi-Fi sort of service
LOS ( Line of Sight)

12. WiMAX Fixed WiMAX (IEEE 802.16-2004) Ex: ETSI HiperMAN
Optimized for Fixed and nomadic applications
in LOS and NLOS environment
10-66 GHz licensed frequency bands (LOS)
Licensed and license-exempt sub 11 GHz bands (LOS & NLOS)
Mobile WiMAX
(IEEE e)
Ex: WiBro
Optimized for Portable and mobile applications in NLOS environment
Sub 6 GHz bands

13. Customer Premise Equipment
Central Office,
Network Management,
VOIP Server etc.
Customer Premise Equipment
Traffic
Aggregation
PtP Wireless
Backhaul
Wireless PMP Access
Base Station

14. Air Interface for Fixed Broadband Wireless Access System
IEEE
Air Interface for Fixed Broadband Wireless Access System
MAC and PHY specifications for GHZ (LOS)
One PHY: Single Carrier
Connection oriented, TDM/TDMA MAC, QOS, Privacy
IEEE a
Amendment to , MAC Modifications and additional PHY Specifications for 2-11 Ghz (NLOS)
Three PHYs: OFDM, OFDMA, Single Carrier
Additional MAC functions: OFDM and OFDMA PHY support, Mesh topology support, ARQ
IEEE d
Combines both IEEE and a
Some modifications to the MAC and PHY
IEEE e
Amendment to
MAC modifications for limited mobility

15. The different flavors of WiMAX
REVd e
Fixed Outdoor
Applications
Indoor Broadband access for residential users
( High Speed Internet, VoIP,…)
CPE
External box connected to PC with built-in antenna
Limited Mobility
Applications
“Portable” Broadband access for consumers
Always Best Connected
CPE
PC Card
Fixed Outdoor
Applications
E1/T1 service for enterprises
Backhaul for Hotspots
Limited residential Broadband access
CPE
External box connected to PC with outside antenna

17. System for WiMAX

18. A TYPICAL WiMAX AND WiLAN DEPLOYMENT
Non-Line-of-sight, point-to-multipoint
Or point-to-point backhaul : a
Non-line-of-sight,
Point-to-multipoint: a
802.11
Telco core network or
Private (fiber) network
Internet Backbone
Access Point

19. WiMAX Point-To-Point backhaul
WiMAX PTP
backhaul
ISP PoP
Wi-Fi Hotspots

20. Point to Multipoint application
WiMAX point-to-multipoint
Wire line or Wireless
backhaul
ISP PoP
WiMAX Base Station
Homes with outdoor/indoor
WiMAX receiver

21. WiMAX as the backbone of meshed networks
WiMAX may enjoy a complementary relationship with Wi-Fi due to differences in the
reach of each of the networks . WiMAX connections can be used to provide backhaul
connections to Wi-Fi hotspots over longer distances. WiMAX could also play a key
role in connecting Wi-Fi hotspots in a mesh-type network to quickly increase
coverage and capacity.
Wi-Fi
WiMAX

23. Factors affecting WiMAX performance (throughput and range)
Frequency Band on which it is operating
Channel Bandwidth
Duplexing Scheme (TDD or FDD)
Modulation (BPSK, QPSK, 16-QAM or 64-QAM) and Code Rate
Antenna Types
Whether LOS or NLOS
Transmit Power
Receiver Sensitivity
The no. of users per base station sector.

25. Standard
Family
Primary Use
Radio Tech
Downlink (Mbps)
Uplink (Mbps) e
WiMAX
Mobile Internet
MIMO-SOFDMA 70
Quoted speeds only achievable at very short ranges, more practically 10 Mbps at 10 km.
HIPERMAN
OFDM
56.9
WiBro
OFDMA 50
Mobile range (900 m)
iBurst
iBurst802.20
HC-SDMA 64
3-12 km
UMTS W-CDMA HSDPA + HSUPA
UMTS/3GSM
Mobile Phone
CDMA/FDD
.384
3.6
5.76
HSDPA downlink widely deployed. Roadmap shows HSDPA up to 28.8 Mbps downstream in the future. Currently, users can expect typical download speeds of 1-2 Mbps but around 200 kbps uplink speeds.
UMTS-TDD
CDMA/TDD 16
Reported speeds according to IPWireless using 16QAM modulation similar to HSDPA+HSUPA
LTE UMTS
UMTS/4GSM
General 4G
OFDMA/MIMO/SCFDMA HSOPA
>100
>50
Still in development
!xRTT
CDMA 2000
CDMA
0.144
Obsoleted by EV-DO
EV-DO 1x Rev.0
EV-DO 1x Rev.A
EV-DO Rev.B
2.45
3.1
4.9xN
0.15
1.8
1.8xN
Rev B note: N is the number of 1.25 MHz chunks of spectrum used . Not yet deployed.

26. Relationship with other Wireless Technologies
Mobile-Fi
Wi-Fi
WiMAX
Max. Speed
2 Mbps
16 Mbps
54 Mbps
100 Mbps
Coverage
Several Miles
300 feet
50 miles
Airwave
Licensed
Unlicensed
Either
Advantages
Range, Mobility
Speed, Mobility
Speed, Price
Speed, Range
Disadvantages
Slow, Expensive
High Price
Short Range
Interference issues

27. Security Issue
Every WiMAX traffic is encrypted using DES (Data Encryption Standard) or
AES (Advanced Encryption Standard) for securing its transmission over the air.
The encryption keys are distributed from the BS to the SSs using PKM ( Privacy Key Management) protocol to ensure that only authorized SSs can receive the keys.
Every WiMAX user device is authenticated using a digital certificate or SIM ( Subscriber Identity Module).
This way, WiMAX keeps user traffic from eavesdropping and protects operator or service provider from becoming a victim of bandwidth theft by unauthorized users.

28. 5) Providing Nomadic connectivity.
USES
1) Connecting Wi-Fi hotspots with each other and to other parts of the internet.
2) Providing a wireless alternative to cable and DSL for last km broadband access.
3) Providing a high-speed mobile data and telecommunications services (4G).
4) Providing a diverse source of Internet connectivity as a part of business continuity plan.
5) Providing Nomadic connectivity.

29. What are the Advantages ? What are the disadvantages ?
A Single WiMAX main Station can serve hundreds of users.
Endpoints install within days instead of the weeks required for wired
connections.
Data rates as high as 280 Mbps and distances of 30 miles are possible.
Users can operate mobile within 3-5 miles of a base station at
data rates up to 75 Mbps.
No FCC radio licensing is required.
Less expensive than DSL or coaxial cable.
What are the disadvantages ?
Line-of-Sight is required for long distance (5-30 mile) connections.
Heavy rains can disrupt the service.
Other wireless electronics in the vicinity can interfere with the WiMAX
connection and cause a reduction in data throughput or even a total disconnect.

30. Advantages over Wi-Fi Analysis
The WiMAX specification provides symmetrical bandwidth over many kilometers
and range with stronger encryption and typically less interference. Wi-Fi is short
range has WEP or WPA encryption and suffers from interference as in
metropolitan areas there are many users.
The fastest Wi-Fi connection can transmit up to 54 Megabits per second under optimal conditions. WiMAX can handle up to 70 Megabits per second.
The biggest difference isn’t speed; its distance. WiMAX outdistances Wi-Fi by miles.
Analysis
WiMAX is not competing other, it is wireless cable replacement technology, which
competes with wired operators.

31. Future developments and IEEE 802.20
MBWA is a technology developed by IEEE It is the future technology
standard for true wireless broadband or 4G and so far iBurst is the only
pre-selected solution with over a dozen commercial deployments worldwide.