WiMAX
What is WiMAX ??
Think about how you access the Internet
today….
3 options !!
• Broadband access
• Wi-Fi access
• Dial-up access
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 802.16 standard
defining wide area wireless data networking .
Typical Network Ranges
Wide Area Network
Metropolitan Area Network
WAN
IEEE 802.16e
IMT-2000(3G)
(Nationwide)
MAN
IEEE 802.16-2004
ETSI HiperMAN/WiMAX
(50 Km)
LAN
IEEE 802.11 (a,b,g)
(150 m)
Local Area Network
PAN
IEEE 802.15
Bluetooth
(10m)
Personal Area Network
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.
WiMAX
WiMAX
WiMAX
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.
Forms of Wireless Service
• NLOS (Non Line of Sight)
Wi-Fi sort of service
• LOS ( Line of Sight)
WiMAX
Fixed WiMAX
(IEEE 802.16-2004)
Ex: ETSI HiperMAN
Mobile WiMAX
(IEEE 802.16e)
Ex: WiBro
• Optimized for Fixed and
nomadic applications
in LOS and NLOS
environment
• Optimized for Portable and
mobile applications in NLOS
environment
• 10-66 GHz licensed
frequency bands (LOS)
• Licensed and licenseexempt sub 11 GHz bands
(LOS & NLOS)
• Sub 6 GHz bands
Central Office,
Network Management,
VOIP Server etc.
Customer Premise Equipment
Traffic
Aggregation
PtP Wireless
Backhaul
Wireless PMP Access
Base Station
IEEE 802.16
• Air Interface for Fixed Broadband Wireless Access System
MAC and PHY specifications for 10-66 GHZ (LOS)
• One PHY: Single Carrier
• Connection oriented, TDM/TDMA MAC, QOS, Privacy
IEEE 802.16 a
• Amendment to 802.16, 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 802.16d
• Combines both IEEE 802.16 and 802.16a
• Some modifications to the MAC and PHY
IEEE 802.16e
• Amendment to 802.16-2004
• MAC modifications for limited mobility
The different flavors of WiMAX
802.16 a
Fixed Outdoor
802.16 REVd
802.16 e
Fixed Outdoor
Limited Mobility
Applications
Applications
Applications
• E1/T1 service for
enterprises
• Backhaul for
Hotspots
• Limited residential
Broadband access
• Indoor Broadband access
for residential users
( High Speed Internet,
VoIP,…)
• “Portable” Broadband
access for consumers
CPE
CPE
CPE
• External box
connected to PC with
outside antenna
• External box connected
to PC with built-in antenna
• PC Card
• Always Best Connected
System for 802.16 WiMAX
A TYPICAL WiMAX AND WiLAN DEPLOYMENT
Non-line-of-sight,
Point-to-multipoint: 802.16a
Non-Line-of-sight, point-to-multipoint
Or point-to-point backhaul : 802.16a
802.11
Telco core network or
Private (fiber) network
Access Point
Internet Backbone
WiMAX Point-To-Point
backhaul
WiMAX PTP
backhaul
ISP PoP
Wi-Fi Hotspots
Point to
Multipoint
application
WiMAX point-to-multipoint
Wire line or Wireless
backhaul
WiMAX Base Station
Homes with outdoor/indoor
WiMAX receiver
ISP PoP
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
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.
Standard
Family
Primary
Use
Radio Tech
Downlink
(Mbps)
Uplink
(Mbps)
802.16 e
WiMAX
Mobile
Internet
MIMOSOFDMA
70
70
Quoted speeds only achievable at
very short ranges, more
practically 10 Mbps at 10 km.
HIPERMAN
HIPERMA
N
Mobile
Internet
OFDM
56.9
56.9
WiBro
WiBro
Mobile
Internet
OFDMA
50
50
iBurst802.
20
Mobile
Internet
HC-SDMA
UMTS W-CDMA HSDPA + HSUPA
UMTS/3G
SM
Mobile
Phone
CDMA/FD
D
.384
3.6
.384
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
UMTS/3G
SM
Mobile
Internet
CDMA/TD
D
16
16
Reported speeds according to
IPWireless using 16QAM
modulation similar to
HSDPA+HSUPA
LTE UMTS
UMTS/4G
SM
General 4G
OFDMA/M
IMO/SCFD
MA
HSOPA
>100
>50
CDMA
2000
Mobile
Phone
CDMA
0.144
CDMA
2000
Mobile
Internet
CDMA/FD
D
iBurst
!xRTT
EV-DO 1x Rev.0
EV-DO 1x Rev.A
EV-DO Rev.B
Mobile range (900 m)
64
64
3-12 km
Still in development
0.144
Obsoleted by EV-DO
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.
Relationship with other Wireless Technologies
3G
Mobile-Fi
Wi-Fi
WiMAX
Max. Speed
2 Mbps
16 Mbps
54 Mbps
100 Mbps
Coverage
Several Miles
Several Miles
300 feet
50 miles
Airwave
Licensed
Licensed
Unlicensed
Either
Advantages
Range,
Mobility
Speed,
Mobility
Speed, Price
Speed, Range
Disadvantages
Slow,
Expensive
High Price
Short Range
Interference
issues
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.
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.
What are the Advantages ?
• 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.
Advantages over Wi-Fi
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.
Future developments and IEEE 802.20
MBWA is a technology developed by IEEE 802.20. 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.