WiMAX Communication
INTERNET
BACKBONE
BWA Operator Network Backbone
By
Saeed Mohi
Adil Al-Shahrani
For
Dr. Landolsi, Mohamed
WiMAX
* WiMAX is a wireless digital communications system
* WiMAX can provide broadband wireless access
(BWA)
* IEEE 802.16, " Wireless Metropolitan Area Networks
(WMAN)“
* up to 30 miles (50 km) for fixed stations,
and 3 - 10 miles (5 - 15 km) for mobile stations.
* The word WiMAX stands for
Worldwide Interoperability for Microwave Access
Is WiMAX different from
Wi-Fi?
• WiMAX to Wi-Fi as Cellular to a Cordless Phone
– Provide the service for large distance
Cordless
•
•
•
•
•
Primarily consumer
License-exempt spectrum
Low cost
Mass market product
Low Power
* Higher power increases coverage area
Cellular
•
•
•
•
Carrier Class
Licensed spectrum
Higher Cost
High Power
WiMAX Standard
• The IEEE standard 802.16 (WiMAX)
– revised for 2-11GHz fixed (802.16.a-2004) and 2-6GHz portable
(802.16e) mobile wireless solutions.
• WiMax uses Orthogonal Frequency Division Multiplexing
(OFDM) for modulation in its physical layer, which bundles data over
narrowband carriers transmitted in parallel at different frequencies.
– OFDM makes WiMax scalable for a fluctuating user base, since the
spectrum can be dynamically reallocated (range: 1.25-20 MHz) with
variations in the number of subscribers.
• There are a number of challenges facing WiMax including:
– RF interference and attenuation
– Operator contention for infrastructure placement to maximize
performance and reach
– Government regulations, spectral licensing/usage management
– Concerns with WiMax base station market growth due to bias towards
voice networks (like GSM and UMTS)
WiMAX Standard
•
Orthogonal frequency-division multiplexing (OFDM), also sometimes called
discrete multitone modulation (DMT),
– complex modulation technique for transmission based upon the idea of
frequency-division multiplexing (FDM) where each frequency channel is
modulated with a simpler modulation. In OFDM the frequencies and modulation
of FDM are arranged to be orthogonal with each other which almost eliminates
the interference between channels
•
Orthogonal Frequency Division Multiple Access (OFDMA) is a multiple access
scheme for OFDM systems. It works by assigning a subset of subcarriers to
individual users.
•
OFDMA features
– OFDMA is the “multi-user” version of OFDM
– Each OFDMA user transmits symbols using sub-carriers that remain orthogonal
to those of other users
– More than one sub-carrier can be assigned to one user to support high rate
applications
– Allows simultaneous transmission from several users better spectral efficiency
– Multiuser interference is introduced if there is frequency synchronization error
– The term "OFDMA" is used in the mobility mode of IEEE 802.16 WirelessMAN
Air Interface standard, commonly referred to as WiMAX.
WiMAX Standard
• cellular 3G is voice-centric while WiMax is
data-centric.
• WiMax can achieve data rates up to
75Mbps for fixed stations
WiMax Standards
802.16
802.16a
802.162004
802.16e2005
Date
December
Completed 2001
Spectrum 10-66 GHz
January
June
December
2003
2004
2005
< 11 GHz < 11 GHz < 6 GHz
Operation
LOS
Non-LOS NonLOS
Bit Rate
32-134 Mbps Up to 75
Mbps
Up to 75
Mbps
Up to 15
Mbps
Cell
Radius
1-3 miles
3-5 miles
1-3 miles
3-5 miles
Non-LOS and
Mobile
802.16 Standards History
• First standard based on proprietary implementations of DOCSIS/HFC
architecture in wireless domain
802.16
(Dec 2001)
• Original fixed wireless broadband air Interface
for 10 – 66 GHz: Line-of-sight only, Point-toMulti-Point applications
802.16c
(2002)
802.16a
(Jan 2003)
802.16REVd
(802.16-2004)
(Oct 2004)
802.16e
(802.16-2005)
(Dec 2005)
• Extension for 2-11 GHz: Targeted for nonline-of-sight, Point-to-Multi-Point
applications like “last mile” broadband access
• Adds WiMAX System Profiles and Errata for
2-11 GHz
• MAC/PHY Enhancements to support
subscribers moving at vehicular speeds
WiMAX Standard
• The presence of two versions of WiMAX
• 802.16-2004 WiMAX only supports fixed access,
products are available.
• 802.16e WiMAX supports mobile and fixed
access but products are still.
• Vendors need to understand what demand there
is for these two technologies in order to refine
their product roadmaps and provide the service
IEEE 802.16 Specifications
•
•
•
802.16a
– use the licensed and
license-exempt
frequencies from 2 to
11Ghz
– Support Mesh-Network
802.16b
– Increase spectrum to 5
and 6GHz
– Provide QoS (for realtime voice and video
service)
802.16c
– Represents a 10 to 66GHz system profile
•
802.16d
– Improvement and fixes for 802.16a
•
802.16e
– Addresses on Mobile
– Enable high-speed signal handoffs necessary for communications with users moving
at vehicular speeds
What are they aiming for?
BROADBAND WIRELESS ACCESS
802.16/a
Backhaul
WiFi
802.16
LOS to fixed
outdoor
antenna
802.16e
WiMAX
NLOS to MSS
(laptop/PDA..)
Base Station
WiFi
Fixed
Wireless Access:
WiFi
802.16a
802.16a
NLOS to fixed
outdoor
antenna
to fixed
DSLNLOS
to homes
and business –
Indoor
antenna
MSS: Mobile Subscriber Station; LOS: Line of Sight; NLOS: Non Line of Sight
•
How WiMax Works
• WiMax can provide 2 forms of wireless service:
•
- Non-LOS where a small antenna on a computer connects to
the tower. Uses lower frequency range (2 to 11 GHz).
•
- LOS, where a fixed antenna points straight at the WiMax
tower from a rooftop or pole. The LOS connection is stronger and
more stable, so it is able to send a lot of data with fewer errors.
Uses higher frequencies, with ranges reaching a possible 66 GHz.
• Freq. increases, so Peak of fingers (multipaths) decreases
• Through stronger LOS antennas, WiMax transmitting stations
would send data to WiMax enabled computers or routers set up
within 30 (3,600 square miles of coverage) mile radius ~ 50 km.
WiMax is well suited to offer
both fixed and mobile access
EXAMPLE SEIMENS
SkyMAX – Forerunner in the WiMAX Arena
SkyMAX BaseStation
Future Proof Platform
Software upgradeable to
IEEE802.16e SOFDMA
(Scalable OFDM Access)
Flexible and Reliable
Channel Size Software Configurable
up to 14MHz
FDD and TDD Duplex scheme
Carrier-Grade redundancy
Siemens
SkyMAX Base
Station
Highest Range
Highest range, High Power
system
Subchanneling and RX
Diversity (in one ODU)
Scalable
High Scalability “Pay as you
grow”
Triple Play services with
guaranteed QoS
SkyMAX – Forerunner in the WiMAX Arena
Fixed BWA Reference Architecture
Data
SkyMAX
Residential CPE
Back-end
User DB
CRM
Billing
Server Farm
Public Internet
WIP
End User
Access Gateway
SkyMAX
Business CPE
IP “Managed”
Network
Voice Gateway
Voice
End Users
SkyMAX
Basestation
User Equipment
WiMAX (SkyMAX)
and
Radio Access:
Applications
BS and CPE
Video
Data
PSTN
GbE
Backhauling and
Integration in Back-end
(e.g user Authentication
charging/billing)
Core Network
WiMAX Network
802.16 Network Entry
• Scanning
– Scan for BS downlink channel
– Synchronize with BS
– Specifies channel parameters
• Ranging
– Set PHY parameters correctly
– Establish the primary management channel (for negotiation, authentication,
and key management)
• Registration
– Result in establishment of secondary management connection (for transfer
of standard based management messages such as DHCP, TFTP )
• Establishment of transport connection
– MAC provides service for upper layers
Worldwide WiMAX Trials
>150
802.16
Planned Carrier Trials
2005
2006
2007
Source: Intel estimates
4G Competitors
•
A generation is defined by the result of technology changes over a 10-15 year
time frame.
–
Thus, 4G would refer to whatever is deployed in the 2010-2015 period, assuming 3G
deployment spans the 2000-2009 period. Typically, this means a new air-interface with
higher data rates
•
Ideally, 4G would provide users with on demand high quality video and audio.
•
4G may use OFDM (Orthogonal Frequency Division Multiplexing), and also
OFDMA (Orthogonal Frequency Division Multiple Access) to better allocate
network resources to multiple users.
•
Unlike the 3G networks which are a jumble of circuit switched and packet
switched networks, 4G will be based on packet switching only. This will allow
low-latency data transmission.
•
According to a Visant Strategies study (quoted in Wireless Week on February 1st,
2006), there will be multiple competitors in this space (4G), and gave the following
projections:
•
•
•
•
WiMAX 7.2 - million units by 2010
TD-SCDMA 100 - million subscribers (in China) by 2010
Flash-OFDM 13 - million subscribers in 2010
UMTS FDD - Valued at $2 billion in 2010
Next Wireless
Fixed Mobile Convergence
Example:
• Korean will start the service by next year (WiBro)
Next Wireless
• wireless broadband will emerge as the mainstream
technology.
• Data traffic is growing more (10 times) compared to the
voice traffic
• Consequence, the past concept of telephone networks,
which also carry data might be replaced by the concept
of data networks that also carry voice.
• The cost for this service could be much lower than
current high-speed Internet-subscription fees because
the provider never had to run cables.
Thank you
• Questions??
News about WiMAX
www.wimaxforum.org