WiMAX (802.16) is a wireless technology that provides broadband connectivity using the IEEE 802.16 standards. It was developed to provide "last mile" broadband access using wireless technology. Key features of WiMAX include the use of OFDMA, TDD, and MIMO to provide broadband speeds over long distances. It has applications for small business connectivity, wireless backhaul, nomadic broadband access, and private networks.

1. Wimax (802.16)
A Road to Mobile Life
SUBMITTED BY:
PRATIK ANAND
354/09
7TH SEM.
ECE

2. TOPICS
Development of Wireless Communication
Wi-MAX Introduction
WiMAX Forum
Technical specifications
Network Architecture
WiMAX Key Technology: OFDMA, TDD, MIMO
Application Scenarios
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5. What is WiMAX
WiMAX or “Worldwide Interoperability for Microwave Access” had
its origins in backhaul connectivity using microwave access such
as LMDS/MMDS
WiMAX has become a “hot topic” in the wireless industry, with
visible and aggressive backing from INTEL, among others
WiMAX is designed to provide “last-mile” or “backhaul”
connectivity using wireless
“Last-mile” refers to a wireless connection from a major trunk
line to a business or residential user
Using IEEE 802.16 Broadband Wireless Access (BWA)
standard, approved in January 2003, to provide operations in
the <11GHz spectrum range
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6. WiMAX Forum
 In April of 2001, the WiMAX forum is set up. This forum participates in
authenticating the standardization and interoperability of the broadband
radio access products based on IEEE 802.16 and ETSI HiperMAN.
 This forum is organized by many radio communication equipment suppliers,
component suppliers, operators, which is a nonprofit organization.
 In November of 2004, the Network Working Group (NWG) is set up, which
participates in setting downing the network standards for the IEEE 802.16d
and IEEE 802.16e.

7. IEEE 802.16 Working Group
 In 1999, the IEEE working group is set up, which studies the
broadband radio access technology standard. The aim of this group is
IEEE 802.16 Working Group
to establish a global broadband radio access standard.
 This group sets down the broadband access system standards,
including the air interface standards and associated standards.
 At the beginning of 2003, this group issues the 802.16a standard that
defines the 2 GHz to 11 GHz NLOS fixed access system.
 On October 1 of 2004, this group issues the 802.16d fixed access
standard.
 In the end of 2005, this group issues the 802.16e standard. Now, the
802.16e Release3 has been issued.

8. Introduction to IEEE 802.16 Series
SN Technical Field
802.16 10-66 GHz, fixed broadband wireless access system air
standard
802.16a 2-11 GHz fixed broadband wireless access system air
standard
802.16c Supplementary provisions about the compatibility of 10-66
GHz fixed broadband wireless access system
802.16d 2-11 GHz fixed wireless access system air standard
802.16e 2-11 GHz fixed and mobile broadband wireless access
system air standard
802.16f Fixed broadband wireless access system air interface MIB
requirements
802.16g Fixed and mobile broadband wireless access system air
interface management plane flow and service requirements
802.16d and 802.16e are two mainstream Um interface standards.

11. WiMAX Vision: Broadband Everywhere
3 1
2
FRACTIONAL E1 for RESIDENTIAL & SoHo
SMALL BUSINESS BACKHAUL for DSL LEVEL SERVICE
HOTSPOTS
Mobile
Backhaul 4
WMAN Nomadic Coverage -->
E1+ LEVEL SERVICE 802.16d 802.16d handoff from HOT SPOTS
ENTERPRISE H
H H
H H
H
H H
802.16e H
5 = wide area coverage
outside of Hot Spots
INTERNET
BACKBONE
BWA Operator Network
Backbone Mobility
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12. 12

13. Access Service Network (ASN)
The ASN consists of BS and ASN-GW. The ASN can
access to multiple connectivity service networks
(CSNs) and provide radio access service to the CSN
of different network service providers (NSPs). The
ASN manages the air interface of IEEE 802.16 and
provides radio access to the WiMAX subscribers.

14. Orthogonal Frequency Division Multiplexing (OFDM) is a multiplexing
technique that subdivides the bandwidth into multiple frequency sub-
carriers. In an OFDM system, the input data stream is divided into several
parallel sub-streams and each sub-stream is modulated and transmitted on
a separate orthogonal sub-carrier. It enables a large number of sub-carriers
(up to 2048).

15. Orthogonal Frequency Division Multiple Access (OFDMA) is a multiple-
access/multiplexing scheme that provides multiplexing operation of data
streams from multiple users onto the downlink sub-channels and uplink
multiple accesses by means of uplink sub-channels.

16. TDD Frame Structure
The 802.16e supports TDD operation; however the initial release of Mobile
WiMAX certification profiles will only include TDD. With ongoing releases,
FDD profiles will be considered by the WiMAX Forum to address specific
market opportunities where local spectrum regulatory requirements either
prohibit TDD or are more suitable for FDD deployments. TDD is the preferred
duplexing mode for the following reasons:
TDD enables adjustment of the downlink/uplink ratio to efficiently support
asymmetric downlink/ uplink traffic, while with FDD, downlink and uplink
always have fixed and generally, equal DL and UL bandwidths.
TDD assures channel reciprocity for better support of link adaptation,
MIMO and other closed loop advanced antenna technologies.
Unlike FDD, which requires a pair of channels, TDD only requires a single
channel for both downlink and uplink providing greater flexibility for
adaptation to varied global spectrum allocations.
Transceiver designs for TDD implementations are less complex and
therefore less expensive.

17. Advanced Features of WiMAX Technology
Adaptive Modulation and Coding (AMC): Support for QPSK,16QAM &
64QAM are mandatory in the DL with Mobile WiMAX.
Hybrid Automatic Repeat Request (HARQ): supported by Mobile WiMAX.
HARQ is enabled using “Stop and Wait” protocol which provides fast
response to packet errors and improves cell edge coverage. A dedicated
ACK channel is provided in the uplink for HARQ ACK/NACK signaling.

18. MIMO: Smart antenna technologies typically involve complex vector
or matrix operations on signals due to multiple antennas. OFDMA
allows smart antenna operations to be performed. OFDMA is very
well-suited to support smart antenna technologies. In fact, MIMO-
OFDM/OFDMA has evolved as the corner-stone for next generation
broadband communication systems.

19. APPLICATIONS
 Connectivity for SMBs
 Wimax Backhaul
 Nomadic Broadband
 Private Networks