1. Wimax (802.16)
A Road to Mobile Life

2. Nortel Corporate Presentation
TOPICS
Development of Wireless Communication
Wi-MAX Introduction
WiMAX Forum
Technical specifications
Network Architecture
WiMAX Key Technology: OFDMA, TDD, MIMO
Application Scenarios
© 2004 Nortel

6. Wireless networks Wireless PANs (Bluetooth – IEEE 802.15)
very low range
wireless connection to printers etc
Wireless LANs (WiFi – IEEE )
infrastructure as well as ad-hoc networks possible
home/office networking
Multihop Ad hoc Networks
useful when infrastructure not available, impractical, or expensive
military applications, emergencies
Wireless MANs (WiMAX )
Similar to cellular networks
traditional base station infrastructure systems
Sridhar Iyer
IIT Bombay

7. IIT Bombay
Sridhar Iyer

8. WiMAX
Goal: Provide high-speed Internet access to home and business subscribers, without wires.
Base stations (BS) and subscriber stations (SS)
Centralized access control to prevents collisions
Supports applications with different QoS requirements
WiMAX is a subset of IEEE standard
IIT Bombay
Sridhar Iyer

9. IEEE standards
(10-66 GHz, line-of-sight, up to 134Mbit/s)
(minimizing interference between coexisting WMANs)
802.16a (2-11 Ghz, Mesh, non-line-of-sight)
802.16b (5-6 Ghz)
802.16c (detailed system profiles)
P802.16e (Mobile Wireless MAN)
IIT Bombay
Sridhar Iyer

10. Nortel Corporate Presentation
What is WiMAX
WiMAX or “Worldwide Interoperability for Microwave Access”
WiMAX has become a “most famous topic” in the wireless industry
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 Broadband Wireless Access (BWA) standard, approved in January 2003, to provide operations in the <11GHz spectrum range
© 2004 Nortel

11. 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 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 d and IEEE e.

12. IEEE 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 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 a standard that defines the 2 GHz to 11 GHz NLOS fixed access system.  On October 1 of 2004, this group issues the d fixed access standard.
 In the end of 2005, this group issues the e standard. Now, the e Release3 has been issued.

13. Introduction to IEEE 802.16 SeriesSN
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 e are two mainstream Um interface standards.

16. WiMAX Vision: Broadband Everywhere
Nortel Corporate Presentation
WiMAX Vision: Broadband Everywhere
BWA Operator Network Backbone
INTERNET
BACKBONE
Mobile Backhaul 3
RESIDENTIAL & SoHo DSL LEVEL SERVICE 1
802.16d
FRACTIONAL E1 for SMALL BUSINESS
E1+ LEVEL SERVICE ENTERPRISE
BACKHAUL for HOTSPOTS 2 H
WMAN Nomadic Coverage --> handoff from HOT SPOTS 4
= wide area coverage outside of Hot Spots
Mobility 5
802.16e
© 2004 Nortel

17. Nortel Corporate Presentation

18. 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 and provides radio access to the WiMAX subscribers.

19. 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).

20. 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.

21. TDD Frame Structure
The e 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.

22. 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.

23. 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.

24. APPLICATIONS Connectivity for SMBs Wimax Backhaul Nomadic Broadband
Private Networks

25. THANK YOU