Wimax (802.16)Wimax (802.16)

A Road to Mobile LifeA Road to Mobile Life

Development of Wireless Communication Wi-MAX Introduction WiMAX Forum Technical specifications Network Architecture WiMAX Key Technology: OFDMA, TDD, MIMO Application Scenarios

2

TOPICS

Sridhar Iyer IIT Bombay 6

Wireless networks Wireless PANs (Bluetooth –

IEEE 802.15) very low range wireless connection to printers

etc

Wireless LANs (WiFi – IEEE 802.11) 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-802.16)– Similar to cellular networks– traditional base station

infrastructure systems

Sridhar IyerIIT Bombay 7

Sridhar IyerIIT Bombay 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 802.16 standard

Sridhar IyerIIT Bombay 9

IEEE 802.16 standards 802.16.1 (10-66 GHz, line-of-sight, up to

134Mbit/s) 802.16.2 (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)

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 802.16 Broadband Wireless Access (BWA) standard, approved in January 2003, to provide operations in the <11GHz spectrum range

10

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.

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.

Introduction to IEEE 802.16 Series

SN Technical Field

802.16 10-66 GHz, fixed broadband wireless access system airstandard

802.16a 2-11 GHz fixed broadband wireless access system airstandard

802.16c Supplementary provisions about the compatibility of 10-66GHz 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 accesssystem air standard

802.16f Fixed broadband wireless access system air interface MIBrequirements

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.

WiMAX Vision: Broadband Everywhere

16

BWA Operator Network Backbone

INTERNETBACKBONE

Mobile Backhaul

3

RESIDENTIAL & SoHo DSL LEVEL SERVICE

1

802.16d

FRACTIONAL E1 for SMALL BUSINESS

E1+ LEVEL SERVICE ENTERPRISE

BACKHAUL for HOTSPOTS

2

802.16d

H

H

HH

H

H

H

H

H

WMAN Nomadic Coverage --> handoff from HOT SPOTS

4

= wide area coverage outside of Hot Spots

Mobility

5802.16e

17

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.

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).

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.

TDD Frame StructureThe 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.

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.

Advanced Features of WiMAX Technology

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.

Connectivity for SMBsWimax BackhaulNomadic BroadbandPrivate Networks

APPLICATIONS