Wimax (802.16)A Road to Mobile Life SUBMITTED BY: PRATIK ANAND 354/09 7TH SEM. ECE
TOPICS Development of Wireless Communication Wi-MAX Introduction WiMAX Forum Technical specifications Network Architecture WiMAX Key Technology: OFDMA, TDD, MIMO Application Scenarios2
What is WiMAXWiMAX or “Worldwide Interoperability for Microwave Access” hadits origins in backhaul connectivity using microwave access suchas LMDS/MMDSWiMAX has become a “hot topic” in the wireless industry, withvisible and aggressive backing from INTEL, among othersWiMAX 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 5
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 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 requirements802.16d and 802.16e are two mainstream Um interface standards.
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 Mobility11
Access Service Network (ASN)The ASN consists of BS and ASN-GW. The ASN canaccess to multiple connectivity service networks(CSNs) and provide radio access service to the CSNof different network service providers (NSPs). TheASN manages the air interface of IEEE 802.16 andprovides radio access to the WiMAX subscribers.
Orthogonal Frequency Division Multiplexing (OFDM) is a multiplexingtechnique that subdivides the bandwidth into multiple frequency sub-carriers. In an OFDM system, the input data stream is divided into severalparallel sub-streams and each sub-stream is modulated and transmitted ona 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 datastreams from multiple users onto the downlink sub-channels and uplinkmultiple accesses by means of uplink sub-channels.
TDD Frame StructureThe 802.16e supports TDD operation; however the initial release of MobileWiMAX certification profiles will only include TDD. With ongoing releases,FDD profiles will be considered by the WiMAX Forum to address specificmarket opportunities where local spectrum regulatory requirements eitherprohibit TDD or are more suitable for FDD deployments. TDD is the preferredduplexing mode for the following reasons:TDD enables adjustment of the downlink/uplink ratio to efficiently supportasymmetric downlink/ uplink traffic, while with FDD, downlink and uplinkalways 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 singlechannel for both downlink and uplink providing greater flexibility foradaptation to varied global spectrum allocations.Transceiver designs for TDD implementations are less complex andtherefore less expensive.
Advanced Features of WiMAX TechnologyAdaptive 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.
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.