802.16 Overview 工研院電通所 M100 林咨銘 tmlin@itri.org.tw 2005/1/13
Outline Introduction 802.16 Working group WiMAX 802.16 Overview Comparison of IEEE standards Wi-Fi vs WiMAX Summary 2
Introduction Current IEEE wireless standard includes : 802.11 Wireless Local Area Network 802.15 Wireless Personal Area Network 802.16 Wireless Metropolitan Area Network 802.20 Wireless Wide Area Network WWAN >15 km 802.20 WMAN 6~9 km 74.7 Mbit/s in 20MHz 802.16 WLAN <100 m 11-54 Mbit/s 802.11a/b/g WPAN <10 m 802.15.1 (Bluetooth) 802.15.3 (UWB) 802.15.4 (ZigBee) 3
Introduction 802.20 Bandwidth Assumptions Bandwidth (MHz) Mobility Mobile (Vehicular) Pedestrian (Nomadic) WWAN 2G/2.5G(IMT-2000) Cellular cdma2000 1xEV-DO, cdma2000 1xEV-DV WCDMA HSDPA 802.16e 802.16a (WiMAX) 2G/2.5G 1xEV-DO, 1xEVDV, 802.20 HSDPA 802.16 Bluetooth UWB 1.25 1.25 5 20 79 x 1 MHz > 100 Fixed (Stationary) 802.15.1 (Bluetooth) 802.11 (WLAN) 802.15.3a (UWB) 0.1 1.0 3.1 10 100 Peak Data Rate per User (Mbits/second) Commercial Proposed 4 Source: International Telecommunications Union and WiMAX Forum
802.16 Working Group IEEE 802.16 standard completed in October 2001, and published on 8 April 2002 Offers an alternative access to backhaul networks Allow for extension of the WirelessMan networking protocols directly to the individual user Designed a set of air interfaces based on a common MAC protocol but with physical layer specifications dependent on the spectrums of use 5
Standard Evolution 802.16 (2001) Fixed Wireless Broadband 10-66 GHz 802.16c (2002) 802.16 Amendment System Profiles 10-66 GHz 802.16a (2003) 802.16-2004 (Jun. 2004) 802.16 Amendment Fixed Wireless Broadband 2-11 GHz 802.16-2004 Revision Combination of 802.16, 802.16c, and 802.16a 802.16e (expected 2005) 802.16 Amendment for Combined Fixed and Mobile Wireless Broadband From 2-6 GHz 6
802.16 Working Group PICS : Protocol Implementation Conformance Statement < 11 GHz 10... 66 GHz MAC PHY 802.16e Mobility Enhancements (scalability) SOFDMA 802.16a SCa OFDM-256 OFDMA-2048 802.16-2001 TDMA FDD/TDD Single Carrier 802.16c System Profiles 802.16-2004 (802.16REVd) NetMan Conformance Coexistence Source : Siemens, 2004 802.16f: MIB for 802.16-2004 802.16g: Mgmt. Plane Procedures and Services Conf.-01: PICS ProFo. Conf.-02: Test Suites Conf.-03: Radio Tests 802.16.2-2001 Coexistence 802.16.2-REVa 7
Network Architecture - PMP 8
Network Architecture - Mesh Mesh Topology 9
WiMAX World Interoperability for Microwave Access Principle Support IEEE 802.16 standard Propose and promote access profiles for the IEEE 802.16 standard Certify interoperability levels both in network and the cell Promote use of broadband wireless access overall 10
WiMAX Evolution Fixed Nomadic Portable Mobile Wireless DSL Hot Zone no handover (regulatory reasons) Hot Zone session continuity Mobility seamless handover WiMAX Profile#0 WiMAX Profile#1 (802.16-2004/802.16e) WiMAX Profile#2 (802.16-2004/802.16e/802.16g) 11 Source : Siemens, 2004
WLAN - Spectrum UNII ISM ISM 1 2 3 4 5 GHz ISM: Industrial, Scientific & Medical Band Unlicensed band UNII: Unlicensed National Information Infrastructure band Unlicensed band 12
WiMAX - Spectrum UNII International Licensed ISM US Licensed International Licensed Japan Licensed ISM 1 2 3 4 5 GHz 802.16a has both licensed and license-exempt options License 2.3(Korea), 2.5(U.S.), 3.5(various countries), 4.8 GHz(Japan) License-exempt 2.4, 5.X GHz (ISM) 13
802.16 Standard Overview Reference Model Convergence Sublayer (CS) Mapping external network data into MAC SDU Classifying external network SDU Associating to MAC connection ID Payload header suppression Common Part Sublayer (CPS) Core MAC functionality System access Bandwidth allocation Connection establishment Connection maintenance Security Sublayer Authentication Security key exchange Encryption PHY Multiple sections Each appropriate to a frequency range and application 14
802.16 Standard Overview Air Interface 15
802.16 Standard Overview Frame Structure - TDD TTG : Transmission Transition Gap RTG : Receive Transition Gap FCH : Frame Control Header DLFP: Downlink Frame Prefix DLFP DL-MAP,UL-MAP,DCD,UCD 16
802.16 Standard Overview MAC Layer Point-to-Multipoint or Mesh topologies Connection oriented Flows are distinguished by SFID and CID Network protocol are interfaced via Convergence layers Protocol independent core Support IPv4, IPv6, Ethernet and ATM Support for difficult user environment High bandwidth, hundreds of users per channel Continuous and burst traffic Very efficient use of spectrum Flexible QoS offerings Data is transmitted in variable length PDUs Fragmentation Packing Concatenation Subframe starting with a frame control section Indicate PHY transitions on the downlink, as well as bandwidth allocations, and burst profiles on the uplink Support multiple 802.16 PHY options 17
802.16 Standard Overview PHY Layer Modulation and coding scheme may be adjusted individually to each SS on a frame-by-frame basis Both TDD and FDD variants are defined Channel bandwidth various from 1.25~20 MHz The system uses a frame duration of 0.5, 1, 2,, 20 ms Variable block size and error correction capabilities Coding and Modulation are indicated in burst profiles Burst profiles is specified by the UIUC (Uplink Interval Usage Code) and DIUC (Downlink Interval Usage Code) in the UL-MAP and DL-MAP to access the radio The uplink subframe contains contention-based allocations for initial system access 18
802.16 Standard Overview Adaptive PHY 19
Network Entry and Initialization Scan for downlink channel DL-MAP DCD Register with BS REG-REQ REG-RSP Obtain uplink parameters UL-MAP UCD Establish IP connectivity Ranging & automatic adjustments RNG-REQ RNG-RSP UL-MAP Establish Time of Day Negotiate basic capabilities SBC-REQ SBC-RSP Transfer operational parameters TFTP-REQ TFTP-RSP SS authorization and key exchange PKM-REQ PKM-RSP Establish provisioned connections DSA-REQ DSA-RSP DSX-RVD Normal Operation 20
Scheduling types Unsolicited Grant Service (UGS) Real-time, periodic fixed size packets (e.g. T1 or VoIP without silence suppression) Restrictions on BW requests (Poll-Me bit) Slip Indicator (SI) Eliminates the overhead and latency of bandwidth requests Real-Time Polling Service (rtps) Real-time, periodic variable sizes packets (e.g MPEG or VoIP with silence suppression) BS issues periodic unicast polls. Cannot use contention requests, but piggybacking is ok. Non-Real-Time Polling Service (nrtps) Variable sized packets with loose delay requirements (e.g. FTP) BS issues unicast polls regularly (not necessarily periodic). Can also use contention requests and piggybacking. Best Effort Service Never polled individually Can use contention requests and piggybacking 21
Adaptive Antenna System Support Concentrating its radiation to individual SS and adapting the antenna pattern Increase spectral efficiency linearly with the number of antenna elements Reducing interference by steering nulls in the direction of co-channel interferers Bursts can be concurrently transmitted to spatially separated SSs Improvement range and system capacity 22
Comparison of IEEE standards IEEE Standard 802.11b 802.11g 802.11a 80216 802.16a 802.16e 802.20 Date ratified 1999/9 2003/6 1999/9 2001/12 2003/1 Half 2005 (expected) End 2005 (expected) Access type LAN MAN WAN Mobility support Portable Fixed Portable Pedestrian speed (<150 kph) Vehicular speed (<250 kph) Channel conditions NLOS LOS NLOS NLOS NLOS Max cell range 100m 50m 50m 2-5 km 7-10 km (max 50 km) 2-5 km Not decided Spectrum License-exempt Licensed and license-exempt Licensed Frequency band 2.4 GHz 2.4 GHz 5 GHz 10-66 GHz 2-11 GHz 2-6 GHz < 3.5 GHz Max data rate 11 Mbps 54 Mbps 54 Mbps 32-134 Mbps in 28 MHz Up to 75 Mbps in 20 MHz Up to 15 Mbps in 5 MHz > 4 Mbps (expected) Channel Bandwidth 20 MHz 20,25,28 MHz 1.25-20 MHz 1.25-20 MHz 1.25-40 MHz (expected) Spectrum efficiency (bps/hz) 0.55 2.7 2.7 4.8 3.75 ~3 >1 (expected) Modulation DSSS OFDM OFDM QPSK, 16QAM and 64QAM OFDM 256 carriers, plus QPSK, 16QAM, 64QAM and OFDMA 2048 carrier Not decided QoS 802.11e (not ratified) will introduce QoS functionality Yes Yes Product availability Current available 2H 2004, WIMAX certified 1H 2005 2006 (expected) Not know Mesh Mesh No Yes No No LOS = line-of-sight NLOS = non line-of-sight DSSS = direct sequence spread spectrum OFDM = orthogonal frequency division multiplexing 23
Wi-Fi vs WiMAX Why Wi-Fi is not the candidate of BWA Range Coverage over a wide area requires a huge amount of APs Extend the range limitation makes HW expensive QoS Current product do not build in QoS 802.11e only produce the prioritized traffic Security WEP is insufficient to protect authentication and data communication WPA is not yet widely used 24
Wi-Fi vs WiMAX Why WiMAX is the BWA solution? Standard-based solution Wide coverage range NLOS Cost Flexible bandwidth options World wide spectrum usage Flexible channel efficiency QoS Mesh support 25
Wi-Fi vs WiMAX WiMAX and Wi-Fi are designed to complement and strengthen each other Non Line of Sight Point to Multi-point Line of Sight BACKHAUL 802.16 Line of Sight BACKHAUL 802.16 802.16e 802.11 802.16a INTERNET BACKBONE 26
Summary 802.16 is born of some superior features High coverage High data rate Efficient bandwidth usage Some techniques are cooked to enhance the 802.16 systems Mobility is supported in the 802.16e AAS improve range and system capacity DFS (Dynamic Frequency Selection) reduce the interference in the license-exempt band 802.16 will play a critical role in recent years 27
References IEEE 802.16-2001 IEEE 802.16a TM - 2003 IEEE 802.16 TM 2004 WiMAX Forum - http://www.wimaxforum.org/ Seimens http://www.siemens-mobile.com/ WiMAX Technology Status & Standards Progress 28