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WiMAX Revolution: Broadband Wireless Access Basics

Discover the IEEE 802.16/WiMAX standard and its impact on broadband services, backhaul, and private networks. Learn about its history, key features, deployment scenarios, and sources for more information.

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WiMAX Revolution: Broadband Wireless Access Basics

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  1. Broadband Wireless Access:A Brief Introduction to IEEE 802.16 and WiMAX Prof. Dave Michelson davem@ece.ubc.ca UBC Radio Science Lab

  2. Introduction • The IEEE 802.16/WiMAX standard promises to revolutionize wireless delivery of broadband services: • an alternative to DSL and cable modems • backhaul for access points and base stations • long-range connections for private networks • With standards, development, and certification well-advanced, the next major challenge is deployment. • Now is a good time for wireless professionals to become familiar with WiMAX wireless technology

  3. Introduction - 2 • What is IEEE 802.16/WiMAX? • a wide area alternative to IEEE 802.11/WiFi? • a threat to cellular telephony (voice and data)? • a method for breaking wireline monopolies? • a method for providing backhaul to IEEE 802.11/WiFi access points? • a single standard or a family of standards? • a universal solution for broadband wireless access?

  4. Introduction - 3 • How is IEEE 802.16/WiMAX different from (or better than) other wide area wireless standards? • use of OFDM with provision for OFDMA and MIMO? • support for a wide range of channel bandwidths (and, as a result, performance levels)? • implementation of differentiated QoS? • support for multiple usage models? • use of system profiles to manage design options?

  5. Objective This presentation introduces IEEE 802.16/WiMAX by: • Briefly reviewing its history • Summarizing its key features (and the key players) • Reviewing alternative use cases and deployment scenarios • Suggesting sources of additional information

  6. 1. A Brief History of IEEE 802.16/WiMAX • In the mid-1990’s, various groups began to promote “last-mile” fixed wireless access solutions. • Multiple goals: • Provide the capacity and reliability of wireline but with the flexibility and ease of deployment of wireless • Provide a versatile system for corporate or institutional backhaul/distribution networks • Break the monopolies of incumbent carriers

  7. A Brief History of IEEE 802.16/WiMAX - 2 Interest soon focused in two approaches. • LMDS (in Canada, LMCS) • operates in mm-wave spectrum under LoS conditions • uses conventional QAM modulation with ATM-derived upper layers to provide high speed service • MMDS (and other nearby bands) • operates near 2 GHz, usually under LoS conditions • may use any of various PHY, MAC, and NET layers

  8. A Brief History of IEEE 802.16 and WiMAX - 3 • High costs, lack of standards and fear of vendor lock-in drove off potential LMDS customers. • In 1999, IEEE 802.16 was formed to address these issues by developing open standards for LMDS. • In 2001, the IEEE 802.16 standard for BWA systems operating in the 10-66 GHz range was released! • Since then, however, interest has shifted to a new version of the IEEE 802.16 standard for BWA systems operating in the range 2-11 GHz

  9. A Brief History of IEEE 802.16 and WiMAX - 4 • Early BWA concepts were based on early WLAN technology and had limited capability. • In the mid-1990’s, AT&T developed a proprietary “last-mile” access solution (Project Angel) that: • operated near 2 GHz under either LoS or NLoS conditions • used OFDM and other advanced concepts • delivered high capacity, throughput, and QoS.

  10. A Brief History of IEEE 802.16 and WiMAX - 5 • By the late 1990’s, many other manufacturers began to pursue development of similar products. • In response, IEEE 802.16 formed a subgroup to extend the LMDS standard to the range 2-11 GHz. • Our work at AT&T led to the propagation and channel models adopted by IEEE 802.16. • IEEE 802.16a was published in 2003. • IEEE 802.16a/b/c and various updates were incorporated into IEEE 802.16-2004.

  11. A Brief History of IEEE 802.16 and WiMAX - 6 • IEEE 802.16e seeks to provide the additional features required to serve mobility users. • Use of Scalable OFDMA, MIMO, etc. permits 63 Mbps DL and 28 Mbps UL in a 10 MHz channel. • Optimized handover ensures latency < 50 ms. • Flexible key management ensures security. • South Korea’s WiBro is based upon IEEE 802.16e. • IEEE 802.16e was ratified in December 2005

  12. A Brief History of IEEE 802.16 and WiMAX - 7 • IEEE 802.16’s approach is being used by many other groups including IEEE 802.20, 802.22, 3GPP - LT • For example, IEEE 802.20 (Mobile Broadband Wireless Access) was established on 11 Dec 2002. • Aim – specify an air interface designed for IP-based services operating in bands below 3.5 GHz with peak data rates of over 1 Mbit/s. • A draft IEEE 802.20 specification was balloted and approved on 18 Jan 2006.

  13. A Brief History of IEEE 802.16 and WiMAX - 8 • In 2001, the WiMAX Forum was formed to address issues beyond standards development, e.g., • marketing and promotion • development of system profiles • development of certification procedures • government lobbying • In January 2005, the WiMAX Forum selected Cetecom Spain as its official certification laboratory.

  14. A Brief History of IEEE 802.16 and WiMAX - 9 • Many pre-WiMAX and WiMAX networks have been trialed and deployed in recent months. • Pre-WiMAX has several meanings: • compliant but not yet certified • compliance is possible after a firmware upgrade • mostly compliant, but not completely

  15. A Brief History of IEEE 802.16 and WiMAX - 10 The WiMAX Value Chain • IEEE 802.16 – Standards Working Group • WiMAX forum – Industry Advocacy Group • Chip Vendors • Equipment Vendors • System Integrators/VARs • Carriers/Service Providers • End Users • Certification Labs • Consultants • Information Providers

  16. 2. Key Features of WiMAX • Major goal of IEEE 802.16 (2-11 GHz): provide a “universal” solution for broadband wireless access • point-to-multipoint, LoS or NLoS • ranges of “several” km; urban, suburban, rural • Problem: Can one size really fit all? Different applications have different requirements and constraints for spectrum and performance! • Solution: Allow choice of options within a consistent framework. Offer a limited set of standard profiles.

  17. Key Features of WiMAX - 2 • Operating Frequency: 2 – 11 GHz*** • Allocations: Licenced and Unlicenced** • Channel Bandwidth: 1.25 – 20 MHz • Modulation: Single carrier*, 256 OFDM, 2048 OFDMA • BPSK*, QPSK, 16-QAM, 64-QAM, 256-QAM* • Antenna system support: Diversity, MIMO, SDMA • Duplexing: FDD, H-FDD, TDD** • Data Rates: From T1 (1.5 MB/s) to over 70 Mb/s

  18. Key Features of WiMAX - 3 • WiMAX supports flexible frequency allocation and use of system profiles

  19. Key Features of WiMAX - 4 BPSK, QPSK, 16QAM, 64QAM 52 carriers,312.5 kHzspacing 4 BPSK Pilots 802.11a (18 MHz) 200 carriers,90 kHzspacing BPSK, QPSK, 16QAM, 64QAM 8 BPSK Pilots ... 200 carriers,6.7 kHzspacing ... 802.16 (20 MHz) :10 MHz7.0 MHz3.5 MHz: 1.5 MHz

  20. Key Features of WiMAX - 5 • An estimate of the maximum data rate of a WiMAX system operating in the 5 GHz band using OFDM • System parameters • BW = 20 MHz • SCM = 64-QAM (1 symbol = 6 bits) • No. of data subcarriers = 192 • Raw data rate = 100 Mb/s • After accounting for coding/MAC/TDD overhead, the effective data rate is closer to 70 Mb/s

  21. Key Features of WiMAX - 6 The IEEE 802.16 MAC layer supports • OFDM and OFDMA • ARQ (Automatic Repeat Request) • Dynamic Frequency Selection • Mesh Networking • Advanced Antenna Systems • Differentiated Quality of Service • Enhanced Security

  22. 3. Key Deployment Scenarios • Links from carriers to major customers • Backhaul for access points and cellular base stations • Long-range connections for private networks • Supervisory control and data acquisition • An alternative to DSL and cable modems • An alternative to cellular data services

  23. 4. Our Research Interest in Fixed Wireless • As systems move to higher frequencies, are deployed in more challenging environments, or become more complex, models must be updated and extended • Past work has shown that the fixed wireless channel can range be extremely harsh. Transmitted Signal

  24. Our Research Interest in Fixed Wireless - 2 • Existing channel models do not completely capture the dynamics of fixed wireless channels

  25. Our Research Interest in Fixed Wireless - 3 • Fixed wireless channel dynamics is concerned with the measurement and simulation of the time-varying properties of the channel over the long and short-term. • Issues include: • physical-statistical description of the channel, • effect of alternative antenna configurations, • development of impairment mitigation strategies, • development of more effective radio resource management schemes.

  26. Our Research Interest in Fixed Wireless - 3 • Current Sponsors • Graduate Students: • Joy Zhang, Jin Ng, Howard Huang, Anthony Liou

  27. 5. Probing Further • IEEE 802.16 - www.ieee802.org/16/

  28. Probing Further - 2 • WiMAX Forum - www.wimaxforum.org

  29. Probing Further - 3 • WiMAX @ Intel - www.intel.com/go/wimax

  30. Probing Further - 4 • Other industry portals, e.g., • www.wimaxpro.com • www.wimax-industry.com • www.wimax.com • Booksellers, e.g., • www.chaptersindigo.ca • www.amazon.ca • WiMAX conferences • Vendors (white papers, etc.)

  31. Summary • IEEE 802.16/WiMAX broadband wireless access supports: • channel bandwidths between 1.5 and 20MHz • data rates ranging from 1.5Mbps to over 70Mbps • the available spectrum and channel widths in different countries or licensed to different providers • advanced quality-of-service features that ensure high performance for data, voice and video • system profiles that permit a certain degree of customization within the IEEE 802.16 framework

  32. Summary - 2 • The IEEE 802.16/WiMAX community has already achieved several significant milestones: • the IEEE 802.16 standard has been released and refined. • the WiMAX forum is addressing the needs of industry for promotion, certification, etc. • vendors have developed silicon and equipment. • As rollout begins, operators will begin addressing issues that arise during deployment and operation.

  33. Summary - 3 What will it take for WiMAX to be successful? • Equipment must perform as advertised: • Coverage, reliability, and interoperability • Quality of service, throughput and capacity • Deployment must be straightforward; design rules should reduce the need for network tuning • WiMAX must return value (e.g., performance/cost) that is an order of magnitude higher than existing technology can.

  34. Next…. • Andrew Tsui (Bell Canada) will describe one of the largest pre-WiMAX rollouts to date • Angela Choi (Industry Canada) will summarize spectrum allocation and regulatory issues After a break… • Ben Zarlingo (Agilent Technologies) will describe WiMAX test and measurement solutions • Angela Ikemoto and Michael Fite (Agilent) will demonstrate measurement of actual WiMAX signals

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