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FB 1 – Communication Networks Andreas Könsgen – Summer Term 2014 Chapter 8: WMAN - IEEE 802.16 / WiMax Introduction and Overview
FB 1 – Communication Networks Andreas Könsgen – Summer Term 2014
Chapter 8: WMAN - IEEE 802.16 / WiMax
Introduction and Overview
FB 1 – Communication Networks Andreas Könsgen – Summer Term 2014
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IEEE 802.16 and WiMAX• IEEE Working Group on Broadband Wireless Access,
established 1999• Worldwide Interoperability for Microwave Access• Objective: Standardisation of Wireless Metropolitan Area
Network (WMAN)• WiMAX: industry consortium
– 802.16 provides standardised PHY and MAC– Interoperability between devices– Compatibility to higher protocol layers– Network architecture
• First standard published in 2001
FB 1 – Communication Networks Andreas Könsgen – Summer Term 2014
IEEE 802.16 evolution (1)802.16 802.16a 802.16-
2004802.16e
Date Completed
December 2001
January 2003
June 2004 December 2005
Spectrum 10-66 GHz < 11 GHz < 11 GHz < 6 GHz
Operation LOS, only SC Non-LOSOFDM
Non-LOSOFDMA
NLOS and Mobile
Bit Rate 32-134 Mbps Up to 75 Mbps
Up to 75 Mbps
Up to 15 Mbps
Cell Radius 2-4 km 5-8 km 5-8 km 2-4 km
Hussain, APRICOT 2006www.cse.wustl.edu/~jain/cse574-06/ftp/wimax
FB 1 – Communication Networks Andreas Könsgen – Summer Term 2014
802.16-2009• Air Interface for Fixed and Mobile Broadband Wireless Access
System• PHY and MAC Layers for Combined Fixed and Mobile
Operation in Licensed Bands (former 802.16e) • Network Management (NetMan): Management Information
Base (MIB), Management Plane Procedures and Services• Coexistence in license-exempt bands
IEEE 802.16 evolution (2)
FB 1 – Communication Networks Andreas Könsgen – Summer Term 2014
Further developments• IEEE 802.16h: Improved coexistence mechanisms in license-
exempt operation (2010)• IEEE 802.16j: Multihop Relay (2009)
– PMP compliant, multihop operation for OFDMA PHY
• IEEE 802.16m: Advanced Air Interface with data rates of 100 Mbit/s mobile and 1 Gbit/s fixed (2011)– Also known as Mobile WiMAX Release 2 or WirelessMAN-
Advanced
– Aiming at fulfilling the ITU-R IMT-Advanced requirements on 4G systems
• IEEE 802.16p: Enhancements to Support Machine-to-Machine Applications (2012)
• IEEE 802.16-2012• IEEE 802.16n: Reliable Operation (2013)
IEEE 802.16 evolution (3)
FB 1 – Communication Networks Andreas Könsgen – Summer Term 2014
• Fundamentally different MAC layer approaches:– 802.11: distributed control, contention based access– 802.16: centrally coordinated, frame based
• Similar OFDM based PHY modes• Quality of service (QoS) support
– Guaranteed multimedia QoS in 802.16– In the first years, no QoS support in 802.11 standard
• Higher data rates due to reduced MAC overhead• Much longer distances due to allocated frequency band and higher
transmit power
802.16 vs. 802.11
FB 1 – Communication Networks Andreas Könsgen – Summer Term 2014
WiMax deployment: point-to-point backbone (LOS)
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FB 1 – Communication Networks Andreas Könsgen – Summer Term 2014
WiMAX deployment: backhaul links
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point-to-multipoint, non-line-of-sight, stationary
FB 1 – Communication Networks Andreas Könsgen – Summer Term 2014
WiMAX deployment: user access
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point-to-multipoint, non line-of-sight, mobile
FB 1 – Communication Networks Andreas Könsgen – Summer Term 2014
WiMAX Protocol Stack
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Handling higher layer protocols
Channel access, connection handling, QoS
Authentication, secure key exchange, encryption
FB 1 – Communication Networks Andreas Könsgen – Summer Term 2014
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802.16 profiles and performance comparison
http://walrandpc.eecs.berkeley.edu/228S06/L6.pdf
FB 1 – Communication Networks Andreas Könsgen – Summer Term 2014
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MAC layer• For data transport, base station controls channel• variable-length time slot in a superframe is assigned by
base station to each mobile station• Encapsulation of different (wired) packet formats on the
air interface: Ethernet, ATM, raw IP• Connection-oriented: station needs to register in order to
get a time slot allocated• Because of time slots, QoS provisioning easy • Connection setup by random access• DES/AES encryption
FB 1 – Communication Networks Andreas Könsgen – Summer Term 2014
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QoS classes
• Unsolicited Grant Service (UGS)– Periodic fixed-size packets, e.g. T1 transport
• Extended Real-Time Polling Service (ertPS)– Periodic variable-size packets, e.g. VoIP
• Real-time polling service (rtPS)– Periodic variable-size packets, e.g. MPEG stream
• Non-real-time polling service (nrtPS)– Delay-tolerant streams, minimum throughput, e.g. FTP
• Best Effort (BE)– No QoS requirements, e.g. HTTP
