1. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 20081 IEEE 802.20 – Mobile Broadband Wireless Access

2. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 20082 Abstract Mobile Broadband Wireless Access (802.20) is a IEEE standard formed to develop a cellular standard that focuses on vehicular mobility in a metropolitan area environment. It falls under the WWAN category. It is a packet switched technology, designed to operate in frequencies below 3.5 GHz and optimized to carry IP traffic for mobile users traveling with speeds up to 250 km/h. Standard includes Physical and MAC layer specifications and is compatible to 802 Architecture and Functional requirements

3. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 20083 IEEE 802.20 – Outline Motivation for new Standard Services and Applications Physical Layer MAC Layer Handoff procedures Comparison between 802.20 and 802.16e Conclusion

4. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 20084 Motivation for new Standard – IEEE 802.20 Wi-Max was designed to provide broadband wireless access and aims at maximizing throughput rather than mobility 802.20 is the first standard that takes into consideration mobility classes, with speeds up to 250 km/h Extends broadband wireless access to mobile users Approved Dec 11 th 2002, Nicknamed as Mobile-Fi Optimized for high speed IP based wireless data service The standard forms the basis of seamless integration of – work, home and mobile

5. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 20085 IEEE 802.20 : Services Vision of a seamless integration of three user domains: work, home and mobile. From “IEEE 802.20 System Requirement V1.0”, P802.20-PD-06r1, [1]

6. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 20086 IEEE 802.20 – Mission and Scope of Project The goal is to enable worldwide deployment of affordable, always-on, ubiquitous mobile broadband wireless access networks. To ensure co-existence and compatibility. Scope : To develop specification of Physical and MAC layers of the air interface Operating in licensed bands below 3.5 GHz Optimized for IP-data transport Offers Peak data rates per user in excess of 1Mbps Support vehicular mobility of 250 Km/h in a MAN environment From ”Mission and Scope”, http://ieee802.org/20/index.html

7. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 20087 IEEE 802.20 : Services Supports video, full graphic web browsing, e-mail, file transfer, streaming video and audio. IP Multicast Location-Based-Servers. VPN connections VoIP On-line multiplayer gaming Broadcast and Multicast support Needs a PC card interface with devices. From “IEEE 802.20 System Requirement V1.0”, P802.20-PD-06r1, [1]

8. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 20088 Example - Railway Application 802.20 based Broadband Railroad Digital Network – BRDN Meet the ever-increasing demand for M-commerce and Wi-Fi enabled trains 802.20 was selected since it supports high speeds From “IEEE 802.20 Based Broadband Railroad Digital Network - The Infrastructure for M-Commerce on the Train ”, [10]

9. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 20089 802.20 Features CharacteristicTarget Value MobilityVehicular mobility classes up to 250 km/hr (as defined in ITU-R M.1034-1) Sustained spectral efficiency> 1 b/s/Hz/cell Peak user data rate (Downlink (DL))> 1 Mbps* Peak user data rate (Uplink (UL))> 300 kbps* Peak aggregate data rate per cell (DL)> 4 Mbps* Peak aggregate data rate per cell (UL)> 800 kbps* Airlink MAC frame RTT< 10 ms Bandwidthe.g., 1.25 MHz, 5 MHz Spectrum (Maximum operating frequency)< 3.5 GHz Spectrum (Frequency Arrangements)Supports FDD (Frequency Division Duplexing) and TDD (Time Division Duplexing) frequency arrangements Spectrum AllocationsLicensed spectrum allocated to the mobile service From “IEEE 802.20 System Requirement V1.0”, P802.20-PD-06r1, [1]

10. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200810 IEEE 802.20: Network Architecture Access Network: Collection of Access Nodes or Access Points.  AT can be in communication with more that one Access Node  Each AN-AT pairing has its own protocol stack - ROUTE Serving Access Node: Access Point housing serving sector. Contains sector that provides air-interface attachment for the AT  Routes can be tunneled between ANs without the serving AN needing to read the or manage the packet exchanged  Changes based on radio conditions Anchor Access Node: Access Point that provides internet connectivity. May change to minimize the number of hops a packet has to traverse to reach the AT From “UMBFDD Draft Technology Overview”, IEEE C802.20-07/09, [2]

11. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200811 Protocol Layering – 802.20 From “FDD Technology overview presentation”, IEEE C802.20-05-59r1, [5] Application Sublayer Radio Link Sublayer Lower MAC Layer Physical Layer

12. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200812 Physical Layer System is deployable in 1.25 - 20 MHz flexible bandwidths Targets cell radius of 15km Bandwidths supports Frequency and Time Division Duplexing Reverse links support both CDMA and OFDMA CDMA is used for low rate data transmissions Also supports the option of fast frequency hopping spread spectrum technology – Flash-OFDM Forward links support OFDMA The system uses Adaptive Coding and Modulation Supports QPSK, 16 QAM, 8-PSK and 64 QAM Support Hybrid ARQ Frequency reuse - Fractional Frequency Reuse FFR From “Draft Standard for Local and Metropolitan Area Networks – Standard Air Interface for Mobile Broadband Wireless Access Systems Supporting Vehicular Mobility – Physical and Media Access Control Layer Specification”, IEEE 802.20/D3.0m, [4]

13. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200813 Fractional Frequency reuse FFR Figure. Fractional Frequency Reuse F1, F2, and F3 are different sets of sub-channels, allocated to users at cell edges. F = F1+F2+F3. The whole sub-channels (F) are allocated to users at cell centers From “Fraction Frequency Re-use”, www.conniq.com/WiMAX/images/fractional-frequency-reuse [3]

14. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200814 Physical Layer (Contd) Error Detection CRC – 24 bits for Data Channels and 9 bits for dedicated control channels Forward Error Correction turbo codes, convolutional codes and LDPC codes Standard defines Physical channels - Forward and Reverse Channels Separate channels for Control and Traffic Channels have unique modulation, encodings and purpose CDMA and OFDM control channels are used CDMA Control Channels are preferred for Fast Access and Fast request CDMA control channels provides efficient handoff control OFDMA Control Channels are used for highly periodic control transmissions – CQI From “Draft Standard for Local and Metropolitan Area Networks – Standard Air Interface for Mobile Broadband Wireless Access Systems Supporting Vehicular Mobility – Physical and Media Access Control Layer Specification”, IEEE 802.20/D3.0m, [4]

15. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200815 Physical Layer (contd) Forward Channels : From “Draft Standard for Local and Metropolitan Area Networks – Standard Air Interface for Mobile Broadband Wireless Access Systems Supporting Vehicular Mobility – Physical and Media Access Control Layer Specification”, IEEE 802.20/D3.0m, [4] Forward Link Channels

16. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200816 Physical Layer (contd) Reverse Link Channels From “Draft Standard for Local and Metropolitan Area Networks – Standard Air Interface for Mobile Broadband Wireless Access Systems Supporting Vehicular Mobility – Physical and Media Access Control Layer Specification”, IEEE 802.20/D3.0m, [4]

17. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200817 Physical Layer (contd) Transmission in the FL and RL is divided into units of superframes In FDD, each superframe consists of 25 PHY frames In 1:1 TDD, 4 FL frames, 4 RL Frames are transmitted From “Draft Standard for Local and Metropolitan Area Networks – Standard Air Interface for Mobile Broadband Wireless Access Systems Supporting Vehicular Mobility – Physical and Media Access Control Layer Specification”, IEEE 802.20/D3.0m, [4] FDD Super frame Structure TDD Super frame Structure

18. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200818 Physical Layer (contd) Power control Fast closed loop power control Standard has mechanism for inactive mode and active mode Supports Multi-antenna capability in both Access Nodes and Mobile Terminals

19. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200819 Addressing AT Addressing UATI: Universal Access Terminal Identifier  128 bits – temporary identity given by the system  Not hardware derived, therefore not unique.  Not used to resolve identity of AT  Shortened – 32 bits used for paging. MACID  11 bits long  AT assigned one MACID per sector.  Unique within the sector  Used to exchange unicast packets with AT Does not require IP address assigned to the AT to operate Does not use EUI-48 bits or 64 bits given to AT for during it manufacture. From “Draft Standard for Local and Metropolitan Area Networks – Standard Air Interface for Mobile Broadband Wireless Access Systems Supporting Vehicular Mobility – Physical and Media Access Control Layer Specification”, IEEE 802.20/D3.0m, [4]

20. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200820 MAC Layer Some Protocols used Basic packet consolidation protocol  Provides packet consolidation on the transmit side and de-multiplexing on receive side  Protocol maintains 2 token buckets for each stream –They could be used for traffic policing and shaping –Or to hint the scheduler for transmission  Consolidated packet : consists of route packets from upper layers –Given the transmission rate, the length of packet should not increase the maximum payload size.  Along with packets received from upper layers, priority and transmission deadlines could also be included From “Draft Standard for Local and Metropolitan Area Networks – Standard Air Interface for Mobile Broadband Wireless Access Systems Supporting Vehicular Mobility – Physical and Media Access Control Layer Specification”, IEEE 802.20/D3.0m, [4]

21. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200821 MAC Layer (contd) Basic Access Channel MAC protocol Describes procedures for AT and AN to transmit and receive Access Probe Access Probe used for initial access or handoff AN responds to Access Probe with a Access Grant Protocol defines Ns and Np. From “Draft Standard for Local and Metropolitan Area Networks – Standard Air Interface for Mobile Broadband Wireless Access Systems Supporting Vehicular Mobility – Physical and Media Access Control Layer Specification”, IEEE 802.20/D3.0m, [4] Access Sequence

22. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200822 MAC Layer (contd) Basic Reverse Traffic Channel MAC Protocol Assignments are specified by set of hop-ports and PHY frames Hop-ports assigned for a given set of PHY frames for particular AT. Sets of hop-ports are assigned in assignment blocks using channel tree Transmission is multiplexed in time and frequency domain Basic Forward Traffic Channel MAC Protocol Defines procedures required for an AN to transmit and AT to receive Transmission is multiplexed in time and frequency domain Uses MACID assigned to AT ( unique in sector ) From “FDD Technology overview presentation”, IEEE C802.20-05-59r1, [5]

23. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200823 Radio Link Protocol Provides segmentation and reassembly Ensures in order delivery of upper layer packets even during handoff Increases link layer reliability through NACK transmission QoS support – defines multiple flows From “FDD Technology overview presentation”, IEEE C802.20-05-59r1, [5] QoS Implementation

24. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200824 QoS (contd) RL and FL subband scheduling Multi-user diversity gains through frequency sensitive scheduling  enables multi-user diversity gains for latency sensitive users Design supports two hopping modes  diversity mode - global hopping across the band  subband mode-localized hopping From “FDD Technology overview presentation”, IEEE C802.20-05-59r1, [5] Subband Scheduling

25. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200825 Handoff Important feature of cellular mobility Types of Handoffs Inter-sector Inter-Access Node Inter-carrier Desired Characteristics Minimize MAC/Network layer signaling overhead Minimize latency for handoff decisions  In Layer 1 and layer 2 handoff  In Layer 3 handoff 802.20 proposes to use: Mobile Controlled Handoff (MIP4) and Network Controlled Handoff Layer 2 triggers (Low Latency MIPv4) Make before break technique ( MIP4 MBB) From “Mobile-Controlled Handoff for MBWA”, IEEE C802.20-03/17, [6]

26. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200826 Handoff (contd) Mobile controlled Handoff Consider : Inter-Sector or Inter AN : Layer 2 Handoff Uses 2 control channels - R-CQICH and R-REQCH For FL handoff: AT monitors R-CQICH of all sectors in active set For RL handoff: AT uses R-REQCH to indicate the desired RL sector Handoff completes when AT receives assignment from new sector From “FDD Technology overview presentation”, IEEE C802.20-05-59r1, [5] Forward Link HandoffReverse Link Handoff

27. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200827 Handoff (contd) Layer 2 Triggers to Network Layer During Layer 3 Handoffs ( different IP subnet) A significant percentage of handoffs between 802.20 Access Nodes is likely to cause a cause layer 3 handoff due to high speed mobility in MA environment IEEE 802.20, proposes to use layer 2 triggers along with Mobile IP to reduce the latency in Mobile IP ( RFC 4881) From “Support for Layer 2 Triggers for Faster Handoffs”, IEEE P802.20-03/95 [7]

28. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200828 Handoff (contd) Make-Before-Break Mobile maintains PHY and MAC connectivity with more than one Access Node (BS) Resources in new Access Node are allocated before releasing resources in the old Access Node This helps in reducing handoff latency Improves performance – reducing packet loss Inter-Base Tunnel From “Handoff procedure for MBWA”, IEEE C802.20-03/85, [6] Layer 3 Handoff

29. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200829 Difference Between 802.20 and 802.16e From “MBWA and 802.16e: Two Markets –Two Projects”, [14] and “MBWA 802.20: A Comparison with Mobile WiMax“, http://ieee802.org/20/Contributions.html Features802.20802.16e Operating Spectrum3.5 GHz2 – 6 GHz Typical Channel Bandwidth Between 1.25 MHz to 5 MHzGreater than 5Mhz SpeedSupports Vehicular mobility 250km/hSupports > 60 km/h FL capacity 3 times more users than 802.16e VoIP capacity Greater by 3 times than 802.16e RL Spectral efficiencies Much better than 802.16e Latency 802.20 has significantly lower than

30. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200830 Future 802.20 currently in final stages of standardization Kyocera announces - 802.20 will begin to appear in their iBurst base stations and terminals by the 4 th quarter of 2009 “Kyocera enhances iBurst with Mobile Broadband Technology”, http://global.kyocera.com/prdct/telecom/office/iburst/news/080410.html

31. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200831 Conclusion IEEE 802.20 specifies unique solution to PHY and MAC layer of the air interface operating in the licensed spectrum below 3.4 GHz. The standard provides support to vehicular mobility in metropolitan environment and covers wide area of up to 15 km. The standard uses combination of OFDMA, CDMA, Fast Frequency Hopping spread spectrum technologies, better cell architectures, advanced digital signal processing techniques like Adaptive Antennas and better handoff techniques to achieve its goal.

32. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200832 References [1] IEEE 802.20-PD-06r1, “IEEE 802.20 System Requirement Document (V 1.0)” [2] IEEE C802.20-07/09, “UMBFDD Draft Technology Overview” [3] “Fraction Frequency Re-use”, www.conniq.com/WiMAX/images/fractional-frequency-reuse, retrieved April 26,2008 [4] IEEE 802.20/D3.0m, “Draft Standard for Local and Metropolitan Area Networks – Standard Air Interface for Mobile Broadband Wireless Access Systems Supporting Vehicular Mobility – Physical and Media Access Control Layer Specification”, November 2007 [5] IEEE C802.20-05-59r1, “FDD Technology overview presentation” [6] IEEE C802.20-03/84, “Handoff procedure for MBWA” [7] IEEE P802.20-03/95, “Support for Layer 2 Triggers for Faster Handoffs” [8] Lawton, George. "What Lies Ahead for Cellular Technology." IEEE Computer Journal 38(6) (2005): 14-17 [9] Kuran, Mehmet S, Tuna Tugcu, and "A Survey on Emerging Broadband Wireless Access technologies." Science Direct Computer Networks 51(2007): 3013-3046 [10] Zou, Fumin, Xinhua Jiang. "IEEE 802.20 Based Broadband Railroad Digital Network - The Infrastructure for M-Commerce on the Train." The 4th International Conference on Electronic Commerce (ICEB) 2004: 771-776. [11] EEE 802.20 Working Group, System requirements for 802.20 Mobile Broadband Wireless Access Systems http://www.ieee802.org/20/Contribs/C802.20-06-04.pdf.

33. University of Kansas | School of Engineering Department of Electrical Engineering and Computer Science Ramya Naidu M April 29, 200833 Refernces (contd) [12] http://www.wimax.com/ [13] “Kyocera enhances iBurst with Mobile Broadband Technology”, http://global.kyocera.com/prdct/telecom/office/iburst/news/080410.html, Retrieved April 26, 2008 [14] “MBWA and 802.16e: Two Markets –Two Projects”, 802.16sgm-02/16 or 802m_ecsg-02/15