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IEEE Std. 802.16 Technique Overview

系統暨網路管理實驗室 Systems & Network Management Lab. IEEE Std. 802.16 Technique Overview. nmgmt.cs.nchu.edu.tw. Reporter ：黃文帥 2007/09/18. 1. 2. 3. What is WiMAX. Physical Layer. Frame Structure. Contents. What is WiMAX. Scope: - Specifies the air interface, MAC (Medium Access Control),

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IEEE Std. 802.16 Technique Overview

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  1. 系統暨網路管理實驗室Systems & Network Management Lab IEEE Std. 802.16 Technique Overview nmgmt.cs.nchu.edu.tw Reporter：黃文帥 2007/09/18

  2. 1 2 3 What is WiMAX Physical Layer Frame Structure Contents LOGO

  3. What is WiMAX • Scope: - Specifies the air interface, MAC (Medium Access Control), PHY (Physical Layer). • Purpose: - Enable rapid worldwide deployment of cost-effective broadband wireless access product. - Facilitate competition in broadband access by providing alternatives to wireless broadband access. • Main advantage: - Fast deployment, dynamic sharing of radio resources and low cost. LOGO

  4. What is WiMAX Deployment LOGO

  5. What is WiMAX Adaptive Modulation • Maximize throughput. • Minimize average power. • Minimize average bit error rate. LOGO

  6. What is WiMAX 802.11 vs 802.16 • 802.11 is not strictly synchronized. 802.16 is a slotted system and all the transmission must be synchronize. • 802.11 uses two-way (Data/ACK) or four-way (RTS/CTS/Data/ACK) handshaking to access channel and transmit data. 802.16 uses a three-way handshaking to set up connection before data transmission (Request/Grant/Transmit). • 802.11 does not distinguish control channel and data channel. In 802.16, the control channel and data channel are separated. • In 802.11, a station must compete for every packet. In 802.16, a station can reserve multiple slots for the following packets. LOGO

  7. Physical Layer Introduction • Support framing. • Support both Time Division Duplex (TDD) and Frequency Division Duplex (FDD), as well as half-duplex FDD (H-FDD). • Burst transmission format which supports adaptive burst profiling. - Data allocations within a frame are referred as bursts. - Transmission parameters, including the modulation and coding schemes (burst profiles), may be adjusted individually to each SS on a frame-by-frame basis. - Burst profiles are broadcast via MAC management messages Downlink Channel Descriptor (DCD) and Uplink Channel Descriptor (UCD) periodically. - The actual transmission bandwidth is allocated by BS and broadcast in MAC management messages Downlink MAP (DL-MAP) and Uplink MAP (UP-MAP) in each frame. - Adapt to multiple modulation levels：BPSK, QPSK, QAM-16, QAM-64. LOGO

  8. Physical Layer PHY Duplexing Option • TDD - The UL and DL transmissions occur at different times and usually share the same frequency. (SS does not receive and transmit data at the same time) - A TDD frame has a fixed duration and contains one DL and one UL subframe, whose durations can vary. • FDD - The UL and DL channels are located on separate frequencies. - A fixed duration frame is used for both UL and DL transmissions. - The H-FDD SS does not receive and transmit data at the same time. LOGO

  9. Physical Layer TDD Frame Structure • PS (Physical Slot) - A unit of time, depend on the PHY specification, for allocating bandwidth. LOGO

  10. Physical Layer FDD Bandwidth Allocation LOGO

  11. Frame Structure Downlink Subframe • TTG/RTG (Transmit/Receive Transition Gap) - A gap between the downlink burst and the subsequent uplink burst in a time division duplex (TDD) transceiver. LOGO

  12. Frame Structure Uplink Subframe • SSTG (Subscriber Station Transition Gap) LOGO

  13. Frame Structure OFDMA Frame Structure LOGO

  14. Thank You !

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