1. March 22, 2004 Prof. Paul Lin 1 CPET 355 4. The Medium Access Control Sublayer – Broadband Wireless LAN IEEE 802.16 Paul I-Hai Lin, Professor Electrical and Computer Engineering Technology Purdue University, Fort Wayne Campus

2. March 22, 2004 Prof. Paul Lin 2 Broadband Applications Internet services Internet services Telephony Telephony Heavy-duty Multimedia Heavy-duty Multimedia

3. March 22, 2004 Prof. Paul Lin 3 Broadband Wireless LAN 802.16 Characteristics 802.16 Characteristics 10 to 66 GHz range10 to 66 GHz range Service to building (non-mobile users)Service to building (non-mobile users) Full-duplexFull-duplex Several KmSeveral Km More users per cellMore users per cell Easily absorbed by water, fog, snowEasily absorbed by water, fog, snow Integrate with datagram protocols (PPP, IP, and Ethernet), and ATMIntegrate with datagram protocols (PPP, IP, and Ethernet), and ATM

4. March 22, 2004 Prof. Paul Lin 4 The 802.16 Protocol Stack Data Link Layer (3-sublayer) Data Link Layer (3-sublayer) Service Specific Convergence SublayerService Specific Convergence Sublayer MAC sublayer common partMAC sublayer common part Security sublayerSecurity sublayer Physical Layer (2-sublayer) Physical Layer (2-sublayer) Transmission Convergence SublayerTransmission Convergence Sublayer Physical Medium SublayerPhysical Medium Sublayer QPSK (2-bit/baud) – 50 Mbps, distant subscriber QPSK (2-bit/baud) – 50 Mbps, distant subscriber QAM-16 (4-bit/baud) – 100 Mbps, medium distance QAM-16 (4-bit/baud) – 100 Mbps, medium distance QAM-64 (6-bit/baud) – 150 Mbps, close-in subscriber QAM-64 (6-bit/baud) – 150 Mbps, close-in subscriber

5. March 22, 2004 Prof. Paul Lin 5 The 802.16 Classes of Services Constant bit rate service – voice (uncompressed), fixed data/time Constant bit rate service – voice (uncompressed), fixed data/time Real-time variable bit rate service – Compressed multimedia Real-time variable bit rate service – Compressed multimedia Non Real-Time Variable Bit Rate Service – Large file transfer Non Real-Time Variable Bit Rate Service – Large file transfer Best-Efforts Service Best-Efforts Service Per stationPer station Per connectionPer connection

6. March 22, 2004 Prof. Paul Lin 6 The 802.16 Frame Structure Courtesy – Computer Networks, Andrew Tanenbaum, Page 309, Figure 4-34, Prentice Hall, 2003

7. March 22, 2004 Prof. Paul Lin 7 IEEE 802.16 Generic Frame Structure 0 – First bit is zero 0 – First bit is zero EC – 1-bit, encrypted payload or not EC – 1-bit, encrypted payload or not Type – 6-bit frame type, packing and fragmentation Type – 6-bit frame type, packing and fragmentation CI – 1-bit, final checksum presence or not CI – 1-bit, final checksum presence or not EK – 2-bit, encryption keys EK – 2-bit, encryption keys Length – 11-bit, length of frame, including header Length – 11-bit, length of frame, including header Connection ID – 16-bit Connection ID – 16-bit Header CRC – 8-bit (X 8 +X 2 +X+1) Header CRC – 8-bit (X 8 +X 2 +X+1)

8. March 22, 2004 Prof. Paul Lin 8 IEEE 802.16 Bandwidth Request Frame 1,0 – First two bits 1,0 – First two bits Type – 6-bit frame type, packing and fragmentation Type – 6-bit frame type, packing and fragmentation Bytes Needed – 16-bit Bytes Needed – 16-bit Connection ID – 16-bit Connection ID – 16-bit Header CRC – 8-bit (X 8 +X 2 +X+1) Header CRC – 8-bit (X 8 +X 2 +X+1)