Wi MAX Protocol CSCE 4520 5520 Fall 2006 Shori

Wi. MAX Protocol CSCE 4520/5520 Fall 2006 Shori Fukatsu

Contents List n Wi. MAX Protocol l About Wi. MAX l Physical layer l MAC layer Fixed / Mobile Wi. MAX n Wi. MAX vs Wi-Fi n Wi. MAX applications n Reference n Quiz n 2

Wi. MAX n n Worldwide Interoperability for Microwave Access “a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL” Metropolitan Area Network (MAN) Based on IEEE 802. 16 3

Purpose of Wi. MAX n n To provide point-to-multipoint wireless access to Internet and other networks To provide high data rates over 10 -40 km 4

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Wi. MAX Architecture MIB – Management Information Base 6

802. 16 protocol 7

802. 16 protocol stack n 802. 16 covers data link and physical layer 8

IEEE 802. 16 Standards n n n 802. 16. 1 (10 -66 GHz, line-of-sight, up to 134 Mbit/s) 802. 16. 2 (minimizing interference between coexisting WMANs. ) 802. 16 a (2 -11 Ghz, Mesh, non-line-of-sight) 802. 16 b (5 -6 Ghz) 802. 16 c (detailed system profiles) 802. 16 e (Mobile Wireless MAN) – called Mobile. Wi. MAX 9

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Physical layer (PHY) 11

PHY cont. QPSK: 2 bits/baud (< 10 km) n QAM-16: 4 bits/baud (6 -10 km) n QAM-64: 6 bits/baud (>6 km) n n Example: a 25 MHz bandwidth, QPSK can deliver 50 Mbps, QAM-16 100 Mbps, QAM -64 150 Mbps Baud (Bd): measure of the symbol rate; the number of distinct symbolic changes (signalling event) made to the transmission medium per second in a digitally modulated signal 25 Bd means that 25 symbols are transmitted per second. 12

PHY cont. n TDD (time-division duplex) - use same bandwidth for uplink and downlink - controlled by timing n n FDD (frequency-division duplex) - use different frequency for uplink and downlink OFDM (orthogonal frequency-division multiplexing) - enhancement of frequency division multiplexing (FDM) - maximize use of bandwidth 13

TDD and FDD 14

OFDM uses bandwidth which is not available for use in FDM 15

MAC layer n n Protocol-Independent core (IP, ATM, etc) Support multiple 802. 16 PHYs 16

MAC cont. n 1. 2. 3. Each MAC packet contains three components MAC header; contains frame control information variable length frame body; contains information specific to the frame type frame check sequence (FCS); contains an IEEE 32 -bit cyclic redundancy code (CRC). 17

MAC cont. n Generic Uplink/Downlink header 18

Downlink Header 19

Downlink Header n n n n n Encryption Control (EC): Indicates whether the payload is encrypted Encryption Key Sequence (EKS): An index into a vector of encryption key information Length: Length in bytes of the entire MAC frame Connection Identifier: A unidirectional, MAClayer address that identifies a connection to equivalent peers Header Type: Indicates whether this is a generic or bandwidth request header ARQ Indicator: Indicates whether the frame belongs to an ARQ enabled connection Fragment Control: Used in fragmentation and reassembly Fragment Sequence Number: Sequence number of the current fragment Header Check Sequence: 8 -bit CRC to detect errors in the header 20

Uplink Header 21

Uplink Header n n Slip indicator: indicate a slip of uplink grants relative to the uplink queue depth Poll-me: request a poll by the base station Grants per interval: the number of bandwidth grants required in the next time interval Piggyback request: the number of bytes of uplink capacity requested 22

Bandwidth request and allocation n SSs may request bandwidth in 3 ways: ¨ Use the ”contention request opportunities” interval upon being polled by the BS (multicast or broadcast poll). ¨ Send a standalone MAC message called ”BW request” in an allready granted slot. ¨ Piggyback a BW request message on a data packet. 23

Bandwidth request and allocation cont. n BS grants/allocates bandwidth in one of two modes: n n Grant Per Subscriber Station (GPSS) Grant Per Connection (GPC) n Decision based on requested bandwidth and Qo. S requirements vs available resources. n Grants are realized through the UL-MAP (Uplink message). 24

Bandwidth request and allocation cont. 25

Fixed and Mobile Wi. MAX n n Fixed Wi. MAX is optimized for home/office networks Mobile Wi. MAX is optimized for mobiles 26

Fixed Wi. MAX n n n IEEE 802. 16 d T 1/E 1 substitute 1 BS – thousands of user < 50 km coverage < 75 Mbps 27

Fixed Wi. MAX Architecture 28

Mobile Wi. MAX n n n IEEE 802. 16 e 2 -3 km coverage (optimal) High speed hand over (< 50 ms latencies) Ensures performance at vehicular speeds greater than 120 km/h < 30 Mbps for downlink < 15 Mbps for uplink 29

Wi. MAX vs Wi-Fi 30

Wi. MAX vs Wi-Fi cont. Wi. MAX is designed to cover large area (multiple homes/buildings), while Wi-Fi is to cover small area (a home/building) 31

Comparison of Wi. MAX, Wi. Fi and 3 G technology 32

Wi. MAX vs Wi-Fi cont. 33

Wi. MAX applications Broadband Internet n Multimedia n IP multimedia subsystem (IMS) n Cellular Alternative n 34

Broadband Internet • Fixed Wi. MAX is substitute for T 1 • Mobile Wi. MAX has larger coverage than Wi. Fi 35

Multimedia n n Mobile TV IPTV (TV broadcasting via IP network) 36

Traditional networks n n Different device, different network For example: TV is only for watching TV Phone is only for call 37

IMS network n n n One network provides multiple things For example: Watch TV and use Internet via cell phone 38

Wi. MAX as cellular alternative n n Support IP by default Vo. IP 39

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Reference n n n n Frank Ohrtman: “Wimax overview”: http: //www. wimax. com/education/wimax_overview “The 802. 16 Wireless. MAN™ MAC: It’s Done, but What Is It? ” (200111 -12) Zheng Yu Huang (2006 -10 -25): ”Considerations for Next Generation Telecommunications Deployments in China”, Intel Corporation Michael Richardson and Patrick Ryan (2006 -3 -19): “Wi. MAX: Opportunity or Hype? ” “Adaptive Modulation” (2004), Intel Corporation Tim Sanders (2005 -9 -21): ”Wi. Max/802. 16 Revealed”, http: //www. wifiplanet. com/tutorials/article. php/3550476 Michael F. Finneran (2004 -6 -1) “Wi. MAX versus Wi-Fi”, d. Brn Associates, Inc. 41

n n n n Israel Koffman and Vincentzio Roman (2002): “Broadband Wireless Access Solutions Based on OFDM Access in IEEE 802. 16”, IEEE Communications Magazine April 2002 Wi. MAX Forum (2006 -8): “Mobile Wi. MAX – Part I: A Technical Overview and Performance Evaluation” dailywireless. org (2005 -7 -8): “Mobile Wi. MAX Chips”, http: //www. dailywireless. org/2005/07/08/mobile-wimax-chips/ Carl Eklund, Roger B. Marks, Kenneth L. Stanwood and Stanley Wang (2002 -6): “IEEE Standard 802. 16: A Technical Overview of the Wireless. MAN™ Air Interface for Broadband Wireless Access”, IEEE Communications Magazine June 2002 Robert Healey (2003): “Network Architecture for Wi. MAX applications”, Juniper Networks, Inc. Kuo-Hui Li (2006 -6 -5): “Wi. MAX Network Architecture”, Intel Mobility Group “Technology Primer Wi. MAX”, http: //www. tektronix. com/wimax 42

Quiz 1. 2. 3. How much bps can QPSK (2 bits/Bd), QAM-16 (4 bits/Bd) and QAM-64 (6 bits/Bd) can deliver if a bandwidth is 20 MHz? What is the difference between OFDM and FDM? What are the differences between Wi. MAX and Wi-Fi? 43

Answer 1. 2. 3. QPSK - 40 Mbps, QAM-16 - 80 Mbps, QAM-64 120 Mbps (slide #11) See slide #14 The main difference is that Wi. MAX is focused on MAN, while Wi-Fi is LAN technology. (slide #30 -33) 44