1. IEEE 802.11 Concepts 資工碩職一 492515174 周俊弘

2. Introduction Overview of the Emerging 802.11 Standard 802.11 Architecture DSSS v.s. FHSS OFDM Modulation Reference

3. IEEE 802.11 802.11MAC and PHY spec., 1/2 Mbps in 2.4 GHz band 802.11aOFDM, 6/9/12/18/25/36/48/54 Mbps, in 5 GHz band 802.11b Higher Speed, 5.5/11Mbps, in 2.4 GHz band (CCK modulation) 802.11d802.11 MAC Bridge On-going: 802.11eenhanced MAC for supporting QoS 802.11DSInter-Access Point Protocol (IAPP) across a Distribution System 802.11h Dynamic Channel Selection and Transmit Power Control in 5 GHz 802.11gmandatory: CCK (11Mbps)/OFDM (upto54Mbps) in 2.4 GHz band optional: CCK/PBCC-22M, CCK/OFDM 802.11i enhanced MAC for improvements in security 802.11fInter-Access Point Protocol

4. ISM Unlicensed Frequency band

5. Current Popular Wireless Technology Comparison

6. GLOBAL SPECTRUM ALLOCATION AT 2.4GHz Frequency band of operation: 2.400 Ghz ~ 2.483 Ghz unlicensed Globally represented *Nor America:FCC part 15.247 - 15.249 *Europe:ETS 300 – 328 *Japan:RCR-STD-33A

7. Comparison of Next Generation WLANs IEEE 802.11bIEEE 802.11gIEEE 802.11aHiperLAN 2 Freq. Band (GHz) And Max. power (dBm) 2.400~2.4835 | 30/20 2.4465~2.4835 (France) | 20 2.471~2.497 (Japan) | 10/MHz 2.445~2.475 (Spain) | 20 2.400~2.4835 | 30/20 2.4465~2.4835 (France) | 20 2.471~2.497 (Japan) | 10/MHz 2.445~2.475 (Spain) | 20 5.150~5.250 | 16 5.250~5.350 | 23 5.725~5.825 | 29 (US only) 5.150~5.250 | 23 5.250~5.350 | 23 5.470~5.725 | 30 (Europe only) Number of channels 14 (overlapping), 3 (non-overlapping) 11 (US), 13 (Europe, but 2 Spain, 1 France), 11+1 (Japan) -4,4,44,4,11 ModulationDirect Sequence Spread Spectrum OFDM52 OFDM Data rate (Mbps) and (sub-carrier) modulation 1 (BPSK),2 (QPSK),5.5 (CCK) and 11 (CCK) 546 (BPSK),9 (BPSK),12 (QPSK),18 (QPSK), 24(16QAM), 36(16QAM), 48 (64QAM), 54 (64QAM) 6 (BPSK),9 (BPSK),12 (QPSK),18 (QPSK), 27(16QAM), 36(16QAM), 54 (64QAM) Multiple Access CSMA/CA or CSMA/RTS/CTS (option) TDMA (ATM-like) Encryption40 bits or 128 bits(options) RC4 WEP /WEP2 56 (DES), 168 (triple-DES)

8. IEEE802.11 WLAN Standards Support three (3) Physical (PHY) layer type:DSSS,FHSS,Infrared Light (IR). Medium Access Control (MAC) sublayer Support peer to peer(Ad Hoc) & infrastructure High data rata extension using existing MAC layer Provides reliable,efficient Wireless data networking Robust against interference

9. IEEE802.11 WLAN Standards Short Description of the Standards: IEEE Std 802.11-1997 specifies a single Medium Access Control (MAC) sublayer and 3 Physical Layer Specifications. Signle MAC Three PHYs DSSS: This PHY provides both 1 and 2Mbit/s operation. The 1Mbit/s version uses Differential Binary Phase Shift Keying (DBPSK) and the 2Mbit/s version uses Differential Quadrature Phase Shift Keying (DQPSK). FHSS: This PHY provides for 1Mbit/s (with 2Mbit/s optional) operation. The 1Mbit/s version uses 2 level aussian Frequency Shift Keying (GFSK) modulation and the 2Mbit/s version uses 4 level GFSK. Infrared: This PHY provides 1Mbit/s with optional 2Mbit/s. The 1Mbit/s version uses Pulse Position Modulation with 16 positions (16-PPM) and the 2Mbit/s version uses 4-PPM

10. Why Spread Spectrum Technology ? Immunity of interference and jamming Immunity of multi-path fading (typical indoor environment) Low detectability / probability of intercept Message privacy Multiple access via Code-Division (CDMA)

11. What are the Spread Spectrum Signals? TxRx

12. DSSS Data rates 5.5 Mbps and 11 Mbps.

13. FHSS Data rates 1 Mbps and 2 Mbps. Carrier Hops Every 400ms (IEEE 802.11 Standard)

14. DSSS v.s. FHSS. ItemsDSSSFHSS ThroughputHighLow CapacityUsing AP to Extend Capacity Fixed TX DistanceLongMed. Processing GainYESNO SynchronizationEasyDifficult Effective BWLargeMed. Multi-path Fading Protection YESNO Anti-jamming Capability GoodBetter CostMedcheap

15. modulation

17. Reference IEEE Std 802.11a-1999 (Supplement to IEEE Std 802.11-1999) IEEE Std 802.11b/D8.0, Sept 2001 (Draft Supplement to IEEE Std 802.11 1999 Edition) IEEE 802.11 Tutorial by Jim Zyren and AI Petrick IEEE 802.11 Wireless LAN:Can We Use It for Multimedia? Editor: Peiya Liu CWNA EXAM PW0-100