IEEE 802.11 Handbook

Bob O'Hara is a co-founder of Airespace, a venture-funded startup company that is leading the IEEE 802.11 industry into the second stage of wireless local area network (WLAN) evolution. He is actively involved in the development of networking, telecommunications, and computing standards and products. His areas of expertise are network and communication protocols and their implementation, operating systems, system specification and integration, standards development, cryptography and its application, strategy development, and product definition. Mr. O'Hara has been involved with the development of the IEEE 802.11 WLAN standard since 1992. He was the technical editor of that standard and chairman of the revisions and regulatory extensions tasks groups. He is currently chairman of the maintenance and task group. In 2004, he was selected of one of the fifty most powerful people in networking by Network World. Al Petrick is vice president of marketing and business development at WiDeFi, a fabless semiconductor company developing 802.11 WiFi® semiconductors for the wireless consumer electronics market. Mr. Petrick's experience includes over 23 years of combined marketing and systems engineering in wireless communications and semiconductor technology. Prior to WiDeFi, he held executive management marketing and business development positions at Icefyre and Intersil. At Intersil, now Conexant, formally Harris Semiconductor, he pioneered the PRISM WLAN chipset from inception into a successful Wi-Fi product line. Mr. Petrick serves as vice chairman of the IEEE 802.11 WLAN Working Group. He has published various marketing and technical papers on wireless communications for leading wireless trade publications, marketing analysts, and financial analysts. Mr Petrick co-authored with Bob O'Hara  the first edition of the IEEE 802.11 Handbook: A Designer's Companion. He serves on a number of advisory boards for Wi-Fi product companies.

• Introduction xxvAcronyms and abbreviations xxxiChapter 1 Similarities and differences between wireless and wired local area networks (LANs) 1Similarities between WLANs and wired LANs 1Differences between WLANs and wired LANs 1Chapter 2 IEEE 802.11: First international standard for WLANs 5IEEE 802.11 architecture 5STA 6Basic service set (BSS) 6Extended service set (ESS) 8Distribution system (DS) 9Services 10STA services 10Distribution services 11Interaction between some services 12Summary 15Chapter 3 Medium access control (MAC) 17MAC functionality 17MAC frame exchange protocol 17Dealing with the media 18Hidden node problem 18Retry counters 21Basic access mechanism 22Timing intervals 23Distributed coordination function (DCF) 24Centrally controlled access mechanism (i,e„ PCF) 24Frame formats 28General frame format 29Frame Control field 31Duration/ID field 37Address fields 37Sequence Control field 39Frame Body field 40FCS field 40Control frame subtypes 41Request to Send (RTS) [control] frame 41Clear to Send (CTS) [control] frame 42Acknowledge (ACK) [control] frame 42Power Save Poll (PS-Poll) [control] frame 44Contention-Free End (CF-End) and CF-End plus ACK (CF-End + ACK) [control] frames 44Data frame subtypes 45Simple data frame 45Data with Contention-Free Acknowledgment (Data + CF-ACK) frame 48Data with Contention-Free Poll (Data + CF-Polt) frame 48Data + CF-ACK + CF-Poll frame 49Null Function (no data) frame 49Con tent ion-Free Acknowledgment (CF-ACK) (no data) frame 49Contention-Free Poll (CF-Poll) (no data) frame 49CF-ACK + CF-Potl (no data) frame 50Management frame subtypes 50Beacon [management] frame 51Probe Request and Probe Response [management] frames 52Authentication [management] frame 53Deauthentication [management] frame 54Association Request and Association Response [management] frames 54Reassociation Request and Reassociation Response [management] frames 54Disassociation [management] frame 55Announcement Traffic Indication Message (ATIM) [management] frame 55Action [management] frame 55Components of the management frame body 55Fixed fields 55Information elements 68Other MAC operations 86Fragmentation 86Privacy 89WEP details 92Chapter 4 IEEE 802.11i security enhancements 95Robust security network (RSN) 96IEEE 802.1 X Authentication and Key Management Protocol (AKMP) 105Details of IEEE 802.1X EAP AKMP operation 108EAPOL-Key frames 109PSK AKMP 112Details of PSK AKMP operation 113PMK caching 114Preauthentication 114Transition security networks (TSNs) 115Confidentiality: New encryption algorithms 116Fixing WEP: Temporal Key Integrity Protocol (TKIP) 116TKIP operation 117Michael MIC 120TKIP-encrypted frame description 120Attack countermeasures 122New transforms 122CCMP-encrypted frame description 124Security management 126Changes to existing attributes and tables 126New attributes and tables 127Chapter 5 IEEE P802.11e quality of service (QoS) enhancements 137Background: What is QoS and why is QoS needed? 137IEEE P802.1 le: What’s in and what’s out 138The Scope of IEEE 802.11 standard 138Mandatory and optional features 138Limits of WLANs 138Background of the legacy IEEE 802.11 MAC 139Fundamentals of IEEE P802.1 le operation 140Hybrid coordination function (HCF) 140Enhanced distributed channel access (EDCA) 142EDCA admission control 144HCF controlled channel access (HCCA) 145IEEE P802.1 le frame formats 145New control frame subtypes 146New data frame subtypes 148New extensions to management frames 154Action [management] frames 159New information element formats 169Optional features in IEEE P802.1 le 182Contention-free bursts (CFBs) 182Block acknowledgments 182Direct link setup (DLS) 183Automatic power save delivery (APSD) 187IEEE P802.1 le as part of complete QoS implementation 187Scheduling and admission control 187Adapting to varying wireless channel conditions 188Interface to higher layers 189Conclusion 190Chapter 6 IEEE 802.1 lh dynamic frequency selection (DFS) and transmit power control (TPC) 191Users of the 5 GHz frequency  192New parts to the IEEE 802.11 protocol 192Transmit power control (TPC) 197TPC operation 199Spectrum management 200Detection of radar operation 205Chapter 7 IEEE 802.11d international operation 207New roaming requirements 208Country information element 210International roaming with FH PHYs 212Request information element and its protocol 214Chapter 8 IEEE 802.1 IF Inter Access Point Protocol (IAPP) 217Going beyond the MAC 217More about mobility 218Chapter 9 MAC management 221Tools available to meet the challenges 222Authentication 223Association 225Address filtering (MAC function) 227Privacy (MAC function) 228Power management 228Power management in an IBSS 228Power management in an infrastructure BSS 230Synchronization 232Timer synchronization in an infrastructure BSS 233Timer synchronization in an IBSS 234Synchronization with FH PHYs 235Scanning 235Joining a BSS 237Combining management tools 237Combining power-saving periods with scanning 237Preauthentication 238Areas for improvement 239Scanning and roaming 239Use of status and reason codes 240Chapter 10 MAC management information base (M1B) 241STA management attributes 241MAC attributes 246Chapter 11 The physical layer (PHY) 251PHY functionality 251Direct sequence spread spectrum (DSSS) PHY 252DSSS PLCP sublayer 252Data scrambling 255DSSS modulation 255Barker spreading method 256DSSS operating channels and transmit power requirements 258Frequency hopping spread spectrum (FHSS) PHY 261FHSS PLCP sublayer 261PSDU data whitening 264FHSS modulation 264FHSS channel hopping 265Infrared (IR) PHY 2671R PLCP sublayer 267IR PHY modulation method 270Geographic regulatory bodies 271Chapter 12 PHY extensions to IEEE 802.11 273IEEE 802.1 la: Orthogonal frequency division multiplexing (OFDM) PHY 273OFDM PLCP sublayer 274IEEE 802.11 a modulation 276PLCP and data scrambler 276Convolutional encoding 276IEEE 802.1 la OFDM 277OFDM operating channels and regulatory domains 278Transmit power requirements 281Geographic regulatory bodies 283Globalization of spectrum at 5 GHz 284IEEE 802.1 lb: 2.4 high-rate direct sequence spread spectrum (HR/DSSS) PHY 285HR/DSSS PLCP sublayer 285High-rate data scrambling 2881EEE 802.1 1 high-rate operating channels 2891EEE 802.1 1 DSSS high-rate modulation and data rates 290Complementary code keying (CCK) modulation 290DSSS packet binary convolutional coding (PBCC) 292Frequency-hopping spread spectrum (FHSS) interoperability 294Chapter 13 IEEE 802.11j operation in Japan at 4.9 GHz and 5 GHz 295Expanded Country information element 295Mandatory and optional modes of operation 299PLCP header, Signal field, and Rate subfield 300Extended frequency bands and transmit RF power levels 302Transmit mask and adjacent channel interference 304Spurious emissions 306Regulatory domain references 307Number of frequency channels and data rates 308Receiver sensitivity, CCA, and slot time 309Transmitter error vector magnitude (EVM) 311Chapter 14 IEEE 802.11g higher data rates in 2.4 GHz frequency band 313Network deployment and user scenario 313Mandatory and optional modes of operation 314Optional modes of operation 316PPDU formats 319Operating channels 321Operation of lEEE 802.llgCSMA/CA and CCA 323Key system specifications 324Chapter 15 IEEE 802.1 In higher data rates beyond 54 Mbit/s 327Channel bonding 328Higher order modulation 329Multiple input multiple output (MIMO) 329Chapter 16 System design considerations for IEEE 802.11 WLANs 333The Medium 333Multipath 334Path loss in a WLAN 337Es/No vs BER performance 339Data rate vs aggregate throughput 341WLAN installation and site survey 341Interference in the 2.4 GHz frequency band 342Antenna diversity 343Power management defined 344Glossary 349Index 353