802.11n：A.Survival.Guide(2012.4)Matthew.Gast.pdf

802.11n：A.Survival.Guide(2012.4)Matthew.Gast.pdf 文字版，非扫描版802.11n: A Survival guideMatthew S gastO REILLYBeijing· Cambridge· Farnham·Koln· Sebastopol· Tokyo802.1In A Survival guideby matthew S GastCopyright@ 2012 Matthew Gast. All rights reservedPrinted in the United States of americaPublished by O Reilly Media, Inc, 1005 Gravenstein Highway North, Sebastopol, CA 95472O'Reilly books may be purchased for educational, business, or sales promotional use. Online editionsarealsoavailableformosttitles(http://my.safaribooksonline.com).Formoreinformationcontactourcorporate/institutionalsalesdepartment800-998-9938orcorporate@oreilly.comEditors: Mike Loukides and Meghan Blanchette Cover Designer: Karen MontgomeryProduction Editor: Rachel SteelyInterior Designer: David FutatoProofreader: Kristen Borglustrators: Robert romano and Rebecca DemarestRevision History for the First Edition:201203-30First releaseSeehttporeillycom/catalog/errata.csp?isbn=9781449312046forreleasedetailsNutshell Handbook, the Nutshell Handbook logo, and the O Reilly logo are registered trademarks ofO'Reilly media, Inc. 802. 11n: A Survival guide, the image of a barbastelle bat, and related trade dressare trademarks of o' Reilly media, IncMany of the designations used by manufacturers and sellers to distinguish their products are claimed asrademarks. Where those designations appear in this book, and O Reilly Media, Inc, was aware of atrademark claim, the designations have been printed in caps or initial capsWhile every precaution has been taken in the preparation of this book, the publisher and author assumeno responsibility for errors or omissions, or for damages resulting from the use of the information contained hereinISBN:978-1-449-31204-61333128185In memory of Nicholas A. Jeremica(December 5, 1977-December 12, 2006)And for Maria, Max, and nicolewho no doubt miss him even more than i doTable of contentsForewordPrefaceX1. Introduction to 802.11n-2009The Technology of 802. 11nPhysical layer(Phy) enhancementsLink layer(MAc) Enhancements802.1In: first We take the lan. then We take the worldPart the phy2. Mimo and the 802. 11n phyThe big Idea: MIMO and Data StreamsSpatial StreamsRadio chRelationship Between Spatial Streams and Radio Chains3. Channels, Framing and Coding17Channel Structure and layout17Channel structureRegulatory rules and operating ChannelsTransmission: Modulation and guard interval20Modulation and Coding Set (mcs20Guard intervalPLCP Framing22HT Mixed Mode Plcp Format24Transmission and Reception Process27802.11n SpeedComparison 1: 802.1la/g versus lxl lInComparison 2 20 MHz versus 40 MHz channels30Mandatory Phy features4. Advanced phy features for performance33Beamformingypes of BeamformingSpace- Time block Code(STBC37Low-Density Parity Check(LDPC)38Part the mac5. MAC Basics,41Frame Changes41Airtime Efficiency Improvements45A-MPDU45A-MSDU47Aggregation Compared49Block acknowledgment49Reduced interfaame SpRIE52Protection of Non-HT Transmissions53Protection Mechanisms54Protection rules55Security56Mandatory mac Features6. Advanced MAC Features for Interoperability59Radio Medium CoordinationClear-Channel Assessment(CCA)60Channel width Selection(20/40 MHz BSS)40 MHz Intolerance for Channel Width interoperability64Power-Saving64Spatial multiplexing(sm) power Save65Power-Save Multi-Poll(PSMP65Part Ill. Using 802. 1In to build a Network7. Planning an 802.11n Network69What's On Your Network?70Mobile End-User devicesTraffic and Application Mix74ⅵ i Table of ContentsNetwork IntegrationNetwork services76Backbone connectiⅤit79Power requirementsSecurityTKIP Transition Planning and Support83User Authentication84Design Checklist848. Designing and Installing an 802.11n Network................ 87Network Architecture for 802. 11n87Architecture Comparison802.1 1n hardwaTechnology"Waves”98Wi-Fi Alliance CertificationCoverage and Capacity planning103AP Mounting locations104Channel Types and layout105AP Transmit Power Setting106Network Management107Network analysis107Network tuning108Implementation ChecklistAfterwordGlossary115Table of contents|ⅶi