802.11ac: a survival guide : [Wi-Fi at gigabit and beyond

The next frontier for wireless LANs is 802.11ac, a standard that increases throughput beyond one gigabit per second. This concise guide provides in-depth information to help you plan for 802.11ac, with technical details on design, network operations, deployment, and monitoring. Author Matthew Gast—an industry expert who led the development of 802.11-2012 and security task groups at the Wi-Fi Alliance—explains how 802.11ac will not only increase the speed of your network, but its capacity as well. Whether you need to serve more clients with your current level of throughput, or serve your existing client load with higher throughput, 802.11ac is the solution. This book gets you started. Understand how the 802.11ac protocol works to improve the speed and capacity of a wireless LAN Explore how beamforming increases speed capacity by improving link margin, and lays the foundation for multi-user MIMO Learn how multi-user MIMO increases capacity by enabling an AP to send data to multiple clients simultaneously Plan when and how to upgrade your network to 802.11ac by evaluating client devices, applications, and network connections Copyright 4 Table of Contents 7 Foreword 9 Preface 13 Audience 14 Conventions Used in This Book 14 Safari® Books Online 15 How to Contact Us 15 Acknowledgments 16 Chapter 1. Introduction to 802.11ac 19 History 19 The Core Technology of 802.11ac 22 Beamforming and Multi-User MIMO (MU-MIMO) 24 Operating Frequency Band for 802.11ac 26 802.11ac Product Development Plans 27 Chapter 2. The PHY 29 Extended MIMO Operations 29 Radio Channels in 802.11ac 30 Radio Channel Layout 30 Available Channel Map 33 Transmission: Modulation, Coding, and Guard Interval 35 Modulation and Coding Set (MCS) 35 Guard Interval 38 Error-Correcting Codes 39 PHY-Level Framing 39 The VHT Signal Fields 41 The Data Field 46 The Transmission and Reception Process 47 802.11ac Data Rates 50 802.11ac Data Rate Matrix 50 Comparison of 802.11ac Data Rates to Other 802.11 PHYs 53 Mandatory PHY Features 54 Chapter 3. The MAC 55 Framing 55 Frame Size and Aggregation 56 Management Frames 58 Medium Access Procedures 62 Clear-Channel Assessment (CCA) 63 Protection and Coexistence of 802.11ac with Older 802.11 Devices 66 Dynamic Bandwidth Operation (RTS/CTS) 68 Security 72 Mandatory MAC Features 74 Chapter 4. Beamforming in 802.11ac 77 Beamforming Basics 78 Null Data Packet (NDP) Beamforming in 802.11ac 83 Single-User (SU) Beamforming 87 Channel Calibration for Single-User Beamforming 88 Multi-User (MU) Beamforming 92 Channel Calibration for Multi-User Beamforming 92 Multi-User MIMO Transmission 96 MU-MIMO Implementation 100 Chapter 5. 802.11ac Planning 105 Getting Ready for 802.11ac 106 Catching the 802.11ac Technology Wave 107 Client Device Mix 109 Application Planning 111 Physical Network Connections 113 Security 116 Additional Planning Considerations 118 802.11ac Radio Planning 119 Available Radio Channels 119 Coverage and Capacity Estimates 119 Equipment Selection 124 Network Architecture for 802.11ac 127 Hardware Considerations 132 Building an 802.11ac Network 136 Channel Selection 136 Network Tuning and Optimization 138 Checklist 141 Glossary 143 About the Author 152 The next frontier for wireless LANs is 802.11ac, a standard that increases throughput beyond one gigabit per second. This concise guide provides in-depth information to help you plan for 802.11ac, with technical details on design, network operations, deployment, and monitoring.Author Matthew Gast—an industry expert who led the development of 802.11-2012 and security task groups at the Wi-Fi Alliance—explains how 802.11ac will not only increase the speed of your network, but its capacity as well. Whether you need to serve more clients with your current level of throughput, or serve your existing client load with higher throughput, 802.11ac is the solution. This book gets you started.Understand how the 802.11ac protocol works to improve the speed and capacity of a wireless LANExplore how beamforming increases speed capacity by improving link margin, and lays the foundation for multi-user MIMOLearn how multi-user MIMO increases capacity by enabling an AP to send data to multiple clients simultaneouslyPlan when and how to upgrade your network to 802.11ac by evaluating client devices, applications, and network connections