Technology - Wireless - Broadband 5 - 802-11 QoS, MIMO & Propagation

Synopsis

This report discusses 802.11’s new QoS arrangements (WMM) and enhancements for greater performance using MIMO (Multiple In Multiple Out) multi-antennae systems using 802.11n. We discuss the behaviour of 2.45 and 5GHz microwaves, with special reference to outdoor propagation, polarisation, point-to-point links, antennae and the Fresnel zone.

Table of Contents

• 1. Synopsis
• 2. 802.11e - Quality of Service (QoS)
  • 2.1 WiFi Multimedia - WMM
  • 2.2 Four priority levels
  • 2.3 WMM Baseline - Enhanced DCF Channel Access (EDCA)
  • 2.4 HCF Controlled Channel Access (HCCA)
  • 2.5 Contention Free Bursts
  • 2.6 Direct Link Protocol (DLP) and piggybacking
  • 2.7 WMM Scheduled Access
  • 2.8 WMM Power Save
  • 2.9 Fast roaming and other enhancements
• 3. 802.11n - MIMO
  • 3.1 The Enhanced Wireless Consortium
  • 3.2 Other enhancements in 802.11n
    • 3.2.1 Frame Aggregation
    • 3.2.2 Block Acknowledgement
    • 3.2.3 Short guard intervals
  • 3.3 Multipath required for enhanced performance
  • 3.4 MIMO for long distance links?
  • 3.5 Reach and diversity
  • 3.6 Adaptive Antennae Systems
• 4. Propagation in and near buildings
• 5. Point-to-point links
  • 5.1 Propagation and Fresnel zone
  • 5.2 Antennae and cabling
  • 5.3 Polarisation
• 6. Related reports
  • 6.1 Market reports
  • 6.2 Technology reports