Wireless Design Principles

• Wireless Signal Mesured in dBm ( Power referenced against one Milliwatt )
• Range is roughly -30dBm to -90dBm
  • -30dBm = Max Achievable ( not desired ).
  • -67dBm = Mininum for real-time Apps.
  • -80dBm = Minimum for communication.
• Noise is always a challenge
• Signal to Noise Ratio ( SNR ) = ( Signal – Noise ) = Value
  • Mininum SNR of 25 is needed for real-time apps.

Wireless Channel Selection: 2.4Ghz and 5Ghz

• 15% – 20% overlap required for seamless roaming.
• -67dBm at cell edges for real-time traffic.
• Multi-floor should be a 3D design.
• 2.4Ghz means fewer clean channels (1 – 11).
• 5Ghz means less range.

Site Survey tips:

• Identify the “Customer Style” you’re dealing with.
• Determine coverage area and key locations ( Good and bad ).
• Do a “floorplan-based WAP map”- Preliminary design.
• Install Waps.
• Do a “Boots on the ground” site survey, floorplan in-hand.
• Make adjustments ( Move WAPs, add Maps) to achieve data rates.
• Document everything you’ve done.