Background:802.11 MAC Layer

• Wireless access scheme:

  • Contention ,Polling ,TDMA methods;

• 802.11 MAC uses contention methods with some polling capabilities;

• Contention methods use following heuristics

  • Random back-off, listen before talk, and mandated inter-frame delay periods
    • to avoid collisions among individual users on shared wireless medium;

• MAC employs a beacon message from Access Point- (AP) to individually polled stations for data exchange at specific times.