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802.11 Arbitration Part 2: Getting your marbles in the right bucket

Part Two: EDCA How is it different than DCF? Wireless is a shared medium. The fundamental method for sharing this medium is DCF, Distributed Coordination Function. This is the method used when QoS is not present. When QoS is present EDCA (Enhanced Distributed Coordination Function) is used to access the channel. EDCA observes many of the same steps as DCF. Carrier sense is performed exactly as it is in DCF. The way a STA observes an IFS and the parameters of the contention window are different. The IFS used in a QoS BSS (Basic Service Set) is called an AIFS (arbitration interframe space). The length of the AIFS is unique for each QoS access category. In DCF the CW has one range, 0-10

802.11 Arbitration: I could have been a contender.

Part One: DCF Wireless is a shared medium. The fundamental method for sharing this medium is DCF, Distributed Coordination Function. This is the method used when QoS is not present. There are 3 major steps a STA must observe to gain access to the WM (wireless medium). They are Carrier Sense, IFS (Inter-Frame Spacing), and the Random Backoff Timer. Now let's go through the details of using DCF for channel access. When a STA needs to transmit it must contend for the medium. This applies to all wireless STA's including access points. The first step a STA performs is carrier sense. When performing physical carrier sense the STA does two things. The STA listens for raw RF energy above it

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802.11 Arbitration Part 2: Getting your marbles in the right bucket

802.11 Arbitration: I could have been a contender.