Abstract:

Negative effect of virtual carrier sensing mechanism on EDCA mechanism is elaborated.Network allocation vector （NAV）of virtual carrier sensing mechanism is indicated that which waste channel resource in the case of uncompleted RTS/CTS four-way handshake.Then the key parameters which effect on the performance of EDCA are discussed and the value of the parameters are deduced under the condition of NAV settings with or without NAV clear mechanism,without consideration of NAV negative effect.At last,simulations show the throughput of EDCA in different access categories（AC）.Apparently the NAV settings of virtual carrier sensing mechanism brought big effect on the throughput of EDCA,and that with NAV clear mechanism is better than that without NAV clear mechanism.

Key words: wireless local area network, enhanced distributed channel access, virtual carrier sensing, network allocation vector