An apparatus and a method for improving packet transmission and reducing latency in VoIP over WLAN using switched beam antennas having multiple directional antenna beams are disclosed. In an access point having a switched beam antenna, or other smart antenna system, the present invention extends the coverage area of an access point for authentication and association of a new WTRU, extends the access points coverage area during in session transmissions with a WTRU, and adjusts data rates. The method also controls Contention Period (CP)/Contention Free Period (CFP) timing amongst beams emanating from an access point having a switched beam antenna, or other smart antenna system. Fast diversity switching, frame level switching, lowered data rates, and scanning multiple directional antenna beams for the optimum transmission beam are disclosed to improve beam selection and packet transmission.