Method to achieve fast active scan in 802.11 wlan

Abstract

A method for fast active scanning and an Access Point apparatus that reduces the delay in convention active scanning. The method includes the step of giving an AP higher priority to transmit a probe response than is currently known. This priority comes at the delay of transmission of the probe response, so preferably the probe response can be delayed by just the time that the AP needs to prepare the response plus the time, if any, for the frame already in the air to finish. According to the invention, a method can include steps for: sending a uni-cast probe request message by an (STA)on a particular channel having at least one Access Point (AP)in communication therewith; receiving by one particular (AP)the probe request message sent by the (STA); sensing by the particular (AP)of a point coordination function (PCF) interframe space (PIFS)of the particular channel; and sending by the particular (AP)of a probe response message to the (STA)in response to the probe request message after the PIFS. As the probe request is uni-cast, there is no need for a backoff interval as only one AP will respond. Since normal traffic utilizes the longer DIFS space plus backoffs to avoid collisions, the AP will always be able to respond to a probe request of scan faster than other items can respond on the channel, thus giving the AP priority when sending the probe response message.