A method to improve the Quality of Service (QoS) in a wireless network, preferably in a WLAN according to the IEEE proposal 802.11e comprising an Access Point (AP) and at least one mobile station (STA) with different Access Categories (ACs) being defined for the transmission of frames depending on their priority, and in which a Power Save Mode (PSM), preferably according to IEEE standard 802.11, is used in the network is characterized in that the PSM queue is separated into several sub-queues at the Base Station.