An apparatus adapted to update a contention window, CW, comprising: a wireless local area network, WLAN, transceiver adapted to receive, during a monitoring period, a plurality of transmissions from a plurality of WLAN devices; a processor adapted to: identify transmission timing of a plurality of data frames encoded in at least some of said plurality of transmissions during said monitoring period; identify interlude timing of a plurality of transmission interludes between said plurality of data frames; calculate a statistical measure of length of said plurality of transmission interludes; update a CW value of said plurality of WLAN devices according to said statistical measure; wherein the plurality of transmissions are identified by the processor being adapted to: extract quality of service, QoS, parameters of each one of said plurality of WLAN devices from said plurality of transmissions, classify said plurality of transmissions as originated from a controlled access point or an uncontrolled access point according to said QoS parameters, and identify said at least some transmissions according to said classification. a wireless local area network, WLAN, transceiver adapted to receive, during a monitoring period, a plurality of transmissions from a plurality of WLAN devices; a processor adapted to: identify transmission timing of a plurality of data frames encoded in at least some of said plurality of transmissions during said monitoring period; identify interlude timing of a plurality of transmission interludes between said plurality of data frames; calculate a statistical measure of length of said plurality of transmission interludes; update a CW value of said plurality of WLAN devices according to said statistical measure; wherein the plurality of transmissions are identified by the processor being adapted to: extract quality of service, QoS, parameters of each one of said plurality of WLAN devices from said plurality of transmissions, classify said plurality of transmissions as originated from a controlled access point or an uncontrolled access point according to said QoS parameters, and identify said at least some transmissions according to said classification. identify transmission timing of a plurality of data frames encoded in at least some of said plurality of transmissions during said monitoring period; identify interlude timing of a plurality of transmission interludes between said plurality of data frames; calculate a statistical measure of length of said plurality of transmission interludes; update a CW value of said plurality of WLAN devices according to said statistical measure; wherein the plurality of transmissions are identified by the processor being adapted to: extract quality of service, QoS, parameters of each one of said plurality of WLAN devices from said plurality of transmissions, classify said plurality of transmissions as originated from a controlled access point or an uncontrolled access point according to said QoS parameters, and identify said at least some transmissions according to said classification. extract quality of service, QoS, parameters of each one of said plurality of WLAN devices from said plurality of transmissions, classify said plurality of transmissions as originated from a controlled access point or an uncontrolled access point according to said QoS parameters, and identify said at least some transmissions according to said classification.