Csma/ca in time and frequency domains

The present invention concerns a method for a communication device to transmit a data packet in a wireless communication system. The method comprises: determining (21) a first set of transmission parameters comprising a first central transmission frequency and a first spectral bandwidth; transmitting (33) a first data packet by applying the first set of transmission parameters; determining (35) whether or not the first data packet collided with a second data packet from a second communication device; determining (37) a second set of transmission parameters, which in case of collision comprises a second central transmission frequency, different from the first central transmission frequency, and a second spectral bandwidth, which is different from the first spectral bandwidth with a first, non-zero probability and the same as the first spectral bandwidth with a second probability; and transmitting (33) a second data packet by applying the second set of transmission parameters.