The invention presents methods and corresponding devices for improving cooperative spectrum initiating sensing. A device (61;61.1) first receives an invitation (17;35) to participate in cooperative spectrum sensing. The device performs an autonomous decision (19) on whether or not to participate in the cooperative spectrum sensing in response to the invitation. If it is determined to participate in the cooperative spectrum sensing to which the invitation relates, spectrum sensing is then performed (21;45). With the invention, sensor selection becomes “distributed”, i.e. it is up to the device itself to decide on participation in the cooperative sensing, rather than having, for example, a central entity determining what devices should act as sensors in the cooperative spectrum sensing. One advantage is that the amount of signalling required for sensor selection can be kept at a minimum, thereby saving communication resources.