In a method for selecting, by a base station, one or more transponders out of a plurality of transponders, selection steps are performed at least at two selection levels or stages. The base station controls all selection steps at the first and second level. The first selection level includes: each transponder generates a random transponder number, the base station generates numbered time slots, each transponder transmits a marker if and when its random transponder number coincides with a time slot number. When a single transponder random number coincides with a time slot number the respective transponder is selected by the base station. If more than one transponder random numbers coincide with a time slot number the second selection procedure is performed at a second selection level as a stochastic or a deterministic or a mixed stochastic-deterministic selection procedure.