1. A method for selecting by a base station at least one transponder out of a plurality of transponders, said method comprising the following steps a) to e) performed as a first selection procedure at a first selection level: a) controlling by said base station (BS) a first selection procedure, b) producing by each transponder (TR 1 , TR 2 ,. .. ) a random transponder number, c) generating in said base station (BS) numbered time slots so that each time slot has a time slot number, d) transmitting by each transponder a marker to said base station during a time slot having a respective time slot number coinciding with said respective random transponder number, e) selecting that transponder which was the only transponder transmitting during said coinciding time slot, f) checking, at a second selection level, whether more transponders than one have transmitted a respective marker in the same time slot to provide a respective collision signal, and g) performing, at said second selection level under the control of said base station and in response to said collision signal a second selection procedure as any one of a stochastic, a deterministic, and a mixed stochastic-deterministic selection procedure.