The present disclosure relates to a mobile terminal and base station and respective operation methods. The mobile terminal comprises circuitry, which in operation, determines a condition for requesting on-demand a transmission of other system information; performs a random access procedure; and receives via broadcast a system information message including the on-demand requested other system information. The system information request message of the random access procedure includes an information element with a bit-pattern conforming to a specific format with at least a part of the bit-pattern for requesting the other system information. And the contention resolution message of the random access procedure includes the same, or the same part of the bit-pattern for detecting collisions during the random access procedure.