A terminal device for use in a wireless telecommunications system, the terminal device comprising: a receiver; a transmitter; and a controller; wherein the receiver is operable to receive a first control message from a base station, the first control message indicating a radio resource for use by at least one of the receiver and transmitter to exchange a signal with the base station and the first control message comprising a code generated on the basis of an identifier of an intended terminal device and a value of a time-dependent parameter at a transmission time of the first control message, the intended terminal device being a terminal device intended for exchanging the signal with the base station; and the controller is operable to: attempt to perform a predetermined process using the code of the first control message, an identifier of the terminal device and the value of the time-dependant parameter at the transmission time of the first control message; wherein: if the predetermined process is not successfully completed, disregard the first control message; if the predetermined process is successfully completed, control at least one of the receiver and transmitter to exchange a signal with the base station using the radio resource indicated by the first control message; wherein the identifier of the intended terminal device is a Radio Network Temporary Identifier, RNTI, of the intended terminal device; the value of the time-dependent parameter at the transmission time of the first control message comprises a system frame number, SFN, of the first control message and a subframe number of the first control message; characterized in that the first control message is repeatedly received a plurality of times and the SFN and subframe number of the first control message are determined to be the SFN and subframe number of the first or final repetition of the first control message. a receiver; a transmitter; and a controller; wherein the receiver is operable to receive a first control message from a base station, the first control message indicating a radio resource for use by at least one of the receiver and transmitter to exchange a signal with the base station and the first control message comprising a code generated on the basis of an identifier of an intended terminal device and a value of a time-dependent parameter at a transmission time of the first control message, the intended terminal device being a terminal device intended for exchanging the signal with the base station; and the controller is operable to: attempt to perform a predetermined process using the code of the first control message, an identifier of the terminal device and the value of the time-dependant parameter at the transmission time of the first control message; wherein: if the predetermined process is not successfully completed, disregard the first control message; if the predetermined process is successfully completed, control at least one of the receiver and transmitter to exchange a signal with the base station using the radio resource indicated by the first control message; wherein the identifier of the intended terminal device is a Radio Network Temporary Identifier, RNTI, of the intended terminal device; the value of the time-dependent parameter at the transmission time of the first control message comprises a system frame number, SFN, of the first control message and a subframe number of the first control message; characterized in that the first control message is repeatedly received a plurality of times and the SFN and subframe number of the first control message are determined to be the SFN and subframe number of the first or final repetition of the first control message. if the predetermined process is not successfully completed, disregard the first control message; if the predetermined process is successfully completed, control at least one of the receiver and transmitter to exchange a signal with the base station using the radio resource indicated by the first control message; wherein the identifier of the intended terminal device is a Radio Network Temporary Identifier, RNTI, of the intended terminal device; the value of the time-dependent parameter at the transmission time of the first control message comprises a system frame number, SFN, of the first control message and a subframe number of the first control message; characterized in that the first control message is repeatedly received a plurality of times and the SFN and subframe number of the first control message are determined to be the SFN and subframe number of the first or final repetition of the first control message.