A wireless telecommunications system including a base station and a terminal device and employing a radio interface having a downlink radio frame structure including radio subframes including an arrangement of reference symbols for channel estimation. The base station is configured to determine a period of time for which certain terminal device specific data are not scheduled for transmission to the terminal device and to communicate this information to the terminal device through selective suppression of at least one reference symbol. Different reference symbol(s) may be suppressed to indicate different periods of time. The terminal device is configured to monitor the reference symbols transmitted by a base station to identify where reference symbols are suppressed, to determine a period of time for which the terminal device is not expected to receive certain types of data and enter a reduced activity mode for that period to conserve processing and power resources.