A wireless telecommunications system (e.g. LTE) comprising a radio interface having a downlink radio frame structure comprising radio sub frames including an arrangement of reference symbols, e.g. cell specific reference symbols (CRS) is described. A base station is configured to determine a period of time for which certain terminal device specific data are not scheduled for transmission to a 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 the base station to identify where reference symbols are suppressed. The terminal device may thus determine, from which reference symbols are suppressed, a period of time for which the terminal device is not expected to receive certain types of data and can thus enter a reduced activity mode for that period.
