A wireless telecommunications system including a base station, a terminal device, and a radio interface having a downlink radio frame structure including radio subframes including an arrangement of reference symbols for channel estimation. The base station determines a time period when certain terminal device specific data are not scheduled for transmission to the terminal device and communicates this information to the terminal device through selective suppression of at least one reference symbol. Different reference symbols may be suppressed to indicate different time periods. The terminal device monitors the transmitted reference symbols to identify where reference symbols are suppressed, to determine a time period when 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, and provide fast physical-layer signaling of periods during which the terminal device may conserve resources by decoding fewer transmissions.