An apparatus of a User Equipment, UE, the apparatus comprising: memory; and processing circuitry, configured to: decode a narrowband physical downlink control channel, NPDCCH, that schedules a transmission, by the UE, of a narrowband physical uplink shared channel, NPUSCH, in one or more radio frames, wherein the radio frames are configured for time-division duplexing, TDD, operation, wherein subframes of the radio frames include uplink subframes and downlink subframes; determine an uplink scheduling delay for the transmission of the NPUSCH based on a sum of a predetermined first number of subframes and a variable second number of subframes, wherein the second number of subframes is based on a window of variable size, wherein the window starts when the first number of subframes has elapsed since reception of the NPDCCH, wherein the window ends when a number of uplink subframes has elapsed since the start of the window, wherein the number of uplink subframes is indicated by an uplink scheduling parameter included in the NPDCCH, wherein the memory is configured to store information identifying the uplink scheduling parameter; characterised in that the processing circuitry is further configured to: determine a transmission window for the transmission of the NPUSCH; and if the transmission window includes one or more downlink subframes: refrain from monitoring for other NPDCCHs during the downlink subframes of the transmission window. memory; and processing circuitry, configured to: decode a narrowband physical downlink control channel, NPDCCH, that schedules a transmission, by the UE, of a narrowband physical uplink shared channel, NPUSCH, in one or more radio frames, wherein the radio frames are configured for time-division duplexing, TDD, operation, wherein subframes of the radio frames include uplink subframes and downlink subframes; determine an uplink scheduling delay for the transmission of the NPUSCH based on a sum of a predetermined first number of subframes and a variable second number of subframes, wherein the second number of subframes is based on a window of variable size, wherein the window starts when the first number of subframes has elapsed since reception of the NPDCCH, wherein the window ends when a number of uplink subframes has elapsed since the start of the window, wherein the number of uplink subframes is indicated by an uplink scheduling parameter included in the NPDCCH, wherein the memory is configured to store information identifying the uplink scheduling parameter; decode a narrowband physical downlink control channel, NPDCCH, that schedules a transmission, by the UE, of a narrowband physical uplink shared channel, NPUSCH, in one or more radio frames, wherein the radio frames are configured for time-division duplexing, TDD, operation, wherein subframes of the radio frames include uplink subframes and downlink subframes; determine an uplink scheduling delay for the transmission of the NPUSCH based on a sum of a predetermined first number of subframes and a variable second number of subframes, wherein the second number of subframes is based on a window of variable size, wherein the window starts when the first number of subframes has elapsed since reception of the NPDCCH, wherein the window ends when a number of uplink subframes has elapsed since the start of the window, wherein the number of uplink subframes is indicated by an uplink scheduling parameter included in the NPDCCH, wherein the memory is configured to store information identifying the uplink scheduling parameter; characterised in that the processing circuitry is further configured to: determine a transmission window for the transmission of the NPUSCH; and if the transmission window includes one or more downlink subframes: refrain from monitoring for other NPDCCHs during the downlink subframes of the transmission window. determine a transmission window for the transmission of the NPUSCH; and if the transmission window includes one or more downlink subframes: refrain from monitoring for other NPDCCHs during the downlink subframes of the transmission window.