A communication device for handling an uplink, UL, transmission, comprising: a storage device, for storing instructions of: receiving a semi-persistent scheduling, SPS, uplink, UL, grant on a control channel in a first transmission time interval, TTI, from a base station, BS, wherein the SPS UL grant indicates a UL frequency resource periodically allocated to the communication device for a plurality of UL transmissions; storing the SPS UL grant as a configured UL grant; initializing the configured UL grant to start in the earliest TTI after the first TTI and applying the configured UL grant to a plurality of TTIs after the earliest TTI; transmitting at least one first repetition of a UL transmission by using a hybrid automatic repeat request, HARQ, process according to the configured UL grant; starting a UL HARQ round trip time, RTT, timer for the HARQ process in response to the UL transmission; and starting a drx-ULRetransmissionTimer for the HARQ process, when the UL HARQ RTT timer expires; monitoring the control channel, when the drx-ULRetransmissionTimer is running in at least one TTI belonging to an off duration of a discontinuous reception, DRX, cycle; and a processing circuit, coupled to the storage device, configured to execute the instructions stored in the storage device. a storage device, for storing instructions of: receiving a semi-persistent scheduling, SPS, uplink, UL, grant on a control channel in a first transmission time interval, TTI, from a base station, BS, wherein the SPS UL grant indicates a UL frequency resource periodically allocated to the communication device for a plurality of UL transmissions; storing the SPS UL grant as a configured UL grant; initializing the configured UL grant to start in the earliest TTI after the first TTI and applying the configured UL grant to a plurality of TTIs after the earliest TTI; transmitting at least one first repetition of a UL transmission by using a hybrid automatic repeat request, HARQ, process according to the configured UL grant; starting a UL HARQ round trip time, RTT, timer for the HARQ process in response to the UL transmission; and starting a drx-ULRetransmissionTimer for the HARQ process, when the UL HARQ RTT timer expires; monitoring the control channel, when the drx-ULRetransmissionTimer is running in at least one TTI belonging to an off duration of a discontinuous reception, DRX, cycle; and receiving a semi-persistent scheduling, SPS, uplink, UL, grant on a control channel in a first transmission time interval, TTI, from a base station, BS, wherein the SPS UL grant indicates a UL frequency resource periodically allocated to the communication device for a plurality of UL transmissions; storing the SPS UL grant as a configured UL grant; initializing the configured UL grant to start in the earliest TTI after the first TTI and applying the configured UL grant to a plurality of TTIs after the earliest TTI; transmitting at least one first repetition of a UL transmission by using a hybrid automatic repeat request, HARQ, process according to the configured UL grant; starting a UL HARQ round trip time, RTT, timer for the HARQ process in response to the UL transmission; and starting a drx-ULRetransmissionTimer for the HARQ process, when the UL HARQ RTT timer expires; monitoring the control channel, when the drx-ULRetransmissionTimer is running in at least one TTI belonging to an off duration of a discontinuous reception, DRX, cycle; and a processing circuit, coupled to the storage device, configured to execute the instructions stored in the storage device.