A communications apparatus includes a first radio frequency (RF) signal processing device, a first baseband signal processing device and a processor. The first RF signal processing device transceives a plurality of RF signals to and from a peer communications apparatus to communicate with the peer communications apparatus in compliance with a first Radio Access Technology (RAT) and processing the RF signals. The first baseband signal processing device processes a plurality of baseband signals corresponding to the RF signals. The processor obtains an uplink scheduling indicating a predetermined time assigned by the peer communications apparatus to transmit uplink data from the baseband signals, determines whether to transmit the uplink data at the predetermined time according to a gap-creation criterion, and transmits padding instead of the uplink data to the peer communications apparatus at the predetermined time when the gap-creation criterion is satisfied.