A wireless communication device is provided with a first radio module and a second radio module inside. The first radio module performs wireless transceiving according to a plurality of first traffic patterns which each indicates allocations of a plurality of first slots for a plurality of forthcoming transmitting or receiving operations, respectively. The second radio module determines an indicator indicating at least one of a plurality of second traffic patterns which each indicates allocations of a plurality of second slots for a plurality of forthcoming transmitting or receiving operations, respectively. Particularly, one or more allocations of the second slots are selectively determined according to the first traffic patterns. Also, the second radio module transmits the indicator to a peer communication device, so that the peer communication device performs transmitting or receiving operations according to the indicator.