A wireless communications method includes: obtaining a plurality of stream inputs, wherein the stream inputs include a first stream input complying with a first packet format and a second stream input complying with a second packet format, and the second packet format is different from the first packet format; applying pre-coding to the stream inputs to generate a plurality of pre-coded stream outputs, respectively; and performing wireless transmission upon the pre-coded stream outputs, wherein downlink Multi-User Multiple-Input Multiple-Output (MU-MIMO) transmission is involved in the wireless transmission of the pre-coded stream outputs.