A method of channel contention procedure with CCA level enhancement is proposed. A wireless device initiates an EDCA channel contention procedure to gain access to the wireless medium. The device determines an intended TX channel width and performs primary channel CCA using a set of CCA levels based on the intended TX channel width for determining channel idle or busy condition in the EDCA procedure. Upon gaining access, the device performs secondary channel CCA and thereby determining a final TX channel width. The device transmits radio signals using the final TX channel width and a TX spectral power density, which is adjusted to be corresponding to the intended TX channel width. By raising CCA levels to be based on the intended transmission channel width, the likelihood of wide channel width transmission is increased. As a result, significant network throughput increase can be accomplished in dense deployment scenarios.