A communication method that operates by determining a first set of physical parameters of a first channel by a coordinator in a wireless communication system; establishing communication with a first set of devices over the first channel; determining a protection period in accordance with a pre-determined rule; broadcasting a channel-adjustment message, wherein the channel-adjustment message comprises a set of instructions for indicating how to adjust from the first channel to a second channel, and the set of instructions comprise channel bandwidth information for indicating how to adjust to a bandwidth of the second channel and central frequency information for indicating how to adjust to a central frequency of the second channel; and communicating with a second set of devices over the second channel during the protection period.