A communications apparatus is provided. A signal processing device receives an RF signal comprising a wanted signal complying with a first wireless communications protocol from an air interface and processes the RF signal according to one or more signal processing parameter(s) to obtain the wanted signal. An interference detector analyzes one or more characteristic(s) of an interference signal of the wanted signal. The interference signal complies with a second wireless communications protocol different from the first wireless communication protocol. A coexistence optimization controller is coupled to the signal processing device and the interference detector, obtains information regarding the characteristic(s) of the interference signal from the interference detector and dynamically adjusts the signal processing parameter(s) according to the characteristic(s) of the interference signal.