Methods for Coordinating Radio Activities in Different Radio Access Technologies and Apparatuses Utilizing the Same

An apparatus for coordinating radio activities in different radio access technologies (RATs) is provided. A first RAT module performs a first channel activity, related to a first RAT, for transmitting or receiving information to or from a first cellular network by using an antenna, and requests that a measurement activity, related to the first RAT, is to be performed for measuring signal power of a serving cell and/or at least one neighbor cell in the first cellular network by using the antenna. A second RAT module requests that a second channel activity, related to a second RAT, is to be performed for transmitting or receiving information to or from a second cellular network by using the antenna. An arbiter schedules performance of the measurement activity between the first and second channel activities.