Mobile station, a base station and a communication method

PROBLEM TO BE SOLVED: To provide suitable switching (hand-over) processing between the channel of a service area based on a CDMA-FDD system and the channel of a service area based on a CDMA-TDD system in a mobile communication system. SOLUTION: While communication based on the CDMA-FDD system is performed in a compression mode, the mobile station measures the receiving level of a down common channel contained in a signal based on the CDMA-TDD system. The measured receiving level is transmitted to the base station. When the instruction of switching to communication based on the CDMA-TDD system is received from the base station, the mobile station performs switching.