Gain control based on the multi-mode wireless communication system in a packet-mode automatic detection method, the transmission signal field method for automatically detecting the packet mode and the packet mode method

PURPOSE: A packet mode auto-detection in multi-mode wireless communication system, a signal field transmission for the packet mode auto-detection, and a gain control based on the packet mode are provided to improve the packet mode detection accuracy. CONSTITUTION: A method for automatically detecting a packet mode in a wireless communication system supporting a multiple transmission mode includes: acquiring at least one of data rate information, packet length information and channel bandwidth information from a transmitted frame; and determining the packet mode on the basis of the phase rotation check result of a symbol transmitted after a signal field signal and at least one of the data rate information, the packet length information and the channel bandwidth information acquired from the transmitted frame.