A method of an efficient low duty mode (LDM) operation for a femto base station is disclosed. The method of a low duty mode (LDM) operation for a femto base station comprises operating at an available interval of a first length according to a default LDM pattern; and operating at an unavailable interval of a second length according to the default LDM pattern, wherein the available interval begins with a frame including a first preamble, the first preamble including information of carrier configuration and system bandwidth.