Apparatus and methods for processing signals are disclosed. A data structure for processing a signal includes a payload part having at least one of data coding information including pilot coding information per a frame and entropy coding information. The data structure includes a header part having main configuration information for the payload part. In the data structure, the main configuration information includes a first time information part having time information for entire frames and a first frequency information part having frequency information for the entire frames. The main configuration information further includes a first internal grouping information part including information for internal-grouping a group having a plurality of data per the frame.