A digital broadcasting system and a method for transmitting and receiving digital broadcast signal are disclosed. The method of processing a digital broadcast signal comprises encoding signaling information for mobile data, forming data groups including mobile data, a plurality of long known data sequences, a plurality of segmented known data sequences and the encoded signaling information, interleaving data in the data groups, transmitting the digital broadcast signal including the data groups having the interleaved data, and wherein the signaling information includes concatenation information indicating whether the segmented known data sequences are concatenated between the data groups included in the digital broadcast signal.