A method of processing a broadcast signal including an interactive broadcast service at a transmitter is disclosed. The method comprises generating an parameter table containing metadata about applications and interactive broadcast events targeted to the applications, dividing the parameter table into a plurality of parameter blocks, inserting each of the parameter blocks into each of a plurality of parameter table sections, generating a trigger which is a signaling element to identify signaling and establish timing of playout of the interactive broadcast events, inserting the trigger into a closed caption channel of the broadcast signal, transmitting the broadcast signal including the closed caption channel and a specific channel carrying the plurality of parameter table sections, wherein the trigger includes location information specifying a location of the parameter table in the broadcast signal.