An apparatus and method for generating a Scheduling Assignment (SA), which reduces a probability of an incorrect action by a User Equipment (UE) in response to a reception of the SA, in a communication system wherein a base station transmits the SA being a first type or a second type and including at least one Information Element (IE). The method includes setting at least one bit in the at least one IE with an arbitrary value, if the SA is of the first type; setting the at least one bit in the at least one IE with a predetermined value, if the SA is of the second type; and setting any remaining bits in the at least one IE with arbitrary values.