A method for a transmitter in a communication system, a method for a receiver, a transmitting apparatus, and a receiving apparatus are provided. The method includes identifying, by a transmitter, information bits in a first downlink control information (DCI) and information bits in a second DCI; appending, by the transmitter, one bit of value zero to the second DCI, if a number of the information bits in the second DCI is equal to a number of the information bits in the first DCI; appending, by the transmitter, one or more zero bits to the second DCI based on a payload size of the second DCI, if the number of the information bits in the second DCI belongs to one of ambiguous sizes; and transmitting, to a receiver, the second DCI, wherein a payload of the second DCI comprises the information bits in the second DCI and at least one zero padding bit appended to the second DCI, and wherein the one or more zero bits is appended to the second DCI until the payload size of the second DCI does not belong to one of the ambiguous sizes and the payload size of the second DCI is not equal to a payload size of the first DCI.