A transmission node for use in a wireless communication network includes a first CPRI unit for transmitting auxiliary data to a second CPRI unit in the transmission node. A memory unit stores control word data of the auxiliary data. A memory write block is connected between the first CPRI unit and the memory unit for writing the control word data to the memory unit based on a first set of frame timing signals received from the first CPRI unit. A memory read and merge block is connected to the memory unit for reading the control word data stored in the memory unit based on a second set of frame timing signals, merging the control word data with IQ data, and transmitting the merged auxiliary data to the second CPRI unit.