Fig. 4
From: OFDMA-based network-coded cooperation: design and implementation using software-defined radio nodes
A simplified block diagram of the OFDMA transmitter. Source node’s data is passed over I/Q block via bit loading block. S/P conversion block is used in order to implement serial-parallel conversion. IDFT is applied to the output of the subcarrier distribution block. Then, P/S conversion is implemented for data transmission. CP is added to ensure circular convolution. Finally, serial digital data is converted to analog data by using D/A block