In the downlink transmission, the physical downlink shared channel (PDSCH) carries the user data (Transport block). The modulation format of PDSCH channel may be QPSK, 16 QAM or 64 QAM. The data (Transport block) arrives to the PDSCH coding unit every transmission time interval (TTI). The generation of the PDSCH signal consists of the following processes:
CRC attaching to the transport block.