From the Transport to the Physical Channel in LTE
- Transport channels are then mapped on the physical channels which are sent over the air interface
- A CRC is calculated and appended to each TB. It allows the receiver to detect errors. It is used by retransmission mechanisms like H-ARQ
- Depending on the Transport Format and the radio quality, the TB is coded and interleaved.
- The H-ARQ is a process running in the UE and in the eNodeB to allow a fast retransmission in case of errors.
- The resulting bit sequence is modulated and mapped on the sub-carriers of the Resource Block used for the transmission (one or several RBs).
- The data are modulated and mapped on the sub-carriers.
- The basic time-frequency unit is the Resource Block.