HARQ

Hybrid Automatic Repeat reQuest (HARQ)

- Highly effective technique that clearly increases the system efficiency

- Terminal requests retransmission when data block is erroneously received.

- Retransmitted and original data blocks are merged using soft combining

- The code rate increases with retransmissions.

- For HARQ we need ACK/NACK (acknowledgement, negative acknowledgement) information from terminal. This information is send via HS-DPCCH.

thanks for the doc