A system and method is provided for communicating in a wireless communication
system
which supports link adaptation or link adaptation and incremental redundancy. The
invention provides link adaptation at multiple code rate by dividing fixed length
RLC blocks into coded sub-blocks. CRC code may be appended to the RLC blocks for
error detection. The sub-blocks are then grouped into transmission units for transmission.
The number of sub-blocks in each group is varied to provide multiple code rates.
Headers are used to identify the transmission units being transmitted. In the case
of retransmission, the transmission units may be expressly identified through extended
headers. One or more of the originally transmitted sub-blocks are dropped and replaced
by the extended headers in the retransmission. Accordingly, the present invention
provides for a retransmission code rate which may be different from the code rate
at which the transmission units were originally transmitted.
