A hybrid ARQ retransmission method involves encoding data packets with a forward
error correction (FEC) technique prior to transmission. The data packets are retransmitted
based on an automatic repeat request and subsequently soft-combined with previously
received erroneous data packets either on a symbol-by-symbol or a bit-by-bit basis.
The symbols of the erroneous data packets are modulated by employing a first signal
constellation. The symbols of the retransmitted data packets are modulated by employing
at least a second signal constellation. Each symbol bit has a mean bit reliability
defined by the individual bit reliabilities over all symbols of the predetermined
signal constellation. The first constellation and the at least second signal constellation
are selected such that the combined mean bit reliabilities for the respective bits
of all transmissions are averaged out.
