  In this work, we consider transmissions over block fading channels and assume
that adaptive modulation and coding (AMC) and hybrid automatic repeat request
(HARQ) are implemented. Knowing that in high signal-to-noise ratio, the
conventional combination of HARQ with AMC is counterproductive from the
throughput point of view, we adopt the so-called layer-coded HARQ (L-HARQ).
L-HARQ allows consecutive packets to share the channel and preserves a great
degree of separation between AMC and HARQ; this makes the encoding and decoding
very simple and allows us to use the available/optimized codes. Numerical
examples shown in the paper indicate that L-HARQ can provide significant
throughput gains compared to the conventional HARQ. The L-HARQ is also
implemented using turbo codes indicating that the throughput gains also
materialize in practice.
