Packet Appending as a Method of Alleviating the Turbo-Cliff Effect in BICM-ID

In this letter, a recent transmission technique, packet-appended bit-interleaved coded modulation with iterative decoding (PA-BICM-ID) is analyzed from another perspective. The main result of this letter is the observation that packet appending outperforms modulation doping in alleviating the turbo-cliff effect, increases goodput at low SNR, and preserves the power to shift the error floor downward, all at the same time. It is also shown that after relaxing some prerequisite assumptions on backward compatibility of PA-BICM-ID with gray-labeled BICM, it becomes possible to simplify the transmitter and receiver designs.