Performance Evaluation of WDM Channel Transmission for Probabilistic Shaping With Partial Multilevel Coding

Rate-Adaptive Concatenated Multi-Level Coding With Novel Probabilistic Amplitude Shaping

“…In [27], [28], it has been proposed to employ both conventional PAS scheme [17] and two-level MLC in a single transmission block. More specifically, the "Labeling1" corresponds to two-level MLC, and the "Labeling2", i.e., the BRGC labeling, corresponds to the conventional scheme.…”

“…Recently, two-level MLC schemes combined with PAS have been studied in [27]- [29]. In [28], it has been demonstrated that their MLC with PAS (referred to as "partial-MLC" in [28]) achieves approximately 38-39% reduction in the estimated power consumption compared to the conventional PAS scheme [17]. However, since the methods presented in [27]- [29] are based on the conventional PAS structure, their MLC fail to achieve the target signal distribution (see Fig.…”

“…However, since the methods presented in [27]- [29] are based on the conventional PAS structure, their MLC fail to achieve the target signal distribution (see Fig. 1 in [28]), and thus degrade a shaping gain. More specifically, in [27]- [29], a BRGC labeling was newly introduced in addition to the original bit-labeling designed for two-level MLC [6], [8], [9], in order to compensate for the shaping performance loss.…”

Geometric Constellation Shaping for Concatenated Two-Level Multi-Level Codes

“…Note that l = m correspond to the conventional BICM system. In this paper, we consider l to be integer, i.e., the number of inner coded bit levels is fixed over the entire transmission block, while it is also possible to mix different numbers of inner coded bit levels [24], [26], [48].…”

“…Although PAS may achieve better achievable information rate (AIR) than GS in general [29], PAS requires an external distribution matcher (DM) whose efficient hardware implementation can be challenging especially for achieving a large shaping gain. Also, since the PAS was originally designed for Gray labeling, which is not necessarily well-suited for MLC, it is not straightforward to apply PAS to MLC [24]- [26]. In contrast, GS does not require a DM, and is compatible with two-level MLC.…”