Coset Shaping: Constructions and Boundson
This addresses the need for efficient shaping in communication systems, but it appears incremental as it builds on existing geometric shaping methods.
The paper tackles the problem of improving the performance of coded QAM and PAM signaling by proposing a new geometric shaping technique called coset shaping, which can be applied to both information and parity bits without added complexity, and shows that the gap to capacity can be made arbitrarily small as code length and modulation order increase.
A new geometric shaping technique, referred to as coset shaping, is proposed and analyzed for coded QAM and PAM signaling. This method can be applied to both information and parity bits without introducing additional complexity. It is shown that, as the error-correcting code length and the modulation order grow, the gap to capacity of the proposed shaping scheme can be made arbitrarily small. A Gallager-type bound is provided together with numerical results, including performance comparisons for the shaping scheme combined with short and mid-length binary-coded, as well as nonbinary LDPC-coded QAM signaling