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

翻译：一种新型几何整形技术——陪集整形被提出并分析，用于编码QAM和PAM信令。该方法可在不增加额外复杂度的情况下同时应用于信息比特和校验比特。研究表明，随着纠错码长度和调制阶数的增长，所提整形方案与信道容量的差距可任意缩小。本文提供了Gallager型界及数值结果，包括该整形方案与短/中长度二进制编码及非二进制LDPC编码QAM信令结合的性能对比。