Hierarchical modulation provides unequal error protection to transmitted data according to their relative importance. In this article, hierarchical modulation constellation based on circular $\theta $ -quadrature amplitude modulation (CTQAM), 4/ ${M}$ -CTQAM, $M = 2^{k}$ , $k \geq 4$ , is proposed. We provide a construction method and bit-to-symbol mapping for the proposed hierarchical modulation constellation. We then examine the bit error rate performance of 4/ ${M}$ -CTQAM and validate the theoretical results through computer simulations in additive white Gaussian noise (AWGN) and Rayleigh fading channels.

中文翻译：

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分层通函 θ-QAM

分层调制根据它们的相对重要性为传输的数据提供了不平等的错误保护。在本文中，基于循环的分层调制星座图 $ \ theta $ -正交幅度调制（CTQAM），4 / $ {M} $ -CTQAM， $ M = 2 ^ {k} $ ， $ k \ geq 4 $ ，建议。我们为提出的分层调制星座图提供了一种构造方法和位到符号映射。然后，我们检查4 / $ {M} $ -CTQAM并通过计算机模拟在加性高斯白噪声（AWGN）和瑞利衰落信道中验证理论结果。