Nonorthogonal multiple access (NOMA) has been widely recognized as a promising spectral efficiency technique for the next generation of wireless communication networks due to its ability to support multiple users in the same orthogonal resource block. In response to the increasing demands for extensive connectivity and high-volume data transmission, a novel index modulation (IM)-aided NOMA scheme has been conceived to improve downlink transmission by capitalizing on the flexibility provided by the constellation rotation design for superposition coding. In the proposed scheme, known as IM aided NOMA with the constellation rotation (IM-NOMA-CR), users are categorized into cell-edge group (far-user accommodated) and cell-center group (near-user accommodated) based on their channel conditions. The rotated constellation-based IM operation is exclusively applied to users in the near-user group, who receive lower power allocations compared to the far-user group, enabling them to transmit additional information while ensuring system reliability. This approach enhances spectral efficiency by activating all subcarriers (orthogonal resource blocks) to transmit information to scheduled users, in contrast to the conventional IM-NOMA scheme. Moreover, extra information can be transmitted through constellation rotation in the superposition coding process, setting it apart from traditional NOMA schemes. Subsequently, the maximum likelihood detector employing successive interference cancellation (ML-SIC) is utilized at the receiving end to decode the intended symbols for all users. Numerical simulations have been carried out to validate the efficacy of the proposed IM-NOMA-CR design, demonstrating a significant enhancement in spectral efficiency and error performance compared to existing NOMA schemes.

中文翻译：

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通过叠加编码旋转增强索引调制辅助非正交多址接入


非正交多址（NOMA）因其在同一正交资源块中支持多个用户的能力而被广泛认为是下一代无线通信网络有前途的频谱效率技术。为了满足对广泛连接和大容量数据传输日益增长的需求，一种新颖的索引调制（IM）辅助NOMA方案被设计出来，通过利用叠加编码的星座旋转设计所提供的灵活性来改善下行链路传输。在所提出的称为具有星座旋转的IM辅助NOMA（IM-NOMA-CR）的方案中，用户根据其使用情况被分为小区边缘组（容纳远用户）和小区中心组（容纳近用户）。渠道条件。基于旋转星座的IM操作专门应用于近端用户组中的用户，与远端用户组相比，这些用户获得较低的功率分配，使他们能够在保证系统可靠性的同时传输附加信息。与传统的 IM-NOMA 方案相比，该方法通过激活所有子载波（正交资源块）向调度用户传输信息来提高频谱效率。此外，叠加编码过程中可以通过星座旋转来传输额外的信息，这使其与传统的NOMA方案不同。随后，在接收端利用采用连续干扰消除（ML-SIC）的最大似然检测器来解码所有用户的预期符号。 已经进行了数值模拟来验证所提出的 IM-NOMA-CR 设计的有效性，证明与现有 NOMA 方案相比，频谱效率和错误性能显着增强。