OFDMA ISAC中时频资源分配的基本权衡
On the Fundamental Trade-Offs of Time-Frequency Resource Distribution in OFDMA ISAC
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中文总结 AI 辅助
本研究针对OFDMA ISAC系统，推导了子载波与感知符号分配对距离和速度CRB及通信速率的影响，确定了最优和最差感知性能的分配方案，并证明子载波分配对速率影响微小，可解除相关约束。
中文摘要 AI 辅助
集成感知与通信（ISAC）被广泛认为是下一代移动通信系统中关键且新兴的技术。然而，如何优化时频域无线电资源分配以同时服务于通信和感知，特别是在出现冲突优先级的情况下，成为一个关键且具有挑战性的问题。针对这一问题，我们首先建立了频域子载波分配与距离克拉美-罗界（CRB）、时域感知符号分配与速度CRB，以及窄带系统中子载波分配与可实现通信速率之间的理论关系。基于推导出的距离和速度CRB表达式，在单用户设备（single-UE）和多用户正交频分多址（OFDMA）ISAC系统中，分别确定了具有最优和最差感知性能的子载波和感知符号分配方案。此外，我们证明了在同步窄带OFDMA ISAC系统中，子载波分配对可实现通信速率的影响微乎其微。这一发现表明，与子载波分配优化相关的可实现速率约束可以被解除。为证实我们的分析，我们提供了仿真结果，展示了所提出分配方案的性能优势。
英文摘要
Integrated sensing and communications (ISAC) is widely recognized as a pivotal and emerging technology for the next-generation mobile communication systems. However, how to optimize the time-frequency domain radio resource distribution for both communications and sensing, especially in scenarios where conflicting priorities emerge, becomes a crucial and challenging issue. In response to this problem, we first formulate the theoretical relationship between frequency domain subcarrier distribution and the range Cramér-Rao bound (CRB), and time domain sensing symbol distribution and the velocity CRB, as well as between subcarrier distribution and achievable communication rates in narrowband systems. Based on the derived range and velocity CRB expressions, the subcarrier and sensing symbol distribution schemes with the optimal and the worst sensing performance are respectively identified under both single-user equipment (single-UE) and multi-UE orthogonal frequency-division multiple access (OFDMA) ISAC systems. Furthermore, it is demonstrated that the impact of subcarrier distribution on achievable communication rates in synchronous narrowband OFDMA ISAC systems is marginal. This insight reveals that the constraints associated with subcarrier distribution optimization for achievable rates can be released. To substantiate our analysis, we present simulation results that demonstrate the performance advantages of the proposed distribution schemes.
