This letter presents a flexible rate-splitting multiple access (RSMA) framework for near-field (NF) integrated sensing and communications (ISAC). The spatial beams configured to meet the communication rate requirements of NF users are simultaneously leveraged to sense an additional NF target. A key innovation lies in its flexibility to select a subset of users for decoding the common stream, enhancing interference management and system performance. The system is designed by minimizing the Cram\'{e}r-Rao bound (CRB) for joint distance and angle estimation through optimized power allocation, common rate allocation, and user selection. This leads to a discrete, non-convex optimization problem. Remarkably, we demonstrate that the preconfigured beams are sufficient for target sensing, eliminating the need for additional probing signals. To solve the optimization problem, an iterative algorithm is proposed combining the quadratic transform and simulated annealing. Simulation results indicate that the proposed scheme significantly outperforms conventional RSMA and space division multiple access (SDMA), reducing distance and angle estimation errors by approximately 100\% and 20\%, respectively.

翻译：本文提出了一种面向近场集成感知与通信的灵活速率分割多址接入框架。为满足近场用户通信速率需求而配置的空间波束，被同时用于感知一个额外的近场目标。其关键创新在于能够灵活选择一部分用户来解码公共流，从而增强干扰管理与系统性能。该系统设计通过优化功率分配、公共速率分配和用户选择，以最小化联合距离与角度估计的克拉美-罗下界。这导出了一个离散的非凸优化问题。值得注意的是，我们证明了预配置的波束足以进行目标感知，无需额外的探测信号。为解决该优化问题，本文提出了一种结合二次变换与模拟退火的迭代算法。仿真结果表明，所提方案显著优于传统速率分割多址接入与空分多址接入，将距离与角度估计误差分别降低了约100%与20%。