The advent of ultra-massive multiple-input-multiple output systems holds great promise for next-generation communications, yet their channels exhibit hybrid far- and near- field beam-squint (HFBS) effect. In this paper, we not only overcome but also harness the HFBS effect to propose an integrated location sensing and communication (ILSC) framework. During the uplink training stage, user terminals (UTs) transmit reference signals for simultaneous channel estimation and location sensing. This stage leverages an elaborately designed hybrid-field projection matrix to overcome the HFBS effect and estimate the channel in compressive manner. Subsequently, the scatterers' locations can be sensed from the spherical wavefront based on the channel estimation results. By treating the sensed scatterers as virtual anchors, we employ a weighted least-squares approach to derive UT' s location. Moreover, we propose an iterative refinement mechanism, which utilizes the accurately estimated time difference of arrival of multipath components to enhance location sensing precision. In the following downlink data transmission stage, we leverage the acquired location information to further optimize the hybrid beamformer, which combines the beam broadening and focusing to mitigate the spectral efficiency degradation resulted from the HFBS effect. Extensive simulation experiments demonstrate that the proposed ILSC scheme has superior location sensing and communication performance than conventional methods.

翻译：超大规模多输入多输出系统的出现为下一代通信带来了巨大前景，但其信道表现出混合远场与近场波束斜视效应。本文不仅克服了该效应，更将其转化为优势，提出了一种集成定位感知与通信框架。在上行训练阶段，用户终端发送参考信号以同时进行信道估计与定位感知。该阶段通过精心设计的混合场投影矩阵克服混合场波束斜视效应，并以压缩感知方式估计信道。随后，基于信道估计结果，可从球面波前感知散射体位置。通过将感知到的散射体视为虚拟锚点，我们采用加权最小二乘法推算用户终端位置。此外，我们提出了一种迭代优化机制，利用精确估计的多径分量到达时间差进一步提升定位精度。在后续下行数据传输阶段，我们利用获取的位置信息进一步优化混合波束成形器，结合波束展宽与聚焦技术，以缓解混合场波束斜视效应导致的频谱效率下降。大量仿真实验表明，所提出的集成定位感知与通信方案在定位感知与通信性能上均优于传统方法。