In this paper, we propose a joint single-base localization and communication enhancement scheme for the uplink (UL) integrated sensing and communications (ISAC) system with asynchronism, which can achieve accurate single-base localization of user equipment (UE) and significantly improve the communication reliability despite the existence of timing offset (TO) due to the clock asynchronism between UE and base station (BS). Our proposed scheme integrates the CSI enhancement into the multiple signal classification (MUSIC)-based AoA estimation and thus imposes no extra complexity on the ISAC system. We further exploit a MUSIC-based range estimation method and prove that it can suppress the time-varying TO-related phase terms. Exploiting the AoA and range estimation of UE, we can estimate the location of UE. Finally, we propose a joint CSI and data signals-based localization scheme that can coherently exploit the data and the CSI signals to improve the AoA and range estimation, which further enhances the single-base localization of UE. The extensive simulation results show that the enhanced CSI can achieve equivalent bit error rate performance to the minimum mean square error (MMSE) CSI estimator. The proposed joint CSI and data signals-based localization scheme can achieve decimeter-level localization accuracy despite the existing clock asynchronism and improve the localization mean square error (MSE) by about 8 dB compared with the maximum likelihood (ML)-based benchmark method.

翻译：本文针对上行链路集成感知与通信系统中存在异步时钟的问题，提出了一种联合单基站定位与通信增强方案。该方案可在用户设备与基站间存在时钟异步导致的定时偏移的情况下，实现用户设备的精准单基站定位，并显著提升通信可靠性。所提方案将信道状态信息增强集成到基于多信号分类的到达角估计中，因此不会给系统增加额外复杂度。我们进一步利用基于多信号分类的距离估计方法，并证明该方法能抑制时变定时偏移相关相位项。通过联合利用用户设备的到达角和距离估计，可实现用户设备的位置估计。最终提出一种基于信道状态信息与数据信号的联合定位方案，该方案可协同利用数据信号与信道状态信息改善到达角和距离估计，从而进一步提升用户设备的单基站定位性能。大量仿真结果表明：增强的信道状态信息可获得与最小均方误差信道估计器等效的误码率性能；所提联合信道状态信息与数据信号定位方案可在时钟异步条件下达到分米级定位精度，相较于基于最大似然估计的基准方法，其定位均方误差改善约8 dB。