Channel charting is an emerging self-supervised method that maps channel state information (CSI) to a low-dimensional latent space, which represents pseudo-positions of user equipments (UEs). While this latent space preserves local geometry, i.e., nearby UEs are nearby in latent space, the pseudo-positions are in arbitrary coordinates and global geometry is not preserved. In order to enable channel charting in real-world coordinates, we propose a novel bilateration loss for multipoint wireless systems in which only the access point (AP) locations are known--no geometrical models or ground-truth UE position information is required. The idea behind this bilateration loss is to compare the received power at pairs of APs in order to determine whether a UE should be placed closer to one AP or the other in latent space. We demonstrate the efficacy of our method using channel vectors from a commercial ray-tracer.

翻译：信道图表是一种新兴的自监督方法，它将信道状态信息映射到低维潜空间，以表征用户设备的伪位置。尽管该潜空间保留了局部几何结构（即邻近的用户设备在潜空间中彼此接近），但其伪位置处于任意坐标系中，且全局几何结构未能得以保持。为实现基于真实世界坐标的信道图表构建，我们针对仅已知接入点位置的多点无线系统提出一种新颖的双边定位损失函数——该方法无需几何模型或真实用户设备位置信息。该双边定位损失的核心思想是通过比较接入点对之间的接收功率，判定潜空间中用户设备应更靠近哪一侧接入点。我们利用商业射线追踪器生成的信道向量验证了该方法的有效性。