RIS-Enabled Cooperative Sidelink Positioning Under Partial Blockage

Reconfigurable intelligent surfaces (RISs) and sidelink communications have enabled radio positioning with zero access points (APs). In this paper, we study a positioning system with
$K$
single-antenna user equipments (UEs), a passive RIS, and zero APs. We show that
$K$
half-duplex UEs, under some blockage, can estimate their positions via two-way sidelink communications. We start by introducing the signal model. Then, we determine which paths are blocked using a deep neural network (DNN) and estimate the channel parameters. Next, we estimate the UEs' positions via one-dimensional search and trilateration. Finally, we evaluate the performance of the proposed algorithm through numerical studies.