WiHound: Target Tracking with ISAC Using EMLSR in Next-Generation IEEE 802.11 WLANs

Next-generation IEEE 802.11 wireless local area network (WLAN) amendments have been proposed to support Wi-Fi stations (STAs) and access points (APs). IEEE 802.11be (Wi-Fi 7) features multi-link operation (MLO) with multi-link device (MLD), where the enhanced multi-link single-radio (EMLSR) operation is promising. Also, IEEE 802.11bf launches a sensing capability, paving the way for integrated sensing and communications (ISAC). Pioneering an innovative combination of EMLSR operation and ISAC functionality in this paper, we propose WiHound, a novel method for target tracking with ISAC using EMLSR in IEEE 802.11 WLANs. Specifically, we adopt the Kalman filter for target tracking and develop a score-based ISAC decision approach for the AP MLD to decide between sensing and communications within each transmit opportunity (TXOP). For a sensing TXOP, we solve a discrete convex optimization problem based on Cramér-Rao lower bound (CRLB) to select three STA MLDs required in trilateration. Conversely, for a communications TXOP, we develop an efficient fairness-aware STA MLD selection heuristic approach toward weighted proportional fairness. Simulation results confirm the superiority of WiHound on striking a balance between sensing and communications. Moreover, we investigate the effect of number of STA MLDs on the sensing performance of WiHound.