Target Tracking With ISAC Using EMLSR in Next-Generation IEEE 802.11 WLANs: Non-Cooperative and Cooperative Approaches

New amendments support Wi-Fi access points (APs) and stations (STAs) in next-generation IEEE 802.11 wireless local area networks (WLANs). IEEE 802.11be (Wi-Fi 7) features multi-link operation (MLO) with multi-link device (MLD) hosting multiple interfaces, highlighting enhanced multi-link single-radio (EMLSR) operation. IEEE 802.11bf features Wi-Fi sensing, enabling integrated sensing and communications (ISAC) in Wi-Fi. In this paper, we pioneer an innovative combination of EMLSR operation and ISAC functionality, considering target tracking with ISAC using EMLSR in IEEE 802.11 WLANs. We establish a unique scenario where AP MLD needs to make ISAC decision and STA MLD selection when its interface gains a transmit opportunity (TXOP). Then, we present key design principles: ISAC decision involves the Kalman filter for target state and a developed time-based strategy for sensing/communications determination, while STA MLD selection involves a Cram\'er-Rao lower bound (CRLB)-based trilateration performance metric along with a developed candidate strategy for UL sensing and involves a developed weighted proportional fairness-aware heuristic strategy for DL communications. We propose novel non-cooperative and cooperative approaches, where each interface leverages its own information and aggregate information across all interfaces, respectively. For proposed non-cooperative and cooperative approaches, simulation results exhibit their tradeoff and superiority about sensing and communications.