A multi-criteria association policy for scalable auxiliary drone networks in large-scale events

Unmanned Aerial Vehicles (UAVs) have become a flexible alternative for providing temporary communication support in scenarios where fixed infrastructure may be overloaded or unavailable. This paper investigates UAV-based auxiliary networks for large-scale events, where sudden user density spikes can degrade the performance of conventional cellular systems. A key challenge in this context is maintaining stable UAV-user associations under high user density and limited UAV resources. Building on our previous Received Signal Strength Indicator-driven Association Policy (RDAP), this work introduces the Enhanced RDAP (e-RDAP), a multi-criteria association policy that combines RSSI, Packet Delivery Ratio (PDR), and communication delay with an adaptive deployment strategy. The proposed policy is evaluated using Network Simulator 3 (NS-3) under static and dynamic mobility scenarios, including realistic human mobility patterns. Results show that e-RDAP improves the reliability-efficiency trade-off compared with RDAP. In the highest-density dynamic scenario, e-RDAP achieves a $$3.8\%$$ 3.8 % improvement in PDR and an $$11.8\%$$ 11.8 % reduction in latency compared with RDAP. It also reduces reassociations by $$17.3\%$$ 17.3 % and controls overhead by $$27\%$$ 27 % compared with RDAP. Compared with the UAV-specific MULB-LA benchmark, e-RDAP also provides higher PDR, lower delay, fewer reassociations, and lower signaling overhead, indicating that QoS-aware multi-criteria association provides additional gains beyond load-aware association alone.