Threshold-Aware Link-Graph Compression with Per-Sensor Observed-Packet Coverage Constraints and Temporal Robustness...

In multi-gateway LoRaWAN deployments, a single uplink packet may be received through several sensor-gateway links, creating link-graph redundancy. We formulate compression as minimum-cardinality selection under aggregate and per-sensor observed-packet coverage constraints. The sensor-separable structure enables an exact dynamic program to certify optima and benchmark a reusable fairness-aware greedy ordering, a threshold-dependent multi-cover greedy, and a coverage-only ablation. Evaluation uses 1,232,813 uplinks observed by at least 1 gateway over 17 calendar months. On this deployment, proposed and multi-cover methods matched the minimum across 1000 threshold pairs. Coverage-only was optimal for 4%, with mean and maximum gaps of 5.84 and 8 links. These methods returned different equal-cardinality subsets for 506 pairs. The proposed subset improved worst-month coverage slack in 437 cases and met both requirements in more months in 53 cases, never in fewer. Retrospective monthly optimization required 9.24-11.59 links on average, versus 19 for an all-month-feasible subset. In a 14-month prospective evaluation, the expanding-window policy achieved pass rates of 78.6%, 57.1%, and 50.0% with three or four reconfigurations of at most two links each, and an unseen sensor caused a common cold-start failure. These results quantify trade-offs among link budget, future-month compliance, and subset stability.