Algorithm 5. Conditional Global Re-clustering with Persistent Tail-Hop Detection

Function ConditionalGlobalReclustering(round t)     Construct Creach(t) from CHs whose route/status reports successfully reach the BS     If ∣Creach(t)∣ = 0        Set ρtail(t) = 0 for numerical safety        Mark this observation as a severe backbone reachability failure        Store ρtail(t) for persistence evaluation        Maintain the current topology        Exit     End if     Calculate ρtail(t) from Creach(t)     Store ρtail(t) for persistence evaluation     Set persistenceFlag = false     If ρtail(t − 1) ≥ θtail AND ρtail(t) ≥ θtail        Set persistenceFlag = true     End if     If persistenceFlag = false        Maintain the current topology        Exit     End if     If t − lastReclusterRound < Trecluster_min        Do not execute global re-clustering at this observation        Maintain the current topology and keep the stored ρtail(t)        Exit     End if     If ongoing local repair, handover, or CH-HELP control procedures are active        Defer the global re-clustering request until the next global-maintenance entry point        Exit     End if Trigger global re-clustering Reset active node roles, including CH and member states. Clear routing tables and hop levels. Execute CH selection to select new cluster heads. Execute backbone route setup to rebuild the backbone routing topology. Update lastReclusterRound = t. End Function