<p>In this paper, we estimate the optimal guard radio resource required to satisfy the handoff call dropping probability (HDP) under a specified target with a minimum new call blocking probability (NBP). It is purely based on the concept of guard radio resources, here referred to as guard channels (GCs). We suggest the optimal guard channel estimation scheme (OGCES) using the linear search technique (LST) to theoretically find the optimal number of GCs to be reserved at each base station. The quality-of-service (QoS) parameters used are the NBP and HDP. Numerical results are found to compare with GC, fractional guard channel (FGC), limited fractional guard channel (LFGC), and uniform fractional guard channel (UFGC) schemes. Numerical results show that this suggested algorithm gives an optimal number of GCs that guarantees the HDP below the given target with a minimum NBP. Further improvement in time complexity is achieved using the binary search technique (BST). It is also found that the LFGC scheme optimizes the blocking performances and further incurs higher time complexity compared to our proposed OGCES scheme. It is further observed that our suggested OGCES scheme shows better new call blocking performance compared to the UFGC scheme.</p>