Channel resource management (e.g., allocation and borrowing) is a critical aspect of wireless cellular networks. Since channel borrowing is an expensive task, incuring long delay, a key design goal of efficient channel resource management is to minimize the total number of channel borrowing operations. This paper focuses on the `Quantum' issue (number of channels) in the channel borrowing and releasing steps. The proposed concept employs the Working Set approach, popular in Operating Systems, into channel resource management, where the quantum of channels transacted during each borrowing and release operation reaches a middle point and would not be too small or too large. An analytical model and steady-state simulation have been used to demonstrate the benefits.