In future wireless networks, the determination of the amount of resource that a base station (cell) must reserve to maintain a certain call dropping probability is likely to become a very important issue. We present in this paper a new algorithm for channel assignment in wireless networks called predictive reservation policy (PRP) based on the fixed channel allocation (FCA) concept. This new dynamic channel reservation scheme adapts the number of guard channels in each cell to: (1) the current number of ongoing calls in neighbouring cells and (2) on the anticipation of the future localisation of users. The proposed scheme for radio channel allocation reduces handoff call blocking probability substantially at the expense of slight increases in new call blocking probability by giving resource access priority to handoff calls over new calls. PRP improves the classical FCA. An approximate analytical model of PRP is presented. The effectiveness of the proposed method is emphasized on a complex configuration.