We propose a wireless resource allocation scheme considering mobility for providing quality of service (QoS) under IT micro mobility domain with differentiated services (DiffServ). In this scheme, each base station provides infinite waiting queue for both assured forwarding (AF) and best effort (BE) handoff flows and guard channels for expedited forwarding (EF) handoff flows. This scheme also allows BE flows to overflow over the region reserved for EF flows with the risk of being preempted by the newly arriving EF flows. If there is no idle channel bandwidth in a new cell after a handoff in heavily crowded area, the EF handoff request is just dropped. Hence, it is required to give a statistical guarantee on the EF handoff success in this wireless mobile environment. The remaining channel bandwidth except for the regions reserved for EF flows in a cell is dedicated to both AF and BE flows. The BE flows preempted by the newly arriving EF flows in a cell are queued, and AF handoff flows has preemptive priority over BE flows existing in dedicated region. We derive the dropping probabilities of both EF and AF flows, and the average system time of BE flows by using a transition rate matrix approach. We also obtain the forced termination probability of EF flow and bandwidth utilization.