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In a multiple service wireless and mobile system, different numbers of channels (or bandwidth) are assigned to different services according to their QoS requirements. Real-time services have the lowest delay tolerance, while they might not need very large bandwidth. Non-real-time services can improve their performance if they are given more bandwidth and they are also not as sensitive to delay as the real-time services. Many channel allocation and resource management schemes have been carried out for wireless system with differentiated services. However, the link status of channel has not been considered very well in those schemes. Many of them just assume that all channels are homogeneous and their status will not charge throughout the service durations. This is not true in real world. In this paper, we take into account the physical channel status in our preemptive priority channel allocation scheme. Transmission rate changes dynamically according to variational channel status as a result of shadowing and fading. Our scheme uses the transmission rate of each channel as one important fact in choosing the channel candidate to be preempted. When the channel originally having a poor transmission rate is assigned to a new user, its link status is very likely to gain some improvements. Therefore, both the user QoS and the system utilization get a boost using this scheme. We evaluate the system performance in terms of blocking probabilities, forced termination probabilities, and average number of user in the system.