Currently most resource allocation algorithms used in wireless communication networks arrange each user’s transmission rate based on the type of user data, while neglecting the quality of the users’ communication channels. In this study, the relationship between the target SINR (interference plus noise ratio) and the BER (bit error rate) requirement was established with consideration of both the communication channel decay and the error control mechanism. A minimum-power constraint was proposed to satisfy the requirement generated by the quality change in communication channels on transmission power. This algorithm analyzes the requirement of each time slot on the maximum transmission capacity, determines the variable capacity and the available channels of each time slot, and decides the transmission priority of data packets based on QoS requirements of various services. Ultimately, the proposed algorithm increases system capacity to satisfy the BER requirements and QoS requirements of various services by the simulation.