Dynamic channel allocation (DCA) and transmit power control (TPC) are known as efficient tools to accommodate the explosive demand for broadband wireless access services, by utilizing the limited radio resources while satisfying predefined quality of service (QoS). However, the high complexity of the interactions between discrete DCA and continuous TPC renders a close-form solution to the joint optimization problem intractable. In this paper, a detailed convergence analysis is addressed and reveals that the optimal channel assignment can strengthen the stability condition of TPC. A distributed algorithm is proposed to interactively perform DCA and TPC in a real time manner, with the ability to adjust power and channel according to network dynamics. A real WLAN is employed to evaluate the performance of the integration. It shows that the joint design approach can offer a substantial improvement in terms of user throughput, power saving and interference mitigation compared with conventional fixed-power random channel allocation algorithm.