Recently, low latency has become one of the most critical requirements in Wi-Fi networks (e.g., for Internet access). Many factors and events such as bufferbloat, which unexpectedly happen, can affect the delay of Wi-Fi networks. Hence, the delay requirement leads to the essential of a management mechanism, which can 1) correctly detect negative behavior in latency; 2) and adjust network settings adaptively. In this paper, we introduce a solution for the two mentioned issues, which uses the emerging Software Defined Networking (SDN) technology. Our SDN-based method can guarantee a predetermined value of delay in the Wi-Fi network by taking advantage of SDN. More specifics, we correctly monitor the delay fluctuation in Wi-Fi networks on an SDN controller. We then deploy a task of queue adjustment when the delay value exceeds the predetermined one. We have developed and evaluated our method using the mininet-wifi emulator and POX controller. The results show that we can maintain the guaranteed delay level for packet transmissions without significant effects on network performance.
