We study the dynamic allocation of bandwidth for video traffic in wireless networks. Our approach consists of two stages. In the first stage, we apply the FARIMA (Fractional Autoregressive Integrated Moving Average) models to forecast traffic based on online traffic measurements. In the second stage, we use the forecast results to allocate bandwidth dynamically. We evaluate our FARIMA-based scheme by comparing it with the ARIMA-based and the static schemes in terms of packet loss probability, queue length and bandwidth utilization. Through the experiments with real traffic traces, we demonstrate our approach works well for highly fluctuating traffic in WiFi.