This paper evaluates the quality of service (QoS) in Wi-Fi networks considering medium access control algorithms. It provides the wireless local area networks (WLAN) traffic analysis based on hotspot statistics. It also studies the distribution of physical layer frame arrival time and channel utilization time. The results show the presence of self-similar distribution dramatically influencing the QoS parameters. The paper suggests QoS evaluation model in Wi-Fi public networks considering both user and signaling traffic.