| （英） |
Wireless LAN service becomes popular. However, expansion of the service area and rapid increase in users significantly deteriorated wireless LAN quality. In particular, Access Points (APs) were placed randomly without being optimized. IEEE 802.11 based WLAN systems have a multi-rate mechanism in physical layer, where the transmission rate that sends each frame is dynamically determined by the transmission quality between the transmitting mobile stations and receiving mobile stations. In that case, a station selects the transmission rate to be used for each frame transmission by the rate switching algorithm. Sustainability is maintained by using a higher transmission rate when the signal rate condition is good, otherwise using a lower transmission rate. This mechanism causes performance anomaly problem. In order to solve this problem, the authors have proposed an autonomous moving access point (AP) that moved to the user’s center of gravity. It showed that the system throughput increased up to about 20%. However, it is not clear that how much quality of experience (QoE) increased. In this paper, the relation between QoE and QoS is clarified by subjective evaluation experiment, and it show how much QoE improves when AP is moved to the center of gravity. |