[Papers] Multiple-transmission-rate scheme using SVC technology and QoE control suitable for multicast distribution over WLAN systems

抄録

Since multicast distribution using a wireless local area network (WLAN) system is broadcast distribution for each group, it can efficiently use bandwidth and is suitable for broadcast-type video delivery services. However, the conventional multicast distribution scheme for WLAN systems has several issues. A multicast is transmitted at a single transmission rate because of the distribution by a group with multiple stations (STAs). Thus, the STAs far from the access point (AP) cannot receive multicast data at a high transmission rate. On the other hand, in the case of a low transmission rate, it is impossible to transmit high-bit-rate video, and the channel utilization efficiency decreases. Furthermore, since there is no retransmission control function, packet loss occurs immediately when a propagation error or packet collision occurs. In conventional related works, the communication quality suitable for multicast distribution over a WLAN is insufficient.

We propose a multicast distribution scheme for WLAN to solve these issues. The proposed scheme transmits using multiple transmission rates according to the location of the STAs using scalable video coding (SVC) technology. Furthermore, the optimum transmission rate can be selected on the basis of the quality of experience (QoE) indicator and the conditions at the locations of the STAs, and the communication quality can be guaranteed. In this study, we confirm that the proposed scheme maintains a high communication quality, even when the multicast distribution area is expanded compared with that obtained by the conventional scheme.