A new leader-based multicast scheme with a Raptor code in IEEE 802.11 multi-rate WLANs

Multimedia streaming using a multicast scheme over IEEE 802.11 multi-rate wireless local area networks (WLANs) faces many challenges owing to the heterogeneous channel conditions of receivers. Although many multicast schemes have been proposed to support multimedia streaming over multi-rate WLANs, those schemes do not deal with multicast transmission efficiently. In this paper, a new leader-based multicast scheme with a Raptor code is proposed. The proposed scheme consists of a leader selection block, a scalable video coding (SVC) block with unequal error protection (UEP), and a link adaptation block with a Raptor code. In the proposed scheme, one of the multicast group members is selected as a multicast group leader according to a leader cost, and then link adaptation operates between the multicast transmitter and the multicast group leader. In addition, SVC, UEP, and Raptor code mechanisms are applied to guarantee the minimum required performance of multicast group members. The proposed scheme aims to enhance the link utilization and guarantees the minimum quality-of-service requirement of multicast group members. Simulation results show that the proposed scheme performs better than previous multicast schemes.