BLBP: A Beacon-Driven Leader Based Protocol for MAC Layer Multicast Error Control in Wireless LANs

In Wireless LANs MAC layer multicast error control schemes lead to shorter delays compared with application layer schemes. In this paper, we enhance a Leader Based Protocol (LBP) and propose a Beacon-driven Leader Based Protocol (BLBP) for the MAC layer multicast error control. Like LBP, BLBP selects one of the multicast group receivers as the leader and allows acknowledgement and negative acknowledgements from the leader receiver and non-leader receivers respectively. The use of the beacon frame is to lead the non-leader receivers to set timers and to announce the sequence number of the following data frame. Thanks to the sequence check based on the beacon frame, BLBP avoids the unnecessary transmissions in LBP. Both the theoretical analysis and simulation experiments show that BLBP can correct nearly all the errors for all receivers in the MAC layer and is more efficient than LBP. BLBP is even more efficient than the application layer automatic repeat request (ARQ) scheme and the total multicast delay is much shorter. BLBP is very good for real-time multicast applications with strict delay constraints.