Adaptive Reliable Multicast in 802.11 Networks

Ubiquitous connectivity in smart city and smart home scenarios gives rise to new uses cases for local distribution of data to multiple devices. In wireless local area networks, the common mode of data transport even for such scenarios is unicast, despite the broadcast nature of wireless medium. This is mainly due to lack of efficient mechanisms for high-throughput reliable multicast transmissions. In this paper we present an adaptive multicast rate control mechanism for IEEE 802.11 wireless networks, which can effectively improve the performance of multicast transfers while tolerating an adjustable level of packet loss at the MAC layer. Then we adapt and employ NORM as the transport layer protocol to complement the proposed multicast transmission rate control, as a proof of concept for cross-layer flexible handling of rate control and reliability. We compare the performance of this multicast approach to the common practice of TCP-based unicast data distribution as well as to the NORM-based multicast distribution at the basic transmission rate. The proposed approach is shown to scale well and improve data distribution performance for any given network topology and multicast receiver group size.