Conflict-Aware Relay Selection for Multicast in MUD based Wireless Networks

Abstract

Multipoint Relays (MPR) [1] selection is a good step toward building a very proficient routing scheme for multicast/broadcast communications. It considers the fact that data transmitted by a node is overheard by all the users in the sender’s communication range, called the Wireless Broadcast Advantage (WBA) [2][4][6]. However, when a node elects its MPR nodes it does not consider their channel qualities (i.e. they do not consider the Multi-User Diversity (MUD) [3][5] factor), that has a significant influence on the network performance. Many other works consider the MUD and the rate adaptation (RA) features [15][16]. However these works are distorted by severe simplifications that are made about some common wireless network problems such as: the number of transmissions, the access scheduling, the interference conflicts, etc. In this paper, we introduce three new MUD, WBA and RA based relay selection schemes. The first one proposed, called the Efficient Multi-user Diversity based Relay (E-MDR) selection scheme, is done over steps by exploiting the channel qualities in term of maximum achievable data rate (or channel capacity). The proposed EMDR based flooding strategy achieves the best multicast throughput without considering concurrent transmissions. It aims jointly (i) to reduce the number of relays, (ii) to maximize the throughput of each single multicast session (or partition), (iii) to reduce the number of transmissions, (iv) to exploit extremely the offered link capacities and as a consequence (v) to enhance the allover network throughput. The second MUD, WBA and RA based relay selection scheme, called the Conflict free Multi-user Diversity based Relay (C-MDR) selection scheme, performs relay selection with consideration of the interference factor. It targets (i) to select relay nodes and their data transmission rates that maximize the multicast throughput, (ii) to consider the effect of access scheduling when choosing relay nodes and (iii) to resolve conflict problems. Finally, the EC-MDR is proposed to do a compromise between C-MDR and E-MDR.