SI-CCMAC: Sender initiating concurrent cooperative MAC for wireless LANs

In wireless LANs, throughput is one of, if not the most, important performance metric. This metric becomes more critical at the bottleneck area of the network, which is normally the area around the Access Point (AP). In this paper, we propose SI-CCMAC, a sender initiating concurrent cooperative MAC for wireless LANs. It is designed to improve the throughput performance in the region near the AP through cooperative communication, where data is forwarded through a two-hop high data-rate link instead of a low data-rate direct link. Further-more, nodes are coordinated to enable concurrent transmissions to further increase throughput. The coordination part of SICCMAC is modeled as a vertex coloring problem, a maximum independent set problem and a MDP problem, depending on different scenarios. For all three modeling, solutions can be found, based on the existing algorithms to optimize the throughput performance while guaranteeing a max-min fairness. Through simulation, we show that SI-CCMAC can significantly shorten the transmission time for stations with low data rate links to the AP and it has better throughput performance than other MAC protocols, such as CoopMAC and legacy IEEE 802.11.