A Medium Access Delay MAC aware metric for Multihop Wireless Networks

Internet predominant transport protocols, such as TCP and TFRC, face performance degradation in Multihop Wireless Networks because of the high loss and link failure rates. Many solutions have been proposed to improve the transport layer operation. These solutions are either based on network state estimation or use information from MAC layer (called MAC metrics) in a cross-layer manner to better comprehend the network state. In this paper, we define the pertinent MAC metrics to reflect the network state, and provide a comparative study among each other, their expected usage and measurement methods at MAC layer. We also investigate the behaviors of MAC metrics through several experiments in order to reveal their effectiveness in reflecting network events such as contention, collision and loss. We show that the Medium Access Delay metric is the most effective to reflect faithfully the MAC states and to detect the network congestion and contention earlier than the other.