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Multimedia services are a major application for IEEE 802.11 WLANs but the current standard does not utilize any rate adaptation technique for multicasting. SARM (SNR- based auto rate for multicast) is a new rate adaptation mechanism for multicasting multimedia content in IEEE 802.11 WLAN environments. Since there is no RTS/CTS or MAC ACK frame in multicast packet transmissions, SARM uses an auxiliary signaling method to obtain the channel quality for each mobile node. By adapting a transmission rate based on the SNR of the node experiencing the worst air-channel, SARM achieves the best quality of service for the prevailing conditions. This reduces the proportion of wireless channel resources assigned to multicasting, allowing more bandwidth for unicast flows.

In mobile ad hoc network (MANET), each end-node operates as an end-host and as a router simultaneously. Thus differently from wired-network, the occurrence of network congestion in end-host leaves much room for consideration. In the case of MANET, we can improve TCP throughput by using flow control algorithm that operates between layers because that algorithm reduces packet drops which caused by network congestion in end-hosts (source or destination). In MANET, usually IEEE 802.11 MAC protocol is used in a link layer transmission of two neighbored nodes for reliability and hidden terminal problem. But this protocol does not offer flow control mechanism in link layer. Link layer flow control can prevent packet drops caused by buffer overflow that can occur just after packet transmission. And in result, this prevention of packet drop can reduce the waste of bandwidth and energy which are limited in wireless environment. In this paper, we propose two flow control algorithms called, respectively, vertical flow control and horizon flow control. We show improved TCP throughput and reduced power consumption in end-nodes through the use of proposed two flow control algorithms in performance evaluation.