Buffer Aware Medium Access Control: A Cross Layer Approach

Abstract

Congestion at any node of a network occurs when packet incoming rate exceeds its outgoing rate. This specific problem degrades the performance of the network in terms of throughput and energy consumption. Hence, designing a more efficient congestion control protocol for the networks having limited energy resources like ad hoc network is much more important. Due to lack of infrastructure in wireless ad hoc networks, interference causes packet drop. IEEE 802.11 medium access control (MAC) protocol implements request to send and clear to send (CTS) mechanism to avoid interference. Similarly, the transport layer protocols control the congestion by managing packet flow rate. Still, drop of packets due to buffer overwhelming have not been controlled completely as buffer availability is ignored by data link layer. In this paper, buffer-aware medium access control (BA-MAC) protocol is proposed to avoid packet drop by sending CTS only if buffer has a free slot. Thus, BA-MAC attempts to reduce packet drop by improving the channel reservation mechanism using cross layer approach. To the best of our knowledge, it is the first attempt that uses cross layer approach between data link and transport layer to control congestion. The performance of the proposed protocol via simulation shows significant improvements over default MAC in terms of throughput, average packet loss and energy efficiency.