A Cross-Layer TCP Protocol with Adaptive Modulation for MANETs

TCP optimization in mobile ad hoc networks is a challenging issue because of some unique characteristics of MANETs. Some of the main reasons behind TCP´s performance degradation in these networks are lossy channels, frequent route failures, network partitions. In this paper, a cross-layer TCP protocol with adaptive modulation for MANET is proposed. Medium access (MAC) layer is responsible to decide the modulation scheme to be used at the physical layer depending on the signal strength and queue length of the receiver. An ns2.30-based simulation analysis of the proposed protocol which provides better TCP performance with minimum congestion than the existing TCP protocols is described. The effects of mobility of nodes, no. of connections on TCP parameters such as throughput, packet delivery ratio and round trip time are investigated.