Abstract-The traditional congestion control mechanism, i.e., TCP, encounters a number of new challenges when applied in mobile ad hoc networks (MANET), such as wireless link error, medium contention, and frequent route failures. And very poor performance of TCP in MANET has been reported in many recent studies. In this paper, we focus on the problems resulting from the medium contention and propose a novel Rate Based end-toend Congestion Control scheme (RBCC). We first illustrate that, under the impact of medium contention, window based congestion control algorithm is unstable and hence may not be appropriate for MANET because the optimum congestion window size is very small and may be even less than one, i.e., the source should send less than one packet in one round trip time (RTT). Based on the novel use of channel busyness ratio, which, we show, is an accurate sign of the network utilization and congestion status, a new rate control scheme has been proposed to efficiently and reliably support the transport service in MANET. In RBCC, a sublayer consisting of a leaky bucket is added under TCP to control the sending rate based on the network layer feedback at the bottleneck node. Extensive simulations show that our scheme significantly outperforms traditional TCP in terms of channel utilization, delay, and fairness. Mobile ad hoc networks (MANETs) have found many applications in battlefield, disaster rescue and conventions, where fixed communications infrastructures are not available and quick network configurations are needed. To provide reliable transport service over and hence fully exploit the potential of MANETs, efficient congestion control is of paramount importance. Unfortunately, traditional TCP congestion control mechanism performs very poorly, as shown in recent studies ( [1]- [7] and reference therein). TCP congestion control has an implicit assumption, which is that any packet loss is due to network congestion. However, this assumption is no longer valid in the MANET as packet losses may well be due to channel bit errors, medium contention, and route failures. To alleviate the impact of mobility, several schemes, such as those in [8]-[11], were proposed to distinguish between route failures from topology changes and network congestion through explicit route failure notifications. Other schemes, like those in [12] , [13] , do not use the network layer feedback but keep the TCP states unchanged when the source first detects the out-of-order packet and retransmission timeout.
RBCC REF , measures the sending rate of each flow by the channel utilization status at the bottleneck node which is the ratio of the total length of the busy period to the total time during a time interval.
Rate-based transport control for mobile ad hoc networks
IEEE Wireless Communications and Networking Conference, 2005
IEEE Wireless Communications and Networking Conference, 2005
Computer Science