Congestion Control for Wireless Ad-Hoc Networks

We study joint design of end-to-end congestion control and Per-link medium access control (MAC) in ad-hoc networks. In the current scenario wireless communication is emerging the world. Wireless Ad Hoc networks demands for higher intermediate node supports for long-range communication. Wireless Ad Hoc network is an emerging communication approach. Ad Hoc networks are usually defined as an autonomous system of nodes connected by wireless links and communicating in a multi-hop fashion. The wireless ad-hoc networks are for easy of deployment without centralized administration or fixed infrastructure, to achieve the goal of less interference communication. In wireless Ad-hoc network the connections between the wireless links are not fixed but dependent on channel conditions as well as the specific medium access control (MAC). The channel medium and transmission links are affected by the interference, delay, and buffer overflow these may cause the network congestion. To avoid network congestion various congestion control methods were developed in past but they were performed less control of end-to-end congestion and less in per link connection control. To overcome the above problems and to improve the resource allocation an efficient method has to be developed

Explicit rate control for MANET

Streaming applications over Mobile Ad-hoc Networks (MANET) require a smooth transmission rate. The Internet is unable to provide this service during traffic congestion in the network. Designing congestion control for these applications is challenging, because the standard TCP congestion control mechanism is not able to handle the special properties of a shared wireless multi hop channel well. In particular, the frequent changes to the network topology and the shared nature of the wireless channel pose major challenges. In this paper, we propose a novel approach, which allows a quick increase of throughput by using explicit feedback from routers

Insights into the Design of Congestion Control Protocols for Multi-Hop Wireless Mesh Networks

The widespread deployment of multi-hop wireless mesh networks will depend on the performance seen by the user. Unfortunately, the most predominant transport protocol, TCP, performs poorly over such networks, even leading to starvation in some topologies. In this work, we characterize the root causes of starvation in 802.11 scheduled multi-hop wireless networks via simulations. We analyze the performance of three categories of transport protocols. (1) end-to-end protocols that require implicit feedback (TCP SACK), (2) Explicit feedback based protocols (XCP and VCP) and (3) Open-loop protocol (UDP). We ask and answer the following questions in relation to these protocols: (a) Why does starvation occur in different topologies? Is it intrinsic to TCP or, in general, to feedback-based protocols? or does it also occur in the case of open-loop transfers such as CBR over UDP? (a) What is the role of application behavior on transport layer performance in multi-hop wireless mesh networks? (b) Is sharing congestion in the wireless neighborhood essential for avoiding starvation? (c) For explicit feedback based transport protocols, such as XCP and VCP, what performance can be expected when their capacity estimate is inaccurate? Based on the insights derived from the above analysis, we design a rate-based protocol called VRate that uses the two ECN bits for conveying load feedback information. VRate achieves near optimal rates when configured with the correct capacity estimate