Bandwidth Estimation Problem & Solutions in IEEE 802.11 based Ad Hoc Networks
Neeraj Kumar Gupta · 2012
With the rise in multimedia applications in ad hoc networks it is necessary to ensure the quality of service support from network. The routers which may be mobile nodes in ad hoc networks should be able to evaluate the resources available in the network, prior to offering guarantees on delay, bandwidth or any other metric. Estimating the available bandwidth is often required before performing admission control, flows management, congestion control or routing based on bandwidth constraints so that before any new flow is admitted the existing flow does not degrade. Lot of work in terms of various tools and techniques has been proposed to evaluate the available bandwidth in last decade; no consensus has yet been arrived. We present a comprehensive review on the various state of art work proposed carried out in this area I. INTRODUCTION Among different wireless technologies, an emerging class of autonomous, self-deployable, self- organizing class of mobile networks popularly known as ad hoc networks has been area of interest for research community. Such networks are characterized by non- specialized routers for routing purpose. . Initially developed for militarily communication and disaster recovery, the rising popularity of multimedia applications has led to commercial usage of these networks. Quality of Service (QoS) in such networks has thus become an unavoidable task. One of the fundamental resources in wireless communication is bandwidth. The network performance can be enhanced by estimating available bandwidth. As compared to wired network, wireless networks have significantly lower capacity. The realized throughput of wireless network link is often much less than the transmission rate. The difference can be accounted for reasons like congestion, hidden terminal problem, effect of neighbour interference and noise in the channel. The channel is shared among various nodes. It is necessary to keep track of the number of potential emitters on the sender side and number of potential scramblers on the receiver side. The collection of such information helps in determining the resource utilization before admitting any new flow. The problem for estimating the available bandwidth can be defined as maximum throughput that is available between two nodes, sender and receiver, so that they do not disturb any ongoing flow in network. The solution becomes trickier in case nodes are mobile. The mobility issue leads to change of links between the nodes and hence the utilization of resource changes dynamically.