Wireless ad-hoc networks are based on shared medium technology where the nodes arrange access to the medium in a distributed way independent of their current traffic demand. This has the inherent drawback that a node that serves as a relay node for transmissions of multiple neighboring nodes is prone to become a performance “bottleneck”. In the present paper such a bottleneck node is modeled via an idealized fluid-flow queueing model in which the complex packet-level behavior (mac) is represented by a small set of parameters. We extensively validate the model by ad-hoc network simulations that include all the details of the widely used ieee 802.11 mac-protocol. Further we show that the overall flow transfer time of a multi-hop flow, which consists of the sum of the delays at the individual nodes, improves by granting a larger share of the medium capacity to the bottleneck node. Such alternative resource sharing strategies can be enforced in real systems by deploying the recently standardized ieee 802.11e mac-protocol.We propose a mapping between the parameter settings of ieee 802.11e and the fluid-flow model, and validate the fluid-flow model and the parameter mapping with detailed system simulations.

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CWI
CWI. Probability, Networks and Algorithms [PNA]
Stochastics

Roijers, F, van den Berg, J.L, & Mandjes, M.R.H. (2007). Fluid-flow modeling of a relay node in an IEEE 802.11 wireless ad-hoc network. CWI. Probability, Networks and Algorithms [PNA]. CWI.