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.

Wireless, ad hoc networks, fluid flow, queueing"
Network design and communication (msc 68M10), Queueing theory (msc 60K25)
Logistics (theme 3), Energy (theme 4)
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.