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Power control-based design considerations for ad hoc and mesh networking
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| Identifier | 000339018 | |||
| Title | Power control-based design considerations for ad hoc and mesh networking | |||
| Alternative Title | Σχεδιαστικές Προσεγγίσεις Ad hoc και Mesh δικτύων με βάση τον Ελεγχο Ισχύος | |||
| Author | Αγγελάκης, Ευάγγελος Γεώργιος | |||
| Thesis advisor | Τραγανίτης, Απόστολος | |||
| Abstract |
a) the properties of transmission powers assigned by a power control scheme, b) adjacent channel interference modeling and mitigation, c) and algorithms for efficient guaranteed maximal matching discovery. Effective power control, interference mitigation and the availability of maximal matchings for use in scheduling, are network functions that take place in the two lowest layers of the OSI model. On the other hand they have a strong effect in higher layers, affecting routing, throughput and delays and thus they are all of great importance in designing ad hoc and mesh networks. We therefore examine through analytical models and simulations how low-layer wireless network parameters such as network density and wireless environment variables, such as the path loss exponent, can affect the power assignment to the transmitters and the feasibility of matchings, under the Signal to interference-plus-noise (SINR) criterion for data reception. We devise a hypothetical application scenario, to examine how malicious jamming nodes can harm an ad hoc network, and whether the network can mitigate these jamming attempts, by simply adapting its transmitting powers. We further introduce, a model for the calculation of the interference power by partially overlapping channels. We combine it with the SINR criterion for data reception to quantify the effect of Adjacent Channel Interference (ACI) in 802.11a, where adjacent channels are widely assumed to be orthogonal. We validate our theoretical model by applying it on a laboratory testbed, where we emulate the wireless channel and establish that in 802.11a immediately adjacent channels and next-to-adjacent channels have the potential to interfere with each other. Our experimental setup was capable to isolate the mechanisms with which the neighboring channel interference affects the 802.11a: the packet capture at the receiver and the Clear Channel Assessment (CCA) mechanism. Through experimentation we quantify the effect of ACI on throughput for both of the mechanisms above. We finally establish a link budgeting tool that accounts for ACI and directional antennas and indicate how to use it to mitigate ACI on a multi-radio mesh node. Finally taking advantage of previous observations for the feasibility of matchings we introduce two algorithms that are guaranteed to find a maximal matching with significant efficiency compared to the brute-force method. In the course of our investigations we verified, through simulations mathematical statements of structural nature for the power assignments methods used. Their complexity did not always allow us to prove them. They are stated as conjectures with sufficient evidence of their validity. Their proof is left as an open challenge for the scientific (mainly mathematical) community. Furthermore, we introduce a basic building block for a tool to optimally design multi-radio nodes for use in mesh networks. This, along with the observations and methodologies provided in this thesis can lead to the design of such a tool for production systems. |
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| Physical description | xviii, 95 σ. : εικ. ; 30 cm. | |||
| Language | English | |||
| Issue date | 2008-07-22 | |||
| Collection | School/Department--School of Sciences and Engineering--Department of Computer Science--Doctoral theses | |||
| Type of Work--Doctoral theses | ||||
| Views | 895 | |||
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