Design and Analysis of Multi-Channel Random Access: A Stochastic Geometry Approach
Date Issued
2012
Date
2012
Author(s)
Kao, Ching-Yueh
Abstract
In this thesis, we study the performance of and devise appropriate random access strategies for users in a decentralized wireless ad hoc network operating on multiple orthogonal frequency channels. The spatial factor of such problems which is still lack of study is considered with the help of tools from stochastic geometry, from which we derived closed-form expressions for performance metric. The interactions between selfish users sharing the radio resources are modeled with a game-theoretic point of view, and the performance are compared with that in the case when there''s a central entity or when the users are cooperative, where we also provide explicit characterizations. The impacts of utilizing channel side information when making access decisions are also explored, where with local channel state information (CSI) available at the transmitter, channel diversity can be exploited and user performance can be improved; but when channel availability information are known by users, a Braess-like paradox, where when more information is provided the performance however degrades, can occur when the user density of the network is high. Finally, mechanisms that may further improve the network performance are introduced. Taking advantage of the time domain resource, an access barring method is proposed to alleviate the interference problem with high user density. On the other hand, frequency diversity can be exploited at low user density with Maximal Ratio Combining (MRC) to improve the performance when the radio devices are capable of accessing multiple channels simultaneously.
Subjects
Multiple channels
random access
wireless ad hoc networks
stochastic geometry
game theory
channel side information
Type
thesis
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