Characterization of Rate Region and User Removal in Interference Channels with Constrained Power
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Date
2007-05-15T20:39:48Z
Authors
Hajar, Mahdavidoost
Journal Title
Journal ISSN
Volume Title
Publisher
University of Waterloo
Abstract
Channel sharing is known as a unique solution to satisfy the increasing
demand for the spectral-efficient communication. In the channel
sharing technique, several users concurrently communicate through
a shared wireless medium. In such a scheme, the interference of
users over each other is the main source of impairment. The task
of performance evaluation and signaling design in the presence of
such interference is known as a challenging problem. In this
thesis, a system including $n$ parallel interfering AWGN
transmission paths is considered, where the power of the
transmitters are subject to some upper-bounds. For such a system,
we obtain a closed form for the boundaries of the rate region
based on the Perron-Frobenius eigenvalue of some non-negative
matrices. While the boundary of the rate region for the case of
unconstrained power is a well-established result, this is the
first result for the case of constrained power. This result is
utilized to develop an efficient user removal algorithm for
congested networks. In these networks, it may not be possible for
all users to attain a required Quality of Service (QoS). In this
case, the solution is to remove some of the users from the set of
active ones. The problem of finding the set of removed users with
the minimum cardinality is claimed to be an NP-complete problem. In this thesis, a novel sub-optimal removal
algorithm is proposed, which relies on the derived boundary of the
rate region in the first part of the thesis. Simulation results
show that the proposed algorithm outperforms other known schemes.
Description
Keywords
Interference Channels, Constrained Power, Rate Region, Wireless Communication