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UBC Theses and Dissertations
Adaptive resource allocation for multiuser OFDM-based cognitive radio systems Qin, Tao
Abstract
Major challenges in the design of next generation wireless communication systems include harsh propagation environments and scarce resources such as power and spectrum. Cognitive radio (CR) is a promising concept for improving the utilization of scarce radio spectrum resources. Orthogonal frequency division multiplexing (OFDM) is regarded as a technology which is well-matched for CR systems. Dynamic resource allocation is an important task in such systems. In this thesis, a novel fair multiuser resource allocation algorithm for OFDM CR systems is presented. Although not optimal, the algorithm has low computational complexity. The algorithm attempts to maximize the total transmit bit rate (system throughput) of a group of secondary (unlicensed or CR) users subject to (1) a total transmit power constraint for secondary users, (2) a maximum tolerable interference level which can be tolerated by primary (licensed) users. The algorithm is fair in the sense that it tries whenever possible to allocate bits to users who have not received their fair share of service. Simulation results show that the proposed algorithm achieves a performance close to optimal. The effect on system throughput of changing various system parameter values is also examined. A novel cost minimization algorithm for multiuser OFDM cognitive radio systems is also proposed. The objective is to minimize a cost function which takes into account the interference power experienced by the primary user as well as the base station transmit power for secondary users given minimum bit rate requirements for each secondary user. It is found that the proposed algorithm provides a performance which is fairly close to optimal. The influence of a relative weight parameter on the base station (BS) transmit power for secondary users and the primary user interference power is also discussed.
Item Metadata
Title |
Adaptive resource allocation for multiuser OFDM-based cognitive radio systems
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
2007
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Description |
Major challenges in the design of next generation wireless communication systems
include harsh propagation environments and scarce resources such as power and
spectrum. Cognitive radio (CR) is a promising concept for improving the utilization
of scarce radio spectrum resources. Orthogonal frequency division multiplexing
(OFDM) is regarded as a technology which is well-matched for CR systems. Dynamic
resource allocation is an important task in such systems.
In this thesis, a novel fair multiuser resource allocation algorithm for OFDM CR
systems is presented. Although not optimal, the algorithm has low computational
complexity. The algorithm attempts to maximize the total transmit bit rate (system
throughput) of a group of secondary (unlicensed or CR) users subject to (1) a total
transmit power constraint for secondary users, (2) a maximum tolerable interference
level which can be tolerated by primary (licensed) users. The algorithm is fair in
the sense that it tries whenever possible to allocate bits to users who have not received
their fair share of service. Simulation results show that the proposed algorithm
achieves a performance close to optimal. The effect on system throughput of changing
various system parameter values is also examined.
A novel cost minimization algorithm for multiuser OFDM cognitive radio systems
is also proposed. The objective is to minimize a cost function which takes into account
the interference power experienced by the primary user as well as the base station
transmit power for secondary users given minimum bit rate requirements for each
secondary user. It is found that the proposed algorithm provides a performance which
is fairly close to optimal. The influence of a relative weight parameter on the base
station (BS) transmit power for secondary users and the primary user interference
power is also discussed.
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Genre | |
Type | |
Language |
eng
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Date Available |
2011-03-09
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0101067
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.