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Transmit Power Adaptation for Multiuser OFDM Systems

Cited 886 time in Web of Science Cited 1197 time in Scopus
Authors
Jang, Jiho; Lee, Kwang Bok
Issue Date
2003-02
Publisher
Institute of Electrical and Electronics Engineers (IEEE)
Citation
IEEE J. Select. Areas Commun., vol. 21, pp. 171-178, Feb. 2003
Keywords
Channel capacitydownlinkmulticarrierorthogonal frequency division multiplexing (OFDM)power controlwater-filling
Abstract
In this paper,we develop a transmit power adaptation
method that maximizes the total data rate of multiuser orthogonal
frequency division multiplexing (OFDM) systems in a downlink
transmission. We generally formulate the data rate maximization
problem by allowing that a subcarrier could be shared by multiple
users. The transmit power adaptation scheme is derived by solving
the maximization problem via two steps: subcarrier assignment for
users and power allocation for subcarriers.We have found that the
data rate of a multiuser OFDM system is maximized when each
subcarrier is assigned to only one user with the best channel gain
for that subcarrier and the transmit power is distributed over the
subcarriers by the water-filling policy. In order to reduce the computational
complexity in calculating water-filling level in the proposed
transmit power adaptation method, we also propose a simple
method where users with the best channel gain for each subcarrier
are selected and then the transmit power is equally distributed
among the subcarriers. Results show that the total data rate for
the proposed transmit power adaptation methods significantly increases
with the number of users owing to the multiuser diversity
effects and is greater than that for the conventional frequencydivision
multiple access (FDMA)-like transmit power adaptation
schemes. Furthermore, we have found that the total data rate of
the multiuser OFDM system with the proposed transmit power
adaptation methods becomes even higher than the capacity of the
AWGN channel when the number of users is large enough.
ISSN
0733-8716
Language
English
URI
http://hdl.handle.net/10371/7454
DOI
https://doi.org/10.1109/JSAC.2002.807348
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College of Engineering/Engineering Practice School (공과대학/대학원)Dept. of Electrical and Computer Engineering (전기·정보공학부)Journal Papers (저널논문_전기·정보공학부)
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