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@PHDTHESIS{Liu:82739,
author = {Liu, Chunhui},
othercontributors = {Mathar, Rudolf},
title = {{O}ptimum resource allocation for heterogeneous wireless
{OFDM} networks},
address = {Aachen},
publisher = {Publikationsserver der RWTH Aachen University},
reportid = {RWTH-CONV-143111},
pages = {VI, 142 S. : graph. Darst.},
year = {2011},
note = {Zsfassung in dt. und engl. Sprache. - Prüfungsjahr: 2011.
- Publikationsjahr: 2012; Aachen, Techn. Hochsch., Diss.,
2011},
abstract = {The popularity of orthogonal frequency division
multiplexing (OFDM) has been evident by the present and the
next-generation broadband wireless standards. In OFDM
systems, two principle transmission resources are provided,
i.e., subcarriers and transmission power. The primal
challenge for designing wireless networks is to use the
transmission resources as efficiently as possible while
satisfying requirements of data transmission. Future
cellular networks are expected to provide a large variety of
services with diverse quality-of-service requirements. Thus,
this thesis investigates resource allocation for unicasting
by a single or multiple Base Stations (BSs), where a mixture
of real time and non-real time applications is considered,
so called heterogeneous resource allocation. First, with
duality theory a dual optimum of resource allocation is
determined for unicasting by a single BS. Simulations
demonstrate that the duality gap between the dual and primal
optima decreases approximately exponentially in the number
of subcarriers. Thus, the dual optimum is qualified to be a
reference for evaluating heuristic solutions. To reduce the
computational complexity, heuristic methods are then
proposed. It is verified by simulations that the obtained
suboptimal solutions are close to the dual optimum.
Furthermore, two different scenarios are considered for
unicasting by multiple BSs. If signals received from
different BSs are synchronized, each user may be served by
more than one BS. Otherwise, each user can be covered by
only one BS. The dual optimal and heuristic solutions for
single-cell heterogeneous resource allocation are extended
to these multicell scenarios. Simulations show that the
derived suboptimal solutions approach the dual optima.
Moreover, a novel strategy of resource allocation is
proposed, which differs from the water-filling strategy. We
suggest that a rate is symmetrically allocated to
subcarriers assigned to each user. In doing so, the
signaling overhead is reduced and a better balance of energy
consumption is achieved for signaling and data transmission.
The asymptotic limits are deduced for the resulting
instantaneous per-symbol performance loss. By using the
simplicity of the proposed strategy, heuristic solutions are
designed for heterogeneous resource allocation. With
signaling overhead additionally considered, the proposed
strategy achieves better energy efficiency than the
water-filling solution, when the resource allocation scheme
is frequently updated. Finally, we deal with two important
practical issues on resource allocation. On one hand,
channels are measured at receivers and then imperfect
channel knowledge is fed back to the transmitter. An upper
bound is deduced for resource allocation in the presence of
imperfect channel knowledge. On the other hand, the
transmission rate must be discrete because of a limited
number of available coding and mapping schemes. A
non-iterative method is proposed for optimally quantizing
the output rates of a water-filling solution.},
keywords = {Ressourcenallokation (SWD) / Funknetz (SWD) / OFDM (SWD)},
cin = {613410},
ddc = {620},
cid = {$I:(DE-82)613410_20140620$},
typ = {PUB:(DE-HGF)11},
urn = {urn:nbn:de:hbz:82-opus-39690},
url = {https://publications.rwth-aachen.de/record/82739},
}
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