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Space-Frequency Equalization in Broadband Single Carrier Systems

Broadband wireless access systems can be used to deliver a variety of high data
rate applications and services. Many of the channels being considered for such
applications exhibit multipath propagation coupled with large delay spreads. Cur-
rently, orthogonal frequency division multiplexing is employed in these channels
to compensate the effect of dispersion. Single carrier (SC) modulation in conjunc-
tion with frequency-domain equalization (FDE) at the receiver has been shown to
be a practical alternate solution as it has lower peak to average power ratio and is
less sensitive to frequency offsets and phase noise compared to OFDM. The effect
of multipath propagation increases with increasing data rate for SC systems. This
leads to larger inter-symbol-interference (ISI) spans. In addition the achievable ca-
pacity of SC-broadband systems depends on their ability to accommodate multiple
signal transmissions in the same frequency band, which results in co-channel inter-
ference (CCI) when detecting the desired data stream. The effects of CCI and ISI
are more pronounced at high data rates. The objective of this research is to investi-
gate and a develop low-complexity frequency domain receiver architectures capable
of suppressing both CCI and ISI and employing practical channel estimation.
In this thesis, a linear and a non-linear receiver architecture are developed in the
frequency domain for use in highly dispersive channels employing multiple input
multiple output (MIMO) antennas. The linear receiver consists of parallel branches
each corresponding to a transmit data stream and implements linear equalization
and demodulation. Frequency domain joint CCI mitigation and ISI equalization is
implemented based on estimated channel parameters and is called space-frequency
Broadband wireless access systems can be used to deliver a variety of high data
rate applications and services. Many of the channels being considered for such
applications exhibit multipath propagation coupled with large delay spreads. Cur-
rently, orthogonal frequency division multiplexing is employed in these channels
to compensate the effect of dispersion. Single carrier (SC) modulation in conjunc-
tion with frequency-domain equalization (FDE) at the receiver has been shown to
be a practical alternate solution as it has lower peak to average power ratio and is
less sensitive to frequency offsets and phase noise compared to OFDM. The effect
of multipath propagation increases with increasing data rate for SC systems. This
leads to larger inter-symbol-interference (ISI) spans. In addition the achievable ca-
pacity of SC-broadband systems depends on their ability to accommodate multiple
signal transmissions in the same frequency band, which results in co-channel inter-
ference (CCI) when detecting the desired data stream. The effects of CCI and ISI
are more pronounced at high data rates. The objective of this research is to investi-
gate and a develop low-complexity frequency domain receiver architectures capable
of suppressing both CCI and ISI and employing practical channel estimation.
In this thesis, a linear and a non-linear receiver architecture are developed in the
frequency domain for use in highly dispersive channels employing multiple input
multiple output (MIMO) antennas. The linear receiver consists of parallel branches
each corresponding to a transmit data stream and implements linear equalization
and demodulation. Frequency domain joint CCI mitigation and ISI equalization is
implemented based on estimated channel parameters and is called space-frequency

Identiferoai:union.ndltd.org:canterbury.ac.nz/oai:ir.canterbury.ac.nz:10092/4421
Date January 2009
CreatorsKongara, Gayathri
PublisherUniversity of Canterbury. Electrical and Computer engineering
Source SetsUniversity of Canterbury
LanguageEnglish
Detected LanguageEnglish
TypeElectronic thesis or dissertation, Text
RightsCopyright Gayathri Kongara, http://library.canterbury.ac.nz/thesis/etheses_copyright.shtml
RelationNZCU

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