THESIS
2013
xii, 119 pages : illustrations ; 30 cm
Abstract
Efficient use of the wireless spectrum is a key objective in wireless communication systems.
One research area that is attracting growing interest is the development of novel duplexing
technologies. In this thesis, we look into the designs and applications of three novel duplexing
techniques for wireless communication systems: single channel full-duplex, subcarrier-based
duplexing and spatial-division duplexing. Full-duplex enables devices to transmit and receive
signals simultaneously using the same channel, which can potentially double the capacity of
wireless communication systems. Subcarrier-based duplexing assigns different subcarriers of
an OFDM system for transmission and reception, laying the foundation for various cooperative
communication schemes proposed in the litera...[
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Efficient use of the wireless spectrum is a key objective in wireless communication systems.
One research area that is attracting growing interest is the development of novel duplexing
technologies. In this thesis, we look into the designs and applications of three novel duplexing
techniques for wireless communication systems: single channel full-duplex, subcarrier-based
duplexing and spatial-division duplexing. Full-duplex enables devices to transmit and receive
signals simultaneously using the same channel, which can potentially double the capacity of
wireless communication systems. Subcarrier-based duplexing assigns different subcarriers of
an OFDM system for transmission and reception, laying the foundation for various cooperative
communication schemes proposed in the literature that require so. Spatial-division duplexing
utilizes beamforming techniques to separate transmitting and receiving signals, and can exploit
the spatial degree of freedom in MIMO systems to improve the total data rate.
In this thesis, we first study the feasibility of full-duplex wireless communications. The
effects of various imperfect system characteristics are investigated, and we have proposed a
baseband echo cancellation scheme to suppress the self-interference. The performance of the
proposed scheme is evaluated by both analysis and simulation, and the improvement in the
overall capacity/throughput is studied.
Using a similar approach of echo cancellation to suppress the interference between the
transmitting and receiving subcarriers, we then propose a transceiver structure that achieves
subcarrier-based duplexing, which is applied to a cooperative OFDMA system to examine its
performance under realistic conditions.
In the third part of this thesis, we investigate full-duplex wireless communication based
on multi-antenna techniques. In particular, we consider a multi-user MIMO system where the
base station serves multiple uplink and downlink users simultaneously. An efficient algorithm
is proposed to jointly design the beamformers of the BS and MSs to suppress self-interference
and maximize the weighted sum data rate.
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