The increasing demand for high-mobility and high data rate in wireless
communications results in constraints and problems in the limited radio spectrum,
multipath fading, and delay spread.
The multiple-input multiple-output (MIMO) system has been generally
considered as one of the key technologies for the next generation wireless
communication systems. MIMO systems which utilize multiple antennas in both
the transmit side and the receive side can overcome the abovementioned
challenges since they are able to increase the channel capacity and the spectrum
usage efficiency without the need for additional channel bandwidth.
The detection algorithm is a big bottleneck in MIMO systems. Generally, it is
expected to fulfill two main goals simultaneously: low computational complexity
and good error rate performance. However, the existing detection algorithms are
either too complicated or suffering from very bad error-rate performance.
The purpose of this thesis is to comprehensively investigate the detection
algorithms of MIMO systems, and based on that, to develop new methods which
can reduce the computational complexity while retain good system performance.
Firstly, the background and the principle of MIMO systems and the previous work
on the MIMO decoding algorithms conducted by other researchers are thoroughly
reviewed. Secondly, the geometrical analysis of the signal detection is
investigated, and a geometric decoding algorithm which can offer the optimum
BLER performance is proposed. Thirdly, the semidefinite relaxation (SDR)
detection algorithms are extended to high-order modulation MIMO systems, and a
novel SDR detector for 256-QAM constellations is proposed. The theoretical
analysis on the tightness and the complexity are conducted. It demonstrates that
the proposed SDR detector can offer better BLER performance, while its
complexity is in between those of its two counterparts. Fourthly, we combine the
SDR detection algorithms with the sphere decoding. This is helpful for reducing
the computational complexity of the traditional sphere decoding since shorter
initial radius of the hyper sphere can be obtained. Finally, the novel
lattice-reduction-aided SDR detectors are proposed. They can provide
near-optimum error rate performance and achieve the full diversity gain with very
little computational complexity added compared with the stand-alone SDR
detectors. / published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy
| Identifer | oai:union.ndltd.org:HKU/oai:hub.hku.hk:10722/174460 |
| Date | January 2011 |
| Creators | Shao, Ziyun., 邵子韵. |
| Contributors | Yuk, TTI, Cheung, SW |
| Publisher | The University of Hong Kong (Pokfulam, Hong Kong) |
| Source Sets | Hong Kong University Theses |
| Language | English |
| Detected Language | English |
| Type | PG_Thesis |
| Source | http://hub.hku.hk/bib/B47752804 |
| Rights | The author retains all proprietary rights, (such as patent rights) and the right to use in future works., Creative Commons: Attribution 3.0 Hong Kong License |
| Relation | HKU Theses Online (HKUTO) |
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