Spelling suggestions: "subject:"multikulti""
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Multi-user Non-Cooperative and Cooperative Systems with HARQRauf, Zahid January 2013 (has links)
The performance and reliability of wireless communication links can be improved by employing multiple antennas at both ends, thereby creating multiple-input multiple-output (MIMO) channels. However, once multiple co-channel users are added to the system it can be difficult to provide as many receive antennas as transmit antennas, resulting in a so-called overloaded (rank-deficient) system. Under overloaded conditions, maximum likelihood (ML) detection works well, but its exponential complexity prohibits its use and suboptimal linear detectors perform poorly.
In this thesis, new signal processing techniques for multi-user overloaded systems using hybrid automatic repeat request (HARQ) protocols are investigated. The HARQ retransmissions are used to form virtual receive antennas, which can efficiently transform an overloaded system into a critically loaded system (i.e. a system with an equal number of transmit and receive antennas).
In the first part of the thesis, a multi-user non-cooperative overloaded system is considered. At first, it is demonstrated that the suboptimal linear minimum mean square error (MMSE) detector leads to significant performance degradation compared to an ML detector for such systems. To overcome this drawback, two multi-user transmission schemes are proposed that work well under overloaded conditions. The proposed schemes allow us to apply linear multi-user detection (MUD) algorithms without requiring additional antennas or hardware chains. Monte-Carlo simulations demonstrate that the proposed schemes can result in significant gains in terms of bit-error-rate (BER) and dropped packet performance.
In the second part, the performance of multiple HARQ processes for a two-hop multi-source multi-relay decode-and-forward (DF) relaying network with no direct link are analyzed. Dealing with multiple HARQ processes at each relay, a retransmission scheme is proposed that utilizes virtual antennas to achieve increased receive diversity and improved throughput compared to traditional orthogonal (time division) retransmissions. A novel forwarding strategy at the relay(s) to destination link is proposed with the objective of further improving throughput. Finally, the end-to-end outage probability and throughput efficiency of the proposed retransmission and forwarding schemes are found analytically and confirmed with Monte-Carlo simulations.
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Computational approach to non-linear morphologyKiraz, George Anton January 1996 (has links)
No description available.
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Combinator reduction on networks of small processorsTunmer, Michael Luke January 1990 (has links)
No description available.
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Development and application of probe atomisation in line-source and continuum-source electrothermal atomic absorption spectrometryCarroll, J. H. January 1987 (has links)
No description available.
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Community mental health teams in Northern Ireland : how are they organised?; are service users satisfied?Cunningham, Gerard January 2002 (has links)
No description available.
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Economic development and internationalisation as viewed through the investment development path : with special reference to the Korean economyHwang, Jin Sung January 1994 (has links)
No description available.
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The political mobilisation of cultural identityLongman, Christopher Mark January 2002 (has links)
No description available.
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Control aspects of bipedal walkingArcher, Nigel John January 1993 (has links)
No description available.
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Synthesis of separation systems for multi-component mixtures with emphasis on energy recovery and integrationKakhu, A. I. January 1988 (has links)
No description available.
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Technological effort : a study of its influencing factors in MNCs and local firms in the electronics and electrical industries in MalaysiaNoor, Abd Halim Mohd January 1999 (has links)
No description available.
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