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Recent MIMO applications have noticeably magnified the importance of multi antennas. Antenna engineers are therefore constantly challenged with the temptation to search for optimum designs. In recent years, evolutionary optimization (EO) techniques are finding growing applications to the design of electromagnetic systems of increasing complexity. Among various EO's, nature inspired techniques such...
Two techniques, i.e. differential and complementary feedbacks, are derived to reduce the feedback overhead for MIMO transmit beamforming. The unitary beamforming matrix is the cumulative product of the fed back unitary matrixes for differential feedback. The fed back matrix depicts the incremental change of the beamforming matrix and it is quantized by small vector codebooks. The overhead can be further...
Mobile transmit diversity (MTD) technology can provide beam forming benefit and result in an additional diversity gain on the top of the traditional diversity gain from the multiple antennae. The MTD technology also benefits the network capacity by reducing the interference to the neighboring cells (sectors). In this paper, we present the measurement results of the 42% and 45% increases on the reverse...
In this paper, we present a survey of noncooperative game theory as an analysis tool in multiple antenna systems and summarize the major conclusions drawn. We study various multiple antenna systems and show how the lack of cooperation among the different entities is used by game theory to find fundamental limits and design algorithms that achieve these limits
Complex orthogonal designs of maximum possible rate of full, 3/4, and 3/4 have been presented for 2, 3, and 4 transmit antennas respectively. For 5 and 6 transmit antennas, two generalized complex orthogonal space-time block codes of rates 7/11 and 3/5 were proposed recently. In this paper, we propose three complex orthogonal space-time block codes whose rates are up to 2/3, 2/3, and 5/8 for 5, 6,...
A small supergain circular array with electronic scanning and "zoom-in" features has been proposed. The array utilizes the orthogonal modes existing in the array systems as bases for beamforming. A mode-decomposition network is proposed that separates the different modes into different circuit ports and matches them individually. Consequentially the modes can be combined to achiever higher...
This contribution analytically studies the influence of transmitter (TX) as well as receiver (RX) IQ mismatch on the performance of multiple-antenna OFDM systems based on direct-conversion. Analytical expressions are derived for the probability of error for MIMO OFDM systems in both nonfaded and Rayleigh faded channels. The results can be used to derive matching specifications for the TX- and RX-branches...
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