• Current Optics and Photonics
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• v.1 no.1
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• pp.34-44
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• 2017

Stereoscopic (S3D) displays present different images to the two eyes. Temporal multiplexing and spatial multiplexing are two common techniques for accomplishing this. We compared the effective resolution provided by these two techniques. In a psychophysical experiment, we measured resolution at various viewing distances on a display employing temporal multiplexing, and on another display employing spatial multiplexing. In another experiment, we simulated the two multiplexing techniques on one display and again measured resolution. The results show that temporal multiplexing provides greater effective resolution than spatial multiplexing at short and medium viewing distances, and that the two techniques provide similar resolution at long viewing distance. Importantly, we observed a significant difference in resolution at the viewing distance that is generally recommended for high-definition television.

• Journal of information and communication convergence engineering
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• v.6 no.4
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• pp.359-363
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• 2008

In this paper, the capacity of MIMO fading channel in the OFDM-based spatial multiplexing systems is analyzed when there is scattering at both transmitter and receiver. The employed MIMO channel model is spanning from the correlated low-rank case to uncorrelated high-rank case at both transmitter and receiver. The effects of spatial fading correlation on the capacity of MIMO channel is examined when the channel is known and unknown at the transmitter. We also evaluate the impacts of a channel estimation error at the transmitter on the MIMO channel capacity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.9
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• pp.797-801
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• 2013

Visible light communication (VLC) is a rapidly growing area of research and applications, due to the potential and predicted high efficiency of bandwidth. One of the key challenges in VLC technology is the choice of devices which are going to be deployed VLC features. Smartphone rationally uses the most widely deployed visible light sensor i.e. image sensor in camera, which could be used to receive the intensity modulated data. Image sensor based VLC system would be the most deployable scenario but initially the capacity was not much attractive compared with photodetector based VLC system. Here, the spatial multiplexing is proposed in MIMO based VLC system to increase the system capacity by utilizing the property of spatial separation of optical light sources in smartphone's camera module. The active pixels of imaging plane act as the multiple receivers which could be able to use on MIMO spatial multiplexing to enhance the system performance.

• Journal of information and communication convergence engineering
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• v.10 no.3
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• pp.215-219
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• 2012

This paper applies transmit antenna selection algorithms to spatial-temporal combining-based spatial multiplexing (SM) ultra-wideband (UWB) systems. The employed criterion is based on the largest minimum output signal-to-noise ratio of the multiplexed streams. It is shown via simulations that the bit error rate (BER) performance of the SM UWB systems based on the two-dimensional Rake receiver is significantly improved by antenna diversity through transmit antenna selection on a log-normal multipath fading channel. When the transmit antenna diversity through antenna selection is exploited in the SM UWB systems, the BER performance of the spatial-temporal combining-based zero-forcing (ZF) receiver is also compared with that of the ZF detector followed by the Rake receiver.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4A
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• pp.322-331
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• 2010

This paper introduces a new efficient design scheme for spatial multiplexing (SM) systems over closed loop multiple-input multiple-output (MIMO) wireless channels. Extending the orthogonalized spatial multiplexing (OSM) scheme which was developed recently for transmitting two data streams, we propose a new SM scheme where a larger number of data streams can be supported. To achieve this goal, we partition the data streams into several subblocks and execute the block-diagonalization process at the receiver. The proposed scheme still guarantees single-symbol maximum likelihood (ML) detection with small feedback information. Simulation results verify that the proposed scheme achieves a huge performance gain at a bit error rate (BER) of $10^{-4}$ over conventional closed-loop schemes based on minimum mean-square error (MSE) or bit error rate (BER) criterion. We also show that an additional 2.5dB gain can be obtained by optimizing the group selection with extra feedback information.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.5A
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• pp.394-401
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• 2007

MIMO transmission systems can have various transmission modes, which result from the various combinations of the antenna diversity with spatial multiplexing. In this paper, we find the optimal mode to maximize the capacity with the BER constraint and the optimal selection (diversity transmission or spatial multiplexing transmission) for transmission of each transmission antenna, if necessary. The computer simulation results show that the proposed scheme has more capacity than the conventional scheme.

• Proceedings of the Optical Society of Korea Conference
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• 1998.08a
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• pp.218-219
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• 1998

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.9A
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• pp.772-780
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• 2005

In this paper, an efficient pre-processing in space tine block coded-spatial multiplexing systems is presented. The pre-processing scheme is designed empirically with extending the diagonally weighted orthogonal space time-block coded diversity system to spatial multiplexing system. Simulation results show the proposed scheme outperforms both the precoder using the predefued codebooks and typical antenna selection scheme over moderate doppler frequency in limited feedback channel.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.2C
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• pp.229-237
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• 2010

The conventional detection methods developed for spatially-multiplexed MIMO systems such as OSIC and QRD-M show performance difference for each user depending on the order of detection when they are applied to detection of multi-user signals in uplink multiuser systems based on collaborative spatial multiplexing. In this paper, a signal detection method for uplink multiuser systems based on collaborative spatial multiplexing is proposed to provide similar performance for each user while its performance is close to the case of ML detection. Compared with QRD-M method, computational complexity of the proposed signal detection method is similar in the case of QPSK, and significantly lower in the case of high modulation order with 16-QAM and 64-QAM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.4A
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• pp.337-344
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• 2011

In this paper, a multiple-input and multiple-output (MIMO) spatial multiplexing (SM) relay system is studied in a bit error rate (BER) sense, where every node is deployed with multiple antennas. In order to efficiently use the limited power resource, it is essential to optimally allocate the power to nodes and antennas. In this context, the power allocation (PA) algorithm based on minimum BER (MBER) for a MIMO SM relay system is proposed, which is derived by direct minimization of the average BER, and divided into inter-node and inter-antenna PA algorithm. The proposed scheme outperforms the conventional equal power allocation (EPA) algorithm without extra power consumption.