Browsing by Author "Lee, Ming-Chun"

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A Low Complexity Configuration Selection Algorithm in IA-aided Uplink Coordinated Multipoint Systems
(2014-01-01)
Lee, Ming-Chun
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Huang, Chung-Jung
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Chung, Wei-Ho
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Lee, Ta-Sung
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電機資訊學士班
This work investigates the configuration selection in IA-aided UL CoMP systems which pursues the maximal achievable sum rate. The configuration is defined by the number of data streams transmitted in each user. Intuitively, the solution can be found by exhaustively calculating the achievable sum rate for all the possible configurations, and select the configuration leading to the maximal achievable sum rate. The exhaustive search method is infeasible due to its high complexity. Based on the characteristics of IA-aided UL CoMP systems, an algorithm is proposed to obtain the configuration with extremely low complexity, and the proposed approach achieves comparable performance as in exhaustive method.
BER Analysis for Spatial Modulation in Multicast MIMO Systems
(2016-07)
Lee, Ming-Chun
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Chung, Wei-Ho
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Lee, Ta-Sung
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電機學院
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College of Electrical and Computer Engineering
In this paper, we investigate the bit error rate (BER) for multicast multiple-input multiple-output (MIMO) systems, employing spatial modulation (SM) and its variants, called multicast SM-type MIMO systems, in Rayleigh fading channels. The system BER, here, is derived by first attaining the BER of the worst receiver of each channel realization set, and then averaging over all possible sets. We first consider the uncorrelated channels. By exploiting the system statistics, a tight BER upper bound is proposed and the diversity is discussed for the systems. We then perform the asymptotic analysis, and show that the BER of the multicast SM-type MIMO system can be alternatively analyzed by analyzing the simple point-to-point SM-type MIMO system with Weibull fading channels. Through this property, a closed-form asymptotic BER upper bound is provided and the impact of the receiver number on BER is analyzed. Subsequently, our investigation is extended to correlated channels where all the receivers share the same correlation statistics. The BER analysis is performed again through the framework similar to the uncorrelated case. In the analysis, the tight upper bound is derived and the effect of correlations is analyzed. Moreover, we provide an explicit expression for the SNR degradation caused by the receive correlation through the analysis. Finally, simulations are exploited to evaluate the BER of the multicast SM-type MIMO systems and validate the analyses.
Generalized Precoder Design Formulation and Iterative Algorithm for Spatial Modulation in MIMO Systems With CSIT
(2015-04-01)
Lee, Ming-Chun
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Chung, Wei-Ho
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Lee, Ta-Sung
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電機資訊學士班
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Undergraduate Honors Program of Electrical Engineering and Computer Science
In this paper, we propose two generalized precoder designs to enhance the bit error rates for the general category of spatial modulation (SM) in multiple-input multiple-output (MIMO) systems with channel state information at the transmitter (CSIT). We investigate typical SM-MIMO systems and propose two optimization formulations for designing precoders. Our design rationale for the first formulation is to maximize the minimum Euclidean distance among codewords; for the second formulation, it is to minimize the total signal power for the lower-bounded Euclidean distances among codewords. Since both formulations are non-convex and their optimal solutions are generally intractable, we propose an algorithm that acquires effective solutions by iteratively solving the alternative convex problem linearized and approximated from the original non-convex problem. Discussions on complexity analysis, performance comparisons, design challenges, and robustness in imperfect CSIT are then provided. By generalizing the design formulations, the proposed precoder designs can be extended to generalized SM, which completes the investigation for virtually all SM-type systems. Simulation results show that the proposed designs improve the performance of SM-/GSM-MIMO systems and outperform existing precoding methods with a potentially higher complexity cost.
Limited Feedback Precoder Design for Spatial Modulation in MIMO Systems
(2015-11-01)
Lee, Ming-Chun
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Chung, Wei-Ho
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Lee, Ta-Sung
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電機資訊學士班
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Undergraduate Honors Program of Electrical Engineering and Computer Science
We investigate the limited feedback precoding for spatial modulation in multiple-input multiple-output systems via using the codebook. To enhance bit error rate, we propose a codebook design which iteratively trains the codebook by two criteria. The first criterion is to partition the training set by assigning the best codeword to each training symbol; the second criterion is to optimize the codewords according to the assigned training symbols. Simulation results show that the proposed codebook design can effectively improve the SM-MIMO systems with small overhead.
Linear transceiver design in uplink coordinated multipoint multiple-input multiple-output systems
(2014-11-27)
Lee, Ming-Chun
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Chung, Wei-Ho
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Huang, Chung-Jung
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Chung, Gang-Han
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Lee, Ta-Sung
The authors investigate linear transceiver design in uplink (UL) coordinated multipoint transmission and reception (CoMP) multiple-input multiple-output (MIMO) systems with joint detections. A two-stage design algorithm is proposed by exploiting the technique of interference alignment, optimising the structure of the effective channel and employing power loading, with the goal to achieve high throughput and convergence performance. In contrast to conventional CoMP transceiver design, which is investigated under a predefined number of data streams transmitted by each user, the authors further investigate the selection of the number of data streams, called the configuration selection, and propose a corresponding low-complexity algorithm. By combining the proposed linear transceiver algorithm and low-complexity configuration selection algorithm, this work presents a new practical framework for linear transceiver design in UL CoMP MIMO systems. The simulation results confirm that the proposed algorithms achieve higher sum-rate performance than prior linear transceivers used in UL CoMP MIMO systems. Furthermore, the proposed transceiver offers comparable performance to existing IA-aided transceivers with significantly faster convergence.
Precoder Design for Space Shift Keying in MIMO Systems with Limited Feedback
(2014)
Lee, Ming-Chun
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Chung, Wei-Ho
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Lee, Ta-Sung
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電機工程學系
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Department of Electrical and Computer Engineering
In multiple-input multiple-output (MIMO) systems adopting space shift keying (SSK), the use of adaptive precoder on transmitter offers the opportunity to improve its performance significantly. One major challenge in precoder operation is the difficulty in obtaining the full channel state information on transmitter (CSIT). In this work, we investigate the precoder design for SSK-MIMO systems with limited feedback through using the codebook for the precoding. We formulate a distortion metric to evaluate the quality of a codebook based on the maximum minimum Euclidean distance criterion and propose a codebook design criterion accordingly. Two effective codebook design algorithms are proposed based on thorough analysis of the criterion. Simulation results show the performance improvement of the proposed codebook-based precoding, and also support our analyses on the codebook design.
Sectorization with Beam Pattern Design Using 3D Beamforming Techniques
(2013)
Lee, Chang-Shen
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Lee, Ming-Chun
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Huang, Chung-Jung
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Lee, Ta-Sung
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電機工程學系
This paper presents a framework for a three-dimensional (3D) beam pattern design with a load-balanced cell sectorization strategy. First, characteristics of the 3D beam pattern were observed, and convex optimization was used to provide a solution based on the criteria that describe the observations. In addition, a user equipment (UE) determination problem that arose because of cell sectorization was also addressed. By incorporating a beam pattern design with a proposed UE determination scheme, a framework of a backward compatible system was completed. The network performance regarding throughput for cell sectorization with a dedicated beam pattern design was evaluated and the simulation results show that the proposed system is superior compared to the conventional system and other proposed sectorization schemes.