The Experts below are selected from a list of 1821 Experts worldwide ranked by ideXlab platform
Shaolei Chen - One of the best experts on this subject based on the ideXlab platform.
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joint optimization of transmit power and Codebook Size for multiuser miso systems
Vehicular Technology Conference, 2012Co-Authors: Xiaoming Chen, Zhaoyang Zhang, Lei Lei, Shaolei ChenAbstract:Transmit power and feedback bandwidth are two limited and interrelated resources which are crucial to system performance in wireless channel with feedback, so it is necessary to maximize their utilization efficiencies in the joint sense. In this paper, we investigate the inherent relationship between transmit power and Codebook Size in multiuser limited feedback MISO system by making use of Grassmann line packing theory, as an effort to provide an insight on how to jointly distribute the two resources to fulfill the diverse requirements. Then, the impact of feedback delay on the tradeoff relation is characterized in detail, and we find that even with relatively small delay, there is considerable performance loss with respect to the ideal case. Thereby, much more transmit power or feedback bandwidth should be consumed to achieve the same performance target. Finally, the theoretical claims are validated by numerical results.
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VTC Fall - Joint Optimization of Transmit Power and Codebook Size for Multiuser MISO Systems
2012 IEEE Vehicular Technology Conference (VTC Fall), 2012Co-Authors: Xiaoming Chen, Zhaoyang Zhang, Lei Lei, Shaolei ChenAbstract:Transmit power and feedback bandwidth are two limited and interrelated resources which are crucial to system performance in wireless channel with feedback, so it is necessary to maximize their utilization efficiencies in the joint sense. In this paper, we investigate the inherent relationship between transmit power and Codebook Size in multiuser limited feedback MISO system by making use of Grassmann line packing theory, as an effort to provide an insight on how to jointly distribute the two resources to fulfill the diverse requirements. Then, the impact of feedback delay on the tradeoff relation is characterized in detail, and we find that even with relatively small delay, there is considerable performance loss with respect to the ideal case. Thereby, much more transmit power or feedback bandwidth should be consumed to achieve the same performance target. Finally, the theoretical claims are validated by numerical results.
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VTC Fall - Adaptive Bit Allocation in Rateless Coded MISO Downlink System with Limited Feedback
2012 IEEE Vehicular Technology Conference (VTC Fall), 2012Co-Authors: Shaolei Chen, Xiaoming Chen, Zhaoyang Zhang, Huazi Zhang, Chau YuenAbstract:Rateless coding is a new type of feed-forward incremental redundancy channel coding technique which can be incorporated with MIMO technology to exploit both the diversity and coding gain with possibly reduced channel feedback. In this paper, the benefits of limited feedback beamforming and rateless coding are investigated jointly in a multiple-input single-output (MISO) downlink system. Based on weight enumerator analysis and with the goal of improving the effective channel gain, we propose an adaptive bit allocation scheme by taking advantage of the inherent relationship between the feedback Codebook Size and the number of transmitted coded bits. Given the feedback Codebook Size, we derive the required minimum number of coded bits for a reliable data recovery. In addition, for the service with time delay constraint, the required feedback Codebook Size is also determined. Finally, numerical results are presented to validate our theoretical analysis.
Yen-chin Wang - One of the best experts on this subject based on the ideXlab platform.
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Codebook Size design for rvq based tomlinson harashima precoded mimo broadcast channels
IEEE Transactions on Vehicular Technology, 2015Co-Authors: Fan-shuo Tseng, Yen-chin WangAbstract:In this paper, we study the Codebook Size design strategies in the multiple-input–multiple-output (MIMO) broadcast channel (BC) systems. We adopt the nonlinear Tomlinson–Harashima precoder (THP), which is designed by the imperfect channel direction information (CDI) acquired from the random vector quantization (RVQ) feedback mechanism. Under the limitation of the total feedback rate, we flexibly allocate the Size of each user's Codebook so that the overall channel capacity is maximized. Since the design problem is not convex, directly finding out the optimum allocation of Codebook Size is not attainable. However, by sophisticatedly using the discrete majorization theory, we can derive the Codebook Size allocation strategies for the high- and the low-signal-to-noise-ratio (SNR) regions. Interestingly, the results show that the equal Size Codebook is preferable in the low-SNR region, whereas the Codebook allocates the whole available Codebook Size to a single user in the high-SNR region. Simulations certify the theoretical result of our design.
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Codebook Size Design for RVQ-Based Tomlinson–Harashima Precoded MIMO Broadcast Channels
IEEE Transactions on Vehicular Technology, 2015Co-Authors: Fan-shuo Tseng, Yen-chin WangAbstract:In this paper, we study the Codebook Size design strategies in the multiple-input–multiple-output (MIMO) broadcast channel (BC) systems. We adopt the nonlinear Tomlinson–Harashima precoder (THP), which is designed by the imperfect channel direction information (CDI) acquired from the random vector quantization (RVQ) feedback mechanism. Under the limitation of the total feedback rate, we flexibly allocate the Size of each user's Codebook so that the overall channel capacity is maximized. Since the design problem is not convex, directly finding out the optimum allocation of Codebook Size is not attainable. However, by sophisticatedly using the discrete majorization theory, we can derive the Codebook Size allocation strategies for the high- and the low-signal-to-noise-ratio (SNR) regions. Interestingly, the results show that the equal Size Codebook is preferable in the low-SNR region, whereas the Codebook allocates the whole available Codebook Size to a single user in the high-SNR region. Simulations certify the theoretical result of our design.
Xiaoming Chen - One of the best experts on this subject based on the ideXlab platform.
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joint optimization of transmit power and Codebook Size for multiuser miso systems
Vehicular Technology Conference, 2012Co-Authors: Xiaoming Chen, Zhaoyang Zhang, Lei Lei, Shaolei ChenAbstract:Transmit power and feedback bandwidth are two limited and interrelated resources which are crucial to system performance in wireless channel with feedback, so it is necessary to maximize their utilization efficiencies in the joint sense. In this paper, we investigate the inherent relationship between transmit power and Codebook Size in multiuser limited feedback MISO system by making use of Grassmann line packing theory, as an effort to provide an insight on how to jointly distribute the two resources to fulfill the diverse requirements. Then, the impact of feedback delay on the tradeoff relation is characterized in detail, and we find that even with relatively small delay, there is considerable performance loss with respect to the ideal case. Thereby, much more transmit power or feedback bandwidth should be consumed to achieve the same performance target. Finally, the theoretical claims are validated by numerical results.
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VTC Fall - Joint Optimization of Transmit Power and Codebook Size for Multiuser MISO Systems
2012 IEEE Vehicular Technology Conference (VTC Fall), 2012Co-Authors: Xiaoming Chen, Zhaoyang Zhang, Lei Lei, Shaolei ChenAbstract:Transmit power and feedback bandwidth are two limited and interrelated resources which are crucial to system performance in wireless channel with feedback, so it is necessary to maximize their utilization efficiencies in the joint sense. In this paper, we investigate the inherent relationship between transmit power and Codebook Size in multiuser limited feedback MISO system by making use of Grassmann line packing theory, as an effort to provide an insight on how to jointly distribute the two resources to fulfill the diverse requirements. Then, the impact of feedback delay on the tradeoff relation is characterized in detail, and we find that even with relatively small delay, there is considerable performance loss with respect to the ideal case. Thereby, much more transmit power or feedback bandwidth should be consumed to achieve the same performance target. Finally, the theoretical claims are validated by numerical results.
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VTC Fall - Adaptive Bit Allocation in Rateless Coded MISO Downlink System with Limited Feedback
2012 IEEE Vehicular Technology Conference (VTC Fall), 2012Co-Authors: Shaolei Chen, Xiaoming Chen, Zhaoyang Zhang, Huazi Zhang, Chau YuenAbstract:Rateless coding is a new type of feed-forward incremental redundancy channel coding technique which can be incorporated with MIMO technology to exploit both the diversity and coding gain with possibly reduced channel feedback. In this paper, the benefits of limited feedback beamforming and rateless coding are investigated jointly in a multiple-input single-output (MISO) downlink system. Based on weight enumerator analysis and with the goal of improving the effective channel gain, we propose an adaptive bit allocation scheme by taking advantage of the inherent relationship between the feedback Codebook Size and the number of transmitted coded bits. Given the feedback Codebook Size, we derive the required minimum number of coded bits for a reliable data recovery. In addition, for the service with time delay constraint, the required feedback Codebook Size is also determined. Finally, numerical results are presented to validate our theoretical analysis.
Yukinobu Hoshino - One of the best experts on this subject based on the ideXlab platform.
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A proposal of prior probability-oriented clustering in feature encoding strategies.
PloS one, 2019Co-Authors: Yuki Shinomiya, Yukinobu HoshinoAbstract:Codebook-based feature encodings are a standard framework for image recognition issues. A Codebook is usually constructed by clusterings, such as the k-means and the Gaussian Mixture Model (GMM). A Codebook Size is an important factor to decide the trade-off between recognition performance and computational complexity and a traditional framework has the disadvantage to image recognition issues when a large Codebook; the number of unique clusters becomes smaller than a designated Codebook Size because some clusters converge to close positions. This paper focusses on the disadvantage from a perspective of the distribution of prior probabilities and presents a clustering framework including two objectives that are alternated to the k-means and the GMM. Our approach is first evaluated with synthetic clustering datasets to analyze a difference to traditional clustering. In the experiment section, although our approach alternated to the k-means generates similar results to the k-means results, our approach is able to finely tune clusters for our objective. Our approach alternated to the GMM significantly improves our objective and constructs intuitively appropriate clusters, especially for huge and complicatedly distributed samples. In the experiment on image recognition issues, two state-of-the-art encodings, the Fisher Vector (FV) using the GMM and the Vector of Locally Aggregated Descriptors (VLAD) using the k-means, are evaluated with two publicly available image datasets, the Birds and the Butterflies. For the results of the VLAD with our approach, the recognition performances tend to be worse compared to the original VLAD results. On the other hand, the FV using our approach is able to improve the performance, especially in a larger Codebook Size.
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The objective values of the GMM and ours with the soft objective with respect to the Codebook Size on the Butterflies.
2019Co-Authors: Yuki Shinomiya, Yukinobu HoshinoAbstract:The objective values of the GMM and ours with the soft objective with respect to the Codebook Size on the Butterflies.
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The objective values of the GMM and ours with the soft objective with respect to the Codebook Size on the Birds.
2019Co-Authors: Yuki Shinomiya, Yukinobu HoshinoAbstract:The objective values of the GMM and ours with the soft objective with respect to the Codebook Size on the Birds.
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The objective values of the k-means and ours with the hard objective with respect to the Codebook Size on the Butterflies.
2019Co-Authors: Yuki Shinomiya, Yukinobu HoshinoAbstract:The objective values of the k-means and ours with the hard objective with respect to the Codebook Size on the Butterflies.
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The objective values of the k-means and ours with the hard objective with respect to the Codebook Size on the Birds.
2019Co-Authors: Yuki Shinomiya, Yukinobu HoshinoAbstract:The objective values of the k-means and ours with the hard objective with respect to the Codebook Size on the Birds.
Zhaoyang Zhang - One of the best experts on this subject based on the ideXlab platform.
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joint optimization of transmit power and Codebook Size for multiuser miso systems
Vehicular Technology Conference, 2012Co-Authors: Xiaoming Chen, Zhaoyang Zhang, Lei Lei, Shaolei ChenAbstract:Transmit power and feedback bandwidth are two limited and interrelated resources which are crucial to system performance in wireless channel with feedback, so it is necessary to maximize their utilization efficiencies in the joint sense. In this paper, we investigate the inherent relationship between transmit power and Codebook Size in multiuser limited feedback MISO system by making use of Grassmann line packing theory, as an effort to provide an insight on how to jointly distribute the two resources to fulfill the diverse requirements. Then, the impact of feedback delay on the tradeoff relation is characterized in detail, and we find that even with relatively small delay, there is considerable performance loss with respect to the ideal case. Thereby, much more transmit power or feedback bandwidth should be consumed to achieve the same performance target. Finally, the theoretical claims are validated by numerical results.
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VTC Fall - Joint Optimization of Transmit Power and Codebook Size for Multiuser MISO Systems
2012 IEEE Vehicular Technology Conference (VTC Fall), 2012Co-Authors: Xiaoming Chen, Zhaoyang Zhang, Lei Lei, Shaolei ChenAbstract:Transmit power and feedback bandwidth are two limited and interrelated resources which are crucial to system performance in wireless channel with feedback, so it is necessary to maximize their utilization efficiencies in the joint sense. In this paper, we investigate the inherent relationship between transmit power and Codebook Size in multiuser limited feedback MISO system by making use of Grassmann line packing theory, as an effort to provide an insight on how to jointly distribute the two resources to fulfill the diverse requirements. Then, the impact of feedback delay on the tradeoff relation is characterized in detail, and we find that even with relatively small delay, there is considerable performance loss with respect to the ideal case. Thereby, much more transmit power or feedback bandwidth should be consumed to achieve the same performance target. Finally, the theoretical claims are validated by numerical results.
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VTC Fall - Adaptive Bit Allocation in Rateless Coded MISO Downlink System with Limited Feedback
2012 IEEE Vehicular Technology Conference (VTC Fall), 2012Co-Authors: Shaolei Chen, Xiaoming Chen, Zhaoyang Zhang, Huazi Zhang, Chau YuenAbstract:Rateless coding is a new type of feed-forward incremental redundancy channel coding technique which can be incorporated with MIMO technology to exploit both the diversity and coding gain with possibly reduced channel feedback. In this paper, the benefits of limited feedback beamforming and rateless coding are investigated jointly in a multiple-input single-output (MISO) downlink system. Based on weight enumerator analysis and with the goal of improving the effective channel gain, we propose an adaptive bit allocation scheme by taking advantage of the inherent relationship between the feedback Codebook Size and the number of transmitted coded bits. Given the feedback Codebook Size, we derive the required minimum number of coded bits for a reliable data recovery. In addition, for the service with time delay constraint, the required feedback Codebook Size is also determined. Finally, numerical results are presented to validate our theoretical analysis.