The Experts below are selected from a list of 2697 Experts worldwide ranked by ideXlab platform
Ming Lei - One of the best experts on this subject based on the ideXlab platform.
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Retrieving Channel Reciprocity for Coordinated Multi-Point Transmission with Joint Processing
IEEE Transactions on Communications, 2014Co-Authors: Chenyang Yang, Gang Wang, Ming LeiAbstract:In time division duplex coordinated multi-Point Transmission with joint processing (CoMP-JP) systems, the uplink-downlink channels are no longer reciprocal. Due to the difficulty of antenna calibration among the coordinated base stations (BSs), practical downlink channels differ from uplink channels by multiplicative ambiguity factors, which lead to severe performance degradation. In this paper, we propose an inter-BS antenna calibration strategy to facilitate downlink CoMP-JP Transmission, whose basic idea is to estimate the ambiguity factors. To establish the observation equations for estimation, an extra uplink training frame except for the regular uplink and downlink frames is introduced, and existing signalling framework of limited feedback can also be reused. To improve the estimation performance, we can either select multiple users or employ multiple frames of one user to assist the calibration. After establishing the observation equations respectively with uplink training or limited feedback, the weighted least square criterion is used for estimation. We proceed to analyze and compare the mean square errors of the estimators, and provide a principle to select the users for assisting calibration. Simulation results show that the channel reciprocity is largely retrieved by the proposed antenna calibration strategy, which provides substantial throughput gain over the CoMP-JP systems without inter-BS calibration.
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WCNC - Retrieving channel reciprocity for coordinated multi-Point Transmission
2013 IEEE Wireless Communications and Networking Conference (WCNC), 2013Co-Authors: Chenyang Yang, Gang Wang, Ming LeiAbstract:Due to the difficulty of self antenna calibration among different base stations (BSs), the uplink-downlink channels are no longer reciprocal in time division duplex coordinated multi-Point Transmission with joint processing (CoMP-JP) systems. To retrieve the channel reciprocity, we propose an inter-BS antenna calibration method. Specifically, we estimate the inter-BS ambiguity factors with weighted least square criterion by using the uplink and downlink channel estimates and the received signal of a calibration sounding signal of multiple supporting users or multiple frames. We then analyze the mean square error of the proposed estimator, and compare the performance of the estimators with multiple supporters and with multiple frames. Simulation results show that the channel reciprocity is largely retrieved by the proposed antenna calibration method, which provides substantial throughput gain over the CoMP-JP systems without calibration.
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WCNC - Low complexity channel estimation in TDD coordinated multi-Point Transmission systems
2013 IEEE Wireless Communications and Networking Conference (WCNC), 2013Co-Authors: Zhilin Chen, Chenyang Yang, Gang Wang, Xueying Hou, Shengqian Han, Ming LeiAbstract:Coordinated multi-Point Transmission (CoMP) is a promising strategy to provide high spectral efficiency for cellular systems. To facilitate multicell precoding, downlink channel is estimated via uplink training in time division duplexing systems by exploiting channel reciprocity. Virtual subcarriers in practical orthogonal frequency division multiplexing (OFDM) systems degrade the channel estimation performance severely when discrete Fourier transform (DFT) based channel estimator is applied. Minimum mean square error (MMSE) channel estimator is able to provide superior performance, but at the cost of high complexity and more a priori information. In this paper, we propose a low complexity channel estimator for CoMP multi-antenna OFDM systems. We employ series expansion to approximate the matrix inversion in MMSE estimator as matrix multiplications. By exploiting the feature of frequency domain training sequences in prevalent systems, we show that the proposed estimator can be implemented by DFT. To reduce the required channel statistical information, we use the average channel gains instead of channel correlation matrix, which leads to minor performance loss in CoMP systems. Simulation results show that the proposed channel estimator performs closely to the MMSE estimator.
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coordinated multi Point Transmission with non ideal channel reciprocity
Wireless Communications and Networking Conference, 2012Co-Authors: Shengqian Han, Chenyang Yang, Gang Wang, Dalin Zhu, Ming LeiAbstract:This paper studies robust Transmission strategies for downlink time division duplex coordinated multi-Point (CoMP) systems with non-ideal uplink-downlink channel reciprocity due to imperfect antenna calibration. By exploiting the statistics of antenna calibration errors, we first characterize the optimal parametric precoder structure that maximizes the weighted sum rate, based on which a closed-form robust signal-to-leakage-plus-noise ratio (RSLNR) precoder with properly selected parameters is then proposed. Simulation results show that the proposed precoder together with user scheduling provides near-optimal performance and data sharing among coordinated BSs may become detrimental depending on the employed precoders and the accuracy of antenna calibration.
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WCNC - Coordinated multi-Point Transmission with non-ideal channel reciprocity
2012 IEEE Wireless Communications and Networking Conference (WCNC), 2012Co-Authors: Shengqian Han, Chenyang Yang, Gang Wang, Dalin Zhu, Ming LeiAbstract:This paper studies robust Transmission strategies for downlink time division duplex coordinated multi-Point (CoMP) systems with non-ideal uplink-downlink channel reciprocity due to imperfect antenna calibration. By exploiting the statistics of antenna calibration errors, we first characterize the optimal parametric precoder structure that maximizes the weighted sum rate, based on which a closed-form robust signal-to-leakage-plus-noise ratio (RSLNR) precoder with properly selected parameters is then proposed. Simulation results show that the proposed precoder together with user scheduling provides near-optimal performance and data sharing among coordinated BSs may become detrimental depending on the employed precoders and the accuracy of antenna calibration.
Chenyang Yang - One of the best experts on this subject based on the ideXlab platform.
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Retrieving Channel Reciprocity for Coordinated Multi-Point Transmission with Joint Processing
IEEE Transactions on Communications, 2014Co-Authors: Chenyang Yang, Gang Wang, Ming LeiAbstract:In time division duplex coordinated multi-Point Transmission with joint processing (CoMP-JP) systems, the uplink-downlink channels are no longer reciprocal. Due to the difficulty of antenna calibration among the coordinated base stations (BSs), practical downlink channels differ from uplink channels by multiplicative ambiguity factors, which lead to severe performance degradation. In this paper, we propose an inter-BS antenna calibration strategy to facilitate downlink CoMP-JP Transmission, whose basic idea is to estimate the ambiguity factors. To establish the observation equations for estimation, an extra uplink training frame except for the regular uplink and downlink frames is introduced, and existing signalling framework of limited feedback can also be reused. To improve the estimation performance, we can either select multiple users or employ multiple frames of one user to assist the calibration. After establishing the observation equations respectively with uplink training or limited feedback, the weighted least square criterion is used for estimation. We proceed to analyze and compare the mean square errors of the estimators, and provide a principle to select the users for assisting calibration. Simulation results show that the channel reciprocity is largely retrieved by the proposed antenna calibration strategy, which provides substantial throughput gain over the CoMP-JP systems without inter-BS calibration.
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WCNC - Retrieving channel reciprocity for coordinated multi-Point Transmission
2013 IEEE Wireless Communications and Networking Conference (WCNC), 2013Co-Authors: Chenyang Yang, Gang Wang, Ming LeiAbstract:Due to the difficulty of self antenna calibration among different base stations (BSs), the uplink-downlink channels are no longer reciprocal in time division duplex coordinated multi-Point Transmission with joint processing (CoMP-JP) systems. To retrieve the channel reciprocity, we propose an inter-BS antenna calibration method. Specifically, we estimate the inter-BS ambiguity factors with weighted least square criterion by using the uplink and downlink channel estimates and the received signal of a calibration sounding signal of multiple supporting users or multiple frames. We then analyze the mean square error of the proposed estimator, and compare the performance of the estimators with multiple supporters and with multiple frames. Simulation results show that the channel reciprocity is largely retrieved by the proposed antenna calibration method, which provides substantial throughput gain over the CoMP-JP systems without calibration.
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WCNC - Low complexity channel estimation in TDD coordinated multi-Point Transmission systems
2013 IEEE Wireless Communications and Networking Conference (WCNC), 2013Co-Authors: Zhilin Chen, Chenyang Yang, Gang Wang, Xueying Hou, Shengqian Han, Ming LeiAbstract:Coordinated multi-Point Transmission (CoMP) is a promising strategy to provide high spectral efficiency for cellular systems. To facilitate multicell precoding, downlink channel is estimated via uplink training in time division duplexing systems by exploiting channel reciprocity. Virtual subcarriers in practical orthogonal frequency division multiplexing (OFDM) systems degrade the channel estimation performance severely when discrete Fourier transform (DFT) based channel estimator is applied. Minimum mean square error (MMSE) channel estimator is able to provide superior performance, but at the cost of high complexity and more a priori information. In this paper, we propose a low complexity channel estimator for CoMP multi-antenna OFDM systems. We employ series expansion to approximate the matrix inversion in MMSE estimator as matrix multiplications. By exploiting the feature of frequency domain training sequences in prevalent systems, we show that the proposed estimator can be implemented by DFT. To reduce the required channel statistical information, we use the average channel gains instead of channel correlation matrix, which leads to minor performance loss in CoMP systems. Simulation results show that the proposed channel estimator performs closely to the MMSE estimator.
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coordinated multi Point Transmission with non ideal channel reciprocity
Wireless Communications and Networking Conference, 2012Co-Authors: Shengqian Han, Chenyang Yang, Gang Wang, Dalin Zhu, Ming LeiAbstract:This paper studies robust Transmission strategies for downlink time division duplex coordinated multi-Point (CoMP) systems with non-ideal uplink-downlink channel reciprocity due to imperfect antenna calibration. By exploiting the statistics of antenna calibration errors, we first characterize the optimal parametric precoder structure that maximizes the weighted sum rate, based on which a closed-form robust signal-to-leakage-plus-noise ratio (RSLNR) precoder with properly selected parameters is then proposed. Simulation results show that the proposed precoder together with user scheduling provides near-optimal performance and data sharing among coordinated BSs may become detrimental depending on the employed precoders and the accuracy of antenna calibration.
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WCNC - Coordinated multi-Point Transmission with non-ideal channel reciprocity
2012 IEEE Wireless Communications and Networking Conference (WCNC), 2012Co-Authors: Shengqian Han, Chenyang Yang, Gang Wang, Dalin Zhu, Ming LeiAbstract:This paper studies robust Transmission strategies for downlink time division duplex coordinated multi-Point (CoMP) systems with non-ideal uplink-downlink channel reciprocity due to imperfect antenna calibration. By exploiting the statistics of antenna calibration errors, we first characterize the optimal parametric precoder structure that maximizes the weighted sum rate, based on which a closed-form robust signal-to-leakage-plus-noise ratio (RSLNR) precoder with properly selected parameters is then proposed. Simulation results show that the proposed precoder together with user scheduling provides near-optimal performance and data sharing among coordinated BSs may become detrimental depending on the employed precoders and the accuracy of antenna calibration.
Gang Wang - One of the best experts on this subject based on the ideXlab platform.
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Retrieving Channel Reciprocity for Coordinated Multi-Point Transmission with Joint Processing
IEEE Transactions on Communications, 2014Co-Authors: Chenyang Yang, Gang Wang, Ming LeiAbstract:In time division duplex coordinated multi-Point Transmission with joint processing (CoMP-JP) systems, the uplink-downlink channels are no longer reciprocal. Due to the difficulty of antenna calibration among the coordinated base stations (BSs), practical downlink channels differ from uplink channels by multiplicative ambiguity factors, which lead to severe performance degradation. In this paper, we propose an inter-BS antenna calibration strategy to facilitate downlink CoMP-JP Transmission, whose basic idea is to estimate the ambiguity factors. To establish the observation equations for estimation, an extra uplink training frame except for the regular uplink and downlink frames is introduced, and existing signalling framework of limited feedback can also be reused. To improve the estimation performance, we can either select multiple users or employ multiple frames of one user to assist the calibration. After establishing the observation equations respectively with uplink training or limited feedback, the weighted least square criterion is used for estimation. We proceed to analyze and compare the mean square errors of the estimators, and provide a principle to select the users for assisting calibration. Simulation results show that the channel reciprocity is largely retrieved by the proposed antenna calibration strategy, which provides substantial throughput gain over the CoMP-JP systems without inter-BS calibration.
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WCNC - Retrieving channel reciprocity for coordinated multi-Point Transmission
2013 IEEE Wireless Communications and Networking Conference (WCNC), 2013Co-Authors: Chenyang Yang, Gang Wang, Ming LeiAbstract:Due to the difficulty of self antenna calibration among different base stations (BSs), the uplink-downlink channels are no longer reciprocal in time division duplex coordinated multi-Point Transmission with joint processing (CoMP-JP) systems. To retrieve the channel reciprocity, we propose an inter-BS antenna calibration method. Specifically, we estimate the inter-BS ambiguity factors with weighted least square criterion by using the uplink and downlink channel estimates and the received signal of a calibration sounding signal of multiple supporting users or multiple frames. We then analyze the mean square error of the proposed estimator, and compare the performance of the estimators with multiple supporters and with multiple frames. Simulation results show that the channel reciprocity is largely retrieved by the proposed antenna calibration method, which provides substantial throughput gain over the CoMP-JP systems without calibration.
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WCNC - Low complexity channel estimation in TDD coordinated multi-Point Transmission systems
2013 IEEE Wireless Communications and Networking Conference (WCNC), 2013Co-Authors: Zhilin Chen, Chenyang Yang, Gang Wang, Xueying Hou, Shengqian Han, Ming LeiAbstract:Coordinated multi-Point Transmission (CoMP) is a promising strategy to provide high spectral efficiency for cellular systems. To facilitate multicell precoding, downlink channel is estimated via uplink training in time division duplexing systems by exploiting channel reciprocity. Virtual subcarriers in practical orthogonal frequency division multiplexing (OFDM) systems degrade the channel estimation performance severely when discrete Fourier transform (DFT) based channel estimator is applied. Minimum mean square error (MMSE) channel estimator is able to provide superior performance, but at the cost of high complexity and more a priori information. In this paper, we propose a low complexity channel estimator for CoMP multi-antenna OFDM systems. We employ series expansion to approximate the matrix inversion in MMSE estimator as matrix multiplications. By exploiting the feature of frequency domain training sequences in prevalent systems, we show that the proposed estimator can be implemented by DFT. To reduce the required channel statistical information, we use the average channel gains instead of channel correlation matrix, which leads to minor performance loss in CoMP systems. Simulation results show that the proposed channel estimator performs closely to the MMSE estimator.
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coordinated multi Point Transmission with non ideal channel reciprocity
Wireless Communications and Networking Conference, 2012Co-Authors: Shengqian Han, Chenyang Yang, Gang Wang, Dalin Zhu, Ming LeiAbstract:This paper studies robust Transmission strategies for downlink time division duplex coordinated multi-Point (CoMP) systems with non-ideal uplink-downlink channel reciprocity due to imperfect antenna calibration. By exploiting the statistics of antenna calibration errors, we first characterize the optimal parametric precoder structure that maximizes the weighted sum rate, based on which a closed-form robust signal-to-leakage-plus-noise ratio (RSLNR) precoder with properly selected parameters is then proposed. Simulation results show that the proposed precoder together with user scheduling provides near-optimal performance and data sharing among coordinated BSs may become detrimental depending on the employed precoders and the accuracy of antenna calibration.
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WCNC - Coordinated multi-Point Transmission with non-ideal channel reciprocity
2012 IEEE Wireless Communications and Networking Conference (WCNC), 2012Co-Authors: Shengqian Han, Chenyang Yang, Gang Wang, Dalin Zhu, Ming LeiAbstract:This paper studies robust Transmission strategies for downlink time division duplex coordinated multi-Point (CoMP) systems with non-ideal uplink-downlink channel reciprocity due to imperfect antenna calibration. By exploiting the statistics of antenna calibration errors, we first characterize the optimal parametric precoder structure that maximizes the weighted sum rate, based on which a closed-form robust signal-to-leakage-plus-noise ratio (RSLNR) precoder with properly selected parameters is then proposed. Simulation results show that the proposed precoder together with user scheduling provides near-optimal performance and data sharing among coordinated BSs may become detrimental depending on the employed precoders and the accuracy of antenna calibration.
Sonia Aissa - One of the best experts on this subject based on the ideXlab platform.
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coordinated multi Point Transmission a poisson delaunay triangulation based approach
IEEE Transactions on Wireless Communications, 2020Co-Authors: Yan Li, Sonia AissaAbstract:Coordinated multi-Point (CoMP) Transmission is a cooperating technique among base stations (BSs) in a cellular network, with outstanding capability at inter-cell interference (ICI) mitigation. ICI is a dominant source of error, and has detrimental effects on system performance if not managed properly. Based on the theory of Poisson-Delaunay triangulation, this paper proposes a novel analytical model for CoMP operation in cellular networks. Unlike the conventional CoMP operation that is dynamic and needs on-line updating occasionally, the proposed approach enables the cooperating BS set of a user equipment (UE) to be fixed and off-line determined according to the location information of BSs. By using the theory of stochastic geometry, the coverage probability and spectral efficiency of a typical UE are analyzed, and simulation results corroborate the effectiveness of the proposed CoMP scheme and the developed performance analysis.
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unified analytical volume distribution of poisson delaunay simplex and its application to coordinated multi Point Transmission
IEEE Transactions on Wireless Communications, 2018Co-Authors: Sonia AissaAbstract:For Poisson-Delaunay triangulations in $d$ -dimensional Euclidean space $\mathbb {R}^{d}$ , a structured and computationally efficient form of the probability density function (PDF) of the volume of a typical cell is analytically derived in this paper. In particular, the ensuing PDF and the corresponding cumulative density function are exact and unified, applicable to spaces of arbitrary dimension ( $d \ge 1$ ). Then, the special cases and shape characteristics of the resulting PDF are thoroughly examined. Finally, various applications of the obtained distribution functions are outlined and, in particular, a novel coordinated multi-Point Transmission scheme based on Poisson-Delaunay triangulation is developed and the pertinent void cell effect is precisely evaluated by using the obtained distribution functions.
Dacheng Yang - One of the best experts on this subject based on the ideXlab platform.
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A multi-Point Transmission scheme for cross-tier interference mitigation in downlink heterogeneous networks
Journal of High Speed Networks, 2014Co-Authors: Atif Hameed, Dacheng Yang, Xian-ling Wang, Weiwei ZhangAbstract:Heterogeneous network (HetNet) deployment comprising of high power macro nodes overlaid with pico nodes and various other types of low power nodes has been considered as one of the key enabling technology in 3GPP LTE-Advanced. HetNet can significantly enhance the capacity and coverage of cellular networks. However, severe inter-cell interference (ICI) between high power macro and low power pico nodes is a critical performance limiting factor for cell-edge users in HetNet. Coordinated multiPoint Transmission (CoMP) has been recognized as an effective technique to mitigate ICI in LTE-A. However, backhaul overhead and complexity are critical issues in CoMP. In this paper we propose a novel scheme that utilizes the benefits of HetNet to improve the system capacity and coverage. Moreover it exploits coordinated multi-Point Transmission to effectively mitigate ICI with reduced feedback overhead and complexity. In our scheme the users with high signal to interference plus noise ratio are served by the respective macro and pico cells. However, for users in high interference region, coordinated multi-Point joint Transmission is adopted to increase the radio signal strength and effectively mitigate ICI. The proposed scheme outperforms the conventional system with reduced backhaul overhead and complexity. System level simulations illustrate that the proposed scheme attains higher performance as compared to conventional schemes.
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Antenna mismatch and calibration problem in coordinated multi-Point Transmission system
IET Communications, 2012Co-Authors: Fan Huang, Yafeng Wang, Jian Geng, Dacheng YangAbstract:Recently, Coordinated Multi-Point (CoMP) Transmission/Reception technology is introduced into the fourth-generation cellular mobile communication system. Time-division duplex (TDD) system is more suitable to apply CoMP when joint processing is needed because it can easily get the channel information through channel reciprocity. Actually, a crucial Point to realise channel reciprocity is the antenna calibration, especially in the inter-base station (BS) case. Self-antenna calibration within the BS in the conventional system has been studied in previous works. In this paper, the authors investigate the impact of un-calibrated antennas of BSs and mobile stations (MSs) on the precoding matrix of two precoding techniques [block diagonal (BD) and zero forcing (ZF)] in the CoMP system. A theoretical model is set and analysed. The discussion of some properties gives a complete overview of the calibration problem in the CoMP system. In addition, the authors propose a practical scheme to solve inter-BS antenna calibration problem. System simulation results, which validate their analysis, are presented to show the necessity of antenna calibration.
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VTC Fall - Efficient Multi-Point Transmission Scheme for HSDPA Networks
2011 IEEE Vehicular Technology Conference (VTC Fall), 2011Co-Authors: Wei Yang, Yongyu Chang, Shuhui Liu, Dacheng YangAbstract:To meet the increasing demand for mobile broadband, multiple carrier features were subsequently introduced into UMTS Release-8 to Release-10. As a consequence, the UE capabilities of rejecting inter-stream interference have increased considerably. To fully utilize the UE capabilities and wireless resources, multi-Point Transmissions raised concerns in 3GPP High Speed Downlink Packet Access (HSDPA) standardizing process. Multi-Point Transmission is a promising technique to increase both the average cell throughput and cell edge user throughput. A novel cooperative sector selection algorithm, which takes both channel condition and sector loading into consideration, and an adaptive precoding Transmission scheme are proposed for HSPA multi-Point Transmission. Through the system level simulation, the proposed Transmission scheme effectively outperforms the non-cooperative system and non-adaptive cooperative scheme on both the average sector throughput and sector-edge UEs' rates significantly.
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performance analysis of antenna calibration in coordinated multi Point Transmission system
Vehicular Technology Conference, 2010Co-Authors: Fan Huang, Yafeng Wang, Jian Geng, Dacheng YangAbstract:Coordinated Multi-Point (CoMP) Transmission/Rec-eption technology has shown to improve the system performance. In Time-division duplex system, it can easily obtain channel information by the channel reciprocity. However, a crucial Point to realize the channel reciprocity is the antenna calibration problem. This paper aims at analyzing the impact of un-calibrated channel on the precoding matrix under zero forcing precoding in CoMP system. A theoretical model is set and some properties presented in this work give an overview of the calibration problem. Additionally, we propose a new scheme for inter BS calibration. System simulation results show the necessity of antenna calibration.
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VTC Fall - Clustering Approach in Coordinated Multi-Point Transmission/Reception System
2010 IEEE 72nd Vehicular Technology Conference - Fall, 2010Co-Authors: Fan Huang, Yafeng Wang, Jian Geng, Dacheng YangAbstract:Multi-cell cooperation has been regarded as a promising technique of the future cellular wireless network to achieve higher Transmission rate and better QoS (quality of service) performance. Cooperation among base stations can be classified into two categories: centralized and distributed cooperation. In this work, we mainly consider efficient and practical cooperation clustering approaches in the downlink Coordinated Multi-Point (CoMP) system. A novel Multi-Layered clustering method is proposed for distributed cooperation, which is able to make a significant enhancement with limited overhead increment compared with traditional static clustering. We also develop a new concept for centralized cooperation. Simulation results are presented under the block diagonal precoding algorithm.
