| Multiuser MIMO Downlink Transmission Schemes over Time-Varying Channels |
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| 作者姓名： | 王红梅 许希斌 赵明 周世东 姚彦 |
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| 作者单位： | Tsinghua National Laboratory for Information Science and Technology，Department of Electronic Engineering，Tsinghua University |
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| 基金项目： | Supported by the National High-Tech Research and Development （863） Program of China （No. 2006AA01Z282） and the Tsinghua-Qualcomm Project |
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| 摘 要： | The performance of multiuser multiple-input-multiple-output （MIMO） downlink systems with block diagonalization （BD） depends on the accuracy of the channel state information （CSI） available at the trans- mitter and the receiver. In time-varying channels, the CSI available at the transmitter （CSIT） is always out-dated due to an inherent time delay between the uplink channel estimation and the downlink data transmission in time division duplexing （TDD） systems. This leads to a drastic degradation of system capacity. This paper first analyzes the effect of the outdated CSIT on multiuser MIMO downlink systems using the BD method and then proposes two linear processing methods, BD precoding with user selection and scheduling at the transmitter and total minimum mean squared error （MMSE） decoding at the receiver （TBDUSS-RTMMSE） and BD preceding at the transmitter with partial MMSE decoding at the receiver （TBD-RPMMSE）, to mitigate the interference among data streams and users. Analysis and simulation results show that these methods can effectively reduce the impairment of the outdated CSIT to increase the system sum capacity in a suitable time delay region of the CSIT.
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| 关 键 词： | 多输入多输出系统 下行链路系统 时间变化无线通道 最小平方误差 |
| 收稿时间： | 20 July 2007 |
Multiuser MIMO Downlink Transmission Schemes over Time-Varying Channels |
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| Hongmei Wang, ê&#x;, Xibin Xu, »ì , Ming Zhao,
, Shidong Zhou, &#x;ì,Yan Yao, Ú .Multiuser MIMO Downlink Transmission Schemes over Time-Varying Channels[J].Tsinghua Science and Technology,2008,13(6):769-777. |
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| Authors: | Hongmei Wang ê&#x; Xibin Xu »ì Ming Zhao
Shidong Zhou &#x;ì Yan Yao Ú |
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| Institution: | aTsinghua National Laboratory for Information Science and Technology, Department of Electronic Engineering, Tsinghua University, Beijing 100084, China |
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| Abstract: | The performance of multiuser multiple-input-multiple-output (MIMO) downlink systems with block diagonalization (BD) depends on the accuracy of the channel state information (CSI) available at the transmitter and the receiver. In time-varying channels, the CSI available at the transmitter (CSIT) is always out-dated due to an inherent time delay between the uplink channel estimation and the downlink data transmission in time division duplexing (TDD) systems. This leads to a drastic degradation of system capacity. This paper first analyzes the effect of the outdated CSIT on multiuser MIMO downlink systems using the BD method and then proposes two linear processing methods, BD precoding with user selection and scheduling at the transmitter and total minimum mean squared error (MMSE) decoding at the receiver (TBDUSS-RTMMSE) and BD precoding at the transmitter with partial MMSE decoding at the receiver (TBD-RPMMSE), to mitigate the interference among data streams and users. Analysis and simulation results show that these methods can effectively reduce the impairment of the outdated CSIT to increase the system sum capacity in a suitable time delay region of the CSIT. |
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| Keywords: | multiuser multiple-input-multiple-output (MIMO) downlink system time-varying wireless channel outdated channel state information minimum mean squared error (MMSE) |
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