中国邮电高校学报(英文) ›› 2009, Vol. 16 ›› Issue (4): 78-83.doi: 10.1016/S1005-8885(08)60252-6

• Wireless • 上一篇    下一篇

Adaptive modulation for SVD-based MIMO systems with outdated CSI

颜智,王文博,王晓婷,郑侃   

  1. Key Laboratory of Universal Wireless Communication, Ministry of Education, Beijing University of Posts and Telecommunications, Beijing 100876, China
  • 收稿日期:2008-07-19 修回日期:1900-01-01 出版日期:2009-08-31
  • 通讯作者: 颜智

Adaptive modulation for SVD-based MIMO systems with outdated CSI

YAN Zhi , WANG Wen-bo, WANG Xiao-ting, ZHENG Kan   

  1. Key Laboratory of Universal Wireless Communication, Ministry of Education, Beijing University of Posts and Telecommunications, Beijing 100876, China
  • Received:2008-07-19 Revised:1900-01-01 Online:2009-08-31
  • Contact: YAN Zhi

摘要:

The performance of singular value decomposition (SVD)-based multiple-input multiple-output (MIMO) with adaptive modulation (AM) is dependent on the accuracy of the channel state information (CSI) at the transmitter and the receiver. However, for a time-varying channel, the CSI obtained at the transmitter or the receiver is incorrect owing to an inherent delay or error. A typical system employing SVD suffers degradation in capacity when outdated CSI is used to transmit data. This article first addresses the adaptive modulation MIMO system designed under perfect CSI assumption. Based on that, two scenarios of outdated CSI are investigated and analyzed. The effect of imperfect CSI on the system performance is focused on and a simple post processing SNR (pSNR) adjustment design is proposed on AM system in the two scenarios for reducing degradation in average spectral efficiency (ASE). Simulation results show that these designs provide good performance in an adaptive way, and enable the adaptive MIMO system considerably more to be robust against CSI imperfection.

关键词:

;MIMO,;SVD,;adaptive;modulation,;outdated;CSI

Abstract:

The performance of singular value decomposition (SVD)-based multiple-input multiple-output (MIMO) with adaptive modulation (AM) is dependent on the accuracy of the channel state information (CSI) at the transmitter and the receiver. However, for a time-varying channel, the CSI obtained at the transmitter or the receiver is incorrect owing to an inherent delay or error. A typical system employing SVD suffers degradation in capacity when outdated CSI is used to transmit data. This article first addresses the adaptive modulation MIMO system designed under perfect CSI assumption. Based on that, two scenarios of outdated CSI are investigated and analyzed. The effect of imperfect CSI on the system performance is focused on and a simple post processing SNR (pSNR) adjustment design is proposed on AM system in the two scenarios for reducing degradation in average spectral efficiency (ASE). Simulation results show that these designs provide good performance in an adaptive way, and enable the adaptive MIMO system considerably more to be robust against CSI imperfection.

Key words:

MIMO;SVD;adaptive modulation;outdated CSI