Timing alignment for subband precoding based coordinated multi-point OFDM systems

作者：Zhang Xiujun; Xia Liang; Zhao Yifei; Zhou Shidong^*

来源：Journal of Tsinghua University(Science and Technology), 2012, 52(11): 1545-1549.

• Channel state information feedbacks
• Coordinated multi point (CoMP)
• Coordinated multi points
• Downlink scheduling
• Feed back information
• Multiuser multiple-input multiple-output systems
• Phase rotation approach
• Zero-forcing beam-forming

In orthogonal frequency division multiplexing (OFDM) based coordinated multi-point (CoMP) systems, per-subband processing for channel state information (CSI) feedback and precoding is an efficient method to reduce feedback overhead. However, when the transmissions from cooperative base stations to certain users suffer different delays, the users will experience larger equivalent multi-path delays, which will further increase the error in the CSI feedback in a subband. This study analyzes the impact of different delays from cooperative base stations on the CSI feedback error. Long-term statistics on the differences in the transmission delays are used to develop a phase rotation approach in the frequency domain for timing alignment to reduce the impact of the different delays. Simulations show that this method achieves a significant system sum rate gain with only a few additional computations and a little feedback information, so it is suitable for practical OFDM based CoMP systems.

• 出版日期2012-11
• 单位清华大学