Reduced-Feedback Multi-cell Coordinated Transmission

• Main Authors: Chun-Hao Yeh, 葉峻豪
• Other Authors: 蘇炫榮
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/87061067324741255181

碩士 === 國立臺灣大學 === 電信工程學研究所 === 100 === The cell-edge performance would be extremely degraded by the aggressive inter-cell interference when the frequency reuse factor of one is considered to maximize the spectral efficiency in next-generation communication systems. In multi-cell multi-input multi-output (MIMO) downlink cellular system, we propose the coordinated beamforming (CB) algorithms to suppress the serious inter-cell interference. Although we combat the out-of-cell interference through the cooperation between base stations (BSs), the backhaul-exchange between BSs and the estimation of interference-channels at user-end are not required in the proposed CB. From the viewpoint of practical systems, the proposed CB could be distributively implemented with only little revision to practical existing algorithms in cellular systems. The main idea is to obtain the inter-cell interference information at user-end and then iteratively adjust the transmit/receive beamformings to avoid the interference with one another. Besides, in order to reduce the feedback overhead of users, the whitening filter is considered to pre-process the inter-cell interference information at user-end, and we have proven that the adopted performance metric would not be changed by adding the whitening filter in user-end. In addition to proposed CB, we propose several methods to further improve the performance by paying additional costs. The simulation results verify the benefit of multi-cell coordinated transmission and compare the proposed schemes with other existing algorithms.