Analysis on Codebook Based Precoding and Eigen Based Beamforming in UTRAN LTE

With enough channel state information feedback, the close-loop multiple-input multiple-output (MIMO) yields large improvements in the system performance. Usually, it is divided into two main areas. One is codebook based precoding (CBP), and the other is non-codebook based precoding (NBP). For the channel reciprocity property, the eigen-based beamforming (EBB) is a promising case in the NBP group. We study both the CBP and EBB in UTRAN LTE in this paper. First, we have proposed a novel rank adaptation algorithm which can improve the system performance and reduce the complexity. Next, a new truncated outer-loop power control algorithm is presented to mitigate the intercell interference. Finally, the performance of EBB and CBP are compared in four aspects. They are in the antenna array gain, the coverage ability, the frequency selective scheduling gain and the dual-polarized antenna case. The simulation results are provided using dynamic system level simulator.