Feedback Generation for Cell-Edge Transmission in Unsynchronized Coordinated Networks
Multi-point transmission in coordinated networks enables reliable coverage and high data rates for cell-edge users in 4G Long Term Evolution (LTE) systems. To provide theoretical proven multi-point coordination gain in the practical deployed networks, accurate channel state information (CSI) feedback is required. This paper focuses on CSI feedback generation, that is, on precoding matrix index (PMI) selection, supporting coherent reception for the users located at the cell-edge of unsynchronized coordinated LTE networks. The received signal at user equipment and the theoretical lower bound of the joint transmission are analyzed. The impact of timing offset on feedback generation in coordinated networks is evaluated as well.