Radio communication system, radio base station apparatus, user terminal and radio communication method

摘要

The present invention is designed to reduce the space to install antennas and still increase the system capacity despite the state of the distribution of user terminals in cells. According to the radio communication method of the present invention, a radio base station apparatus selects precoding vectors from a codebook that is set in advance to be uneven with respect to the direction of the arrangement of antenna elements, based on communication quality information of the user terminals in the cell, multiplies signals to supply to each antenna element by the selected precoding vectors, and transmits the signals multiplied by the precoding vectors to the user terminals, and the user terminal receives a signal from the radio base station apparatus, extracts a reference signal from the received signal and measures channel quality; and feeds back a communication quality feedback signal, including the measured channel quality, to the radio base station apparatus, via the uplink.

主权项

1. A radio communication system comprising a radio base station apparatus to form a cell and user terminals to establish radio connection with the radio base station apparatus, wherein:
the radio base station apparatus comprises: an array antenna having a plurality of antenna elements that are arranged in one direction; a processor configured to select precoding vectors from a codebook formed with precoding vectors that are set in advance to be uneven with respect to the direction of the arrangement of the antenna elements, such that the angle of transmission beams corresponding to the precoding vectors with respect to the direction of the arrangement of the antenna elements assumes angular intervals taking into account the unevenness of the distribution of the user terminals instead of assuming regular angular intervals, based on communication quality information that is fed back from the user terminals in the cell; wherein the processor is configured to multiply signals to supply to each antenna element by the selected precoding vectors; and a transmitter configured to transmit the signals multiplied by the precoding vectors to the user terminals; and the user terminals comprise: a receiver configured to receive a signal from the radio base station apparatus; a processor configured to extract a reference signal from the received signal and measure channel quality; and a transmitter configured to feed back a communication quality feedback signal, including the measured channel quality, to the radio base station apparatus, via an uplink.