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

摘要

To reduce overhead of CSI feedback without decreasing throughput in applying CoMP transmission, a radio communication method of the invention is characterized by including, in a user terminal measuring quality information for each of cells to perform Coordinated Multi-Point transmission, and notifying a radio base station apparatus of the quality information, in the radio base station apparatus calculating a quality difference between the cells to perform Coordinated Multi-Point transmission, by using the quality information for each the cells from the user terminal, determining granularity of inter-cell channel state information for each of the cells based on the quality difference, and notifying the user terminal of the granularity, and, in that the user terminal generating inter-cell channel state information for each of the cells according to the granularity from the radio base station apparatus, and transmitting the inter-cell channel state information for each of the cells to radio base station apparatuses of cells to perform Coordinated Multi-Point transmission.

主权项

1. A radio communication system comprising:
a plurality of radio base station apparatuses, wherein at least one radio base station apparatus of the plurality of radio base station apparatuses includes:
a transmission section that performs signal processing on Coordinated Multi-Point transmissions of a downlink signal sent to a user terminal;a calculation section that calculates a quality difference between the cells performing Coordinated Multi-Point transmission by using quality information associated with each cell from the user terminal; anda determination section that determines granularity of inter-cell channel state information for each cell based on the quality difference between the cells performing Coordinated Multi-Point transmission; and the user terminal including:
a reception section that receives a downlink Coordinated Multi-Point transmission signal from a radio base station apparatus;a notification section that notifies the at least one radio base station apparatus of quality information associated with each cell performing Coordinated Multi-Point transmission;a generation section that generates inter-cell channel state information for each cell according to the granularity notified from the at least one radio base station apparatus; anda transmission section that transmits the inter-cell channel state information for each cell to the radio base station apparatus associated with Coordinated Multi-Point transmission.