Method for feeding back CQI (Channel Quality Indicator) information and channel quality estimation, user terminal and base station

Abstract

The invention discloses a method for feeding back CQI (Channel Quality Indicator) information and channel quality estimation, a user terminal and a base station. The user terminal feeds back a precoding matrix indication W1 which is optimally matched with a channel matrix from a base station of a service cell to the user terminal and a reference precoding matrix indication W2 which sets a matching degree with a channel matrix from the base station of a cooperative cell to the user terminal to the base station of the service cell; the user terminal confirms the channel quality indication CQI1 according to the W1 and the channel matrix from the base station of the service cell to the user terminal, confirms a channel quality indication CQI2 according to the W2 and the channel matrix from the base station of the cooperative cell to the user terminal and reports the CQI1 and the CQI2 to the base station of the service cell; and the base station adjusts the CQI2 according to the information fed back by the user terminal by combining with the dispatching information and direction information which are fed back by the cooperative cell. The invention achieves the aims of accurately estimating interference as much as possible, reducing the block error rate and improving the throughput in such a way that the user terminal reports the channel quality indication relevant information to assist the base station to carry out CQI adjustment.

Description

technical field [0001] The present invention relates to LTE-A (Long Term Evolution-Advanced) cooperative scheduling technology, in particular to a method for feeding back CQI information and channel quality estimation, a user terminal and a base station. Background technique [0002] Coordinated Multiple Point (CoMP) transmission is an important feature of LTE-A (Long Term Evolution-Advanced), among which Coordinated BeamForming (CBF) technology is getting more and more attention because of its advantages of avoiding and reducing interference. more and more attention. [0003] Coordinated beamforming (CBF) technology is to exchange information between multiple coordinated cells to perform coordinated scheduling of space, time, and frequency resources to reduce interference between coordinated cells. The basic idea of ​​the coordinated beamforming CBF is: the data received by a user equipment (User Equipment, UE) is sent only from the serving cell of the UE, and the interfer...

AI Technical Summary

Problems solved by technology

[0008] The serving cell uses the CQI information fed back by the terminal to select the modulation and coding method (MCS) of the serving cell to reduce inter-cell interference. Due to the need for continuous coordinated scheduling, while reducing interference, it also brings rapid interference changes and inaccurate channel quality estimation. The problem: the serving cell only expects and cannot force the cooperating cell to use which precoding matrix

Therefore, the serving cell cannot accurately estimate the channel quality, resulting in improper selection of modulation and coding methods, improper coordination of beam directions, and inter-cell interference

Compared with the interference caused by cooperative beamforming CBF, if the channel quality estimation is inaccurate, the interference information may change more drastically. In the case of accurate channel quality estimation and successful beam direction coordination, The interference information is reduced or even 0, but once the channel estimation is inaccurate and the beam direction coordination fails, the interference is high

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