Method and terminal for estimating channel quality indication in TDD system

The invention discloses a method of estimating channel quality indication (CQI) in a time division duplex (TDD) system. The method is as follows: according to the shared reference signal transmitted by the base station, the terminal estimates the channel, obtains the channel estimation matrix on each downlink subcarrier; using the channel estimation matrix of the subcarrier in the sub-band frequency, to obtain the channel estimation matrix corresponding to the sub-band frequency; using the channel estimation matrix corresponding to the sub-band frequency, to obtain the pre-coding matrix used by the sub-band frequency at next downlink transmission; using the channel estimation matrix of the subcarrier in the sub-band frequency and the pre-coding matrix of the sub-band frequency, to compute CQI corresponding to the sub-band frequency. The invention also discloses a user terminal. Adopting the invention, when using the non-codebook pre-coding processing mode in the TDD system, and when the terminal estimates CQI of the downlink channel, the pre-coding grain is embodied in CQI, and more accurate downlink channel quality information can be obtained.