A method of selecting at least one user terminal (2a, 2b, 2c, 2d, 2e, 2f) so as to enhance calibration for reciprocity error between uplink and downlink in a network equipment in time division duplex communication systems, the method being performed by a device and the method comprising the following steps: A. obtaining channel quality related information between a plurality of first user terminals (2a, 2b, 2c, 2d, 2e, 2f) and a first base station, wherein said channel quality related information is used for indicating channel qualities between said plurality of first user terminals (2a, 2b, 2c, 2d, 2e, 2f) and said first base station; B. selecting, at least one first user terminal (2a, 2b, 2c, 2d, 2e, 2f) as a calibration user terminal (2a, 2b, 2c, 2d, 2e, 2f) for calibrating said reciprocity error between uplink and downlink, according to said channel quality related information, wherein when said first base station works at single cell mode, said step B further comprises: B1. selecting at least one candidate user terminal (2a, 2b, 2c, 2d, 2e, 2f) from said plurality of first user terminals (2a, 2b, 2c, 2d, 2e, 2f) according to said channel quality related information, wherein the channel quality between said at least one candidate user terminal (2a, 2b, 2c, 2d, 2e, 2f) and said first base station is greater than a first predetermined threshold; B2. judging whether the number of said at least one candidate user terminal (2a, 2b, 2c, 2d, 2e, 2f) is greater than a predetermined number N: - taking N said user terminal (2a, 2b, 2c, 2d, 2e, 2f) which is the top N user terminal (2a, 2b, 2c, 2d, 2e, 2f) as to the channel quality with said first base station in said at least one candidate user terminal (2a, 2b, 2c, 2d, 2e, 2f) as said calibration user terminal (2a, 2b, 2c, 2d, 2e, 2f), when the number of said at least one candidate user terminal (2a, 2b, 2c, 2d, 2e, 2f) is greater than N; - taking said at least one candidate user terminal (2a, 2b, 2c, 2d, 2e, 2f) as said calibration user terminal (2a, 2b, 2c, 2d, 2e, 2f), when the number of said at least one candidate user terminal (2a, 2b, 2c, 2d, 2e, 2f) is less than or equal to N. A. obtaining channel quality related information between a plurality of first user terminals (2a, 2b, 2c, 2d, 2e, 2f) and a first base station, wherein said channel quality related information is used for indicating channel qualities between said plurality of first user terminals (2a, 2b, 2c, 2d, 2e, 2f) and said first base station; B. selecting, at least one first user terminal (2a, 2b, 2c, 2d, 2e, 2f) as a calibration user terminal (2a, 2b, 2c, 2d, 2e, 2f) for calibrating said reciprocity error between uplink and downlink, according to said channel quality related information, wherein when said first base station works at single cell mode, said step B further comprises: B1. selecting at least one candidate user terminal (2a, 2b, 2c, 2d, 2e, 2f) from said plurality of first user terminals (2a, 2b, 2c, 2d, 2e, 2f) according to said channel quality related information, wherein the channel quality between said at least one candidate user terminal (2a, 2b, 2c, 2d, 2e, 2f) and said first base station is greater than a first predetermined threshold; B2. judging whether the number of said at least one candidate user terminal (2a, 2b, 2c, 2d, 2e, 2f) is greater than a predetermined number N: - taking N said user terminal (2a, 2b, 2c, 2d, 2e, 2f) which is the top N user terminal (2a, 2b, 2c, 2d, 2e, 2f) as to the channel quality with said first base station in said at least one candidate user terminal (2a, 2b, 2c, 2d, 2e, 2f) as said calibration user terminal (2a, 2b, 2c, 2d, 2e, 2f), when the number of said at least one candidate user terminal (2a, 2b, 2c, 2d, 2e, 2f) is greater than N; - taking said at least one candidate user terminal (2a, 2b, 2c, 2d, 2e, 2f) as said calibration user terminal (2a, 2b, 2c, 2d, 2e, 2f), when the number of said at least one candidate user terminal (2a, 2b, 2c, 2d, 2e, 2f) is less than or equal to N. - taking N said user terminal (2a, 2b, 2c, 2d, 2e, 2f) which is the top N user terminal (2a, 2b, 2c, 2d, 2e, 2f) as to the channel quality with said first base station in said at least one candidate user terminal (2a, 2b, 2c, 2d, 2e, 2f) as said calibration user terminal (2a, 2b, 2c, 2d, 2e, 2f), when the number of said at least one candidate user terminal (2a, 2b, 2c, 2d, 2e, 2f) is greater than N; - taking said at least one candidate user terminal (2a, 2b, 2c, 2d, 2e, 2f) as said calibration user terminal (2a, 2b, 2c, 2d, 2e, 2f), when the number of said at least one candidate user terminal (2a, 2b, 2c, 2d, 2e, 2f) is less than or equal to N.