Beam Information Acquisition Method and Apparatus and Communications System

A beam information acquisition apparatus, configured in a user equipment, the beam information acquisition apparatus comprising:

• a first signal receiving unit configured to receive a first reference signal transmitted by a base station at K antenna elements;
• where, K is less than M, M being the number of antennas in the same polarization direction in each column in a vertical direction in the base station;
• a channel estimating unit configured to perform channel estimation according to the first reference signal;
• an index calculating unit configured to calculate a beam index according to a result of the channel estimation;
• a first information transmitting unit configured to feed the beam index back to the base station;
• a second signal receiving unit configured to receive a second reference signal weighted by using weighting vectors and transmitted by the base station;
• a power calculating unit configured to calculate receiving power of multiple transmission antenna ports according to the second reference signal;
• a power comparing unit configured to obtain feedback information on the multiple transmission antenna ports by comparing the receiving power with a predefined threshold value;
• and
• a second information transmitting unit configured to transmit the feedback information to the base station.

A communications system, comprising:

• a base station having a planar antenna array comprising multiple antenna elements, the multiple antenna elements forming multiple columns in a vertical direction and multiple rows in a horizontal direction;
• the base station is configured to transmit a first reference signal to a user equipment by using K antenna elements, receive a beam index fed back by the user equipment, determine a vector having a length K according to the beam index, estimate a vector having a length L according to the vector having a length K, determine multiple weighting vectors based on the vector having a length L, perform weighting on a second reference signal by using the multiple weighting vectors, transmit the weighted second reference signal to the user equipment, receive feedback information on multiple transmission antenna ports fed back by the user equipment, and acquire beam weighting information according to the feedback information;
• where, M is the number of antennas in the same polarization direction in each column in the vertical direction in the base station, K is less than M, and K≦L≦M;
• and
• a user equipment configured to receive a first reference signal transmitted by the base station at K antenna elements, perform channel estimation according to the first reference signal, calculate a beam index according to a result of the channel estimation, feed the beam index back to the base station, receive a second reference signal weighted by using weighting vectors and transmitted by the base station, calculate receiving power of multiple transmission antenna ports according to the second reference signal, obtain feedback information on the multiple transmission antenna ports by comparing the receiving power with a predefined threshold value, and transmit the feedback information to the base station.