Community antenna system in the closed loop mode and the method thereof

A community antenna system in a closed loop mode when a mobile terminal has multiple antennas, comprising:

• a downlink channel matrix processing module, adapted to perform the pre-weighting processing on transmission signals according to a first group of downlink channel information corresponding to a first antenna array and a second group of downlink channel information corresponding to a second antenna array;
• a first beamforming module, adapted to perform the weighting processing on the pre-weighting processed transmission signal according to a downlink beamforming weight vector generated via the first cluster of steering vectors corresponding to a first antenna array to form a first directional beam directed to the target mobile terminal and transmit the first directional beam via the first antenna array;
• a second beamforming module, adapted to perform the weighting processing on the pre-weighting processed transmission signal according to a downlink beamforming weight vector generated via the second cluster of steering vectors corresponding to a second antenna array to form a second directional beam directed to the target mobile terminal and transmit the second directional beam via the second antenna array;
• a first antenna array, in which antenna array elements have the same polarization mode, adapted to transmit the first directional beam;
• and
• a second antenna array, in which antenna array elements have the same polarization mode that is orthogonal to that of the first antenna array, adapted to transmit the second directional beam;
• wherein the downlink channel matrix processing module comprises:
• a first group channel information unit, adapted to obtain the first group of downlink channel information according to a receiving signal or feedback information of the first antenna array, wherein the first group of downlink channel information comprises M downlink channel information corresponding to M receiving antennas of a target mobile terminal, and M is a positive integer;
• a second group channel information unit, adapted to obtain the second group of downlink channel information according to a receiving signal or feedback information of the second antenna array, wherein the second group of downlink channel information comprises M downlink channel information corresponding to M receiving antennas of a target mobile terminal;
• a downlink channel matrix processing unit, adapted to obtain a downlink channel matrix according to the first group of downlink channel information and the second group of downlink channel information, and perform singular value decomposition on the downlink channel matrix;
• a first pre-weighting processing unit, adapted to select a first element of an input vector corresponding to a specific singular value according to the singular value decomposition result of the downlink channel matrix processing unit to perform the pre-weighting processing on a transmission signal, and transmit the pre-weighting processed transmission signal to the first beamforming module;
• and
• a second pre-weighting processing unit, adapted to select a second element of an input vector corresponding to a specific singular value according to the singular value decomposition result of the downlink channel matrix processing unit to perform the pre-weighting processing on a transmission signal, and transmit the pre-weighting processed transmission signal to the second beamforming module.