2D active antenna array operation for wireless communication systems

1. A method for operating a large scale antenna array in a wireless communication system, the method comprising:

receiving, by a base station (BS), one or more signals, the one or more signals including information for beamforming to a plurality of user equipments (UEs) using a full-dimensional multiple-input multiple-output (FD-MIMO) beamforming scheme, wherein the FD-MIMO beamforming scheme includes same time resources and same frequency resources that are co-scheduled to the plurality of UEs;

determining and compensating for, by the base station, a time delay of the one or more signals associated with one or more antenna arrays that are distributed in the large scale antenna array, wherein determining and compensating further comprises:

detecting a sample level mismatch for each of a plurality of common public radio interface (CPRI) connections associated with one or more antenna arrays that are distributed in the large scale antenna array;

compensating for the detected sample level mismatch for each of the plurality of CPRI connections;

detecting delay differences within channels in the plurality of CPRI connections introduced by components therein;

compensating for the detected delay differences within the channels in the plurality of CPRI connections to less than 1 nanosecond; and

performing a multi-user (MU) joint beamforming on the one or more signals to one or more UEs based upon the determined and compensated time delay.

2. The method of claim 1 further comprising:

performing a virtualization of the one or more antenna array in accordance with a 2 dimensional (2D) plane associated with a signal generated from a precoder;

updating the precoder in accordance with an estimation of a plurality of channels, wherein the estimation of the plurality of channels is performed on a per resource block (RB) basis; and

transmitting the one or more signal at the one or more antenna arrays to the plurality of UEs using the FD-MIMO beamforming scheme.

3. The method of claim 2 , wherein updating the precoder comprises:

estimating one or more uplink channel, wherein the one or more uplink channel comprises one or more per frequency resource element (RE) in accordance with a per RB based precoder generation associated with one or more sounding reference signal (SRS);

assigning four SRS symbols to two radio sub-frames included in the radio frame each of which includes two SRS symbols; and

predicting a channel quality information to compensate a difference between a channel quality indicator (CQI) received from the plurality of UEs and a desired CQI using a gain difference value between a beamformed gain and a virtualized gain.

4. The method of claim 2 , further comprising:

performing precoding using a low complexity precoding scheme that reduces K times of matrix inversion to 1 time and an N×N dimension of matrix inversion to a K×K, wherein the low complexity precoding scheme is determined in accordance with a channel matrix that is approximated by a precoding matrix indicator (PMI) and a signal to interference noise ratio (SINR) that is obtained after mapping of a CQI feedback.

5. The method of claim 4 , wherein the K is determined as a number of UEs being served and the N is determined as a number of antennas to be used to transmit antenna beams to the UEs.

6. The method of claim 1 , wherein the large scale antenna array comprises a plurality of vertically arranged panels each of which includes a plurality of sub-arrays that is arranged in an n number horizontal ×1vertical configuration, each of the sub-arrays including a plurality of patch elements fed with a corporate feed network.

7. The method of claim 1 , further comprising performing a timing and phase alignment for distributed radio frequency units that connect a base band unit of the BS through separate common public radio interface connections.

8. The method of claim 1 , wherein the large scale antenna array comprises one or more virtualization pattern including one or more time domain symbol and multiple virtualized symbols, the large scale antenna array activating one or more antenna element.

9. The method of claim 1 , wherein a scrambling identification (SCID) is allocated into one or more demodulation reference signal (DMRS) port that is mapped to one or more co-scheduled UEs that share the same time resources and the same frequency resources.

10. The method of claim 1 , wherein compensating for the detected delay differences further comprises compensating for the detected delay differences within the channels in the plurality of CPRI connections to less than 1 nanosecond.

11. A base station (BS) comprising:

a large scale antenna array;

at least one transceiver configured to receive one or more signals, the one or more signals including information for beamforming to a plurality of user equipments (UEs) using a full-dimensional multiple-input multiple-output (FD-MIMO) beamforming scheme, wherein the FD-MIMO beamforming scheme includes same time resources and same frequency resources that are co-scheduled to the plurality of UEs; and

at least one hardware controller configured to:

determine and compensate for a time delay of the one or more signals associated with one or more antenna arrays that are distributed in the large scale antenna array, the determination and compensation further configures the at least one hardware controller to:

detect a sample level mismatch for each of a plurality of common public radio interface (CPRI) connections associated with one or more antenna arrays that are distributed in the large scale antenna array;

compensate for the detected sample level mismatch for each of the plurality of CPRI connections;

detect delay differences within channels in the plurality of CPRI connections introduced by components therein;

compensate for the detected delay differences within the channels in the plurality of CPRI connections; and

perform a multi-user (MU) joint beamforming on the one or more signals to one or more UEs based upon the determined and compensated time delay.

12. The BS of claim 11 , wherein the at least one hardware controller is configured to:

perform a virtualization of the one or more antenna array in accordance with a 2 dimensional (2D) plane associated with a signal generated from a precoder;

update the precoder in accordance with an estimation of a plurality of channels, wherein the estimation of the plurality of channels is performed on a per resource block (RB) basis; and

transmit the one or more signals at the one or more antenna arrays to the plurality of UEs using the FD-MIMO beamforming scheme.

13. The BS of claim 12 , wherein updating the precoder comprises:

estimating one or more uplink channel, wherein the one or more uplink channel comprises one or more per frequency resource element (RE) in accordance with a per RB based precoder generation associated with one or more sounding reference signal (SRS);

assigning four SRS symbols to two radio sub-frames included in the radio frame each of which includes two SRS symbols; and

predicting a channel quality indicator (CQI) to compensate a difference between a CQI received from the plurality of UEs and a desired CQI using a gain difference value between a beamformed gain and a virtualized gain.

14. The BS of claim 12 , further comprising:

performing precoding using a low complexity precoding scheme that reduces K times of matrix inversion to 1 time and an N×N dimension of matrix inversion to a K×K, wherein the low complexity precoding scheme is determined in accordance with a channel matrix that is approximated by a precoding matrix indicator (PMI) and a signal to interference noise ratio (SINR) that is obtained after mapping of a CQI feedback.

15. The BS of claim 14 , wherein the K is determined as a number of UEs being served and the N is determined as a number of antennas to be used to transmit antenna beams to the UEs.

16. The BS of claim 11 , wherein the large scale antenna array comprises a plurality of vertically arranged panels each of which includes a plurality of sub-arrays that is arranged in an n number horizontal ×1 vertical configuration, each of the sub-arrays including a plurality of patch elements fed with a corporate feed network.

17. The BS of claim 11 , wherein the hardware controller is further configured to perform a timing and phase alignment for distributed radio frequency units that connect a base band unit of the BS through separate common public radio interface connections.

18. The BS of claim 11 , wherein the large scale antenna array comprises one or more virtualization pattern including one or more time domain symbol and multiple virtualized symbols, the large scale antenna array activating one or more antenna element.

19. The BS of claim 11 , wherein a scrambling identification (SCID) is allocated into one or more demodulation reference signal (DMRS) port that is mapped to one or more co-scheduled UEs sharing the same time resources and the same frequency resources.

20. The BS of claim 11 , wherein the at least one hardware controller is further configured to compensate for the detected delay differences within the channels in the plurality of CPRI connections to less than 1 nanosecond.