Method and apparatus for generating reference signal in analog/digital mixed BF system

• US 9,125,070 B2
• Filed: 03/29/2013
• Issued: 09/01/2015
• Est. Priority Date: 03/29/2012
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Tae-Young, Han, Shuangfeng, Park, Jeong-Ho
• Primary Examiner(s): HAN, CLEMENCE S
• Application Number:
  US13/853,699
• Publication Number:
  US 20130258972A1
• Time in Patent Office: 886 Days
• US Class Current: 1/1
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0634 Antenna weights or vector/matrix coefficients
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

A millimeter radio wave communication system. In a method for operating a base station (BS) in an analog/digital mixed BF system, an analog BF direction is determined. A digital BF precoder is determined for the determined analog BF direction. Digital BF precoding is performed using the digital BF precoder with respect to the determined analog BF direction. A DownLink Reference Signal (DL RS) is transmitted in the analog BF direction on which the digital BF precoding has been performed.

Claims

1. A method for operating a base station (BS) in an analog/digital mixed BF system, the method comprising:

determining an analog beamforming (BF) direction;

determining a digital BF precoder for the determined analog BF direction;

performing digital BF precoding using the digital BF precoder with respect to the determined analog BF direction; and

transmitting a downlink reference signal (DL RS) in the analog BF direction on which the digital BF precoding has been performed.

2. The method of claim 1, further comprising:

receiving feedback from a mobile station (MS).

3. The method of claim 2, wherein the feedback comprises at least one of best analog BF direction information or best digital BF subcarrier index determined by the MS.

4. The method of claim 1, wherein determining the digital BF precoder for the determined analog BF direction comprises:

allocating a digital BF precoder on consecutive frequency resources in a frequency domain.

5. The method of claim 1, further comprising:

if a power boost is applied to the DL RS, transmitting an indication to the MS that the power boost is applied.

6. A method for operating a mobile station (MS) in an analog/digital mixed beamforming (BF) system, the method comprising:

receiving a downlink reference signal (DL RS) transmitted by a base station (BS);

determining a precoder from the DL RS; and

transmitting information regarding the determined precoder to the BS, wherein the information regarding the determined precoder comprises information on a subcarrier that is determined based on powers associated with each of a plurality of subcarriers.

7. The method of claim 6, further comprising:

receiving frequency allocation information from the BS.

8. The method of claim 6, wherein the information regarding the selected precoder comprises information on a best subcarrier.

9. The method of claim 6, wherein selecting the precoder from the DL RS comprises:

calculating average power for a plurality of subcarriers; and

determining the subcarrier comprisinng a largest average power.

10. The method of claim 6, wherein the information regarding the determined precoder comprises information of a best analog BF direction and information of a best digital BF subcarrier index determined by the MS.

11. A base station (BS) in an analog/digital mixed beamforming (BF) system, the BS comprising:

a controller configured to determine an analog BF direction, determine a digital BF precoder for the determined analog BF direction, perform digital BF precoding using the digital BF precoder on the determined analog BF direction, and generate a downlink reference signal (DL RS) directed to the analog BF direction on which the digital BF precoding has been performed;

a transceiver configured to transmit the DL RS;

a plurality of antennas comprising a plurality of antenna elements; and

a plurality of radio frequency (RF) chains connected to the antenna elements, the RF chains configured to form a beam to the analog beam direction determined by the controller.

12. The BS of claim 11, wherein the transceiver is configured to receive feedback from a mobile station (MS).

13. The BS of claim 12, wherein the feedback comprises at least one of best analog BF direction information and best digital BF subcarrier index determined by the MS.

14. The BS of claim 11, wherein in determining the digital BF precoder for the determined analog BF direction, the controller is configured to allocate a digital BF precoder on consecutive frequency resources in a frequency domain.

15. The BS of claim 11, wherein if a power boost is applied to the DL RS, the transceiver is configured to transmit an indication to the MS that the power boost is applied.

16. A mobile station (MS) in an analog/digital mixed beamforming (BF) system, the MS comprising:

A transceiver configured to receive a downlink reference signal (DL RS) from a base station (BS) and transmit information regarding a precoder to the BS;

a channel estimator configured to estimate a channel based on a DL beam direction using the DL RS; and

a controller configured to determine the precoder from the DL RS with consideration of channel information based on the DL beam direction,

wherein the information regarding the precoder comprises information on a subcarrier that is determined based on powers associated with each of a plurality of subcarriers.

17. The MS of claim 16, wherein the receiver is configured to receive frequency allocation information from the BS.

18. The MS of claim 16, wherein the information regarding the precoder comprises information on a best subcarrier.

19. The MS of claim 16, wherein in determining the precoder from the DL RS, the controller is configured to calculate average power for the plurality of subcarriers, and determine the subcarrier comprising a largest average power.

20. The MS of claim 16, wherein the information regarding the precoder comprises information of a best analog BF direction and information of a best digital BF subcarrier index determined by the MS.