METHOD AND DEVICE FOR REPORTING ANTENNA CALIBRATION INFORMATION AND DETERMINING ANTENNA CALIBRATION FACTOR

• US 20130034010A1
• Filed: 04/19/2011
• Published: 02/07/2013
• Est. Priority Date: 04/19/2010
• Status: Active Grant

• Current Assignee: Datang Mobile Communications Equipment Company Limited (China Information Communication Technology Group Co. Ltd.)
• Original Assignee: China Academy of Telecom Technology (China Information Communication Technology Group Co. Ltd.)
• Inventors: Gao, Qiubin, Sun, Shaohui, Miao, Deshan, Qin, Fei
• Granted Patent: US 9,219,624 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04B 17/12 of transmit antennas, e.g. of the amplitude or phase
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04B 17/24 with feedback of measurements to the transmitter
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0057 Physical resource allocation for CQI
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

A method and device for reporting antenna calibration information and determining antenna calibration factor are provided by the present invention. When reporting the antenna calibration information, a user equipment (UE) estimates the downlink equivalent baseband channel from a plurality of antennas of the base station to the UE; according to the equivalent baseband channel, determines the amplitude response and delay value to be reported, and then reports the amplitude response and delay value to the base station. When determining the antenna calibration factor, according to the uplink signal sent by the UE on the base station-directed time-frequency resources, the base station determines the amplitude response and the delay value; according to the amplitude response and delay value reported by the UE and according to the amplitude response and delay value determined by the uplink signal, the base station calculates the antenna calibration factor. Because the UE pre-processing process is added, the sensitivity degrees to the channel estimation error and to the channel Doppler extension are reduced.

Claims

1. A method for reporting antenna calibration information, comprising:

estimating, by a User Equipment, UE, an equivalent downlink baseband channel from each of a plurality of antennas of a base station to an antenna of the UE;

determining, by the UE, an amplitude response ρ

_k and a delay value Δ

_k to be reported according to the equivalent downlink baseband channel; and

reporting, by the UE, ρ

_k and Δ

_k to the base station.

2. The method according to claim 1, wherein determining, by the UE, Δ

_k according to the equivalent downlink baseband channel comprises;

measuring, by the UE, an equivalent downlink baseband channel from a transmission antenna at each of a number N of frequencies f in a frequency band specified by the base station to the antenna of the UE, and calculating Δ

_k according to H_k^DL(f_i) by;

linearly fitting phases of H_k^DL(f_i) of the N frequencies, and taking the slope of a straight line resulting from the fitting divided by 2π

as an estimation value of Δ

_k;

or

measuring, by the UE, an equivalent downlink baseband channel from a transmission antenna at each of a number N of frequencies f in a frequency band specified by the base station to the antenna of the UE, linearly fitting phases of

3. The method according to claim 1, wherein determining, by the UE, ρ

_k according to the equivalent downlink baseband channel comprises;

measuring, by the UE, an equivalent downlink baseband channel from a transmission antenna at each of a number N of frequencies f in a frequency band specified by the base station to the antenna of the UE, and calculating, by the UE, ρ

_k according to H_k^DL(f_i) as;

4. The method according to claim 1, wherein before the UE estimates an equivalent downlink baseband channel from each of the plurality of antennas of the base station to the UE, the method further comprises:

receiving, by the UE, an instruction of the base station.

5. A method for determining an antenna calibration factor, comprising:

receiving, by a base station, an uplink signal transmitted from a UE over a time and frequency resource specified by the base station;

estimating, by the base station, an equivalent uplink baseband channel from an antenna of the UE to each of reception antennas of the base station according to the uplink signal;

determining, by the base station, an amplitude response λ

_k and a delay value Π

_k according to the equivalent uplink baseband channel;

receiving, by the base station, ρ

_k and Δ

_k reported from the UE according to claim 1; and

calculating, by the base station, an antenna calibration factor according to λ

_k and Π

_k, and ρ

_k and Δ

_k.

6. The method according to claim 5, wherein determining, by the base station, Π

_k according to the equivalent uplink baseband channel comprises;

calculating, by the base station, Π

_k according to H_k^UL(f_i) by;

linearly fitting phases of H_k^UL(f_i) a number of N frequencies, and taking the slope of a straight line resulting from the fitting as an estimation value of Π

_k;

or

linearly fitting phases of

7. The method according to claim 5, wherein determining, by the base station, an amplitude response λ

_k according to the equivalent uplink baseband channel comprises;

calculating, by the base station, λ

_k according to H_k^UL(f_i) as;

8. The method according to claim 5, wherein before the base station receives the uplink signal transmitted from the UE over the time and frequency resource specified by the base station, the method further comprises:

instructing, by the base station, the UE with a signal quality above a signal threshold and/or at a movement speed below a movement threshold to transmit the uplink signal over the time and frequency resource specified by the base station.

9. The method according to claim 5, wherein the base station calculates the antenna calibration factor according to λ

_k and Π

_k, and ρ

_k and Δ

_k comprises;

with e<sup>−

j2π

Π

kfi</sup> being a phase response of a reception circuit of the base station, calculating, by the base station, the antenna calibration factor as;

c_k(f_i)=e<sup>−

j2π

(Δ

k)fi</sup>e<sup>j2π

(Π

k)fi</sup>ρ

_k/λ

_k;

or

c_k(f_i)=e<sup>−

j2π

(Δ

k)fi</sup>e<sup>j2π

(Π

k)fi</sup>;

or

c_k(f_i)=ρ

_k/λ

_k;

or

c_k(f_i)=e<sup>−

j2π

(Δ

k)fi</sup>ρ

_k;

or

c_k(f_i)=ρ

_k;

or

c_k(f_i)=e<sup>j2π

(Δ

k)fi</sup>;

or

c_k(f_i)=e<sup>j2π

(Π

k)fi</sup>/λ

_k;

or

c_k(f_i)=e<sup>j2π

(Π

k)fi</sup>;

or

c_k(f_i)=1/λ

_k.

10. The method according to claim 9, further comprising:

calibrating, by the base station, by the calibration factor in the following equation the channel estimated according to an uplink pilot signal to obtain an estimation value of a downlink channel;

Ĥ

_k^DL(f_i)=H_k^UL(f_i)c_k(f_i);

and/or

pre-processing a signal to be transmitted in the downlink;

Y_k(f_i)=Y_k(f_i)/c_k(f_i) wherein Y_k(f_i) is a data signal and/or a pilot signal to be transmitted over the k^th antenna of the base station, and Y_k(f_i) is the pre-processed signal.

15. A base station, comprising:

an uplink signal receiving module configured to receive an uplink signal transmitted from a UE over a time and frequency resource specified by the base station;

an equivalent uplink baseband channel module configured to estimate an equivalent uplink baseband channel from an antenna of the UE to each of reception antennas of the base station according to the uplink signal;

an amplitude response module configured to determine an amplitude response λ

_k according to the equivalent uplink baseband channel;

a delay module configured to determine a delay value Π

_k according to the equivalent uplink baseband channel;

a receiving module configured to receive ρ

_k and Δ

_k reported from the UE according to claim 1; and

a calibration factor module configured to calculate an antenna calibration factor according to λ

_k and Π

_k, and ρ

_k and Δ

_k.

16. The base station according to claim 15, wherein the delay module comprises a first determining unit and/or a second determining unit, wherein:

the first determining unit is configured to calculate Π

_k according to H_k^UL(f_i) by;

linearly fitting phases of H_k^UL(f_i of a number of N frequencies, and taking the slope of a straight line resulting from the fitting as an estimation value of Π

_k; and

the second determining unit is configured to linearly fit phases of

17. The base station according to claim 15, wherein the amplitude response module comprises a third determining unit and/or a fourth determining unit, wherein:

the third determining unit is configured to calculate λ

_k according to H_k^UL(f_i) as;

18. The base station according to claim 15, further comprising:

an instructing module configured to instruct the UE with a signal quality above a signal threshold and/or at a movement speed below a movement threshold to transmit the uplink signal over the time and frequency resource specified by the base station.

19. The base station according to claim 15, wherein the calibration factor module is further configured to calculate the antenna calibration factor according to λ

_k and Π

_k, and ρ

_k and Δ

_k by calculating the antenna calibration factor as;

c_k(f_i)=e<sup>−

j2π

(Δ

k)fi</sup>e<sup>j2π

(Π

k)fi</sup>ρ

_k/λ

_k;

or

c_k(f_i)=e<sup>−

j2π

(Δ

k)fi</sup>e<sup>j2π

(Π

k)fi</sup>;

or

c_k(f_i)=ρ

_k/λ

_k;

or

c_k(f_i)=e<sup>−

j2π

(Δ

k)fi</sup>ρ

_k;

or

c_k(f_i)=ρ

_k;

or

c_k(f_i)=e<sup>−

j2π

(Δ

k)fi</sup>;

or

c_k(f_i)=e<sup>j2π

(Π

k)fi</sup>/λ

_k;

or

c_k(f_i)=e<sup>j2π

(Π

k)fi</sup>;

or

c_k(f_i)=1/λ

_k

with e<sup>−

j2π

Π

kfi</sup> being a phase response of a reception circuit of the base station.

20. The base station according to claim 19, further comprising:

a calibrating module configured to calibrate by the calibration factor in the following equation the channel estimated according to an uplink pilot signal to obtain an estimation value of a downlink channel;

Ĥ

_k^DL(f_i)=H_k^UL(f_i)c_k(f_i);

and/or

configured to pre-process a signal to be transmitted in the downlink;

Y_k(f_i)=Y_k(f_i)/c_k(f_i), wherein Y_k(f_i) is a data signal and/or a pilot signal to be transmitted over the k^th antenna of the base station, and Y_k(f_i) is the pre-processed signal.

11. A user equipment, comprising:

an estimating module configured to estimate an equivalent downlink baseband channel from each of a plurality of antennas of a base station to an antenna of the UE;

an amplitude response module configured to determine an amplitude response ρ

_k to be reported according to the equivalent downlink baseband channel;

a delay module configured to determine a delay value Δ

_k to be reported according to the equivalent downlink baseband channel; and

a reporting module configured to report ρ

_k and Δ

_k to the base station.

12. The user equipment according to claim 11, wherein the delay module comprises a first determining unit and/or a second determining unit, where:

the first determining unit is configured for the UE to measure an equivalent downlink baseband channel from a transmission antenna at each of a number N of frequencies f in a frequency band specified by the base station to the antenna of the UE, and calculate Δ

_k according to H_k^DL(f_i) by;

linearly fitting phases of H_k^DL(f_i) of the N frequencies, and taking the slope of a straight line resulting from the fitting divided by 2π

as an estimation value of Δ

_k; and

the second determining unit is configured for the UE to measure an equivalent downlink baseband channel from a transmission antenna at each of a number N of frequencies f in a frequency band specified by the base station to the antenna of the UE, linearly fit phases of

13. The user equipment according to claim 11, wherein the amplitude response module comprises a third determining unit and/or a fourth determining unit, wherein:

the third determining unit is configured for the UE to measure an equivalent downlink baseband channel from a transmission antenna at each of a number N of frequencies f in a frequency band specified by the base station to the antenna of the UE, and calculate ρ

_k according to H_k^DL(f_i) as;

14. The user equipment according to claim 11, wherein the estimating module is further configured to estimate an equivalent downlink baseband channel from each of the plurality of antennas of the base station to the UE upon obtaining an instruction of the base station.