METHOD AND DEVICE FOR CALIBRATING ANTENNA IN A COMP-BASED TDD RADIO COMMUNICATION SYSTEM

• US 20120220331A1
• Filed: 11/04/2009
• Published: 08/30/2012
• Est. Priority Date: 11/04/2009
• Status: Abandoned Application

• Current Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Original Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Inventors: Luo, Qinglin, Shi, Jing
• Application Number:
  US13/505,838
• Publication Number:
  US 20120220331A1
• Time in Patent Office: Days
• US Class Current: 455/517
• CPC Class Codes: H04B 17/14 of the whole transmission and reception path, e.g. self-test loop-back
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems

Abstract

The present invention discloses a method and device for self-calibrating an antenna in a base station of a CoMP-based TDD system, where firstly the relative reciprocity {tilde over (w)}_i of each pair of base station transmitter and receiver of the present base station relative to a calibration transmitter and receiver is calculated, and the relative reciprocity w_i of each pair of base station transmitter and receiver of the present base station relative to a reference base station transmitter and receiver is calculated by selecting one pair of base station transmitter and receiver as the reference base station transmitter and receiver, wherein i=1, 2, . . . , N; then a measurement signal is transmitted from the calibration transmitter of the present base station to the calibration receiver, and a channel response h_c,k of the calibration transmitter and receiver of the present base station is measured, wherein h_c,k=h_ct,kh_cr,k, and k=1, 2, . . . , M; _{then a channel} response h_cr,k of the calibration receiver of the present base station is measured; next the absolute reciprocity w_c,k of the calibration transmitter and receiver of the present base station is calculated in the formula of

$w_{c,k}=\frac{h_{c,k}}{{\left(h_{\mathrm{cr},k}\right)}^2};$

and finally a global relative calibration weight ŵ_i of each pair of base station transmitter and receiver of the present base station from an acquired global reference w_m is calculated in the formula of

${\hat{w}}_i={\stackrel{\_}{w}}_i\frac{w_t}{w_m}.$

The technical solution of the invention can perform antenna calibration of a CoMP-based TDD radio communication system.

Claims

1. A method of self-calibrating an antenna in a base station of a CoMP-based TDD communication system, wherein the method comprises the steps of:

a. calculating the relative reciprocity {tilde over (w)}_i of each pair of base station transmitter and receiver of the present base station relative to a calibration transmitter and receiver, and calculating the relative reciprocity w_i of each pair of base station transmitter and receiver of the present base station relative to a reference base station transmitter and receiver by selecting one pair of base station transmitter and receiver as the reference base station transmitter and receiver, wherein i represents the i^th pair of base station transmitter and receiver among a plurality of pairs of base station transmitters and receivers of the present base station, and i=1, 2, . . . , N;

b. transmitting a measurement signal from the calibration transmitter of the present base station to the calibration receiver, and measuring a channel response h_c,k of the calibration transmitter and receiver of the present base station, wherein h_c,k=h_ct,kh_cr,k, k indicates that the present base station is the k^th base station in the CoMP-based TDD communication system, and k=1, 2, . . . , M; and

M represents the total number of cooperative base stations in the CoMP-based TDD communication system;

c. measuring a channel response h_cr,k of the calibration receiver of the present base station;

d. calculating the absolute reciprocity w_c,k of the calibration transmitter and receiver of the present base station in the formula of

2. The method according to claim 1, wherein after the step e, the method further comprises the step of:

f. calculating the absolute calibration weight w_i of each pair of base station transmitter and receiver of the present base station from the calculated global relative calibration weight ŵ

_i of each pair of base station transmitter and receiver of the present base station in the formula of

w_i={tilde over (w)}_iw_c,k.

3. The method according to claim 1, wherein the step e further comprises the steps of:

e1. receiving the global reference w_m from one of the other cooperative base stations; and

e2. calculating the global relative calibration weight ŵ

_i of each pair of base station transmitter and receiver of the present base station from the received global reference w_m in the formula of

4. The method according to claim 1, wherein the step e further comprises the steps of:

e1′

. transmitting the absolute reciprocity of the reference transmitter and receiver of the present base station to the other cooperative base stations as the global reference w_m over logic links between the present base station and the other cooperative base stations; and

e2′

. calculating the global relative calibration weight ŵ

_i of each pair of base station transmitter and receiver of the present base station from the global reference w_m in the formula of

5. The method according to claim 1, wherein the step c comprises the steps of:

c1. transmitting a random sequence from a random sequence generator of the present base station to the calibration receiver of the present base station;

c2. measuring a channel response h₃=h_RSG,kh_cr,k of the sequence generator and the calibration receiver, wherein h_RSG,k represents a channel response of the random sequence generator of the present base station, and h_cr,k represents the channel response of the calibration receiver of the present base station; and

c3. calculating the channel response h_cr,k of the calibration receiver of the present base station in the formula of

6. The method according to claim 1, the step a comprises the steps of:

a1. transmitting a plurality of orthogonal calibration signals concurrently from a plurality of base station transmitters of the present base station to the calibration receiver of the present base station, and measuring a channel response h_t,i=h_bt,ih_cr of a transmitter calibration loop, wherein h_bt,i represents a channel response of the i^th base station transmitter of the present base station, and h_cr represents the channel response of the calibration receiver of the present base station; and

transmitting calibration signals respectively from the calibration transmitter of the present base station to a plurality of base station receivers of the present base station, and measuring a channel response h_r,i=h_cth_br,i of a receiver calibration loop, wherein h_br,i represents a channel response of the i^th base station receiver of the present base station, and h_ct represents a channel response of the calibration transmitter of the present base station;

a2. calculating the relative reciprocity of each pair of base station transmitter and receiver of the present base station relative to the calibration transmitter and receiver in the formula of

7. A method of calibrating an antenna over the air in a base station of a CoMP-based TDD communication system, wherein the method comprises the steps of:

A. calculating the relative reciprocity {tilde over (w)}_i of each pair of base station transmitter and receiver of the present base station relative to a mobile station transmitter and receiver, wherein i represents the i^th pair of base station transmitter and receiver among a plurality of pairs of base station transmitters and receivers of the present base station, and i=1, 2, . . . , N; and

B. calculating a global relative calibration weight ŵ

_i of each pair of base station transmitter and receiver of the present base station from a received global reference {tilde over (w)}_s in the formula of

8. The method according to claim 7, wherein the step A comprises the steps of:

A1. transmitting a plurality of orthogonal calibration signals concurrently from through a plurality of base station transmitters of the present base station to the mobile station receiver of a mobile station;

A2. receiving a channel response h_t,i=h_bt,ih_AI,ih_mr of a transmitter calibration loop corresponding to the present base station from the mobile station, wherein h_bt,i represents a channel response of the i^th base station transmitter of the present base station, h_AI,i represents a channel response of an air interface of the present base station, and h_mr represents a channel response of the mobile station receiver;

A3. measuring a channel response h_r,i=h_mth_Ai,ih_br,i of a receiver calibration loop corresponding to the present base station from received calibration signals transmitted from the mobile station transmitter of the mobile station to a plurality of base station receivers of the present base station, wherein h_AI,i represents a channel response of the air interface. h_br,i represents a channel response of the i^th base station receiver, and h_mt represents a channel response of the mobile station transmitter; and

A4. calculating the relative reciprocity of each pair of base station transmitter and receiver of the present base station relative to the mobile station transmitter and receiver in the formula of

9. A method of assisting in calibrating an antenna over the air in a mobile station of a CoMP-based TDD communication system, wherein the method comprises the steps of:

i. receiving, at mobile station receiver of the present mobile station, a plurality of orthogonal calibration signals from a plurality of base station transmitters of each of a plurality of base stations;

ii. measuring a channel response h_t,i=h_bt,ih_AI,ih_mr of a transmitter calibration loop corresponding to each base station from the plurality of received orthogonal calibration signals, and transmitting the channel response to each base station, wherein h_bt,i represents a channel response of the i^th base station transmitter of the present base station, h_AI,i represents a channel response of an air interface of the present base station, and h_mr represents a channel response of the mobile station receiver; and

iii. transmitting calibration signals from a mobile station transmitter of the present mobile station to a plurality of base station receivers of each of the plurality of base stations.

10. A self-calibrating device for self-calibrating an antenna in a base station of a CoMP-based TDD communication system, wherein the self-calibrating device comprises:

first calculating means for calculating the relative reciprocity {tilde over (w)}_i of each pair of base station transmitter and receiver of the present base station relative to a calibration transmitter and receiver, and calculating the relative reciprocity w_i of each pair of base station transmitter and receiver of the present base station relative to a reference base station transmitter and receiver by selecting one pair of base station transmitter and receiver as the reference base station transmitter and receiver, wherein i represents the i^th pair of base station transmitter and receiver among a plurality of pairs of base station transmitters and receivers of the present base station, and i=1, 2, . . . , N;

first measuring means for transmitting a measurement signal from the calibration transmitter of the present base station to the calibration receiver, and measuring a channel response h_c,k of the calibration transmitter and receiver of the present base station, wherein h_c,k=h_ct,kh_cr,k, k indicates that the present base station is the k^th base station in the CoMP-based TDD communication system, and k=1, 2, . . . , M; and

M represents the total number of cooperative base stations in the CoMP-based TDD communication system;

second measuring means for measuring a channel response h_cr,k of the calibration receiver of the present base station;

second calculating means for calculating the absolute reciprocity w_c,k of the calibration transmitter and receiver of the present base station in the formula of

11. The self-calibrating device according to claim 10, further comprising:

fourth calculating means for calculating the absolute calibration weight w_i of each pair of base station transmitter and receiver of the present base station from the calculated global relative calibration weight ŵ

_i of each pair of base station transmitter and receiver of the present base station in the formula of

w_i={tilde over (w)}_iw_c,k.

12. The self-calibrating device according to claim 10, wherein the second measuring means comprises:

first transmitting means for transmitting a random sequence from a random sequence generator of the present base station to the calibration receiver of the present base station;

third measuring means for measuring a channel response h₃=h_RSG,kh_cr,k of the sequence generator and the calibration receiver, wherein h_RSG,k represents a channel response of the random sequence generator of the present base station, and h_cr,k represents the channel response of the calibration receiver of the present base station; and

fifth calculating means for calculating the channel response h_cr,k of the calibration receiver of the present base station in the formula of

13. The self-calibrating device according to claim 10, wherein the first calculating means comprises:

fourth measuring means for transmitting a plurality of orthogonal calibration signals concurrently from a plurality of base station transmitters of the present base station to the calibration receiver of the present base station, and measuring a channel response h_t,i=h_bt,ih_cr of a transmitter calibration loop, wherein h_bt,i represents a channel response of the i^th base station transmitter of the present base station, and h_cr represents the channel response of the calibration receiver of the present base station; and

for transmitting calibration signals respectively from the calibration transmitter of the present base station to a plurality of base station receivers of the present base station, and measuring a channel response h_r,i=h_cth_br,i of a receiver calibration loop, wherein h_br,i represents a channel response of the i^th base station receiver of the present base station, and h_ct represents a channel response of the calibration transmitter of the present base station;

sixth calculating means for calculating the relative reciprocity of each pair of base station transmitter and receiver of the present base station relative to the calibration transmitter and receiver in the formula of

14. An over-the-air calibrating device for calibrating an antenna over the air in a base station of a CoMP-based TDD communication system, wherein the over-the-air calibrating device comprises:

eighth calculating means for calculating the relative reciprocity {tilde over (w)}_i of each pair of base station transmitter and receiver of the present base station relative to a mobile station transmitter and receiver, wherein i represents the i^th pair of base station transmitter and receiver among a plurality of pairs of base station transmitters and receivers of the present base station, and i=1, 2, . . . , N; and

ninth calculating means for calculating a global relative calibration weight ŵ

_i of each pair of base station transmitter and receiver of the present base station from a received global reference {tilde over (w)}_s in the formula of

15. The over-the-air calibrating device according to claim 14, wherein the eighth calculating means comprises:

second transmitting means for transmitting a plurality of orthogonal calibration signals concurrently from a plurality of base station transmitters of the present base station to the mobile station receiver of a mobile station;

second receiving means for receiving a channel response h_t,i=h_bt,ih_AI,ih_mr of a transmitter calibration loop corresponding to the present base station from the mobile station, wherein h_bt,i represents a channel response of the i^th base station transmitter of the present base station, h_AI,i represents a channel response of an air interface of the present base station, and h_mr represents a channel response of the mobile station receiver;

fifth measuring means for measuring a channel response h_r,i=h_mth_Ai,ih_br,i of a receiver calibration loop corresponding to the present base station from received calibration signals transmitted from the mobile station transmitter of the mobile station to a plurality of base station receivers of the present base station, wherein h_AI,i represents a channel response of the air interface, h_br,i represents a channel response of the i^th base station receiver, and h_mt represents a channel response of the mobile station transmitter; and

tenth calculating means for calculating the relative reciprocity of each pair of base station transmitter and receiver of the present base station relative to the mobile station transmitter and receiver in the formula of