Multi-access point calibration method and device

• US 9,515,791 B2
• Filed: 06/28/2013
• Issued: 12/06/2016
• Est. Priority Date: 08/14/2012
• Status: Active Grant

• Current Assignee: Guangdong OPPO Mobile Telecommunications Corporation Limited
• Original Assignee: ZTE Corporation
• Inventors: Zhao, Yajun, Mo, Linmei, Xu, Hanqing, Huang, Jun, Li, Yujie, Sun, Baoyu
• Primary Examiner(s): Choi, Eunsook
• Application Number:
  US14/414,296
• Publication Number:
  US 20150207597A1
• Time in Patent Office: 1,257 Days
• Field of Search: None
• US Class Current: 1/1
• 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
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 5/0035 Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 24/06 Testing, supervising or monitoring using simulated traffic
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 56/001 Synchronization between nodes
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/27 between access points
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: H04W 88/10 adapted for operation in multiple networks, e.g. multi-mode access points

Abstract

A method and device for multi-access point calibration are disclosed. The method includes: a base station estimating a value closest to a true parameter deviation in a value interval of an uplink and downlink channel parameter deviation between access points, wherein the parameter deviation includes a phase difference and an amplitude difference; and the base station performing phase and/or amplitude calibration on service data transmitted jointly by the access points according to the value. With the method and device provided in the present document, a cell calculates a parameter difference between different access points, and then calibrates multiple access points according to the parameter difference, so as to solve a problem that the phase difference and amplitude difference exist between the data transmitted jointly between the multiple access points, and thus it can be guaranteed that good coherent transmission is performed between the access points, thereby improving the system performance.

Claims

1. A method for multi-access point calibration, comprising:

a base station estimating a value closest to a true parameter deviation in a value interval of an uplink and downlink channel parameter deviation between access points; and

the base station performing parameter calibration on service data transmitted jointly by the access points according to the estimated value.

2. The method according to claim 1, wherein,

the parameter deviation comprises:

a phase difference and an amplitude difference;

the step of the base station estimating a value closest to a true parameter deviation in a value interval of an uplink and downlink channel parameter deviation between access points comprises at least one of;

the base station estimating a phase difference value closest to a true phase difference in a value interval of an uplink and downlink channel phase difference between the access points; and

, the base station estimating an amplitude difference value closest to a true amplitude difference in a value interval of an uplink and downlink channel amplitude difference between the access points; and

the step of the base station performing parameter calibration on service data transmitted jointly by the access points according to the estimated value comprises at least one of;

the base station performing phase calibration on the data transmitted jointly by the access points according to the estimated phase difference value; and

, the base station performing amplitude calibration on the data transmitted jointly by the access points according to the estimated amplitude difference value.

3. The method according to claim 2, wherein,

the step of the base station estimating a phase difference value closest to a true phase difference in a value interval of an uplink and downlink channel phase difference between the access points comprises:

the base station traversing values in the value interval of the phase difference, and performing phase calibration on the service data transmitted jointly by the access points according to phase differences of traversed values, and transmitting service data on which the phase calibration is performed to a User Equipment (UE); and

according to correct or incorrect receiving judgment information returned by the UE, the base station performing statistics of an error rate or performing open loop link adaption to adjust a Modulation and Coding Scheme (MCS) level, and estimating the phase difference value closest to the true phase difference in the phase differences of the traversed values in accordance with a preset estimation policy according to the error rate or the MCS level.

4. The method according to claim 3, wherein,

the preset estimation policy comprises:

after the base station uses a phase difference in the value interval of the phase difference to calibrate the service data, if a difference between the error rate obtained from the statistics fed back by the UE and an error rate without parameter deviation is less than a preset threshold, judging the phase difference as a phase difference closest to a true phase difference;

or, after the base station uses a phase difference in the value interval of the phase difference to calibrate the service data, if a difference between the MCS level obtained by performing open loop link adaption adjustment according to feedback of the UE and an MCS level without parameter deviation is less than a preset threshold, judging the phase difference as a phase difference closest to a true phase difference;

wherein, the MCS level without parameter deviation is obtained by the base station requesting the UE for acquisition, and the error rate without parameter deviation is an error rate assumed when the UE measures the MCS level without parameter deviation and previously appointed by the base station and the UE;

or, after the base station uses the phase differences of the traversed values to calibrate the service data, comparing the error rate obtained from the statistics according to feedback of the UE or the MCS level obtained by performing the open loop link adaption adjustment, and taking a phase difference with a lowest error rate or a highest MCS level correspondingly obtained in the phase differences of the traversed values as a phase difference closest to a true phase difference;

or, after the base station uses the phase differences of the traversed values to calibrate the service data, comparing the error rate obtained from the statistics according to feedback of the UE or the MCS level obtained by performing the open loop link adaption adjustment, and taking a phase difference with a highest error rate or a lowest MCS level correspondingly obtained in the phase differences of the traversed values plus or minus pi as a phase difference closest to a true phase difference.

5. The method according to claim 2, wherein,

the step of the base station estimating an amplitude difference value closest to a true amplitude difference in a value interval of an uplink and downlink channel amplitude difference between the access points comprises:

the base station traversing values in the value interval of the amplitude difference, performing amplitude calibration on the service data transmitted jointly by the access points according to amplitude differences of traversed values, and transmitting service data on which the amplitude calibration is performed to the UE; and

according to correct or incorrect receiving judgment information returned by the UE, the base station performing statistics of an error rate or performing open loop link adaption to adjust an MCS level, and estimating the amplitude difference value closest to the true amplitude difference in the amplitude differences of the traversed values in accordance with a preset policy according to the error rate or the MCS level.

6. The method according to claim 5, wherein,

the preset policy comprises:

after the base station uses an amplitude difference in the value interval of the amplitude difference to calibrate the service data, if a difference between the error rate obtained from the statistics according to feedback of the UE and an error rate without parameter deviation is less than a preset threshold, judging the amplitude difference as an amplitude difference closest to a true amplitude difference;

or, after the base station uses an amplitude difference in the value interval of the amplitude difference to calibrate the service data, if a difference between the MCS level obtained by performing open loop link adaption adjustment according to feedback of the UE and an MCS level without parameter deviation is less than a preset threshold, judging the amplitude difference as an amplitude difference closest to a true amplitude difference;

wherein, the MCS level without parameter deviation is obtained by the base station requesting the UE for acquisition, and the error rate without parameter deviation is an error rate assumed when the UE measures the MCS level without parameter deviation and previously appointed by the base station and the UE;

or, after the base station uses the amplitude differences of the traversed values to calibrate the service data, comparing the error rate obtained from the statistics according to feedback of the UE or the MCS level obtained by performing the open loop link adaption adjustment, and taking an amplitude difference with a lowest error rate or a highest MCS level correspondingly obtained in the amplitude differences of the traversed values as an amplitude difference closest to a true amplitude difference.

7. The method according to claim 2, wherein,

the step of the base station estimating a phase difference value closest to a true phase difference in a value interval of an uplink and downlink channel phase difference between the access points, and meanwhile estimating an amplitude difference value closest to a true amplitude difference in a value interval of an uplink and downlink channel amplitude difference between the access points comprises:

the base station traversing values in the value interval of the phase difference and the value interval of the amplitude difference, and performing phase calibration and amplitude calibration simultaneously on the service data transmitted jointly by the access points according to phase differences of traversed values and amplitude differences of traversed values, and transmitting service data on which the phase calibration and the amplitude calibration are performed to the UE; and

according to correct or incorrect receiving judgment information returned by the UE, the base station performing statistics of an error rate or performing open loop link adaption to adjust an MCS level, and estimating the phase difference value closest to the true phase difference in the phase differences of the traversed values and the amplitude difference value closest to the true amplitude difference in the amplitude differences of the traversed values in accordance with a preset policy according to the error rate or the MCS level.

8. The method according to claim 7, wherein,

the preset policy comprises:

after the base station uses a phase difference in the value interval of the phase difference and an amplitude difference in the value interval of the amplitude difference to calibrate the service data, if a difference between the error rate obtained from the statistics according to feedback of the UE and an error rate without parameter deviation is less than a preset threshold, judging the phase difference as a phase difference value closest to a true phase difference and the amplitude difference as an amplitude difference closest to a true amplitude difference;

or, after the base station uses a phase difference in the value interval of the phase difference and an amplitude difference in the value interval of the amplitude difference to calibrate the service data, if a difference between the MCS level obtained by performing open loop link adaption adjustment according to feedback of the UE and an MCS level without parameter deviation is less than a preset threshold, judging the phase difference as a phase difference value closest to a true phase difference and the amplitude difference as an amplitude difference closest to a true amplitude difference;

wherein, the MCS level without parameter deviation is obtained by the base station requesting the UE for acquisition, and the error rate without parameter deviation is an error rate assumed when the UE measures the MCS level without parameter deviation and previously appointed by the base station and the UE;

or, after the base station uses a phase difference in the value interval of the phase difference and an amplitude difference in the value interval of the amplitude difference to calibrate the service data, comparing the error rate obtained from the statistics according to feedback of the UE or the MCS level obtained by performing the open loop link adaption adjustment, and taking a phase difference with a lowest error rate or a highest MCS level correspondingly obtained in the phase differences of the traversed values as a phase difference value closest to a true phase difference and an amplitude difference with a lowest error rate or a highest MCS level correspondingly obtained in the amplitude differences of the traversed values as an amplitude difference value closest to the true amplitude difference.

9. The method according to claim 3, further comprising:

before performing at least one of phase calibration on the service data transmitted jointly by the access points according to the phase differences of the traversed values and amplitude calibration on the service data transmitted jointly by the access points according to the amplitude differences of the traversed values, the base station firstly performing code modulation of the MCS level without parameter deviation on the service data.

10. A device for multi-access point calibration, comprising a processor for performing steps in a parameter deviation estimation module and a parameter calibration module, wherein:

the parameter deviation estimation module is configured to estimate a value closest to a true parameter deviation in a value interval of an uplink and downlink channel parameter deviation between access points; and

the parameter calibration module is configured to perform parameter calibration on service data transmitted jointly by the access points according to the estimated value estimated by the parameter deviation estimation module.

11. The device according to claim 10, wherein,

the parameter deviation comprises:

a phase difference and an amplitude difference;

the parameter deviation estimation module comprises;

a phase difference estimation module, configured to;

estimate a phase difference value closest to a true phase difference in a value interval of an uplink and downlink channel phase difference between the access points;

an amplitude difference estimation module, configured to;

estimate an amplitude difference value closest to a true amplitude difference in a value interval of an uplink and downlink channel amplitude difference between the access points; and

a phase difference and amplitude difference estimation module, configured to;

estimate a phase difference value closest to a true phase difference in a value interval of an uplink and downlink channel phase difference between the access points, and meanwhile estimate an amplitude difference value closest to a true amplitude difference in a value interval of an uplink and downlink channel amplitude difference between the access points;

wherein, the parameter calibration module is configured to perform parameter calibration on service data transmitted jointly by the access points in the following way;

performing at least one of phase calibration on the data transmitted jointly by the access points according to the estimated phase difference value and amplitude calibration on the data transmitted jointly by the access points according to the estimated amplitude difference value.

12. The device according to claim 11, wherein,

the phase difference estimation module is configured to estimate a phase difference value closest to a true phase difference in the following way:

traversing values in the value interval of the phase difference, and performing phase calibration on the service data transmitted jointly by the access points according to phase differences of traversed values, and transmitting service data on which the phase calibration is performed to a User Equipment (UE); and

according to correct or incorrect receiving judgment information returned by the UE, performing statistics of an error rate or performing open loop link adaption to adjust a Modulation and Coding Scheme (MCS) level, and estimating a phase difference closest to the true phase difference in the phase differences of the traversed values in accordance with a preset estimation policy according to the error rate or the MCS level.

13. The device according to claim 12, wherein,

the phase difference estimation module is further configured to:

before performing phase calibration on the service data transmitted jointly by the access points according to the phase differences of the traversed values, firstly perform code modulation of the MCS level without parameter deviation on the service data.

14. The device according to claim 12, wherein,

the preset estimation policy comprises:

after the phase difference estimation module uses a phase difference in the value interval of the phase difference to calibrate the service data, if a difference between the error rate obtained from the statistics according to feedback of the UE and an error rate without parameter deviation is less than a preset threshold, judging the phase difference as a phase difference closest to a true phase difference;

or, after the phase difference estimation module uses a phase difference in the value interval of the phase difference to calibrate the service data, if a difference between the MCS level obtained by performing open loop link adaption adjustment according to feedback of the UE and an MCS level without parameter deviation is less than a preset threshold, judging the phase difference as a phase difference closest to a true phase difference;

wherein, the MCS level without parameter deviation is obtained by a base station in which the device is located requesting the UE for acquisition, and the error rate without parameter deviation is an error rate assumed when the UE measures the MCS level without parameter deviation and previously appointed by the base station and the UE;

or, after the phase difference estimation module uses the phase differences of the traversed values to calibrate the service data, comparing the error rate obtained from the statistics according to feedback of the UE or the MCS level obtained by performing the open loop link adaption adjustment, and taking a phase difference with a lowest error rate or a highest MCS level correspondingly obtained in the phase differences of the traversed values as a phase difference closest to a true phase difference;

or, after the phase difference estimation module uses the phase differences of the traversed values to calibrate the service data, comparing the error rate obtained from the statistics according to feedback of the UE or the MCS level obtained by performing the open loop link adaption adjustment, and taking a phase difference with a highest error rate or a lowest MCS level correspondingly obtained in the phase differences of the traversed values plus or minus pi as a phase difference closest to a true phase difference.

15. The device according to claim 11, wherein,

the amplitude difference estimation module is configured to estimate an amplitude difference value closest to a true amplitude difference in the following way:

traversing values in the value interval of the amplitude difference, and performing amplitude calibration on the service data transmitted jointly by the access points according to amplitude differences of traversed values, and transmitting service data on which the amplitude calibration is performed to the UE; and

according to correct or incorrect receiving judgment information returned by the UE, performing statistics of an error rate or performing open loop link adaption to adjust an MCS level, and estimating the amplitude difference value closest to the true amplitude difference in the amplitude differences of the traversed values in accordance with a preset policy according to the error rate or the MCS level.

16. The device according to claim 15, wherein,

the amplitude difference estimation module is further configured to:

before performing amplitude calibration on the service data transmitted jointly by the access points according to the amplitude differences of the traversed values, firstly perform code modulation of the MCS level without parameter deviation on the service data.

17. The device according to claim 15, wherein,

the preset policy comprises:

after the amplitude difference estimation module uses an amplitude difference in the value interval of the amplitude difference to calibrate the service data, if a difference between the error rate obtained from the statistics according to feedback of the UE and an error rate without parameter deviation is less than a preset threshold, judging the amplitude difference as an amplitude difference closest to a true amplitude difference;

or, after the amplitude difference estimation module uses an amplitude difference in the value interval of the amplitude difference to calibrate the service data, if a difference between the MCS level obtained by performing open loop link adaption adjustment according to feedback of the UE and an MCS level without parameter deviation is less than a preset threshold, judging the amplitude difference as an amplitude difference closest to a true amplitude difference;

wherein, the MCS level without parameter deviation is obtained by a base station in which the device is located requesting the UE for acquisition, and the error rate without parameter deviation is an error rate assumed when the UE measures the MCS level without parameter deviation and previously appointed by the base station and the UE;

or, after the amplitude difference estimation module uses the amplitude differences of the traversed values to calibrate the service data, comparing the error rate obtained from the statistics according to feedback of the UE or the MCS level obtained by performing the open loop link adaption adjustment, and taking an amplitude difference with a lowest error rate or a highest MCS level correspondingly obtained in the amplitude differences of the traversed values as an amplitude difference closest to a true amplitude difference.

18. The device according to claim 11, wherein,

the phase difference and amplitude difference estimation module is configured to estimate a phase difference value closest to a true phase difference, and meanwhile estimate an amplitude difference value closest to a true amplitude difference in the following way:

traversing values in the value interval of the phase difference and the value interval of the amplitude difference, and performing phase calibration and amplitude calibration simultaneously on the service data transmitted jointly by the access points according to phase differences of traversed values and amplitude differences of traversed values, and transmitting service data on which the phase calibration and the amplitude calibration are performed to the UE; and

according to correct or incorrect receiving judgment information returned by the UE, performing statistics of an error rate or performing open loop link adaption to adjust an MCS level, and estimating the phase difference value closest to the true phase difference in the phase differences of the traversed values and the amplitude difference value closest to the true amplitude difference in the amplitude differences of the traversed values in accordance with a preset policy according to the error rate or the MCS level.

19. The device according to claim 18, wherein,

the phase difference and amplitude difference estimation module is further configured to:

before performing phase calibration and amplitude calibration on the service data transmitted jointly by the access points according to the phase differences of the traversed values and the amplitude differences of the traversed values, firstly perform code modulation of the MCS level without parameter deviation on the service data.

20. The device according to claim 18, wherein,

the preset policy comprises:

after the phase difference and amplitude difference estimation module uses a phase difference in the value interval of the phase difference and an amplitude difference in the value interval of the amplitude difference to calibrate the service data, if a difference between the error rate obtained from the statistics according to feedback of the UE and an error rate without parameter deviation is less than a preset threshold, judging the phase difference as a phase difference value closest to a true phase difference and the amplitude difference as an amplitude difference closest to a true amplitude difference;

or, after the phase difference and amplitude difference estimation module uses a phase difference in the value interval of the phase difference and an amplitude difference in the value interval of the amplitude difference to calibrate the service data, if a difference between the MCS level obtained by performing open loop link adaption adjustment according to feedback of the UE and an MCS level without parameter deviation is less than a preset threshold, judging the phase difference as a phase difference value closest to a true phase difference and the amplitude difference as an amplitude difference closest to a true amplitude difference;

wherein, the MCS level without parameter deviation is obtained by a base station in which the device is located requesting the UE for acquisition, and the error rate without parameter deviation is an error rate assumed when the UE measures the MCS level without parameter deviation and previously appointed by the base station and the UE;

or, after the phase difference and amplitude difference estimation module uses a phase difference in the value interval of the phase difference and an amplitude difference in the value interval of the amplitude difference to calibrate the service data, comparing the error rate obtained from the statistics according to feedback of the UE or the MCS level obtained by performing the open loop link adaption adjustment, and taking a phase difference with a lowest error rate or a highest MCS level correspondingly obtained in the phase differences of the traversed values as a phase difference value closest to a true phase difference and an amplitude difference with a lowest error rate or a highest MCS level correspondingly obtained in the amplitude differences of the traversed values as an amplitude difference value closest to a true amplitude difference.