Automatic diagnostic for detection of interference in wireless communication system

• US 6,775,544 B2
• Filed: 08/10/2001
• Issued: 08/10/2004
• Est. Priority Date: 06/03/1999
• Status: Expired due to Fees

• Current Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Original Assignee: AT&T Wireless Services Incorporated (AT&T, Inc.)
• Inventors: Ficarra, Louis J.
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): SOBUTKA, PHILIP
• Application Number:
  US09/925,605
• Publication Number:
  US 20010055952A1
• Time in Patent Office: 1,096 Days
• Field of Search: 455/423, 455/424, 455/63.1, 455/67.11, 455/67.13, 455/524, 455/561, 455/562.1, 455/522, 455/226.1, 375/317
• US Class Current: 455/424
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports

Abstract

In an automated diagnostic method for identifying interference events at a receiver of a wireless communication system, the receiver is queried for energy measurement data. From the energy measurement data, a probability distribution of the energy is calculated. An interference event may be identified if the calculated probability distribution exceeds a predetermined threshold.

Claims

1. A method of identifying interference events at a receiver of a wireless communication system, comprising:

querying the receiver for measured noise floor data,

calculating, from the measured noise floor data, a probability distribution of the noise floor,

determining a threshold based on a larger set of receivers, and

identifying an interference event if the calculated probability distribution exceeds the threshold.

2. The method of claim 1, wherein the calculating step calculates a standard deviation of the measured noise floor data.

3. The method of claim 1, wherein the identifying step identifies an interference event if the standard deviation of the noise floor exceeds an expected value of interference energy plus a standard deviation of the expected value of the interference energy.

4. The method of claim 1, wherein the querying step includes querying an Ericsson model CMS 8800 base station for measured noise floor data stored in MCHA 1.

5. The method of claim 1, wherein the wherein the querying step includes querying an Ericsson model CMS 8800 base station for measured noise floor data stored in MCHA 21.

6. A diagnostic testing method for testing a plurality of base stations for interference, comprising:

querying each of the plurality of base station subject to test for measured noise floor data,

calculating, from the measured noise floor data of each base station, a probability distribution of noise floor at the base station,

calculating, from the measured noise floor data, a probability distribution of interference energy of the plurality of base stations to determine a threshold based on the plurality of base stations, and

identifying a base station as suffering interference based on a comparison of the noise floor probability distribution of the base station with the probability distribution of interference energy of the plurality of base stations.

7. The method of claim 6, wherein the calculating step calculates a standard deviation of the measured noise floor data.

8. The method of claim 6, wherein the identifying step identifies an interference event if the standard deviation of the noise floor exceeds an expected value of interference energy plus a standard deviation of the expected value of the interference energy.

9. The method of claim 6, wherein the querying step includes querying an Ericsson model CMS 8800 base station for measured noise floor data stored in MCHA 1.

10. The method of claim 6, wherein the querying step includes querying an Ericsson model CMS 8800 base station for measured noise floor data stored in MCHA 21.

11. A method of identifying interfered channels in a wireless communication system having a plurality of base stations, comprising:

(i) querying each of the plurality of base stations for measured noise floor data of each idle channel at the base station,

(ii) calculating, for each idle channel of each base station, a probability distribution of the noise floor of the channel,

(iii) calculating, from the measured noise floor data, a probability distribution of interference energy for the plurality of base stations subject to test to determine a threshold based on the set of base stations, and

(iv) identifying a channel as suffering interference based on a comparison of the channel'"'"'s noise floor probability distribution with the probability distribution of interference energy for the plurality of base stations.

12. The method of claim 11, wherein step (ii) calculates a standard deviation of the measured noise floor data.

13. The method of claim 11, wherein the identifying step identifies an interference event if the standard deviation of the noise floor exceeds an expected value of interference energy plus a standard deviation of the expected value of the interference energy.

14. The method of claim 11, wherein the querying step includes querying an Ericsson model CMS 8800 base station for measured noise floor data stored in MCHA 1.

15. The method of claim 11, wherein the wherein the querying step includes querying an Ericsson model CMS 8800 base station for measured noise floor data stored in MCHA 21.

16. A method of identifying interfered channels in a wireless communication system having a plurality of base stations, comprising:

querying each of the plurality of base station for measured noise floor data at the base station and for measured data representing channel quality metrics at the base station,

calculating a probability distribution of the noise floor of each base station based upon the measured noise floor data of the respective base station,

calculating a probability distribution of the channel quality data of each base station based upon the measured channel quality metrics,

calculating a probability distribution of interference energy for the plurality of base stations subject to test,

calculating a probability distribution of channel quality metrics for plurality of base stations subject to test to determine a threshold, and

identifying a base station as suffering interference based on a comparison of the base station'"'"'s noise floor probability distribution with the probability distribution of interference energy and a comparison of the base station'"'"'s channel quality probability distribution with the channel quality probability distribution for the plurality of base stations.

17. The method of claim 16, wherein the first calculating step calculates a standard deviation of the measured noise floor data.

18. The method of claim 16, wherein the channel quality metric data is carrier to interference ratio of active channels.

19. The method of claim 16, wherein the channel quality metric data is bit error rates of active channels.

20. The method of claim 16, wherein the querying step includes querying an Ericsson model CMS 8800 base station for measured noise floor data stored in MCHA 1.

21. The method of claim 16, wherein the wherein the querying step includes querying an Ericsson model CMS 8800 base station for measured noise floor data stored in MCHA 21.

22. The method of claim 16, wherein the querying step includes querying an Ericsson model CMS 8800 base station for carrier to interference ratio data stored in MCHA 7.

23. The method of claim 16, wherein the querying step includes querying an Ericsson model CMS 8800 base station for bit error rate data stored in MCHA 26.