METHOD OF USING SNR TO REDUCE FACTORY TEST TIME

• US 20090124252A1
• Filed: 01/15/2009
• Published: 05/14/2009
• Est. Priority Date: 02/25/2005
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: Mallalieu, Jennifer, Harding, Ronald Bruce, Jiao, Qingzhong, Jin, Xin
• Granted Patent: US 7,912,463 B2
• Time in Patent Office: Days
• US Class Current: 455/425
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04B 17/29 Performance testing
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04B 17/336 Signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR]

Abstract

The application relates to wireless networks and more particularly to a method of reducing factory test time of receiver sensitivity in a Code Division Multiple Access (CDMA) wireless device. Under TIA/EIA/-98E, the radio frequency (RF) sensitivity of a CDMA wireless receiver is the minimum received power, measured at the mobile station antenna connector, at which the frame error rate (FER) does not exceed 0.5% with 95% confidence. In order to reduce the test time of FER test method, the relation between correlated energy (or Ec/Io) and FER is determined using simulated traffic and the correlated energy (or Ec/Io) measurement is then used as the test parameter on like models to achieve the same or superior test confidence with significantly reduced test time.

Claims

1. A method of conducting a receiver sensitivity test of a radio frequency (RF) device, said method comprising:

waiting a defined settling time;

forwarding a simulated traffic signal to said RF device;

obtaining N samples at a baseband processor associated with said RF device of a new test quantity of said simulated traffic signal, wherein said new test quantity has a predetermined and monotonic relationship with a known receiver sensitivity test parameter of a defined test standard;

calculating an average of said N samples; and

comparing said calculated average with new test criteria for said new test quantity which corresponds to a pass/fail criteria of said defined test standard for said known receiver sensitivity test parameter.

2. A method according to claim 1 wherein said new test criteria comprises a specified new test quantity threshold defined for N samples of said new test quantity, and wherein said specified new test quantity threshold corresponds to a performance threshold and a defined confidence level for said known receiver sensitivity test parameter according to said pass/fail criteria of said defined test standard.

3. A method according to claim 1 wherein said new test quantity is taken from the group comprising signal to noise ratio, signal to interference ratio, energy per chip to interference density ratio (Ec/lo), energy per bit to interference density ratio (Eb/lo), energy per symbol to interference density ratio (Es/lo), energy per chip to noise density ratio (Ec/No), energy per bit to noise density ration (Eb/No), energy per symbol to noise density ratio (Es/No), carrier power to noise density ratio (C/No), correlated energy, correlated amplitude, symbol error rate and bit error rate.

4. A method according to claim 1 wherein said known receiver sensitivity test parameter is taken from the group comprising frame error rate (FER), packet error rate (PER), and symbol error rate (SER).

5. A method according to claim 2 wherein comparing said calculated average with new test criteria comprises determining if said calculated average is greater than said specified new test quantity threshold.

8. A method according to claim 1 wherein said defined standard is TIA/EIA/-98E, and wherein a specified new test quantity threshold of said new test criteria corresponds to a forward error rate (FER) less than or equal to 0.5% with 95% confidence.

9. A method according to claim 8 wherein said known receiver sensitivity test parameter is frame error rate and said new test quantity is correlated energy.

16. A method according to claim 1 wherein said new test criteria achieves a defined missed detection rate and a defined false alarm rate.

6. A method of conducting a receiver sensitivity test of a radio frequency (RF) device, said method comprising:

waiting a defined settling time;

forwarding a simulated traffic signal to said RF device;

performing at least one iteration of a predefined number of iterations of testing wherein each iteration of testing comprises;

obtaining a multiple, determined by a current iteration, of N samples at a baseband processor associated with said RF device of a new test quantity of said simulated traffic signal, wherein said new test quantity has a predetermined and monotonic relationship with a known receiver sensitivity test parameter of a defined test standard;

calculating a current average of said new test quantity from a current total number of samples obtained during said receiver sensitivity test up to and including said current iteration; and

determining said RF device has passed said receiver sensitivity test and that no further iterations are to be performed in a case where said calculated current average is greater than a specified new test quantity threshold, wherein said specified new test quantity threshold is defined for a number of samples corresponding to said current total number of samples obtained and corresponds to a performance threshold and a defined confidence level for said known receiver sensitivity test parameter according to a pass/fail criteria of said defined test standard; and

determining that another iteration is to be performed in a case where said calculated current average is less than said specified new test quantity threshold;

determining said RF device has failed in a case where after said predefined number of iterations said RF device has not been determined to have passed said receiver sensitivity test.

10. A method according to claim 6 wherein said known receiver sensitivity test parameter is frame error rate and said new test quantity is correlated energy.

12. A method according to claim 6 wherein said known receiver sensitivity test parameter is frame error rate and said new test quantity is signal to noise ratio (SNR) or Ec/lo.

14. A method according to claim 6 wherein said known receiver sensitivity test parameter is symbol error rate and said new test quantity is Ec/lo.

7. A method of conducting a receiver sensitivity test of a radio frequency (RF) device, said method comprising:

waiting a defined settling time;

forwarding a simulated traffic signal to said RF device;

performing at least one iteration of a predefined number of iterations of testing wherein each iteration of testing comprises;

obtaining a multiple, determined by a current iteration, of N samples at a baseband processor associated with said RF device of a new test quantity of said simulated traffic signal, wherein said new test quantity has a predetermined and monotonic relationship with a known receiver sensitivity test parameter of a defined test standard;

calculating a current average of said new test quantity from a current total number of samples obtained during said receiver sensitivity test up to and including said current iteration;

determining said RF device has passed said receiver sensitivity test and that no further iterations are to be performed in a case where said calculated current average is greater than a specified new test quantity upper threshold, wherein said specified new test quantity upper threshold is defined for a number of samples corresponding to said current total number of samples obtained and corresponds to an upper limit for a performance threshold and a defined confidence level for said known receiver sensitivity test parameter according to a pass/fail criteria of said defined test standard; and

determining said RF device has failed said receiver sensitivity test and that no further iterations are to be performed in a case where said calculated current average is less than a specified new test quantity lower threshold, wherein said specified new test quantity lower threshold is defined for a number of samples corresponding to said current total number of samples obtained and corresponds to a lower limit of a performance threshold and a defined confidence level for said known receiver sensitivity test parameter according to said pass/fail criteria of said defined test standard;

determining that another iteration is to be performed in a case where said calculated current average is less than said specified new test quantity upper threshold and greater than said specified new test quantity lower threshold;

determining said RF device has failed in a case where after said predefined number of iterations said RF device has not been determined to have passed said receiver sensitivity test.

11. A method according to claim 7 wherein said known receiver sensitivity test parameter is frame error rate and said new test quantity is correlated energy.

13. A method according to claim 7 wherein said known receiver sensitivity test parameter is frame error rate and said new test quantity is signal to noise ratio (SNR) or Ec/lo.

15. A method according to claim 7 wherein said known receiver sensitivity test parameter is symbol error rate and said new test quantity is Ec/lo.

17. A system for conducting a receiver sensitivity test of a radio frequency (RF) device under test (DUT), the system comprising:

said DUT having a baseband processor and for obtaining N samples at said baseband processor of a new test quantity of a simulated traffic signal, wherein said new test quantity has a predetermined and monotonic relationship with a known receiver sensitivity test parameter of a defined test standard; and

a wireless communications test set for forwarding said simulated traffic signal to said DUT, for receiving and calculating an average of said N samples; and

for comparing said calculated average with new test criteria for said new test quantity which corresponds to a pass/fail criteria of said defined test standard for said known receiver sensitivity test parameter.

18. A system according to claim 17 wherein said DUT is a wireless device operating within a wireless network.

19. A system according to claim 17 wherein said DUT is a base station operating within a wireless network.

20. A system according to claim 17 wherein said baseband processor further includes a function for translating a correlated energy value derived from said estimated amplitude, to a signal to noise ratio (SNR) or Ec/lo.

21. A system according to claim 17 wherein said new test criteria comprises a specified new test quantity threshold defined for N samples of said new test quantity, and wherein said specified new test quantity threshold corresponds to a performance threshold and a defined confidence level for said known receiver sensitivity test parameter according to said pass/fail criteria of said defined test standard.

22. A system according to claim 17 wherein said new test quantity is taken from the group comprising signal to noise ratio, signal to interference ratio, energy per chip to interference density ratio (Ec/lo), energy per bit to interference density ratio (Eb/lo), energy per symbol to interference density ratio (Es/lo), energy per chip to noise density ratio (Ec/No), energy per bit to noise density ration (Eb/No), energy per symbol to noise density ratio (Es/No), carrier power to noise density ratio (C/No), correlated energy, correlated amplitude, symbol error rate and bit error rate.

23. A system according to claim 17 wherein said known receiver sensitivity test parameter is taken from the group comprising frame error rate (FER), packet error rate (PER), and symbol error rate (SER).

24. A system according to claim 21 wherein said wireless communications test set'"'"'s comparing said calculated average with new test criteria comprises determining if said calculated average is greater than said specified new test quantity threshold.

27. A system according to claim 17 wherein said defined standard is TIA/EIA/-98E, and wherein a specified new test quantity threshold of said new test criteria corresponds to a forward error rate (FER) less than or equal to 0.5% with 95% confidence.

28. A system according to claim 27 wherein said known receiver sensitivity test parameter is frame error rate and said new test quantity is correlated energy.

35. A system according to claim 17 wherein said new test criteria achieves a defined missed detection rate and a defined false alarm rate.

25. A system for conducting a receiver sensitivity test of a radio frequency (RF) device under test (DUT), the system comprising:

said DUT having a baseband processor and for obtaining samples at said baseband processor of a new test quantity of a simulated traffic signal, wherein said new test quantity has a predetermined and monotonic relationship with a known receiver sensitivity test parameter of a defined test standard; and

a wireless communications test set for forwarding said simulated traffic signal to said DUT, for receiving and calculating averages of said samples,

wherein said DUT and said wireless communications test set are for performing at least one iteration of a predefined number of iterations of testing wherein each iteration of testing comprises;

said DUT obtaining a multiple, determined by a current iteration, of N samples at said baseband processor of said new test quantity of said simulated traffic signal;

said wireless communications test set receiving from said DUT said multiple of N samples and calculating a current average of said new test quantity from a current total number of samples obtained during said receiver sensitivity test up to and including said current iteration, determining said DUT has passed said receiver sensitivity test and that no further iterations are to be performed in a case where said calculated current average is greater than a specified new test quantity threshold, wherein said specified new test quantity threshold is defined for a number of samples corresponding to said current total number of samples obtained and corresponds to a performance threshold and a defined confidence level for said known receiver sensitivity test parameter according to a pass/fail criteria of said defined test standard, and determining that another iteration is to be performed in a case where said calculated current average is less than said specified new test quantity threshold,

and wherein said wireless communications test set is further for determining that said DUT has failed in a case where after said predefined number of iterations said DUT has not been determined to have passed said receiver sensitivity test.

29. A system according to claim 25 wherein said known receiver sensitivity test parameter is frame error rate and said new test quantity is correlated energy.

31. A system according to claim 25 wherein said known receiver sensitivity test parameter is frame error rate and said new test quantity is signal to noise ratio (SNR) or Ec/lo.

33. A system according to claim 25 wherein said known receiver sensitivity test parameter is symbol error rate and said new test quantity is Ec/lo.

26. A system for conducting a receiver sensitivity test of a radio frequency (RF) device under test (DUT), the system comprising:

said DUT having a baseband processor and for obtaining samples at said baseband processor of a new test quantity of a simulated traffic signal, wherein said new test quantity has a predetermined and monotonic relationship with a known receiver sensitivity test parameter of a defined test standard; and

a wireless communications test set for forwarding said simulated traffic signal to said DUT, for receiving and calculating averages of said samples,

wherein said DUT and said wireless communications test set are for performing at least one iteration of a predefined number of iterations of testing wherein each iteration of testing comprises;

said DUT obtaining a multiple, determined by a current iteration, of N samples at said baseband processor of said new test quantity of said simulated traffic signal;

said wireless communications test set receiving from said DUT said multiple of N samples and calculating a current average of said new test quantity from a current total number of samples obtained during said receiver sensitivity test up to and including said current iteration, determining said DUT has passed said receiver sensitivity test and that no further iterations are to be performed in a case where said calculated current average is greater than a specified new test quantity upper threshold, wherein said specified new test quantity upper threshold is defined for a number of samples corresponding to said current total number of samples obtained and corresponds to an upper limit for a performance threshold and a defined confidence level for said known receiver sensitivity test parameter according to a pass/fail criteria of said defined test standard, determining said DUT has failed said receiver sensitivity test and that no further iterations are to be performed in a case where said calculated current average is less than a specified new test quantity lower threshold, wherein said specified new test quantity lower threshold is defined for a number of samples corresponding to said current total number of samples obtained and corresponds to a lower limit of a performance threshold and a defined confidence level for said known receiver sensitivity test parameter according to said pass/fail criteria of said defined test standard, and determining that another iteration is to be performed in a case where said calculated current average is less than said specified new test quantity upper threshold and greater than said specified new test quantity lower threshold,

wherein said wireless communications test set is further for determining said DUT has failed in a case where after said predefined number of iterations said DUT has not been determined to have passed said receiver sensitivity test.

30. A system according to claim 26 wherein said known receiver sensitivity test parameter is frame error rate and said new test quantity is correlated energy.

32. A system according to claim 26 wherein said known receiver sensitivity test parameter is frame error rate and said new test quantity is signal to noise ratio (SNR) or Ec/lo.

34. A system according to claim 26 wherein said known receiver sensitivity test parameter is symbol error rate and said new test quantity is Ec/lo.