Selecting paging channel mode

• US 6,650,912 B2
• Filed: 09/18/2001
• Issued: 11/18/2003
• Est. Priority Date: 09/18/2000
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Chen, Jiangxin, Amerga, Messay, Neufeld, Arthur, Glazko, Serguei
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): Orgad, Edan
• Application Number:
  US09/956,324
• Publication Number:
  US 20030008691A1
• Time in Patent Office: 791 Days
• Field of Search: 455/574, 455/458, 455/464, 455/513, 455/572, 455/226.1, 455/226.2
• US Class Current: 455/574
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0245 according to signal strength
• CPC Class Codes: H04W 68/00 User notification, e.g. alerting and paging, for incoming communication, change of service or the like
• CPC Class Codes: H04W 68/025 Indirect paging
• CPC Class Codes: H04W 72/54 based on quality criteria
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A quick paging channel (QPCH) is used to receive paging indicators that indicate that a wireless communication device (WCD) has a message on a paging channel relating to, for example, an incoming call to the WCD. When the condition of the quick paging channel is too low to receive paging indicators reliably, the quick paging channel is disabled to avoid false alarms, and the slotted paging channel is used to receive paging messages without monitoring the QPCH. When the QPCH signal is strong, the probability of false alarms is lower, and the quick paging channel is enabled. By using the quick paging channel to receive paging indicators only when the QPCH signal is strong, the wireless communication device can remain in a sleep state for greater periods of time as compared with the use of a slotted paging channel. As a result, standby time may be significantly improved.

Claims

1. A method comprising:

predicting a signal strength in a first paging channel;

receiving a paging indicator on the first paging channel if the predicted signal strength is greater than a threshold;

determining whether the paging indicator indicates a presence of a paging message on a second paging channel; and

receiving and demodulating the paging message on the second paging channel if the paging indicator indicates the presence of the paging message.

2. The method of claim 1, further comprising the step of:

entering into a sleep mode if the paging indicator does not indicate the presence of the paging message.

3. The method of claim 2, further comprising the step of:

disabling the first paging channel and monitoring the second paging channel for a paging message when the predicted signal strength is less than the threshold.

4. The method of claim 1, wherein predicting the signal strength comprises estimating the signal strength as a function of historical pilot Ec/Io information representative of a signal strength of a pilot channel and a total received power spectral density in a carrier band.

5. The method of claim 4, further comprising using a linear filter to estimate the signal strength.

6. The method of claim 5, wherein the linear filter is a finite impulse response (FIR) filter.

7. The method of claim 5, wherein the linear filter is an infinite impulse response (IIR) filter.

8. The method of claim 5, wherein the linear filter comprises a plurality of taps having equal tap weights.

9. The method of claim 5, wherein the linear filter comprises a plurality of taps having exponentially decaying tap weights.

10. The method of claim 4, further comprising using a nonlinear filter to estimate the signal strength.

11. The method of claim 10, wherein the nonlinear filter comprises a Markov filter.

12. The method of claim 4, wherein the historical pilot Ec/Io information comprises at least one of searcher energy information, pilot strength estimate information, and a received signal strength indicator.

13. The method of claim 12, further comprising combining at least two of the searcher energy information, the pilot strength estimate information, and the received signal strength indicator using a maximal ratio combining technique.

14. The method of claim 12, further comprising combining at least two of the searcher energy information, the pilot strength estimate information, and the received signal strength indicator using an equal gain combining technique.

15. The method of claim 1, further comprising demodulating a spread spectrum message received from the second paging channel.

16. A processor readable medium containing processor executable instructions for:

receiving measurements of a signal strength of a first paging channel;

predicting a signal strength of a subsequent slot cycle for the first paging channel based on the received measurements;

receiving a paging indicator on the first paging channel if the predicted signal strength is greater than a threshold;

determining whether the paging indicator indicates a presence of a paging message on a second paging channel; and

configuring a demodulator to enable a paging channel operating mode based on the predicted signal strength.

17. The processor readable medium of claim 16, further containing processor executable instructions for predicting the signal strength by estimating the signal strength as a function of historical pilot Ec/Io information.

18. The processor readable medium of claim 17, further containing processor executable instructions for using a linear filter to estimate the signal strength.

19. The processor readable medium of claim 18, wherein the linear filter is a finite impulse response (FIR) filter.

20. The processor readable medium of claim 18, wherein the linear filter is an infinite impulse response (IIR) filter.

21. The processor readable medium of claim 18, wherein the linear filter comprises a plurality of taps having equal tap weights.

22. The processor readable medium of claim 18, wherein the linear filter comprises a plurality of taps having exponentially decaying tap weights.

23. The processor readable medium of claim 17, further containing processor executable instructions for using a nonlinear filter to estimate the signal strength.

24. The processor readable medium of claim 23, wherein the nonlinear filter comprises a Markov filter.

25. The processor readable medium of claim 17, wherein the historical pilot Ec/Io information comprises at least one of searcher energy information, pilot strength estimate information, and a received signal strength indicator.

26. The processor readable medium of claim 25, further containing processor executable instructions for combining at least two of the searcher energy information, the pilot strength estimate information, and the received signal strength indicator using a maximal ratio combining technique.

27. The processor readable medium of claim 25, further containing processor executable instructions for combining at least two of the searcher energy information, the pilot strength estimate information, and the received signal strength indicator using a equal gain combining technique.

28. An apparatus comprising:

a channel estimator module to predict a signal strength in an alternate paging channel; and

a modem to demodulate a paging indicator using the alternate paging channel when the predicted signal strength is at least a threshold;

wherein the modem determines a presence of a paging message on a main paging channel based on the paging indicator.

29. The apparatus of claim 28, wherein the channel estimator module comprises one or more software modules executing on a processor.

30. The apparatus of claim 28, wherein the channel estimator module is configured to predict the signal strength by estimating the signal strength as a function of historical pilot Ec/Io information.

31. The apparatus of claim 30, further comprising a linear filter to estimate the signal strength.

32. The apparatus of claim 31, wherein the linear filter is a finite impulse response (FIR) filter.

33. The apparatus of claim 31, wherein the linear filter is an infinite impulse response (IIR) filter.

34. The apparatus of claim 31, wherein the linear filter comprises a plurality of taps having equal tap weights.

35. The apparatus of claim 31, wherein the linear filter comprises a plurality of taps having exponentially decaying tap weights.

36. The apparatus of claim 30, further comprising a nonlinear filter to estimate the signal strength.

37. The apparatus of claim 36, wherein the nonlinear filter comprises a Markov filter.

38. The apparatus of claim 30, wherein the historical pilot Ec/Io information comprises at least one of searcher energy information, pilot strength estimate information, and a received signal strength indicator.

39. The apparatus of claim 38, wherein the channel estimator module is configured to combine at least two of the searcher energy information, the pilot strength estimate information, and the received signal strength indicator using a maximal ratio combining technique.

40. The apparatus of claim 38, wherein the channel estimator module is configured to combine at least two of the searcher energy information, the pilot strength estimate information, and the received signal strength indicator using an equal gain combining technique.