Diversity control in wireless communications devices and methods

• US 7,929,921 B2
• Filed: 06/10/2003
• Issued: 04/19/2011
• Est. Priority Date: 06/10/2003
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola Mobility, Inc. (Lenovo Group Ltd.)
• Inventors: Love, Robert T., Stewart, Kenneth A.
• Primary Examiner(s): Appiah; Charles N
• Assistant Examiner(s): Peaches; Randy
• Application Number:
  US10/458,701
• Publication Number:
  US 20040253955A1
• Time in Patent Office: 2,870 Days
• Field of Search: 455/575.7, 455/574, 455/138, 455/135, 455/136, 455/164.2, 455/183, 455/226.1, 455/226.2, 455/101, 455/140, 455/137, 455/273, 455/272, 370/347, 370/321, 375/345, 375/346, 375/349, 375/366, 375/267
• US Class Current: 455/101
• CPC Class Codes: H04B 7/0814 based on current reception conditions, e.g. switching to different antenna when signal level is below threshold
• CPC Class Codes: H04B 7/0825 with main and with auxiliary or diversity antennas
• CPC Class Codes: H04B 7/0877 switching off a diversity branch, e.g. to save power
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• 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 52/42 in systems with time, space, frequency or polarisation diversity
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A wireless communications device (100) includes a primary radio frequency branch (134) and a diversity branch (136), which is enabled and disabled to balance performance and power consumption. Diversity mode operation of the device is controlled, for example, based on one or more of an estimated channel quality indicator, data reception, data rate, state or mode of the station, estimated signal to noise ratio of a pilot signal, battery power level, distance from a serving cell, among other factors.

Claims

1. A method in a wireless communications station having a diversity receive branch, the method comprising:

determining a channel quality indicator with the diversity receive branch enabled,

determining a channel quality indicator with the diversity receive branch disabled;

determining a difference between the channel quality indicator determined with the diversity receive branch disabled and the channel quality indicator determined with the diversity receive branch enabled;

selectively operating diversity mode based upon a comparison of the difference with a threshold.

2. The method of claim 1, wherein selectively operating the diversity mode includes

operating the diversity receive branch when the difference exceeds a first threshold,

not operating the diversity receive branch when the difference does not exceed a second threshold, which is different from the first threshold.

3. The method of claim 1, wherein selectively operating the diversity mode includes:

operating the diversity receive branch when the difference exceeds a first difference threshold,

not operating the diversity receive branch when the difference does not exceed the first difference threshold.

4. The method of claim 1, wherein the wireless communications station includes a single antenna, a primary receive branch and a diversity receive branch both coupled to the single antenna, the method comprising

receiving a signal with the single antenna,

determining the channel quality indicator for the signal received by the single antenna when the diversity receive branch is enabled,

determining the channel quality indicator for the signal received by the single antenna when the diversity receive branch is disabled.

5. A method in a wireless mobile communications station having diversity receive mode capability, the method comprising:

receiving packet information at the wireless mobile communications station;

operating the wireless mobile communications station in diversity reception mode when receiving packet information,

not operating the wireless mobile communications station in diversity reception mode when no additional packet information is received within a specified time interval after receiving the packet information.

6. The method of claim 5,

starting a timer upon first receiving the packet information,

resetting the timer if new packet information is received,

disabling diversity if the timer expires.

7. The method of claim 5,

receiving packet information includes detecting a control channel associated with the packet information,

enabling the diversity receive branch if the control channel is detected.

8. The method of claim 7,

the control channel has first and second parts,

enabling the diversity receive branch if at least one of the first and second parts of the control channel is detected.

9. The method of claim 7,

setting a timer upon detecting the control channel associated with the packet information,

disabling diversity if the timer expires.

10. The method of claim 9,

re-setting a timer upon detecting a subsequent control channel associated with subsequent packet information.

11. The method of claim 5,

disabling diversity if no additional packet information is received within a specified time interval associated with the packet information.

12. The method of claim 5,

modifying power control prior to operating or not operating the wireless mobile communications station in diversity reception mode.

13. A method in a wireless mobile communications station having diversity receive mode capability, the method comprising:

transitioning the wireless mobile communications station between an intermediate state and active and dormant states;

controlling the diversity receive mode capability when transitioning to and from the intermediate state.

14. The method of claim 13, controlling the diversity receive mode capability upon transitioning to and from the intermediate state includes before and after transitioning to and from the intermediate state.

15. The method of claim 13,

the intermediate state is a channel maintenance state,

not operating the diversity receive mode in the channel maintenance state.

16. The method of claim 15, operating in the diversity receive mode in the active state.

17. The method of claim 13, the intermediate state is a FACCH state, disabling diversity receive mode when in the FACCH state.

18. A method in a wireless mobile communications station having diversity receive mode capability, the method comprising:

receiving a signal;

estimating a signal to noise ratio of the received signal without first demodulating the received signal;

enabling diversity reception in the wireless mobile communications station when the estimated signal to noise ratio is less than a specified threshold.

19. The method of claim 18,

receiving the signal includes receiving a pilot signal;

estimating the signal to noise ratio of the received signal by estimating a signal to noise ratio of the pilot signal;

enabling diversity reception in the wireless mobile communications station if the estimated signal to noise ratio of the pilot is less than a specified threshold.

20. The method claim 18,

estimating a signal to noise ratio of the received signal by estimating Ec/Io,

enabling diversity reception in the wireless mobile communications station if the Ec/Io estimation is less than a specified threshold.

21. A method in a wireless mobile communications station having diversity receive mode capability, the method comprising:

determining an anticipated downlink data rate for the wireless mobile communications station;

enabling diversity reception in the wireless mobile communications station if the anticipated data rate exceeds a specified threshold.

22. The method of claim 21,

determining the anticipated downlink data rate for the wireless mobile communications station includes receiving a radio link configuration information.

23. The method of claim 21,

determining the anticipated downlink data rate for the wireless mobile communications station includes determining a data requirement in an application layer;

enabling diversity reception in the wireless mobile communications station in response to a Java API command if the data requirement exceeds a threshold.

24. A method in a wireless mobile communications station having diversity receive mode capability, the method comprising:

determining an estimated distance of the wireless mobile communications station from a serving cell;

controlling diversity reception in the wireless mobile communications station based upon the distance of the wireless mobile communications station from the serving cell.

25. A method in a wireless mobile communications station having diversity receive mode capability, the method comprising:

determining an estimated level of a battery of the wireless mobile communications station;

controlling diversity reception in the wireless mobile communications station based upon the estimated level of the battery of the wireless mobile communications station.

26. A method in a wireless mobile communications station having diversity receive mode capability, the method comprising:

determining a ratio of despread signal power to despread power of cell interferers at the wireless mobile communications station;

controlling diversity reception in the wireless mobile communications station based upon the ratio of despread signal power to despread power of cell interferers at the wireless mobile communications station.