Method and apparatus to improve the robustness of a wireless communication link

• US 8,554,259 B2
• Filed: 02/10/2010
• Issued: 10/08/2013
• Est. Priority Date: 12/14/2009
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Ramasamy, Venkatasubramanian, Deivasigamani, Giri Prassad, Vasudevan, Srinivasan, Narang, Mohit, Xing, Longda, Sebeni, Johnson O.
• Primary Examiner(s): SHARMA, SUJATHA R
• Application Number:
  US12/703,652
• Publication Number:
  US 20110143805A1
• Time in Patent Office: 1,336 Days
• Field of Search: 455/67.13, 455/63.1, 455/501, 455/450, 455/452.1, 455/464, 455/522, 455/127.1, 455/67.11, 455/69, 455/517, 455/68, 455/88, 455/561, 455/318, 370/328, 370/230, 370/432, 370/310, 370/346, 375/141, 375/346, 375/348, 375/146, 375/135, 375/295, 375/297, 375/358
• US Class Current: 455/522
• CPC Class Codes: H04W 52/10 Open loop power control
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/22 taking into account previous information or commands
• CPC Class Codes: H04W 52/241 taking into account channel quality metrics, e.g. SIR, SNR, CIR, Eb/lo
• CPC Class Codes: H04W 52/265 taking into account the quality of service QoS
• CPC Class Codes: H04W 52/283 Power depending on the position of the mobile
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels
• CPC Class Codes: H04W 52/346 distributing total power among users or channels

Abstract

A method and apparatus to improve the robustness of a wireless communication link between a base station and a mobile communication device. The method increases power selectively on portions of an uplink communication signal transmitted from the mobile communication device to the base station. The method monitors a quality metric value at the mobile communication device and sets the transmit power level of the first portion of an uplink communication signal to the first power level, if the monitored quality metric value is in a first range of quality values, or sets the transmit power level of the first portion of the uplink communication signal to a second power level, if the monitored quality metric value is in a second range of quality values. The first portion of the uplink communication signal includes control signals used by a base station to maintain connection of the wireless communication link.

Claims

1. A method for improving robustness of a wireless communication link between a mobile device and a base station, the method comprising:

monitoring a quality metric value at the mobile device;

setting a transmit power level of a first portion of an uplink communication signal to a first transmit power level value when the monitored quality metric value is within a first range of quality metric values; and

setting the transmit power level of the first portion of the uplink communication signal to a second transmit power level value when the monitored quality metric value is within a second range of quality metric values;

wherein the second transmit power level value is greater than the first transmit power level value, thereby improving a robustness of the wireless communication link; and

wherein the quality metric value comprises a timing advance value set by the base station.

2. The method as recited in claim 1, further comprising:

initializing the transmit power level of the first portion of the uplink communication signal to the first transmit power level value; and

repeatedly monitoring the quality metric value and adaptively setting the transmit power level of the first portion of the uplink communication signal in accordance with the monitored quality metric value while the wireless communication link is connected.

3. The method as recited in claim 1, wherein the first portion of the uplink communication signal includes control signals used by the base station to maintain connection of the wireless communication link between the base station and the mobile device.

4. The method as recited in claim 1, further comprising:

monitoring a power storage metric value of the mobile device; and

setting the second transmit power level value based on the monitored power storage metric value.

5. A method for improving robustness of a wireless communication link between a mobile device and a base station, the method comprising:

monitoring a quality metric value at the mobile device;

setting a transmit power level of a first portion of an uplink communication signal to a first transmit power level value when the monitored quality metric value is within a first range of quality metric values;

setting the transmit power level of the first portion of the uplink communication signal to a second transmit power level value when the monitored quality metric value is within a second range of quality metric values, the second transmit power level value being greater than the first transmit power level value, thereby improving a robustness of the wireless communication link;

setting a transmit power level of a second portion of the uplink communication signal to the first power level value when the monitored quality metric value is in the first range of quality values, and

setting the transmit power level of the second portion of the uplink communication signal to a third power level value when the monitored quality metric value is in the second range of quality values;

wherein the third power level value is less than the first power level value.

6. The method as recited in claim 5, further comprising

initializing the transmit power level of the second portion of the uplink communication signal to the first power level value;

and

repeatedly monitoring the quality metric value and adaptively setting the transmit power level of the second portion of the uplink communication signal in accordance with the monitored quality metric value.

7. The method as recited in claim 5, wherein a total average transmit power across the first and second portions of the uplink communication signal when the first portion is set to the second power level value and the second portion is set to the third power level value is no more than when the first and second portions are set to the first power level value.

8. The method as recited in claim 5, wherein the quality metric value comprises a power control level value set by the base station.

9. The method as recited in claim 5, wherein the quality metric value comprises a received downlink transmission quality metric value measured by the mobile device.

10. The method as recited in claim 5, wherein the quality metric value measures indirectly a signal quality of uplink communication signals received at the base station from the mobile device, and the first portion of the uplink communication signal includes control signals used by the base station to maintain connection of the wireless communication link between the base station and the mobile device.

11. A mobile device, comprising:

a wireless interface, the wireless interface configured to communicate with a base station over a wireless link, the wireless link comprising an uplink communication signal transmitted from the mobile device to the base station;

a processor; and

a computer readable apparatus having a non-transitory storage medium with at least one computer program stored thereon, the at least one computer program configured to, when executed on the processor, cause the mobile device to;

monitor a quality metric value;

set a transmit power level of a first portion of an uplink communication signal to a first transmit power level value when the monitored quality metric value is within a first range of quality metric values; and

set the transmit power level of the first portion of the uplink communication signal to a second transmit power level value when the monitored quality metric value is within a second range of quality metric values;

wherein the second transmit power level value is greater than the first transmit power level value; and

wherein the monitored quality metric value comprises a timing advance set by the base station.

12. The mobile device as recited in claim 11, wherein the processor is further configured to:

initialize the transmit power level of the first portion of the uplink communication signal to the first transmit power level value; and

repeatedly monitor the quality metric value and adaptively set the transmit power level of the first portion of the uplink communication signal in accordance with the monitored quality metric value while the wireless communication link is connected.

13. The mobile device as recited in claim 11, wherein the first portion of the uplink communication signal includes control signals used by the base station to maintain connection of the communication link between the base station and the mobile device.

14. The mobile device as recited in claim 11, wherein the processor is further configured to:

monitor a power storage metric value of the mobile device; and

set the second transmit power level value based on the monitored power storage metric value.

15. A mobile device configured to improve a robustness of a wireless communication link with a base station, the mobile device comprising:

a processor;

a radio transceiver in signal communication with the processor; and

computerized logic in communication with the radio transceiver, the computerized logic configured to cause the mobile device to;

set a transmit power level of a first portion of an uplink communication signal transmitted to a first transmit power level value when the monitored quality metric value is within a first range of quality metric value;

set the transmit power level of the first portion of the uplink communication signal to a second transmit power level value when the monitored quality metric value is within a second range of quality metric values, where the second transmit power level value is greater than the first transmit power level value;

set a transmit power level of a second portion of the uplink communication signal to the first power level value when the monitored quality metric value is in the first range of quality values, and

set the transmit power level of the second portion of the uplink communication signal to a third power level value when the monitored quality metric value is in the second range of quality values, where the third power level value is less than the first power level value.

16. The mobile device as recited in claim 15, wherein the computerized logic is further configured to:

initialize the transmit power level of a second portion of the uplink communication signal to the first power level value; and

repeatedly monitor the quality metric value and adaptively set the transmit power level of the second portion of the uplink communication signal in accordance with the monitored quality metric value.

17. The mobile device as recited in claim 15, wherein a total average transmit power across the first and second portions of the uplink communication signal, when the first portion is set to the second power level value and the second portion is set to the third power level value, is no more than when the first and second portions are set to the first power level value.

18. A method for improving robustness of a wireless communication link between a mobile device and a base station, the method comprising:

monitoring a quality metric value and a power storage metric value at the mobile device;

setting a transmit power level of a first portion of an uplink communication signal to a first transmit power level value when the monitored quality metric value is within a first range of quality metric values; and

setting the transmit power level of the first portion of the uplink communication signal to a second transmit power level value when the monitored quality metric value is within a second range of quality metric values;

setting the second transmit power level based on the monitored power storage metric value;

wherein the second transmit power level value is greater than the first transmit power level value, thereby improving a robustness of the wireless communication link.

19. The method as recited in claim 18, further comprising:

initializing the transmit power level of the first portion of the uplink communication signal to the first transmit power level value; and

repeatedly monitoring the quality metric value and adaptively setting the transmit power level of the first portion of the uplink communication signal in accordance with the monitored quality metric value while the wireless communication link is connected.

20. The method as recited in claim 18, wherein the first portion of the uplink communication signal includes control signals used by the base station to maintain connection of the wireless communication link between the base station and the mobile device.

21. The method as recited in claim 18, wherein the quality metric value comprises a timing advance value set by the base station.

22. A mobile device configured to improve a robustness of a wireless communication link, the mobile device comprising:

a processor;

a radio transceiver in signal communication with the processor; and

computerized logic in communication with the transceiver, the computerized logic configured to;

monitor a quality metric value, the quality metric value comprising a timing advance value set by the base station; and

increase a transmit power level of a first portion of an uplink communication signal transmitted on the wireless communication link from the mobile device to the base station based on the monitored quality metric value.

23. The mobile device of claim 22, wherein the quality metric value measures indirectly a signal quality of uplink communication signals received at the base station from the mobile device, and the first portion of the uplink communication signal includes control signals used by the base station to maintain connection of the wireless communication link between the base station and the mobile device.

24. The mobile device of claim 22, the logic further configured to decrease a transmit power level of a second portion of the uplink communication signal transmitted on the wireless communication link from the mobile device to the base station based on the monitored quality metric value.

25. The mobile device of claim 24, wherein the decreased transmit power level of the second portion of the uplink communication signal balances the increased transmit power level of the second portion of the uplink communication signal, so that the average transmit power level of the uplink communication signal is approximately unchanged.