METHODS AND APPARATUS FOR COMMUNICATING INFORMATION USING VARIOUS TRANSMISSION POWER LEVELS

• US 20110205887A1
• Filed: 02/25/2010
• Published: 08/25/2011
• Est. Priority Date: 02/25/2010
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Subramanian, Sundar, Wu, Xinzhou, Li, Junyi, Khude, Nilesh
• Granted Patent: US 8,923,910 B2
• Time in Patent Office: Days
• US Class Current: 370/229
• CPC Class Codes: H04W 52/322 Power control of broadcast channels
• CPC Class Codes: H04W 52/343 taking into account loading or congestion level
• CPC Class Codes: H04W 52/46 in multi hop networks, e.g. wireless relay networks

Abstract

A wireless communications device supports a constant transmission power mode of operation and a time varying transmission power mode of operation for transmitting data, e.g., peer discovery data. The device determines an amount of network congestion and switches between the two modes of operation as a function of the determined amount of network congestion. Various described methods and apparatus are well suited for use in a peer to peer ad hoc wireless communications system in which a limited amount of air link resources are available for peer discovery signaling and the same peer discovery resources are, at times, used concurrently by multiple devices. When network congestion is low, the device operates in the constant transmission power mode. When network congestion is high, the device operates in the time varying power mode. Devices sharing a common peer discovery resource in a local area intentionally select different time varying transmission patterns.

Claims

1. A method of operating a wireless communications device to communicate information, comprising:

transmitting data, during a constant transmission power mode of operation, at a constant transmission power level; and

transmitting data, during a time varying transmission power mode of operation, using a power level that varies as a function of time.

2. The method of claim 1, further comprising:

switching between said constant transmission power mode of operation and said time varying transmission power mode of operation as a function of a determined amount of network congestion.

3. The method of claim 2, wherein said constant transmission power mode of operation and said time varying transmission power mode of operation are used for transmitting broadcast signals.

4. The method of claim 3, wherein said broadcast signals are peer discovery signals,

and wherein transmitting data, during the time varying transmission power mode of operation, includes transmitting the same peer discovery information multiple times, at different power levels, during different peer discovery transmission time periods.

5. The method of claim 3, further comprising:

randomly selecting one of a plurality of different transmission power level patterns to control the transmission power level as a function of time during said time varying transmission power mode of operation.

6. The method of claim 3, further comprising:

selecting one of a plurality of different transmission power level patterns to control the transmission power level as a function of time during said time varying transmission power mode of operation based on which of a plurality of pilot sequences are used by devices in the vicinity of said wireless communications device.

7. The method of claim 1, further comprising:

transmitting pilots at a first power level during said constant transmission power mode of operation; and

transmitting pilots at said first power level during said time varying transmission power mode of operation.

8. The method of claim 7, wherein said pilots are transmitted using a different pilot sequence than is used by a neighboring communications device using the same pilot transmission resources as said communications device.

9. A wireless communications device comprising:

means for transmitting data, during a constant transmission power mode of operation, at a constant transmission power level; and

means for transmitting data, during a time varying transmission power mode of operation, using a power level that varies as a function of time.

10. The communications device of claim 9, further comprising:

means for switching between said constant transmission power mode of operation and said time varying transmission power mode of operation as a function of a determined amount of network congestion.

11. The communications device of claim 10, wherein said constant transmission power mode of operation and said time varying transmission power mode of operation are used for transmitting broadcast signals.

12. The communications device of claim 11, wherein said broadcast signals are peer discovery signals,

and wherein said means for transmitting during the time varying transmission power mode of operation transmits the same peer discovery information multiple times, at different power levels, during different peer discovery transmission time periods.

13. The communications device of claim 11, further comprising:

means for randomly selecting one of a plurality of different transmission power level patterns to control the transmission power level as a function of time during said time varying transmission power mode of operation.

14. The communications device of claim 11, further comprising:

means for selecting one of a plurality of different transmission power level patterns to control the transmission power level as a function of time during said time varying transmission power mode of operation based on which of a plurality of pilot sequences are used by devices in the vicinity of said wireless communications device.

15. The communications device of claim 9, further comprising:

means for transmitting pilots at a first power level during said constant transmission power mode of operation; and

means for transmitting pilots at said first power level during said time varying transmission power mode of operation.

16. A computer program product for use in a wireless communications device, the computer program product comprising:

a computer readable medium comprising;

code for causing at least one computer to transmit data, during a constant transmission power mode of operation, at a constant transmission power level; and

code for causing the at least one computer to transmit data, during a time varying transmission power mode of operation, using a power level that varies as a function of time.

17. A wireless communications device comprising:

at least one processor configured to;

transmit data, during a constant transmission power mode of operation, at a constant transmission power level; and

transmit data, during a time varying transmission power mode of operation, using a power level that varies as a function of time; and

a memory coupled to said at least one processor.

18. The communications device of claim 17, wherein said at least one processor is further configured to:

switch between said constant transmission power mode of operation and said time varying transmission power mode of operation as a function of a determined amount of network congestion.

19. The communications device of claim 18, wherein said at least one processor is further configured to:

randomly select one of a plurality of different transmission power level patterns to control the transmission power level as a function of time during said time varying transmission power mode of operation.

20. The communications device of claim 18, wherein said at least one processor is further configured to:

select one of a plurality of different transmission power level patterns to control the transmission power level as a function of time during said time varying transmission power mode of operation based on which of a plurality of pilot sequences are used by devices in the vicinity of said wireless communications device.