Transmit Power Control

• US 20110164514A1
• Filed: 12/28/2010
• Published: 07/07/2011
• Est. Priority Date: 01/04/2010
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Atheros Communications Incorporated (Qualcomm, Inc.)
• Inventors: Afkhamie, Hassan Kaywan, Cowan, Anthony J., Krishnam, Manjunath, Katar, Srinivas
• Granted Patent: US 8,537,705 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04B 2203/5445 Local network
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

A method for communicating among nodes in a network includes determining, by a transmitter, a first frequency band and at least a second frequency band to be used for communicating data packets, wherein a maximum allowable power spectral density in the first frequency band is greater than a maximum allowable power spectral density in the second frequency band. The method also includes adjusting power spectral density for a first group of frequencies in the first frequency band such that the adjusted power spectral density of the first group does not exceed the maximum allowable power spectral density of the first frequency band and a quantization noise introduced by the transmitter is less than a threshold value for a signal transmitted in the second frequency band. The method further includes modulating at least a portion of a data packet transmitted by the transmitter to at least a first receiver in accordance with the adjusted power spectral density.

Claims

1. A method for communicating among nodes in a network, the method, comprising:

determining, by a transmitter, a first frequency band and at least a second frequency band to be used for communicating data packets, wherein a maximum allowable power spectral density in the first frequency band is greater than a maximum allowable power spectral density in the second frequency band;

adjusting power spectral density for a first group of frequencies in the first frequency band such that the adjusted power spectral density of the first group does not exceed the maximum allowable power spectral density of the first frequency band and a quantization noise introduced by the transmitter is less than a threshold value for a signal transmitted in the second frequency band; and

modulating at least a portion of a data packet transmitted by the transmitter to at least a first receiver in accordance with the adjusted power spectral density.

2. The method of claim 1, wherein the data packet transmitted by the transmitter includes a payload and overhead information.

3. The method of claim 2 wherein at least a portion of at least one of the payload or the overhead information is transmitted in the first frequency band.

4. The method of claim 2, wherein the power spectral density for a group of frequencies in the first frequency band is adjusted such that at least a second receiver is able to receive the overhead information.

5. The method of claim 4, wherein the second receiver is configured to determine from the overhead information whether the transmitter is communicating with at least the first receiver.

6. The method of claim 4 further comprising determining, by the transmitter, a minimum power level for transmitting the overhead information such that at least the second receiver is able to receive the overhead information.

7. The method of claim 6 further comprising monitoring, by the transmitter, at least some transmissions to or from other nodes in the network, the other nodes including at least the first and second receivers, to determine if the other nodes are able to receive the overhead information.

8. The method of claim 1, further comprising adjusting power spectral density for a second group of frequencies in the second frequency band such that the adjusted power spectral density in the second group does not exceed the maximum allowable power spectral density of the second frequency band.

9. The method of claim 8, wherein the first group includes the entire first frequency band, the second group includes the entire second frequency band and the adjustments made to the first group is substantially same as the adjustments made to the second group.

10. The method of claim 1, further comprising:

determining, by the transmitter, a third frequency band to be used for communicating the data packets, wherein a maximum allowable power spectral density in the third frequency band is less than the maximum allowable power spectral density in the second frequency band; and

adjusting power spectral density for at least one of the first and second groups of frequencies such that the quantization noise introduced by the transmitter is less than a second threshold value for a signal transmitted in the third frequency band

11. The method of claim 1, wherein the quantization noise is introduced by a digital to analog converter of the transmitter.

12. The method of claim 11, wherein the same digital to analog converter is used for signals both in the first and second frequency bands.

13. The method of claim 1, where the power spectral density for the first group is further adjusted to increase a data rate between the transmitter and the first receiver in accordance with a characteristic of a channel between the transmitter and the first receiver.

14. The method of claim 1 wherein the power spectral density for the first group is further adjusted such that a second quantization noise introduced by an analog to digital converter in the first receiver is below a third threshold.

15. The method of claim 1, wherein the power spectral density for the first group is further adjusted such that transmissions within the network are not received by at least one node in a neighboring second network.

16. The method of claim 1, wherein the power spectral density for the first group is further adjusted based on available a priori information about the network.

17. The method of claim 16, wherein the a priori information includes one or more of a nature of a link between two nodes in the network, signal to noise ratios (SNR) of various carrier frequencies between the nodes in the network, modulation schemes to be used for each carrier frequency, a code rate and a guard interval to be used by the transmitter, and limitations of hardware used in the network.

18. The method of claim 1, wherein the power spectral density for the first group is further adjusted based on feedback information received from at least the first receiver, the feedback information indicating a need to either increase or decrease transmit power.

19. A system for communicating among nodes in a network, the system comprising:

a transmitter, configured to;

determine a first frequency band and at least a second frequency band to be used for communicating data packets, wherein a maximum allowable power spectral density in the first frequency band is greater than a maximum allowable power spectral density in the second frequency band;

adjust power spectral density for a first group of frequencies in the first frequency band such that the adjusted power spectral density of the first group does not exceed the maximum allowable power spectral density of the first frequency band and a quantization noise introduced by the transmitter is less than a threshold value for a signal transmitted in the second frequency band; and

modulate at least a portion of a data packet transmitted to at least a first receiver in accordance with the adjusted power spectral density.

20. A method for communicating among nodes in a network, the method comprising:

determining, by a transmitter, a data rate to be used for communicating data packets with at least a first receiver in the network, wherein the data rate is chosen from a set of predetermined data rates;

adjusting power spectral density for a group of frequencies such that the adjusted power spectral density of the group does not exceed the maximum allowable power spectral density for the group; and

modulating at least a portion of a data packet transmitted by the transmitter to at least a first receiver in accordance with the adjusted power spectral density.

21. The method of claim 20, wherein the data packet transmitted by the transmitter includes a payload and overhead information.

22. The method of claim 21, wherein the power spectral density for the group of frequencies is adjusted such that at least a second receiver in the network is able to receive the overhead information.

23. The method of claim 21, wherein the power spectral density for the group of frequencies is further adjusted such that transmissions within the network are not received by at least one node in a neighboring second network.

24. A system for communicating among nodes in a network, the system comprising:

a transmitter, configured to;

determine a data rate to be used for communicating data packets with at least a first receiver in the network, wherein the data rate is chosen from a set of predetermined data rates;

adjust power spectral density for a group of frequencies such that the adjusted power spectral density of the group does not exceed the maximum allowable power spectral density for the group; and

modulate at least a portion of a data packet transmitted to at least a first receiver in accordance with the adjusted power spectral density.