Power management in a cellular system

• US 9,544,857 B2
• Filed: 10/10/2012
• Issued: 01/10/2017
• Est. Priority Date: 11/28/2011
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Carter, Alan James Auchmuty, Kwan, Raymond
• Primary Examiner(s): Safaipour, Bobbak
• Application Number:
  US14/360,898
• Publication Number:
  US 20150038190A1
• Time in Patent Office: 1,553 Days
• US Class Current: 1/1
• CPC Class Codes: H04B 17/309 Measuring or estimating channel quality parameters
• CPC Class Codes: H04B 17/382 for resource allocation, admission control or handover
• CPC Class Codes: H04W 52/143 Downlink power control
• CPC Class Codes: H04W 52/241 taking into account channel quality metrics, e.g. SIR, SNR, CIR, Eb/lo
• CPC Class Codes: H04W 52/242 taking into account path loss
• CPC Class Codes: H04W 52/244 Interferences in heterogeneous networks, e.g. among macro and femto or pico cells or other sector / system interference [OSI]
• CPC Class Codes: H04W 52/245 taking into account received signal strength
• CPC Class Codes: H04W 52/26 using transmission rate or quality of service QoS [Quality of Service]
• CPC Class Codes: H04W 52/267 taking into account the information rate
• CPC Class Codes: H04W 52/343 taking into account loading or congestion level
• CPC Class Codes: H04W 52/346 distributing total power among users or channels
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A method of controlling the respective transmit powers allocated by a base station of a cellular communications network to each of a plurality of sub-bands is provided. Information from at least one other base station of the network is received, the information comprising information about a sensitivity of a utility function in a cell served by the other base station to changes in powers allocated to respective sub-bands by the base station. A sub-band is identified in which it would be relatively advantageous to increase a transmit power. It is determined whether a factor relating to a happiness of users in the cell exceeds a threshold value. The transmit power in the identified sub-band is increased only if the happiness factor is less than the threshold value.

Claims

1. A method of controlling respective transmit powers allocated by a base station of a cellular communications network to each of a plurality of sub-bands, the method comprising:

receiving information from at least one other base station of said network, said information comprising information about a sensitivity of a utility function in a cell served by said other base station to changes in downlink transmission powers allocated to respective sub-bands by said base station,

identifying a sub-band in which it would be relatively advantageous to increase a downlink transmit power;

determining whether a factor relating to a service expectation of users in the cell exceeds a threshold value, wherein the factor is defined by each of a respective user'"'"'s average bit rate divided by the respective user'"'"'s required bit rate; and

increasing the downlink transmit power in the identified sub-band only if the factor is less than the threshold value.

2. A method as claimed in claim 1, wherein the factor is defined based on an average service expectation of users in the cell served by the base station.

3. A method as claimed in claim 2, wherein the factor is defined based on a weighted average service expectation of users in the cell served by the base station.

4. A method as claimed in claim 2, wherein the factor is defined based on a standard deviation of the service expectation of users in the cell served by the base station.

5. A method as claimed in claim 2, wherein the factor is defined based on a percentile of the service expectation of users in the cell served by the base station.

6. A method as claimed in claim 5, wherein the factor is defined based on a scaling factor that introduces a degree of conservativeness.

7. A method as claimed in claim 6, comprising adjusting the scaling factor based on a current transmit power in the cell.

8. A method as claimed in claim 7, comprising adjusting the scaling factor based on a measured interference in the cell.

9. A method of determining an effect of interference in a cell served by a base station of a cellular communications network, said interference being caused by transmissions from a base station in at least one neighbouring cell of said network, the method comprising:

obtaining measurements from mobile devices connected to the base station; and

using the measurements to derive a measure of sensitivity of a utility function in said cell served by said base station to changes in downlink transmission powers allocated to respective sub-bands by said base station in said at least one neighbouring cell of said network.

10. A method as claimed in claim 9, comprising:

obtaining measurements from said mobile devices in a plurality of sub-bands.

11. A method as claimed in claim 10, comprising:

repeatedly obtaining each of said measurements, and forming a time averaged value for each of said measurements.

12. A method as claimed in claim 11, comprising forming average measurements from measurements taken by a plurality of mobile devices, for each of said sub-bands.

13. A method as claimed in claim 12, comprising, for each average measurement that is below a threshold value, setting the sensitivity of the utility function for each of a corresponding sub-band to a negative value.

14. A method as claimed in claim 13, wherein said measurements are Channel quality indicator measurements.