POWER MANAGEMENT IN A CELLULAR SYSTEM

• US 20150038190A1
• Filed: 10/10/2012
• Published: 02/05/2015
• Est. Priority Date: 11/28/2011
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Ubiquisys Limited (Cisco Systems, Inc.)
• Inventors: Carter, Alan James Auchmuty, Kwan, Raymond
• Granted Patent: US 9,544,857 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• 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

1-47. -47. (canceled)

48. 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, 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 powers allocated to respective sub-bands by said base station,

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

determining whether a factor relating to a happiness of users in the cell exceeds a threshold value; and

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

49. A method as claimed in claim 48, wherein the happiness factor is defined based on an average happiness of users in a cell served by the base station.

50. A method as claimed in claim 49, wherein the happiness factor is defined based on a weighted average happiness of users in a cell served by the base station.

51. A method as claimed in claim 49, wherein the happiness factor is defined based on a standard deviation of the happiness of users in a cell served by the base station.

52. A method as claimed in claim 49, wherein the happiness factor is defined based on a percentile of the happiness of users in a cell served by the base station.

53. A method as claimed in claim 52, wherein the happiness factor is defined based on a ratio of each user'"'"'s average bit rate to the user'"'"'s required bit rate.

54. A method as claimed in claim 52, wherein the happiness factor is defined based on a scaling factor that introduces a degree of conservativeness.

55. A method as claimed in claim 54, comprising adjusting the scaling factor based on a current transmit power in the cell.

56. A method as claimed in claim 55, comprising adjusting the scaling factor based on a measured interference in the cell.

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

transmitting information from a first base station to 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 first base station to changes in powers allocated to respective sub-bands by said other base station,

wherein said step of transmitting information comprises transmitting information relating to the Relative Narrowband Transmit Power of said cell in each of said sub-bands.

58. A method as claimed in claim 57, wherein the sensitivity of a utility function is determined based on the path gains between the base station and the corresponding transmitters at the other base stations.

59. A method as claimed in claim 58, wherein the sensitivity of a utility function is determined based on the powers at which the other base stations are transmitting in said sub-bands.

60. 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 the sensitivity of a utility function in said cell served by said base station to changes in powers allocated to respective sub-bands by said other base station.

61. A method as claimed in claim 60, comprising:

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

62. A method as claimed in claim 61, comprising:

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

63. A method as claimed in claim 62, comprising forming average measurements from measurements taken by a plurality of mobile devices, for each of said sub-bands.

64. A method as claimed in claim 63, comprising, for each average measurement that is below a threshold value, setting the sensitivity of the utility function for the corresponding sub-band to a negative value.

65. A method as claimed in claim 64, wherein said measurements are Channel quality indicator measurements.

66. A method of estimating a spectral efficiency of a sub-band in a base station on a cellular communications network, the method comprising:

approximating the spectral efficiency by a power function of a Channel Quality Indicator reported by a mobile device making measurements on that sub-band;

approximating the Channel Quality Indicator by a linear function of a Signal to Interference and Noise Ratio measured by the mobile device, wherein the Signal to Interference and Noise Ratio is measured in decibels.

67. A method as claimed in claim 66, wherein the linear function includes a constant offset term.