Methods of power overload control in communication systems

• US 20050243752A1
• Filed: 04/30/2004
• Published: 11/03/2005
• Est. Priority Date: 04/30/2004
• Status: Active Grant

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Alcatel-Lucent USA, Inc. (Nokia Corporation)
• Inventors: Mueckenheim, Jens, Brueck, Stefan, Charriere, Patrick
• Granted Patent: US 7,620,004 B2
• Time in Patent Office: Days
• US Class Current: 370/317
• CPC Class Codes: H04W 52/12 Outer and inner loops
• CPC Class Codes: H04W 52/34 TPC management, i.e. sharing limited amount of power among users or channels or data types, e.g. cell loading
• CPC Class Codes: H04W 52/343 taking into account loading or congestion level

Abstract

Methods of providing power overload control in a communication system having a least one base station serving one or more users of at least one cell are described which may avoid an overload condition in the system. In one aspect, a target signal-to-interference ratio (SIR_target) may be controlled for inner loop power control implemented by the base station, so as to maintain the loading of the communication system below an overload condition. In another aspect, a target block error rate (BLER_target) may be controlled for outer loop power control implemented by the base station, so as to maintain the loading of communication system below an overload condition.

Claims

1. A method of performing power overload control in a communication system, comprising:

estimating a loading of one or more users of a given cell in the system;

comparing the estimated load to a threshold;

, determining an adjustment to a scaling factor based on the comparison; and

adjusting a target signal-to-interference ratio (SIR_target) to control a power overload condition in the system.

2. The method of claim 1, wherein a power overload condition in the system is detected based on the comparison.

3. The method of claim 1, wherein

comparing includes evaluating the estimated load against an overload threshold, and

determining includes reducing the scaling factor by a given amount, if the load estimate is equal to or exceeds the overload threshold.

4. The method of claim 3, wherein determining further includes incrementing the scaling factor by a given amount, if the load estimate is less than the overload threshold.

5. The method of claim 1, wherein the scaling factor is incremented or reduced based on the comparison between a set minimum bound and a set maximum bound.

6. The method of claim 1, further comprising:

filtering the scaling factor based on a filtering coefficient to account for fluctuations in estimated load.

7. The method of claim 6, wherein adjusting includes adjusting SIR_target for inner loop power control as implemented by a base station serving the cell based on the filtered scaling factor and a current SIR_target threshold set by outer loop power control that is implemented by the base station.

8. The method of claim 1, wherein the adjusted SIR_target of all users of the cell or at least a group of users of the cell, for controlling the power overload condition is applicable to controlling an overload condition at one of the cell and network level.

9. A method of providing power overload control in a communication system having a least one base station serving one or more users of at least one cell, comprising controlling a target signal-to-interference ratio (SIR_target) for inner loop power control implemented by the base station so as to maintain the loading of the communication system below an overload condition.

10. The method of claim 9, wherein controlling further includes adjusting SIR_target based on estimated loading of the cell so as to control power at which users transmit information to the base station.

11. The method of claim 10, wherein said controlling is implemented at the base station in addition to existing call admission control and congestion control functionalities to prevent the communication system from reaching an overload condition.

12. A method of performing power overload control in a communication system, comprising:

estimating a loading of one or more users of a given cell in the system;

dividing the estimated load into one or more load areas, each load area associated with a given target block error rate (BLER_target);

providing an adjustment to BLER_target based on a given evaluated load area to control transmit power of users in the cell so as to prevent a power overload condition in the system.

13. The method of claim 12, wherein dividing includes dividing the estimated load into a first load area with an associated first BLER_target value and a second load area with an associated second BLER_target value.

14. The method of claim 13, wherein

the first load area represents an area of relatively high loading and the second load area represents an area of relatively low loading, and

the first BLER_target value is greater than the second BLER_target value.

15. The method of claim 13, wherein

the first load area represents an area of relatively low loading and the second load area represents an area of relatively high loading, and

the first BLER_target value is less than the second BLER_target value.

16. The method of claim 12, wherein providing includes providing an adjusted BLER_target based on the given evaluated load area to outer loop power control implemented by a base station serving users of the at least one cell, the outer loop power control controlling quality of a link between the base station and cell so as to avoid a power overload condition.

17. A method of providing power overload control in a communication system having a least one base station serving one or more users of at least one cell, comprising controlling a target block error rate (BLER_target) for outer loop power control implemented by the base station so as to maintain the loading of the communication system below an overload condition.

18. The method of claim 17, wherein controlling further includes adjusting BLER_target based on estimated loading of the cell so as to control power at which users transmit information to the base station.

19. The method of claim 17, wherein said controlling is implemented at the base station in addition to existing call admission control and congestion control functionalities to prevent the communication system from reaching an overload condition.