Methods of power overload control in communication systems
View Patent ↗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.
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 based on a signal-to-interference ratio;
comparing the estimated load to a threshold;
determining an adjustment to a scaling factor based on the comparison;
filtering the scaling factor; and
adjusting a target signal-to-interference ratio (SIR target ) to control a power overload condition in the system based on the filtered scaling factor.
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 , wherein the filtering step further comprises:
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.