Dynamic handover threshold adjustment for load balancing
Access nodes in a network are configured to periodically measure cell loads and exchange cell load measurements with neighbors. At each access node, cell loads are compared with load thresholds, and with neighboring loads, to determine whether or not load balancing operations should be triggered. Load balancing operations include reducing or increasing an effective coverage area of one or both of the congested cell and the neighbor cell by adjusting a handover threshold parameter, such as a threshold signal level. Adjusting thresholds at a congested cell triggers more handovers from the congested cell to the non-congested cell. Similarly, adjusting thresholds at a non-congested cell prevents handovers from the non-congested cell to the congested cell.
1. A system for load balancing, the system comprising:
a processing node; and
a processor coupled to the processing node, the processor for configuring the processing node to execute operations comprising:
measuring a first cell load of a first frequency band;
upon determining that the first cell load exceeds a load threshold, determining a difference between the first cell load and a second cell load of a second frequency band;
in response to determining that the difference between the first cell load and the second cell load exceeds a difference threshold, adjusting a handover threshold parameter comprising a signal strength of the first frequency band, wherein adjusting the handover threshold parameter further comprises:
increasing a first threshold signal level for the first frequency band; and
decreasing a second threshold signal level for the second frequency band;
transmitting the adjusted handover threshold parameter to a wireless device using the first frequency band; and
upon determining that the first cell load does not exceed the load threshold, incrementally returning the adjusted handover parameter to a default value by a defined value per each loop of a periodic timer,
wherein the adjusted handover threshold parameter causes the wireless device to request a handover to the second frequency band.
2. The system of claim 1 , wherein measuring the first cell load is triggered upon expiration of the periodic timer.
3. The system of claim 2 , wherein the operations further comprise resetting the periodic timer subsequent to adjusting the handover threshold parameter.
4. The system of claim 3 , wherein:
the first frequency band is deployed by a first access node,
the second frequency band is deployed by a second access node, and
the operations further comprise receiving, upon expiration of the periodic timer, the second cell load via a direct connection from the second access node.
5. The system of claim 4 , wherein the operations further comprise transmitting, upon expiration of the periodic timer, the first cell load to the second access node via the direct connection.
6. The system of claim 4 , wherein the operations further comprise measuring a third cell load of the first access node, and determining that the third cell load does not exceed the load threshold.