Dynamic Handover Threshold Adjustment for Wireless Load Balancing
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Solution Overview
Problem
In wireless networks with multiple frequency bands, forced handovers can lead to repeated handovers between access nodes or frequency bands, counteracting load balancing efforts due to inconsistent signal level measurements.
Innovation Solution
Dynamic handover threshold adjustment based on cell load measurements, where thresholds are adjusted to balance load between frequency bands by altering the effective cell radius, encouraging handovers from congested to non-congested bands, and incrementally returning to default values as load balances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If forced handovers are used to perform load balancing operations, then load balancing is improved, but repeated handovers occur that counteract the load balancing efforts
Solution Approach 1:
The patent implements dynamic handover threshold adjustment where the threshold parameter is not fixed but adapts based on current cell load conditions. The network entity continuously monitors cell load and adjusts the handover threshold accordingly, making the handover decision criteria flexible and responsive to changing network conditions, thereby preventing repeated handovers while maintaining load balancing effectiveness
Solution Approach 2:
The system establishes a feedback mechanism where handover performance and cell load conditions are continuously monitored and used to adjust future handover decisions. The network entity receives feedback about handover outcomes and load conditions, then modifies the handover threshold parameter to optimize subsequent handover behavior, creating a closed-loop control system that prevents counterproductive repeated handovers
2Productivity
If handover threshold parameter is adjusted to encourage handovers from congested bands, then load balancing is improved, but signal level measurement inconsistencies cause repeated handovers
Solution Approach 1:
The patent applies preliminary action by proactively adjusting the handover threshold parameter before repeated handovers can occur. The network entity monitors cell load conditions and preemptively modifies the threshold to create a buffer that prevents handover oscillations, rather than reacting after problems occur. This anticipatory adjustment reduces handover decision frequency and prevents time-wasting repeated handovers
Solution Approach 2:
The system dynamically changes the handover threshold parameter based on cell load conditions. Instead of using fixed signal level thresholds, the patent modifies the threshold parameter adaptively, changing it from a static value to a dynamic one that responds to network conditions. This parameter change approach optimizes handover timing and prevents repeated handovers caused by inconsistent measurements
Data Source
AI summary
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.