Handover Threshold Control for Overlay Cells With Traffic Congestion
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Solution Overview
Problem
In an overlay cell configuration where a large zone cell and terrestrial cells share the same frequency, existing handover techniques lead to communication traffic congestion on the large zone cell due to premature handovers to the large zone cell when reception levels from terrestrial cells drop, preventing handovers to terrestrial cells with different frequencies.
Innovation Solution
A communication system that dynamically adjusts the parameter for determining different-frequency-measurement start based on reception-quality levels, allowing handovers to be directed to terrestrial cells with different frequencies to avoid traffic congestion on the large zone cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conventional handover technique is applied in the overlay cell configuration, then UEs can connect to the large zone cell when reception level from terrestrial cell drops below threshold, but communication traffic concentrates on the large zone cell causing capacity exhaustion and quality deterioration
Solution Approach 1:
The invention changes the handover determination parameter from a fixed reception level threshold to a dynamic threshold that considers the large zone cell's communication capacity and current traffic load. The base station adjusts the threshold value based on real-time capacity status, preventing handovers when the large zone cell is near capacity exhaustion, thus avoiding traffic concentration and maintaining service quality for UEs that truly need the large zone cell connection.
2Ease of operation
If UEs hand over to the large zone cell when reception level is high, then connectivity is improved for UEs in out-of-service areas, but communication quality deteriorates due to capacity limitations of the large zone cell
Solution Approach 1:
The invention introduces dynamic adjustment of the handover threshold based on the large zone cell's real-time communication capacity status. Instead of using a static threshold, the base station continuously monitors capacity utilization and adapts the threshold accordingly, making the handover decision process dynamic and responsive to current system conditions, thus balancing connectivity availability with communication quality.
Solution Approach 2:
The invention implements a feedback mechanism where the base station monitors the communication capacity and traffic load of the large zone cell, and uses this information to adjust the handover threshold. The capacity status information feeds back to the handover control logic, enabling the system to prevent handovers when capacity is insufficient, thereby maintaining communication quality while still providing connectivity when appropriate.
Data Source
AI summary
In an overlay cell configuration in which a second cell, a second cell of a same frequency and a third cell of a different frequency are overlapped at least partially with each other, a concentration of communication traffic on the first cell is prevented. It is obtained of a measurement result (MR) including a measurement result of a reception-quality level measured at the same frequency reported by a mobile station connected to a second base station of the same frequency and a cell identifier of a receiving target cell, it is decided whether to change a value of a parameter for determination used for determining a different-frequency-measurement start that is set in the second base station of the same frequency, based on the measured value of the reception-quality level of the signal from the first cell included in the measurement report (MR), when the measurement report (MR) includes the cell identifier of the first cell, and the value of the parameter for determination is changed based on a result of the deciding.