Handover Control Using Target Base Station Preference Levels
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Solution Overview
Problem
Existing handover techniques in wireless communication systems, particularly in LTE-Advanced with carrier aggregation, face challenges in selecting an optimal target cell due to insufficient measurement information, especially in scenarios with high-speed user equipment and interference from multiple cells.
Innovation Solution
A method and device for controlling handover that involve receiving preference levels from the target base station for candidate cells, adjusting handover parameters based on these preferences, and coordinating with self-optimization network functions to prioritize cells, thereby optimizing target cell selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measurement information from neighboring eNB and UE is used for target cell selection, then handover decision can be made, but the measurement information is not sufficient for making an optimal target cell selection among multiple neighboring cells
Solution Approach 1:
The invention segments the target cell selection process into two parts: (1) basic measurement information collection from UE and neighboring eNB, and (2) preference level information provision from target eNB. This segmentation allows each entity to contribute its specific capabilities, with the target eNB providing preference levels that compensate for the insufficiency of basic measurement information in selecting among multiple neighboring cells.
Solution Approach 2:
The target eNB acts as an intermediary that provides preference level information to the source eNB. This preference level information serves as a mediator that bridges the gap between basic measurement information and optimal target cell selection, enabling the source eNB to make better handover decisions by considering the target eNB's perspective on cell suitability.
2Ease of operation
If handover parameter adjustment is made without considering target base station preferences, then handover can be executed, but the selected target cell may not be optimal
Solution Approach 1:
The target eNB performs preliminary action by providing preference level information to the source eNB before the handover execution. This allows the source eNB to adjust handover parameters in advance based on the target eNB's preferences, ensuring that the handover is directed to an optimal target cell rather than just any available cell.
Solution Approach 2:
The target eNB provides feedback in the form of preference level information to the source eNB. This feedback mechanism allows the target eNB to influence the handover decision-making process, enabling the source eNB to select a target cell that aligns with the target eNB's preferences regarding load, interference, and cell capabilities.
3Productivity
If multiple cells are controlled by target base station with carrier aggregation, then data rate can be improved, but interference coordination and load distribution become more complex
Solution Approach 1:
The invention applies local quality by providing different preference levels for different cells controlled by the target eNB. Each cell can have its own preference level reflecting local conditions such as load, interference, and capabilities. This allows the source eNB to select the most appropriate cell for handover based on specific local conditions rather than treating all cells uniformly.
Solution Approach 2:
The invention changes parameters by introducing preference levels as a new parameter that quantifies the suitability of each cell for handover. This parameter transformation converts complex qualitative assessments of cell conditions (load, interference, capabilities) into a usable quantitative metric that can directly guide handover parameter adjustment and target cell selection.
4Reliability
If handover parameter adjustment coordinates with self-optimization network functions, then mobility robustness and load balance are improved, but system complexity increases
Solution Approach 1:
The preference level mechanism serves multiple functions simultaneously: it provides target cell selection guidance, enables interference coordination, supports load distribution, and works with self-optimization network functions. This universal approach consolidates multiple handover optimization goals into a single framework, reducing the need for separate mechanisms for each function.
Data Source
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AI summary
A method, a device and a base station for controlling handover are described. In order to control handover from a source base station to a target base station in a wireless communication system, where the target base station controls multiple cells, preference levels for candidate cells to be used as a target cell for the handover are received from the target base station; and handover parameters for the candidate cells are adjusted by taking the preference levels into account when selecting the target cell for the handover. With the present invention, at least benefits of target eNB inter-cell interference coordination, load optimization among cells, tendency to dedicated-configured cell etc. may be achieved.