Handover Target Selection via Channel Coherence and CSI Rates
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Solution Overview
Problem
Existing handover techniques in wireless communication systems fail to account for varying channel conditions of user equipment (UE) and do not efficiently manage CSI reporting rates, leading to inaccurate resource allocation and excessive uplink signaling overhead.
Innovation Solution
A method and system that select a handover target based on the UE's channel coherence and CSI reporting rates of candidate target base stations, allowing for commensurate CSI reporting frequencies that match the UE's channel condition changes, thereby optimizing network resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the UE reports channel conditions frequently to ensure accurate resource allocation, then the accuracy of channel condition information is improved, but the uplink signaling overhead increases excessively
Solution Approach 1:
The patent changes the parameter of CSI reporting frequency dynamically based on channel coherence. When channel conditions are stable (high coherence), the reporting frequency is reduced. When channel conditions change rapidly (low coherence), the reporting frequency is increased. This resolves the contradiction by adapting the reporting parameter to actual channel conditions rather than using a fixed high frequency.
Solution Approach 2:
The system transitions from static frequent CSI reporting to dynamic adaptive reporting based on channel coherence measurement. The UE measures channel coherence and adjusts reporting behavior accordingly, making the system flexible and responsive to actual channel conditions while minimizing unnecessary signaling overhead.
2Strength
If the UE hands over to the coverage area with the strongest reference signal, then the coverage strength is improved, but the channel condition changes may not be accurately tracked due to mismatched CSI reporting rates
Solution Approach 1:
Before completing the handover to a target coverage area, the UE performs a preliminary measurement of channel coherence in that target area. Based on this preliminary assessment, the UE determines whether the target area's CSI reporting rate is appropriate for its channel conditions. This preliminary action prevents handover to areas that would result in poor channel condition tracking.
Solution Approach 2:
The system implements feedback by measuring channel coherence and using this information to adjust handover decisions and CSI reporting rates. The UE provides feedback about channel coherence measurements, and the network uses this feedback to optimize both handover targeting and reporting rate configuration, ensuring accurate channel condition tracking in the selected coverage area.
Data Source
AI summary
According to aspects of the present disclosure, a method and system are provided for managing handover. In accordance with the disclosure, while a source base station serves a UE, the source base station receives from the UE a measurement report providing an indication of a plurality of candidate target base stations having coverage detected by the UE. Responsive to the report, a CSI reporting rate is determined for each of the candidate targets on a per base station basis. A channel coherence is also determined for the UE. The communication system then selects a target base station from the plurality of candidate targets based on (i) the determined channel coherence and (ii) the determined CSI reporting rates, and the source base station then triggers handover of the UE from the source base station to the selected target base station.