CLI Reporting During 5G Handover to Avoid Cross-Link Interference
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Solution Overview
Problem
Handover procedures in 5G NR networks are prone to failure due to Cross-Link Interference (CLI) between neighboring cells with different transmission directions on overlapping time-frequency resources, leading to UL/DL degradation and potential handover delays.
Innovation Solution
Wireless devices report CLI measurements during handover by storing interference data and transmitting it to the network, allowing the network to mitigate CLI and make informed handover decisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CLI measurements are not reported during handover, then the handover procedure remains simple and fast, but handover failures occur due to undetected Cross-Link Interference
Solution Approach 1:
The system performs CLI measurements on SRS resources from neighboring cells before the handover is executed. The source gNB configures the UE to store CLI measurement results in advance, so that when handover is initiated, the measurement data is already available for immediate use in making informed handover decisions, avoiding the need to perform measurements during the critical handover execution phase.
Solution Approach 2:
The UE reports CLI measurement results (such as SRS-RSRP values) back to the source gNB, which then uses this feedback information to assess the interference situation and make informed decisions about whether to proceed with handover, delay it, or select alternative target cells. This feedback loop enables the system to adapt handover decisions based on actual interference conditions.
2Reliability
If CLI measurements are performed and reported, then handover decisions can be optimized to avoid interference, but the measurement and reporting process adds time and complexity
Solution Approach 1:
CLI measurements are configured and performed in advance during the handover preparation phase, with results stored in the UE before the actual handover execution. This allows the measurement and reporting process to occur without delaying the critical handover execution timeline, as the interference assessment data is already available when the handover decision needs to be made.
Solution Approach 2:
The system performs CLI measurements selectively on specific SRS resources from neighboring cells that are relevant to the handover decision, rather than performing comprehensive measurements on all possible resources. This targeted approach reduces measurement overhead and processing time while still providing sufficient information for making informed handover decisions.
3Adaptability or versatility
If the network node has full knowledge of CLI conditions, then it can make optimal handover decisions to avoid interference, but obtaining complete CLI information increases system complexity
Solution Approach 1:
The system extracts only the essential CLI information needed for handover decisions, specifically the SRS-RSRP measurements from neighboring cells on configured SRS resources. Rather than collecting and processing all possible interference-related data, the system focuses on the most critical metrics that directly impact handover success, simplifying the overall measurement and processing complexity.
Solution Approach 2:
The CLI measurement mechanism using SRS resources serves multiple functions: it provides interference assessment for handover decisions, enables identification of interfering neighboring cells, and supplies data for optimizing handover timing. This multi-functional approach consolidates multiple measurement requirements into a single unified measurement framework, reducing overall system complexity.
Data Source
AI summary
Systems and methods of the present disclosure are directed to a method performed by a wireless device for Cross-Link Interference (CLI) reporting. The method includes storing a CLI measurement. The method includes receiving a request to report the CLI measurement from a network node involved in a handover procedure for the wireless device. The method includes transmitting a CLI measurement report to the network node based on the CLI measurement.