Cross-Link Interference Measurement in Subband Full-Duplex Systems
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Solution Overview
Problem
Current wireless communication systems, particularly 5G NR, face challenges in effectively measuring and managing cross-link interference (CLI) in subband full-duplexing (SBFD) slots, which affects the reception quality of User Equipments (UEs) due to concurrent transmissions from adjacent UEs, leading to interference issues that impact network performance.
Innovation Solution
A method where User Equipments (UEs) receive measurement configurations from base stations to measure cross-link interference using specific resources like CSI-IM/ZP CSI-RS, and report the measured CLI to the base station, enabling informed resource scheduling and interference management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If subband full-duplexing (SBFD) slots are used to enable concurrent uplink and downlink transmissions, then spectrum efficiency and network capacity are improved, but cross-link interference (CLI) between adjacent UEs increases, deteriorating reception quality
Solution Approach 1:
The base station performs preliminary CLI measurements by configuring UEs to measure reference signals (CSI-RS or SRS) from adjacent UEs before actual data transmissions. This advance measurement enables the base station to identify potential interference issues and adjust resource allocation, power control, or scheduling decisions proactively, preventing severe CLI from degrading reception quality while maintaining SBFD operation
Solution Approach 2:
The system implements a feedback mechanism where UEs report measured CLI levels (e.g., RSRP of adjacent UE transmissions) to the base station. The base station uses this feedback to dynamically adjust scheduling decisions, power control parameters, or resource allocation for SBFD slots, creating a closed-loop system that continuously optimizes network performance while mitigating CLI effects
2Measurement precision
If measurement resources are allocated for CLI measurement, then interference assessment accuracy is improved, but available resources for data transmission are reduced, lowering overall system throughput
Solution Approach 1:
The system uses multi-functional reference signals that serve both channel estimation purposes and CLI measurement purposes. Specifically, CSI-RS resources configured for channel state information acquisition can simultaneously be used for measuring adjacent UE interference, and SRS resources used for uplink channel sounding can provide CLI measurement data. This eliminates the need for dedicated exclusive CLI measurement resources, maintaining measurement accuracy while preserving data transmission capacity
Solution Approach 2:
The system leverages existing uplink reference signals (SRS) transmitted by UEs for their own channel quality assessment and uses these same signals as the measurement source for CLI assessment at adjacent UEs. The transmitting UE's own SRS transmission inadvertently provides the measurement opportunity for neighboring UEs, and the base station configures measurement resources that align with existing signaling patterns rather than adding separate dedicated measurement channels
Data Source
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AI summary
In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus is a UE. The UE receives, from a base station, a measurement configuration for measuring cross-link interference, CLI, in a subband full-duplexing, SBFD, slot and a reporting configuration for reporting the CLI (1202). The UE performs measurements of the CLI on measurement resources indicated by the measurement configuration (1204). The UE reports an indication of the measured CLI to the base station according to the reporting configuration (1206).