Subband Reference Signals for Cross-Link Interference Measurement
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Solution Overview
Problem
Wireless communications systems face challenges with cross-link interference (CLI) in subband full duplex (SBFD) scenarios, particularly between neighboring network entities such as gNBs, which affect communication reliability and throughput.
Innovation Solution
Implementing subband-based CLI-RS resource configurations that allow gNBs to measure and mitigate CLI by transmitting on uplink subbands reserved for reception and measuring on downlink subbands reserved for transmission, enabling co-channel CLI measurement and channel assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If subband full duplex is implemented to improve spectrum efficiency, then productivity increases, but cross-link interference between neighboring network entities worsens
Solution Approach 1:
The frequency spectrum is divided into multiple subbands, allowing different subbands to be allocated for different transmission directions (downlink or uplink) within the same time slot. This segmentation enables full duplex operation in some subbands while avoiding interference in others, thus improving spectrum efficiency while controlling cross-link interference.
Solution Approach 2:
Different subbands are configured with different transmission directions based on local interference conditions and traffic demands. Neighboring network entities can be configured with different subband directions to mitigate cross-link interference while maintaining high productivity in less interfered subbands.
2Reliability
If CLI measurement is performed in SBFD symbols to improve interference mitigation, then reliability improves, but measurement complexity increases
Solution Approach 1:
The same reference signal resources are used for both channel measurement and CLI measurement. The network entity can measure both the desired signal channel and interference from neighboring entities using the same RS configuration, eliminating the need for separate measurement resources and reducing overall system complexity while improving reliability.
Solution Approach 2:
Reference signals act as intermediaries that enable the network entity to indirectly measure both channel characteristics and interference levels. By transmitting reference signals in configured subbands, the system enables measurement of both desired signal and interference without requiring direct interference measurement mechanisms.
3Measurement precision
If reference signals are transmitted in uplink subbands for CLI measurement, then measurement precision improves, but transmission resources are consumed
Solution Approach 1:
Reference signals are transmitted only in specific subbands where CLI measurement is needed, rather than across the entire frequency spectrum. This partial transmission approach provides sufficient measurement precision for CLI mitigation while minimizing the consumption of transmission resources and power.
Data Source
AI summary
Certain aspects of the present disclosure provide method for wireless communications at a first network entity, generally including obtaining a configuration indicating subband-based reference signal (RS) resources, measuring, within at least one downlink subband or at least one uplink subband in at least one subband full duplex (SBFD) symbol, at least one of a cross link interference (CLI) caused by a second network entity or a channel between the first and second network entities, wherein the measurement is based on at least one RS of the RS resources indicated in the configuration, and performing one or more actions after measuring the CLI or the channel.