Full Duplex Self-Interference Measurement With Different Subcarrier Spacings
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G NR, face challenges with self-interference issues that limit full duplex capability due to radio frequency leakage and clutter echoes between uplink and downlink beams, affecting latency, spectrum efficiency, and resource utilization.
Innovation Solution
The implementation of a self-interference measurement (SIM) apparatus and method at user equipment (UE) and network entities, which determine and report self-interference between active uplink and downlink beams based on subcarrier spacing, enabling the selection of optimal beam pairs for full duplex communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full duplex communication is implemented at UE, then spectrum efficiency and resource utilization are improved, but self-interference from radio frequency leakage and clutter echoes deteriorates signal quality
Solution Approach 1:
The system performs self-interference measurement (SIM) procedures before establishing full duplex communication, determining suitable UL Tx/DL Rx beam pairs by measuring self-interference levels. This preliminary assessment ensures that beam pairs with acceptable interference characteristics are selected in advance, preventing severe self-interference from degrading signal quality during actual full duplex operation
Solution Approach 2:
The UE measures self-interference on downlink symbols using active UL Tx beams and active DL Rx beams, then reports the measurements to the network entity. The network entity uses this feedback to determine appropriate beam pairs for full duplex communication, creating a closed-loop system that continuously optimizes beam selection based on measured interference conditions
2Measurement precision
If self-interference measurement is performed between UL and DL beams, then beam pair selection for full duplex is improved, but measurement complexity and processing requirements increase
Solution Approach 1:
The self-interference measurement procedure leverages existing downlink reference signals (such as CSI-RS or SS/PBCH blocks) that are already transmitted for other purposes like channel state information acquisition and beam management. By reusing these existing signals for SIM measurements, the system achieves accurate beam pair selection without requiring separate dedicated measurement signals, thereby reducing measurement processing complexity
Solution Approach 2:
The UE performs self-interference measurements using its own transmitted uplink signals as the interference source and its own received downlink signals as the reference. This self-service approach eliminates the need for external interference measurement infrastructure, allowing the UE to autonomously determine suitable beam pairs while reducing overall system complexity
Data Source
AI summary
The present disclosure relates generally to wireless communications, and more particularly, to techniques for self-interference measurement (SIM) at a user equipment (UE). An apparatus for wireless communications may determine downlink (DL) symbols for measuring a self-interference (SI) between an active uplink (UL) transmit (Tx) beam of the UE and an active downlink (DL) receive (Rx) beam of the UE. The active uplink (UL) transmit (Tx) beam may be based on an uplink (UL) subcarrier spacing (SCS), and the active downlink (DL) receive (Rx) beam may be based on a downlink (DL) subcarrier spacing (SCS). The apparatus may perform a self-interference measurement (SIM) between the active uplink (UL) transmit (Tx) beam and the active downlink (DL) receive (Rx) beam. The apparatus may output for transmission, to a network entity, a report of the at least one self-interference measurement (SIM).