CU-Controlled DU Sounding Signals for 5G TDD Cross-Link Interference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current technologies face challenges in efficiently measuring and coordinating Base Station (BS) to Base Station cross-link interference (CLI) in 5G New Radio (NR) systems with time division duplexing (TDD), particularly due to higher output transmit power and antenna gains at gNBs.
Innovation Solution
The proposed solution involves enhancing the F1 interface to facilitate BS-to-BS CLI measurements by configuring distributed units (DUs) with sounding signaling transmission objects and cross-link measurement objects, allowing for coordinated DU-to-DU measurements and reporting back to the centralized unit (CU).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dynamic TDD operation is implemented allowing BS nodes to freely change transmission directions, then network adaptability and traffic handling capability are improved, but cross-link interference between base stations increases
Solution Approach 1:
The system performs preliminary CLI measurements and assessments before configuring dynamic TDD operations. The CU configures DUs to measure CLI on sounding signals from neighboring DUs, and based on these pre-acquired measurements, the system determines safe transmission configurations that avoid harmful interference while maintaining adaptability.
Solution Approach 2:
The system establishes continuous feedback loops where DUs report CLI measurements back to the CU, which then adjusts TDD configurations accordingly. The CU receives CLI measurement results from DUs and uses this feedback to dynamically optimize transmission directions and power levels, resolving the interference issue while preserving adaptability.
2Productivity
If BS transmit power and antenna gains are increased to improve coverage and capacity, then network performance is improved, but BS-to-BS cross-link interference becomes more critical
Solution Approach 1:
The system dynamically adjusts transmission parameters including power levels and antenna beam directions based on real-time CLI measurements. When high power transmission is needed for capacity, the system simultaneously modifies other parameters (beamforming directions, time resource allocation) to steer interference away from neighboring BSs, maintaining productivity while controlling harmful effects.
3Reliability
If CLI measurement procedures are implemented between DUs, then interference coordination capability is improved, but system complexity and coordination overhead increase
Solution Approach 1:
The CU acts as an intermediary that centralizes the coordination of CLI measurements. Instead of complex peer-to-peer coordination between multiple DUs, the CU configures measurement objects, collects results from all DUs, and makes centralized decisions. This reduces measurement coordination complexity while maintaining reliable interference coordination through the mediating CU.
Data Source
AI summary
The present invention introduces a method and a system for base station cross-channel measurement control and configuration. A centralized unit (CU) (301, 601) of a base station configures (304, 305) at least two distributed units (DU) (302, 303, 602, 604) with DU sounding signaling transmission objects and DU cross-link measurement objects. The first DU (302) transmits (306) a sounding signal through an air interface (308) which the second DU (303) measures (307). The second DU (303) reports (309) this to the CU (301). Then the second DU (303) transmits (311) a sounding signal through an air interface (312) which the first DU (302) measures (310). The first DU (302) reports (313) this to the CU (301). Beam-forming can be applied as well. Also neighboring operators can be found by inter-frequency measurements of the sounding signals or Synchronization Signals. The CU (301, 601) can control the DUs (302, 303, 602, 604) with appropriate TDD switching patterns based on the found cross-link interference levels.