NR TDD Duplex Direction Coordination for Cross-Link Interference
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Solution Overview
Problem
Existing LTE technologies inefficiently utilize radio resources due to static or semi-static TDD, wasting resources when only one traffic direction is present, and dynamic TDD systems face cross-link interference issues.
Innovation Solution
Implementing a centralized adaptive TDD mode switch with a logical central entity for coordinated TDD mode switching among cells, using joint traffic direction scheduling and explicit signaling to manage cross-link interference, and incorporating distributed coordination for efficient resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If static or semi-static TDD is used in LTE, then device complexity is reduced and ease of operation is improved, but resource utilization efficiency deteriorates when only one traffic direction exists
Solution Approach 1:
A coordination entity is introduced as an intermediary component that receives traffic direction indications from multiple cells, determines appropriate TDD configurations, and provides coordination information back to the cells. This mediator resolves the contradiction by centralizing the complex decision-making process, thereby improving resource utilization without significantly increasing the operational complexity for individual cells.
Solution Approach 2:
The system dynamically adjusts TDD configurations based on real-time traffic conditions by monitoring traffic direction indications and adapting the TDD mode (e.g., switching between DL-heavy, UL-heavy, or symmetric configurations). This dynamic adaptation enables the system to optimize resource utilization efficiency in response to varying traffic demands while maintaining manageable complexity through structured coordination procedures.
2Productivity
If dynamic TDD is implemented to maximize resource utilization, then productivity is improved, but cross-link interference between cells increases
Solution Approach 1:
The coordination entity implements a feedback mechanism by receiving traffic direction indications from each cell, analyzing the collective traffic patterns, and determining coordinated TDD configurations that prevent cross-link interference. This closed-loop feedback system enables dynamic TDD operation to maximize resource utilization while actively managing and reducing harmful interference effects between cells.
Solution Approach 2:
The coordination entity acts as a mediator that reconciles the conflicting requirements of dynamic resource allocation and interference management. By centralizing the coordination function, it enables cells to operate dynamically without generating harmful cross-link interference, thus resolving the contradiction between improved productivity and reduced harmful factors.
3Productivity
If centralized adaptive TDD mode switching is used, then resource utilization efficiency is improved, but device complexity increases due to the need for coordination entities and signaling
Solution Approach 1:
The coordination system is segmented into distinct functional components: traffic direction indication reception, TDD configuration determination, and coordination information provision. This segmentation allows the complex centralized adaptive TDD mode switching to be managed through modular, well-defined interfaces, thereby improving resource utilization efficiency while keeping the coordination system complexity manageable through structured functional division.
4Productivity
If TDD configurations are changed frequently to adapt to traffic conditions, then resource utilization efficiency is improved, but system stability deteriorates
Solution Approach 1:
The coordination entity implements periodic evaluation of traffic direction indications and TDD configuration adjustments rather than continuous or arbitrary changes. This periodic action pattern allows the system to adapt to traffic conditions and improve resource utilization efficiency while maintaining stability by avoiding excessive or erratic configuration changes, thereby resolving the contradiction between productivity and stability.
Data Source
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AI summary
A method performed in a system comprising a joint traffic direction scheduler configured to coordinate time-division-duplexing (TDD) transmissions for multiple cells comprises obtaining TDD operation information from each of the cells, determining, based on the obtained TDD operation information, a transmission direction to be used by each of the cells during one or more transmission time intervals (TTIs), and indicating to the cells the determined transmission direction.