TDD Uplink Downlink Configuration Alignment for RRC Reestablishment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inconsistencies between uplink (UL) and downlink (DL) configurations in time-division duplexing (TDD) systems lead to communication failures and abnormal operations, particularly for user equipment (UE) supporting enhanced interference management and traffic adaptation (eIMTA), as UE may misinterpret subframes and fail to receive control information or transmit data correctly.
Innovation Solution
A method for handling UL/DL configurations in TDD systems involves receiving and applying multiple configurations across different modes (idle and connected) and during radio resource control (RRC) reestablishment procedures, ensuring alignment between system information and physical layer signaling to prevent communication failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the UE applies the UL/DL configuration from physical layer signaling (PDCCH/EPDCCH) for rapid traffic adaptation, then the UL/DL configuration can be adjusted quickly according to rapid changes of traffic loads, but the UE cannot receive the PDCCH in subframes that are reconfigured as UL subframes in system information, leading to communication failures
Solution Approach 1:
The UE stores the original UL/DL configuration from system information before applying the dynamically signaled configuration. This preliminary preservation of the original configuration enables the UE to fall back to it when communication failures are detected, ensuring reliability while maintaining adaptability benefits.
Solution Approach 2:
The UE monitors for communication failures (such as inability to receive PDCCH) and uses this feedback to determine when to switch back from the dynamically adapted configuration to the original configuration, creating a closed-loop system that balances adaptability and reliability.
2Productivity
If the UE maintains the UL/DL configuration from physical layer signaling during RRC connection reestablishment, then the configuration can respond to rapid traffic changes, but the UE cannot receive random access responses in subframes misidentified as UL subframes, causing RRC reestablishment failure
Solution Approach 1:
The UE preserves the original UL/DL configuration from system information before RRC connection reestablishment. This preliminary action ensures that when the UE needs to perform random access during reestablishment, it uses the correct subframe identification from the original configuration, preventing access failures while allowing rapid traffic adaptation during normal operation.
3Productivity
If the UL/DL configuration is frequently updated via physical layer signaling to match rapid traffic load changes, then the system can efficiently adapt to traffic demands, but inconsistencies between system information and physical layer signaling cause subframe misinterpretation and communication abnormalities
Solution Approach 1:
The original UL/DL configuration from system information serves as an intermediary reference that the UE maintains alongside the dynamically signaled configuration. This intermediary configuration resolves inconsistencies by providing a stable baseline for subframe identification, allowing frequent updates via physical layer signaling without causing communication failures.
Data Source
AI summary
A method of handling an uplink/downlink (UL/DL) configuration for a communication device includes receiving a first UL/DL configuration in first system information from a first cell in an idle mode; applying the first UL/DL configuration; receiving a second UL/DL configuration on a physical DL control channel from the first cell in a connected mode; applying the second UL/DL configuration; receiving a third UL/DL configuration in second system information from the first cell in the connected mode; and applying the third UL/DL configuration.