UE Slot Preference for TDD Alignment in Unlicensed Spectrum
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Solution Overview
Problem
In-device coexistence problems arise when user equipment (UE) communicates using multiple unlicensed spectrum bands concurrently, leading to self-interference due to the close proximity of bands like 5 GHz and 6 GHz, especially with the uncertainty of channel access and timing misalignment in Listen-Before-Talk mechanisms.
Innovation Solution
The UE receives TDD configuration information from a master node and a secondary node, compares the structures to identify preferred slots that avoid simultaneous transmission and reception, and communicates this information to the secondary node to align its TDD structure with the master node's, ensuring that downlink and uplink slots match, thereby preventing self-interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a UE communicates using multiple unlicensed spectrum bands concurrently, then communication capacity and throughput are improved, but self-interference occurs due to close proximity of bands and timing misalignment
Solution Approach 1:
The UE performs preliminary identification of preferred slots by comparing TDD structures of multiple bands before actual communication. This advance planning allows the UE to select slots that avoid simultaneous transmission and reception, preventing self-interference before it occurs while maintaining multi-band communication capacity
Solution Approach 2:
The invention changes the timing parameter selection by identifying preferred slots with different timing characteristics. By selecting specific slots where TDD structures align favorably, the UE transforms the timing parameters to avoid self-interference while maintaining high communication capacity across multiple bands
2Reliability
If Listen-Before-Talk mechanism is used for channel access in unlicensed bands, then channel access fairness is improved, but timing uncertainty and misalignment increase leading to self-interference
Solution Approach 1:
The UE provides feedback to the network about its preferred slots based on LBT outcomes and TDD structure comparisons. This feedback mechanism allows the network to adjust scheduling decisions, resolving the timing uncertainty introduced by LBT while maintaining channel access fairness through coordinated slot selection
Solution Approach 2:
The invention introduces dynamic slot selection that adapts to LBT outcomes. The UE can dynamically identify and switch to preferred slots based on real-time channel access conditions, transforming the static timing uncertainty of LBT into a dynamic advantage where the system adapts to maintain both fairness and timing alignment
3Adaptability or versatility
If TDD structures of master node and secondary node are not aligned, then flexibility in resource allocation is improved, but in-device coexistence problems occur due to simultaneous transmission and reception
Solution Approach 1:
The invention segments the TDD structure into individual slot units that can be independently evaluated and selected. By comparing TDD structures at the slot level and identifying preferred slots, the system maintains overall resource allocation flexibility while ensuring that specific slots are selected to avoid simultaneous transmission and reception conflicts
Data Source
AI summary
A user equipment (UE) receives time division duplexing (TDD) configuration information from a master node (MN), with which the UE is communicating using a first band of unlicensed spectrum and receives TDD configuration information from a secondary node (SN), which is being added to support communications with the UE using a second band of unlicensed spectrum. The UE compares the two TDD structures, identifying DL and UL slots in SN TDD structure which correspond to DL and UL time intervals in the MN TDD structure, designating at least some of those SN slots as preferred DL slots and preferred UL slots. The UE communicates information indicating its preferred DL slots and preferred UL slots in an assistance message to the SN. The SN using UE slot preference information, selects DL and UL slots to be used for UE communications and implements a TDD structure, which avoids an IDC problem.