DCI Format 2_0 Enhancements for NR-U Resource Determination
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Solution Overview
Problem
New radio (NR) systems operating in unlicensed spectrum face challenges in resource determination, including power consumption and efficient channel occupancy, due to limitations in Downlink Control Information (DCI) format 2_0 and frequency domain resource allocation, which affect the monitoring of Physical Downlink Control Channel (PDCCH) and Channel Occupancy Time (COT) structure.
Innovation Solution
Enhancements to DCI format 2_0 include adding a bitmap for available LBT bandwidths, indicating an 'unknown' state for LBT sub-bands, and repurposing the frequency domain resource allocation field to improve resource allocation granularity and flexibility, allowing for more efficient resource management and power saving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DCI format 2_0 is used for resource allocation in NR-U systems, then channel occupancy time (COT) structure can be indicated, but power consumption at UE side increases due to continuous monitoring requirements
Solution Approach 1:
The patent applies partial action by introducing a partial monitoring indication that allows UE to monitor only a subset of PDCCH candidates or specific time resources instead of continuous full monitoring. This partial monitoring approach maintains reliable COT indication reception while reducing power consumption by activating monitoring only when necessary based on the indication state.
Solution Approach 2:
The patent implements periodic action through configured monitoring occasions where UE monitors PDCCH for COT indications at specific periodic intervals rather than continuously. The partial monitoring indication works together with periodic monitoring configurations to further reduce power consumption by allowing UE to enter sleep modes between monitoring occasions while still receiving essential channel occupancy information.
2Productivity
If frequency domain resource allocation field is used with standard granularity, then resource allocation can be provided, but resource allocation precision is insufficient for efficient LBT bandwidth utilization
Solution Approach 1:
The patent applies parameter changes by modifying the interpretation of the frequency domain resource allocation field based on the partial monitoring indication state. When partial monitoring is indicated, the resource allocation field is reinterpreted to provide finer granularity suitable for LBT sub-band allocation. This dynamic parameter interpretation enables precise resource allocation matching the actual monitoring and channel access needs without requiring additional signaling overhead.
3Loss of information
If standard PDCCH monitoring is implemented, then control information can be received, but monitoring complexity increases for multiple LBT sub-bands
Solution Approach 1:
The patent applies segmentation by dividing the PDCCH monitoring task into separate handling for different LBT sub-bands based on the partial monitoring indication. Instead of uniformly monitoring all PDCCH candidates across all sub-bands, the indication enables UE to segment monitoring efforts to only those sub-bands and time resources where control information is actually present or expected, thereby reducing monitoring complexity while ensuring no control information is missed.
Data Source
AI summary
A method for a user equipment (UE) may detect Downlink Control Information (DCI) format 2_0. The DCI format 2_0 may comprise an available resource block (RB) set indicator information element (IE) that indicates a state of Listen Before Talk (LBT) sub-bands, and a Channel Occupancy Time (COT) duration indicator IE. The available RB set indicator is set to an unknown state when there is insufficient time to fully prepare the DCI Format 2_0.