PDCCH Blind Decoding Limits for Low-Power Reduced-Capability UEs
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Solution Overview
Problem
In 5G new radio (NR) access technology communication systems, user equipment (UE) consumes significant power due to monitoring the physical downlink control channel (PDCCH) for downlink control information (DCI), which includes uplink scheduling grant and downlink scheduling allocation information.
Innovation Solution
Implementing reduced PDCCH detection attempt parameters, such as limiting the total DCI monitoring number, specific DCI monitoring number, non-overlapped channel control elements (CCEs), aggregation level number, and total PDCCH detection attempt number, to reduce power consumption and complexity in UE devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE monitors the PDCCH for DCI to obtain scheduling information, then the scheduling information is received accurately, but the power consumption increases
Solution Approach 1:
The patent applies partial action by limiting the UE to monitor only a subset of PDCCH candidates rather than all possible candidates. Specifically, the UE monitors at most 8 non-overlapped CCEs per slot for Type 0 CSS and 4 for Type 1 CSS, which is fewer than the full monitoring capability. This partial monitoring reduces power consumption while still capturing essential scheduling information for reduced capability devices.
Solution Approach 2:
The patent implements local quality by differentiating monitoring requirements between different CSS types (Type 0 and Type 1) and different device capabilities. Reduced capability devices are assigned specific monitoring parameters tailored to their needs, such as limited aggregation levels and restricted CCE monitoring, rather than applying uniform monitoring rules to all UEs. This localized optimization reduces power consumption for specific device types while maintaining reliability.
2Reliability
If the UE monitors more PDCCH candidates with higher aggregation levels, then the detection reliability improves, but the device complexity increases
Solution Approach 1:
The patent segments the PDCCH monitoring task by dividing CSS into distinct types (Type 0 for uplink scheduling, Type 1 for downlink scheduling) and further segmenting the monitoring burden by limiting the number of CCEs to monitor in each type. Reduced capability devices monitor only essential candidates in each segment rather than all candidates across all aggregation levels, reducing complexity while maintaining detection reliability for critical scheduling information.
Solution Approach 2:
The patent applies partial action by having reduced capability devices monitor only a subset of PDCCH candidates at reduced aggregation levels (e.g., limiting to aggregation level 2 or 4 instead of up to 16). This partial monitoring approach reduces the computational complexity and processing burden on reduced capability devices while still providing sufficient detection reliability for their specific use cases.
3Loss of information
If the UE monitors all aggregation levels and CCEs, then the scheduling information is captured completely, but the power consumption and processing load increase
Solution Approach 1:
The patent implements local quality by tailoring the monitoring configuration to the specific needs of reduced capability devices. Instead of requiring all UEs to monitor all aggregation levels and CCEs, the patent assigns reduced monitoring parameters specifically to reduced capability devices, including limited CCE monitoring (8 for Type 0, 4 for Type 1) and restricted aggregation levels. This localized approach ensures scheduling information completeness for reduced capability devices while reducing their power consumption and processing load.
Solution Approach 2:
The patent applies dynamics by making the monitoring configuration adaptive to device capabilities through differentiated CSS type definitions. The system dynamically adjusts which CSS types a reduced capability device monitors and how many CCEs to monitor within each type, based on the device's reduced capability status. This dynamic configuration ensures information completeness while optimizing power consumption for each device type.
Data Source
AI summary
This document generally relates to wireless communication schemes that include setting or determining PDCCH detection attempt parameters by setting or determining at least one of: a total DCI monitoring number, a specific DCI monitoring number, a non-overlapped CCE number, an aggregation level number, or a total PDCCH detection attempt number. The PDCCH detection attempt parameters may correspond to a reduced maximum number of PDCCH candidates per slot per serving cell, and/or a maximum number of non-overlapped CCEs per slot per serving cell. User devices, including reduced capability UEs, may utilize the PDCCH detection attempt parameters when detecting or blindly decoding PDCCH candidates.