PDCCH Search Space Narrowing for Relay UE Power Reduction
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Solution Overview
Problem
In device-to-device (D2D) communication, the relay UE faces increased complexity in decoding physical downlink control channels (PDCCH) due to the need to detect multiple DCI messages from the network, leading to higher power consumption and reduced standby time for low-capability devices.
Innovation Solution
A method to reduce PDCCH decoding complexity by determining a search space based on a first radio network temporary identifier and detecting a target PDCCH using a second radio network temporary identifier, thereby narrowing down the candidate channels and reducing the number of detections required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the relay UE performs multiple detections on PDCCH for each remote UE using their respective radio network temporary identifiers, then the network can successfully schedule multiple remote UEs, but the complexity of PDCCH decoding by the relay UE is greatly increased
Solution Approach 1:
The patent segments the PDCCH decoding process by introducing a two-stage detection mechanism: first detecting PDCCH scrambled with the first RNTI (group-level), then detecting PDCCH scrambled with the second RNTI (individual-level). This segmentation allows the relay UE to efficiently handle multiple remote UEs while reducing overall decoding complexity through hierarchical filtering.
Solution Approach 2:
The patent applies preliminary action by performing initial PDCCH detection using the first RNTI before proceeding to individual RNTI-based detection. This preliminary detection step filters and identifies relevant control information in advance, reducing the burden of subsequent detailed decoding operations for each remote UE.
2Reliability
If the relay UE performs multiple detections on PDCCH to receive DCI for scheduling multiple remote UEs, then complete scheduling information can be obtained, but power consumption increases and standby time is reduced
Solution Approach 1:
The patent segments the power-consuming detection operations into two phases: an initial group-level detection phase using the first RNTI, followed by individual-level detection phases using the second RNTI. This segmentation optimizes power usage by performing coarse-grained filtering first, reducing the number of expensive fine-grained decoding operations required.
Solution Approach 2:
The patent performs preliminary PDCCH detection using the first RNTI to identify and filter relevant control information before committing to full decoding operations. This preliminary action reduces unnecessary power consumption by avoiding complete decoding of irrelevant PDCCH messages that do not pertain to the relay UE or its remote UEs.
Data Source
AI summary
This application provides a physical downlink control channel processing method and a related device. In the method, a search space may be determined based on a first radio network temporary identifier, where the search space is a set of M candidate physical downlink control channels; and a target physical downlink control channel is detected from the search space based on a second radio network temporary identifier, where the first radio network temporary identifier is a radio network temporary identifier of a first device or a second device, the second radio network temporary identifier is the radio network temporary identifier of the second device, first downlink control information carried by the target physical downlink control channel is information that is scrambled by using the second radio network temporary identifier and that is used to schedule the second device, and the second device communicates with a network by using the first device.