Random Access Response Sharing on PDCCH and PDSCH
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Solution Overview
Problem
In current communication protocols, the signaling overheads are high due to separate transmission of random access response (RAR) information for reduced capability UE (REDCAP UE) and common UE on different physical channels, which is not specified and inefficiently uses resources.
Innovation Solution
The method involves carrying the DCI for both REDCAP UE and common UE on the same PDCCH and/or RAR on the same PDSCH, with optional indication using RRC or MAC signaling to ensure correct reception by REDCAP UE, reducing signaling overheads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate PDCCH and PDSCH resources are allocated for REDCAP UE and common UE random access responses, then reception reliability is improved, but signaling overhead increases and resource utilization decreases
Solution Approach 1:
The patent combines the transmission of RAR information for REDCAP UE and common UE onto the same PDCCH and PDSCH resources. The network device multiplexes DCI formats (e.g., using different DCI formats or RAR indexes within the same DCI) to address different UE types simultaneously, thereby reducing signaling overhead and improving resource utilization while maintaining reliable reception through proper resource allocation and identification mechanisms
Solution Approach 2:
The patent makes the PDCCH and PDSCH resources universal by enabling them to serve both REDCAP UE and common UE for random access response transmission. The same physical channels are configured to handle multiple UE types through flexible DCI formatting and RAR indexing, allowing a single resource allocation to fulfill multiple functions and reduce overall signaling requirements
2Reliability
If separate PDCCH and PDSCH resources are allocated for REDCAP UE and common UE random access responses, then reception reliability is improved, but resource utilization decreases
Solution Approach 1:
The patent merges the resource allocation for RAR transmission of different UE types into unified PDCCH and PDSCH resources. By multiplexing DCI formats and RAR indexes within the same physical channels, the system achieves higher resource utilization efficiency while maintaining the ability to reliably deliver RAR information to both REDCAP UE and common UE through proper identification and separation mechanisms
3Measurement precision
If indication signaling is added to specify PDCCH/PDSCH sharing configuration, then reception accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent enables terminal devices to self-determine whether PDCCH and PDSCH resources are shared for RAR transmission by autonomously obtaining configuration parameters (such as bandwidth thresholds) from system information or pre-configuration. This self-service approach eliminates the need for additional dynamic indication signaling, reducing overhead while maintaining accurate reception through the terminal's ability to independently apply the appropriate reception method based on its capabilities and the configured parameters
Data Source
AI summary
A first terminal device determines a first physical random access resource, where the first terminal device is a first-type terminal device; the first terminal device sends a first random access request message on the first physical random access resource; the first terminal device receives first downlink control information DCI, where the first DCI is used to schedule a first random access response RAR. The first terminal device receives the first RAR based on the first DCI; and the first DCI and second downlink control information DCI received by a second terminal device are carried on a same physical downlink control channel PDCCH, and/or the first RAR and a second RAR scheduled by using the second DCI are carried on a same physical downlink shared channel PDSCH, where the second terminal device is a second-type terminal device.