Configured Grant Selection for Uplink Retransmissions
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G NR, face challenges with unsent PUSCH data retransmissions due to downlink symbol collisions, leading to performance losses and inconsistent guidelines for selecting transmission resources, which affects data coverage and reliability.
Innovation Solution
The implementation of a method and apparatus for user equipment (UE) and base stations to determine and select a configured grant for transmitting unsent PUSCH data retransmissions, based on thresholds and spatial relations, to ensure reliable data retransmission without dynamic scheduling, thereby addressing the issue of dropped PUSCH repetitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If downlink symbols are scheduled during uplink transmission time, then downlink communication capacity is improved, but PUSCH data retransmissions are dropped leading to uplink reliability degradation
Solution Approach 1:
The base station pre-configures multiple configured grants with different temporal and spatial characteristics before uplink transmissions occur. These grants are prepared in advance to handle potential PUSCH retransmission scenarios, allowing the UE to immediately select an appropriate grant when a retransmission is needed without waiting for dynamic scheduling
Solution Approach 2:
The system changes the parameters of configured grants including time offsets, frequency resources, and spatial relations to create diverse transmission options. By varying these parameters across multiple grants, the system ensures that at least one grant will be available when downlink-uplink symbol conflicts occur, maintaining uplink reliability while enabling flexible downlink scheduling
2Adaptability or versatility
If dynamic scheduling is used for PUSCH retransmissions, then transmission flexibility is improved, but transmission delays increase due to scheduling request and grant waiting
Solution Approach 1:
Multiple configured grants are pre-configured with different time offsets and spatial relations before transmission needs arise. When a PUSCH retransmission is needed, the UE can immediately select from these pre-prepared grants without needing to request scheduling dynamically, thereby eliminating the scheduling request and grant waiting delays while maintaining transmission flexibility through multiple options
Solution Approach 2:
The system dynamically selects among multiple pre-configured grants based on current channel conditions and transmission requirements. This dynamic selection from static pre-configured options provides flexibility comparable to dynamic scheduling while avoiding the time penalty of scheduling requests and grant acquisition
3Reliability
If multiple configured grants are used for PUSCH retransmission, then retransmission reliability is improved, but device complexity increases due to selection procedure
Solution Approach 1:
Each configured grant is distinguished by specific parameters such as time offset values, frequency resource allocations, and spatial relation configurations. The UE selects among multiple grants by comparing these parameters against current transmission needs and channel conditions, using straightforward parameter matching rather than complex algorithms to determine the most appropriate grant for retransmission
Data Source
AI summary
The present disclosure relates to methods and devices for wireless communication including an apparatus, e.g., a user equipment (UE) and/or base station. In one aspect, the apparatus may determine a selection procedure for uplink transmissions, the selection procedure including information for uplink data retransmissions. The apparatus may also transmit, to a UE, the selection procedure for uplink transmissions. The apparatus may also monitor for at least one uplink transmission from the UE based on the selection procedure for uplink transmissions. In another aspect, the apparatus may receive, from a base station, a selection procedure for uplink transmissions, the selection procedure including information for uplink data retransmissions. The apparatus may also implement the selection procedure for uplink transmissions. The apparatus may also transmit, to the base station, at least one uplink transmission based on the selection procedure for uplink transmissions.