PUCCH Resource Selection for Multicast Feedback Identification
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Solution Overview
Problem
In wireless communications, base stations face inefficiencies in retransmitting multicast messages due to the inability to identify which user equipment (UEs) failed to receive the message, leading to suboptimal transmission parameters and increased retransmissions, especially in UE-shared negative acknowledgment (NACK) feedback scenarios.
Innovation Solution
Implementing a method where UEs select Physical Uplink Control Channel (PUCCH) resources based on downlink control information and group conditions, allowing the base station to identify failing UE groups and adapt transmission parameters for retransmissions, thereby improving multicast message reception success rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multiple UEs share the same PUCCH resources for NACK feedback transmissions, then system overhead is reduced, but the base station cannot determine which UE transmitted the feedback
Solution Approach 1:
The PUCCH resource set is segmented into multiple individual PUCCH resources (first PUCCH resource, second PUCCH resource, etc.), each assigned to specific UE groups. This segmentation allows the base station to identify which UE group transmitted feedback by determining which specific PUCCH resource was used, while still maintaining resource sharing within each group to reduce overall overhead.
Solution Approach 2:
Different PUCCH resources are assigned to different UE groups based on their specific conditions (e.g., geographic location, channel conditions). This local differentiation enables the base station to identify feedback sources at the group level while maintaining the efficiency of resource sharing, as each group has its own designated resources rather than all UEs competing for the same resources.
2Reliability
If the base station retransmits multicast messages to all UEs when feedback is received, then all potential receivers are covered, but transmission efficiency decreases due to unnecessary retransmissions
Solution Approach 1:
The base station performs targeted retransmissions by identifying specific UE groups that failed to receive the multicast message based on which PUCCH resource was used for feedback. Instead of retransmitting to all UEs, the base station sends retransmissions only to the identified groups, improving efficiency while maintaining reliability for those who actually need the message.
Solution Approach 2:
The system implements a feedback mechanism where UEs transmit NACK feedback on specific PUCCH resources when they fail to receive multicast messages. The base station uses this feedback information to identify which UE groups need retransmission, enabling efficient targeted retransmissions rather than blanket retransmissions to all UEs.
3Device complexity
If the base station uses a single set of transmission parameters for all multicast transmissions, then implementation is simple, but transmission performance is suboptimal for different UE groups
Solution Approach 1:
The base station determines different sets of transmission parameters for different UE groups based on their specific conditions (e.g., channel quality, geographic location). This allows optimization of transmission parameters for each group's specific needs while maintaining manageable complexity through group-based management rather than individual UE customization.
Solution Approach 2:
Transmission parameters are segmented into different sets corresponding to different UE groups. The base station maintains multiple parameter sets and selects the appropriate set based on which UE group requires retransmission, enabling optimized performance for each group while keeping the system manageable through organized parameter segmentation.
Data Source
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AI summary
This disclosure provides methods, devices, and systems for resource selection supporting user equipment (UE)-shared multicast feedback. In some systems, a UE and a base station may support multicast communications. The base station may configure a set of physical uplink control channel (PUCCH) resources that the UE may use for multicast feedback messages. The base station may transmit an indication of the set of PUCCH resources to the UE, and the UE may determine to use a PUCCH resource of the set of PUCCH resources based on one or more indications from the base station. The UE may fail to receive a multicast message from the base station and may transmit a UE-shared negative acknowledgment (NACK) feedback message. The base station may re-transmit the multicast message according to a set of transmission parameters that is based on which PUCCH resource was used by one or more UEs for multicast NACK feedback.