Joint HARQ Codebook for Sidelink Feedback Forwarding
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Solution Overview
Problem
Current wireless communication technologies, such as LTE and NR, face challenges in efficiently managing downlink and sidelink feedback transmissions, particularly in scheduling resources and retransmissions, which affects communication reliability and efficiency.
Innovation Solution
The method involves a user equipment (UE) receiving downlink control information to schedule resources for sidelink shared channel transmissions, transmitting data, receiving acknowledgment feedback, and selecting codebook entries for both downlink and sidelink transmissions to be sent in the same physical uplink control channel (PUCCH) slot, allowing for coordinated feedback and potential retransmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If separate feedback transmissions are used for downlink and sidelink, then feedback reliability is maintained, but communication efficiency deteriorates due to increased latency and resource overhead
Solution Approach 1:
The patent combines downlink HARQ-ACK feedback and sidelink HARQ-ACK feedback into a single joint codebook structure. The UE constructs one unified codebook that includes acknowledgment information for both downlink transmissions from the base station and sidelink transmissions to other UEs, transmitting this combined feedback in a single PUCCH resource instead of separate transmissions.
Solution Approach 2:
The joint codebook serves multiple functions simultaneously: it provides acknowledgment for downlink data, acknowledgment for sidelink data, and enables the network to determine both downlink retransmission needs and sidelink retransmission needs from a single feedback message. This multi-functional approach consolidates what would otherwise require separate feedback mechanisms.
2Productivity
If joint feedback is transmitted in the same PUCCH slot, then resource allocation efficiency is improved, but feedback reliability deteriorates due to potential resource conflicts
Solution Approach 1:
The joint codebook is segmented into distinct portions: downlink HARQ-ACK information bits and sidelink HARQ-ACK information bits. The patent specifies different formatting rules for each type of feedback within the unified codebook structure, allowing the network to properly interpret each segment according to its origin and requirements.
Solution Approach 2:
The joint codebook acts as an intermediary structure that reconciles the different feedback requirements of downlink and sidelink transmissions. It provides a standardized format that accommodates both types of acknowledgments while enabling the network to differentiate and process them appropriately through defined interpretation rules.
3Measurement precision
If separate codebooks are used for downlink and sidelink feedback, then feedback accuracy is maintained, but device complexity increases due to dual codebook management
Solution Approach 1:
The patent introduces dynamic determination of codebook types (first type or second type) based on the specific combination of downlink and sidelink transmissions. The UE dynamically selects the appropriate joint codebook formatting approach based on the current transmission scenario, allowing flexibility in how the feedback is structured while maintaining accuracy through defined rules for each dynamic case.
Data Source
AI summary
Certain aspects of the present disclosure provide techniques for multiplexing HARQ feedback in a same slot for downlink and sidelink transmissions. An example method generally includes receiving, from a network entity, a downlink control information (DCI) that schedules resources for at least one physical sidelink shared channel (PSSCH) transmission from the first UE to a second UE, transmitting data to the second UE via the at least one PSSCH transmission using the scheduled resources, receiving, from the second UE, acknowledgment feedback for the at least one PSSCH transmission, selecting at least one codebook entry for providing feedback for at least one downlink transmission from the network entity to the first UE and the acknowledgment feedback for the at least one PSSCH transmission in a same physical uplink control channel (PUCCH) slot, and transmitting the at least one codebook entry to the network entity via at least one PUCCH transmission.