Parallel HARQ-ACK Feedback Transmission in Carrier Aggregation
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Solution Overview
Problem
Current wireless communication systems face limitations in reliability and efficiency due to the inability of user equipment (UE) to transmit feedback messages to both primary and secondary cells in carrier aggregation scenarios, leading to reduced communication reliability and increased latency.
Innovation Solution
The described techniques enable duplicate hybrid automatic-repeat/request acknowledgment (HARQ-ACK) feedback transmission in parallel on both primary and secondary cells, allowing for simultaneous transmission of uplink control channel messages with different payloads or formats, which can be optionally activated or deactivated based on network parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If duplicate HARQ-ACK feedback transmission is enabled in parallel on both PCell and SCell, then communication reliability is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent implements dynamic switching between single-cell and dual-cell feedback transmission modes. The network can activate or deactivate duplicate feedback transmission on SCell based on traffic conditions, channel quality, and power headroom reports from the UE. This dynamic configuration allows the system to adapt between reliability enhancement and complexity reduction, resolving the contradiction by making the system flexible rather than fixed.
Solution Approach 2:
The patent changes the operational parameters of feedback transmission by introducing configurable duplication factors and selective activation mechanisms. The network can adjust whether duplicate feedback is transmitted based on parameters such as traffic type (e.g., URLLC vs. eMBB), channel conditions, and UE power status. This parameter-based control allows optimization of reliability versus complexity trade-offs for different operational scenarios.
2Loss of time
If duplicate HARQ-ACK feedback transmission is enabled in parallel on both PCell and SCell, then latency is reduced, but use of energy increases
Solution Approach 1:
The system dynamically adjusts feedback transmission timing and duplication based on traffic urgency. For time-sensitive traffic like URLLC, duplicate feedback is activated to reduce latency through parallel transmission. For less time-critical traffic, single-cell transmission suffices, conserving energy. The network monitors power headroom reports and adjusts duplication accordingly, enabling latency reduction when needed while managing energy consumption.
Solution Approach 2:
The patent applies partial duplication only when necessary rather than always transmitting duplicate feedback. The network selectively enables duplicate feedback transmission on SCell based on traffic requirements, channel conditions, and power availability. This partial action approach reduces energy consumption compared to continuous duplication while still achieving latency reduction for critical traffic through selective parallel transmission.
3Productivity
If simultaneous transmission of PUCCH messages with different payloads and formats is enabled, then communication efficiency is improved, but device complexity increases
Solution Approach 1:
The patent segments feedback transmission into separate PUCCH resources on different cells, allowing different payloads and formats to be transmitted simultaneously without interference. The PCell and SCell each have independently configured PUCCH resources, enabling parallel transmission of different feedback types (e.g., HARQ-ACK on PCell, CSI on SCell). This segmentation resolves the contradiction by isolating different feedback streams while maintaining overall system efficiency.
Solution Approach 2:
The patent creates a universal feedback transmission framework where both PCell and SCell can handle multiple feedback types (HARQ-ACK, CSI, SR) with different formats. The system is designed to accommodate diverse payload requirements on different cells simultaneously, making the feedback mechanism multi-functional and adaptable to various communication needs while maintaining manageable complexity through standardized procedures.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive a downlink transmission via at least one of a primary cell, a secondary cell, or a combination thereof. The UE may identify a feedback indication for the downlink transmission. The UE may transmit a first feedback message that includes the feedback indication via the primary cell. The UE may transmit a second feedback message that also includes the feedback indication via the secondary cell.