HARQ-ACK Codebook Multiplexing for Overlapping Uplink Channels
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Solution Overview
Problem
The increasing demand for enhanced mobile broadband (eMBB) communication, massive machine type communication (mMTC), and ultra-reliable and low-latency communication (URLLC) in next-generation wireless systems poses challenges in managing HARQ-ACK feedback efficiently, particularly in scenarios involving high data throughput and diverse user equipment (UE) requirements.
Innovation Solution
The implementation of techniques for handling HARQ-ACK codebook configurations, deferral mechanisms, and UCI multiplexing to optimize HARQ-ACK transmission and reception, especially in scenarios with overlapping channels, is proposed to enhance reliability and reduce latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ-ACK feedback is transmitted for every downlink data transmission to ensure reliability, then the reliability of data reception is improved, but the uplink control channel overhead and transmission latency increase
Solution Approach 1:
The patent applies preliminary action by configuring HARQ-ACK codebook parameters and deferral mechanisms in advance through RRC signaling. The UE is pre-configured with codebookType, maxCodeRate, and other parameters that determine how HARQ-ACK feedback will be constructed and transmitted, allowing the system to prepare feedback strategies before actual data transmissions occur, thereby reducing real-time processing latency while maintaining reliability
Solution Approach 2:
The patent implements dynamics by introducing deferral mechanisms that allow HARQ-ACK feedback transmission to be dynamically postponed when uplink resources are unavailable or when channel conditions are poor. The UE can defer HARQ-ACK transmission to later uplink opportunities, and the system dynamically adjusts the timing and resources used for feedback based on current network conditions, balancing reliability requirements with latency constraints
2Loss of information
If HARQ-ACK codebook size is increased to accommodate more downlink transmissions, then the completeness of feedback information is improved, but the uplink control channel resource requirements and transmission complexity increase
Solution Approach 1:
The patent applies parameter changes by introducing configurable codebook parameters such as codebookType (semi-static vs. dynamic), maxCodeRate, and feedback timing indicators that allow the system to adapt the HARQ-ACK codebook size and structure based on traffic conditions. These parameters enable the codebook to scale appropriately - expanding when needed to maintain feedback completeness while contracting to reduce complexity during lighter loads
Solution Approach 2:
The patent implements segmentation by dividing the HARQ-ACK codebook into multiple parts or groups, particularly when dealing with carrier aggregation scenarios. Instead of transmitting a single large codebook containing all HARQ-ACK information across multiple carriers, the feedback is segmented into separate codebooks or groups that can be transmitted independently, reducing the complexity of managing and processing a monolithic large-scale codebook while maintaining complete feedback coverage
3Quantity of substance
If multiple uplink channels are used simultaneously to transmit different types of control information, then the capacity for control signaling is improved, but the resource allocation complexity and potential conflicts between channels increase
Solution Approach 1:
The patent applies universality by enabling the PUCCH and PUSCH channels to serve multiple functions. The PUCCH can carry both HARQ-ACK feedback and scheduling requests, while the PUSCH can carry both uplink data and uplink control information (UCI). This multi-functionality allows the system to efficiently utilize available uplink resources without requiring separate dedicated channels for each control function, thereby increasing control signaling capacity while managing resource allocation complexity through unified channel structures
Solution Approach 2:
The patent implements merging by combining HARQ-ACK feedback transmission with other uplink transmissions. When uplink data is being transmitted on PUSCH, HARQ-ACK feedback is multiplexed onto the same channel rather than requiring a separate PUCCH transmission. This merging of control and data transmissions on the same channel increases the effective capacity for control signaling while reducing the number of separate channel management tasks, thereby lowering resource allocation complexity
Data Source
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AI summary
A UE is configured to enable multiplexing of uplink transmissions of different priorities. When a first uplink channel for transmission of first HARQ-ACK information overlaps with a second uplink channel for transmission of second HARQ-ACK information, the UE may drop transmission of the first HARQ-ACK information and transmit the second HARQ-ACK information, based on the second HARQ-ACK information being a HARQ process-based HARQ-ACK codebook.