HARQ-ACK Codebook Mapping for Variable-Duration Carrier Aggregation
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Solution Overview
Problem
The existing carrier aggregation operation in LTE/LTE-A communication systems needs improvement to support aggregation of different carrier types and enhance data rates beyond 4G, particularly in supporting multiplexing of physical downlink control channel transmissions and hybrid automatic repeat request acknowledgement across cells with varying durations.
Innovation Solution
The solution involves enabling carrier aggregation with different bandwidth reception capabilities, designing a hybrid automatic repeat request acknowledgement codebook, and defining transmission power control processes for overlapping transmissions on cells with varying durations, along with prioritization mechanisms for power allocation to support multiple traffic services with different reliability requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation is implemented with different carrier types and durations, then data rates and system capability are improved, but device complexity and power control difficulty increase
Solution Approach 1:
The patent segments the carrier aggregation system into different duration groups (first duration for some cells, second duration for other cells). This segmentation allows the UE to handle different carrier types independently with appropriate timing configurations, managing complexity through structured division while enabling higher aggregate data rates across the aggregated carriers.
Solution Approach 2:
The patent implements dynamic transmission power control that adapts to different transmission durations. The UE dynamically adjusts power allocation based on which cells are transmitting with first duration versus second duration, and based on the overlap patterns. This dynamic adaptation enables the system to maintain optimal performance across varied carrier configurations without requiring static, overly complex power control mechanisms.
2Adaptability or versatility
If simultaneous transmissions are supported on cells with different durations, then system versatility is improved, but power allocation complexity increases
Solution Approach 1:
The patent establishes preliminary power control rules and prioritization mechanisms before transmissions occur. The UE is configured with advance knowledge of which cells use first duration and which use second duration, and the power allocation priorities are predetermined based on service types and QoS requirements. This preliminary configuration simplifies the actual transmission process by eliminating the need for complex real-time decisions during overlapping transmissions.
Solution Approach 2:
The patent changes the parameter of transmission duration to have two distinct values (first duration and second duration) across different cells. This parameter differentiation enables the system to support diverse service requirements (e.g., eMBB vs. uRLLC) while maintaining manageable power control through clear distinction between duration groups, rather than requiring continuous or highly granular duration adjustments.
3Reliability
If HARQ-ACK codebook is designed for variable durations, then reliability is improved, but processing complexity increases
Solution Approach 1:
The HARQ-ACK codebook is segmented into portions corresponding to different duration groups. The UE generates separate HARQ-ACK feedback for cells using first duration and cells using second duration, organizing the codebook structure to reflect this segmentation. This approach ensures reliable acknowledgment of all transmissions while maintaining processing simplicity through structured organization rather than monolithic handling of all cells uniformly.
Solution Approach 2:
The patent introduces an intermediary mapping relationship between PDSCH receptions and HARQ-ACK feedback that accounts for different durations. This intermediary layer translates the variable duration transmissions into a standardized feedback structure, ensuring that no acknowledgment is missed while keeping the UE processing logic manageable through clear mapping rules rather than complex real-time analysis.
4Reliability
If power allocation prioritization is defined for multiple services, then service reliability is improved, but control mechanism complexity increases
Solution Approach 1:
The patent applies local quality differentiation by assigning different power allocation priorities to different service types and QoS categories. Instead of a uniform power allocation mechanism, the system tailors power priorities locally to each service's requirements (e.g., higher priority for uRLLC traffic, standard priority for eMBB). This localized quality approach ensures each service receives appropriate power protection while keeping the overall control mechanism simpler than a fully customized per-service approach.
Data Source
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AI summary
A method of a user equipment (UE) for constructing a hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook. The method comprises receiving physical downlink control channels (PDCCHs) that convey respective downlink control information (DCI) formats, wherein each DCI format includes a counter field and a slot offset field, receiving physical downlink data channels (PDSCHs) that convey data transport blocks, detecting the DCI formats configuring the received PDSCHs, determining locations for HARQ-ACK bits in a HARQ-ACK codebook based on a value of the slot offset field and a value of the counter field in each detected DCI format, determining a time unit for transmission of the HARQ-ACK codebook based on a value of the slot offset field in each detected DCI format, and transmitting the HARQ-ACK codebook.