HARQ Feedback PUCCH Symbol Reduction for Carrier Aggregation
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Solution Overview
Problem
In 5G NR systems, carrier aggregation across different frequency ranges can result in an excessive number of hybrid automatic repeat request (HARQ) processes, leading to increased latency and reduced performance due to differing numerologies used for component carriers in FR1 and FR2, exceeding the supported number of HARQ processes.
Innovation Solution
Implementing a shorter physical uplink control channel (PUCCH) with a reduced number of symbols, such as 6 or 7 symbols, to transmit HARQ feedback, rather than the conventional 13 or 14 symbols, to maintain the number of HARQ processes below the supported limit, allowing devices to aggregate component carriers across multiple frequency ranges effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If carrier aggregation is implemented across different frequency ranges with different numerologies, then spectral efficiency and service capability are improved, but the number of HARQ processes increases excessively leading to increased latency and reduced performance
Solution Approach 1:
The patent segments the PUCCH transmission into two distinct types: type 1 for HARQ-ACK feedback and type 2 for other uplink control information. This segmentation allows optimized resource allocation where type 1 PUCCH uses a shorter duration (1-2 symbols) specifically for HARQ feedback, reducing the time required for HARQ process completion while maintaining separate handling for other control information
Solution Approach 2:
The patent introduces dynamic PUCCH resource allocation where the network can dynamically indicate which PUCCH resource (type 1 or type 2) should be used for HARQ-ACK feedback based on current transmission conditions. This dynamic adjustment allows the system to adaptively optimize HARQ latency by selecting the shorter type 1 PUCCH when appropriate, while maintaining flexibility for other control information transmission
2Adaptability or versatility
If carrier aggregation is implemented across different frequency ranges with different numerologies, then service capability is improved, but the number of HARQ processes exceeds the supported limit
Solution Approach 1:
The patent segments PUCCH resources into type 1 (shorter duration) and type 2 (longer duration), allowing the system to use type 1 for HARQ-ACK feedback transmission. This segmentation enables more efficient HARQ process management by reducing the time each HARQ process occupies resources, thereby supporting more concurrent HARQ processes within the same device complexity constraints
Solution Approach 2:
The patent changes the PUCCH transmission parameter (duration in symbols) by introducing type 1 PUCCH with 1-2 symbols compared to the conventional type 2 with longer duration. This parameter change directly reduces the time required for HARQ feedback transmission, allowing the system to handle more HARQ processes simultaneously without exceeding device processing capabilities
Data Source
AI summary
Techniques and apparatus for transmitting control information to maintain hybrid automatic repeat request (HARQ) processes for multiple carriers in different frequency ranges, such as frequency range 1 (FR1) and frequency range 2 (FR2), in carrier aggregation scenarios are described. A first numerology of a first component carrier (CC) in FR1 and a second numerology of a second CC in FR2 are determined. A HARQ configuration that includes an indication of a set of physical uplink control channel (PUCCH) resources is determined. A number of symbols of the set of PUCCH resources is based on the first numerology and the second numerology. The HARQ configuration is transmitted to a user equipment (UE). HARQ feedback is transmitted on the first CC for data received on the second CC, using the set of PUCCH resources of the HARQ configuration.