Dynamic HARQ-ACK Codebook Sizing for 5G Wireless Systems
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Solution Overview
Problem
The 5G communication system faces challenges in efficiently managing variable HARQ-ACK feedback time, leading to increased overhead and inconsistency in HARQ-ACK feedback mechanisms, particularly in FDD and TDD systems, where the fixed HARQ-ACK feedback time in LTE systems is not flexible enough to accommodate varying service requirements and user equipment capabilities.
Innovation Solution
A method for dynamically determining the HARQ-ACK/NACK codebook size and bit mapping, allowing for flexible HARQ-ACK/NACK timing and resource allocation in the uplink control channel, using control signaling that includes timing indications and dynamic signaling to optimize the HARQ-ACK/NACK feedback process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed HARQ-ACK feedback time is used as in LTE systems, then system simplicity is maintained, but scheduling flexibility and adaptability to varying service requirements are reduced
Solution Approach 1:
The patent implements dynamic HARQ-ACK feedback timing by introducing a variable timing indicator field in downlink control information, allowing the feedback time to be dynamically adjusted based on service requirements and UE capabilities rather than using a fixed timing as in LTE systems
Solution Approach 2:
The patent changes the timing parameter of HARQ-ACK feedback from a fixed value to a variable value that can be indicated through control signaling, enabling adaptation to different service types and UE capabilities while maintaining system operability
2Productivity
If variable HARQ-ACK feedback time is implemented, then scheduling flexibility is improved, but overhead and inconsistency in feedback mechanisms increase
Solution Approach 1:
The patent creates a universal HARQ-ACK codebook structure that can accommodate variable timing requirements through a unified determination method, allowing the same codebook framework to handle both fixed and variable timing scenarios without requiring separate mechanisms for each case
Solution Approach 2:
The patent introduces timing indication fields in downlink control information that provide feedback to the UE about the appropriate timing for HARQ-ACK transmission, enabling the system to dynamically adjust feedback timing while maintaining consistent codebook structure and reducing overhead through standardized signaling
3Adaptability or versatility
If dynamic HARQ-ACK/NACK timing is allowed, then adaptability to service requirements is enhanced, but determination of codebook size and bit mapping becomes more difficult
Solution Approach 1:
The patent determines the HARQ-ACK codebook size in advance based on pre-configured parameters such as the number of downlink carriers, transport blocks per carrier, and codeblock groups per transport block, allowing the UE to prepare the codebook structure before actual feedback transmission without real-time calculation complexity
Solution Approach 2:
The patent segments the HARQ-ACK codebook into structured units based on downlink carriers, transport blocks, and codeblock groups, with each segment having a predetermined bit allocation that simplifies the overall codebook construction and bit mapping process despite variable timing requirements
Data Source
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AI summary
The present disclosure relates to a pre-5th-Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4th-Generation (4G) communication system such as Long Term Evolution (LTE). A method and an apparatus of transmitting a HARQ-ACK/NACK (Hybrid Automatic Repeat Request-Acknowledgment/Negative Acknowledgment) and a downlink transmission method and apparatus are provided. The method of transmitting the HARQ-ACK/NACK includes: receiving, by a user equipment, a PDSCH (Physical Downlink Shared Channel) and a control signaling from a base station in downlink time unit(s); determining, by a user equipment, an uplink time unit in which the HARQ-ACK/NACK corresponding to the received PDSCH is fed back, a size of a HARQ-ACK/NACK codebook for the uplink time unit, and bit positions where the HARQ-ACK/NACKs corresponding to respective downlink time units corresponding to the same uplink time unit are in the HARQ-ACK/NACK codebook, based on the control signaling; generating the HARQ-ACK/NACK codebook, by a user equipment, based on the size of the HARQ-ACK/NACK codebook and the bit positions where the HARQ-ACK/NACKs corresponding to the respective downlink time units corresponding to the same uplink time unit are in the HARQ-ACK/NACK codebook; and transmitting, by a user equipment, the HARQ-ACK/NACK codebook in the uplink time unit. The present disclosure enables the user equipment to figure out a size and bit mapping of a HARQ-ACK/NACK codebook exactly in the case where HARQ-ACK/NACK feedback time is variable.