Dynamic Semi-Static HARQ Codebooks for Reduced UL Feedback
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Solution Overview
Problem
The existing semi-static HARQ codebook in 5G NR systems results in inefficient network resource usage and increased UL transmission times due to the UE device transmitting a fixed number of ACK/NACK bits regardless of actual data transmission, leading to unnecessary ACK/NACK bits even when no data is received.
Innovation Solution
Intelligently determining subsets of K1 values for UL slots based on actual data transmission, reducing the number of ACK/NACK bits transmitted by the UE device, and optimizing HARQ reporting through predefined and dynamic codebook combinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the UE device transmits a fixed number of ACK/NACK bits in semi-static HARQ codebook, then the HARQ reporting is simplified and standardized, but the network resource usage becomes inefficient and UL transmission time increases due to unnecessary ACK/NACK bits
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed, static HARQ codebook to a dynamic codebook that adapts its size based on actual downlink data transmissions. The UE determines the codebook size dynamically by counting actual PDSCH receptions and SPS release configurations, allowing the ACK/NACK bit sequence to vary in length according to real network conditions rather than following a predetermined fixed structure
Solution Approach 2:
The patent changes the parameter of codebook size from a fixed value to a variable parameter. The determination of codebook size is based on changing parameters such as the number of actual PDSCH receptions, SPS release configurations, and other downlink transmissions. This allows the system to adjust the HARQ feedback length according to actual traffic conditions, reducing unnecessary feedback bits while maintaining reliability for actual data transmissions
2Stability of the object's composition
If the UE device transmits a fixed number of ACK/NACK bits in semi-static HARQ codebook, then the HARQ reporting structure is standardized, but the UL transmission time increases due to unnecessary ACK/NACK bits
Solution Approach 1:
The patent implements dynamics by making the HARQ codebook size adaptive rather than fixed. The UE dynamically determines the codebook size based on actual downlink transmissions, which reduces the number of transmitted ACK/NACK bits when there is less downlink activity. This dynamic adjustment directly reduces UL transmission time while maintaining a stable and standardized reporting structure through clear determination rules based on PDSCH receptions and SPS configurations
3Reliability
If the UE device transmits all ACK/NACK bits regardless of actual data reception, then the HARQ reporting is comprehensive and standardized, but the number of unnecessary ACK/NACK bits increases
Solution Approach 1:
The patent applies the extraction principle by removing unnecessary ACK/NACK bits from the HARQ feedback. Instead of transmitting a fixed comprehensive codebook, the UE extracts and transmits only the ACK/NACK bits corresponding to actual downlink data receptions and SPS release configurations. This selective transmission maintains reliability for actual data while eliminating redundant feedback bits that would otherwise be transmitted unnecessarily
Solution Approach 2:
The patent changes the quantity parameter of ACK/NACK bits from a fixed value to a variable that depends on actual downlink transmissions. The codebook size parameter is determined dynamically based on the number of PDSCH receptions, SPS release configurations, and other actual downlink activities. This ensures that the number of transmitted bits accurately reflects the amount of downlink data that requires acknowledgment, maintaining completeness while reducing redundancy
Data Source
AI summary
In a system, apparatus, method, and non-transitory computer readable medium, a UE device may be caused to, obtain a plurality of subsets of acknowledgement/negative acknowledgement (AN) offset values associated with at least one desired transmission frame from at least one RAN node, the desired transmission frame including at least one DL slot and at least one UL slot, receive DL data from the at least one RAN node in the at least one DL slot, determine a number of AN bits to transmit to the at least one RAN node for at least one UL slot based on the plurality of subsets of AN offset values, and transmit AN indications to the at least one RAN node in the at least one UL slot based on the received DL data and the determined number of AN bits for the at least one UL slot.