Unified HARQ Codebook for Multiple SPS and CG Configurations
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Solution Overview
Problem
In 3GPP Rel-16, multiple Semi-Persistent Scheduling (SPS) or Configured Grant (CG) configurations require separate HARQ codebooks for each configuration, leading to inefficient use of resources as N configurations necessitate N bits for HARQ feedback, even when only one configuration is used for transmission alignment.
Innovation Solution
A method where a single HARQ codebook is allocated for N configurations, using a single HARQ acknowledgement (ACK/NACK) bit within the codebook, which can be repeated or span multiple bits, to transmit feedback for all associated channels, reducing the resource requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate HARQ codebooks are allocated for each SPS/CG configuration, then feedback reliability for each configuration is ensured, but resource overhead increases linearly with the number of configurations
Solution Approach 1:
The patent merges multiple separate HARQ codebooks into a single unified HARQ codebook that serves multiple SPS/CG configurations. Instead of allocating N separate codebooks for N configurations, a single codebook is shared across all configurations, reducing the total number of bits required for HARQ feedback while maintaining the ability to provide reliable feedback for each configuration through proper bit mapping and acknowledgment mechanisms.
Solution Approach 2:
The unified HARQ codebook is designed to serve multiple functions simultaneously - it provides HARQ feedback for multiple different SPS/CG configurations within a single codebook structure. This multi-functional approach allows the same codebook resource to be universally applied across different configurations, eliminating the need for configuration-specific codebooks and reducing overall resource overhead.
2Reliability
If N bits are allocated for HARQ feedback across N configurations, then each configuration receives dedicated feedback, but resource efficiency decreases when not all configurations are actively transmitting
Solution Approach 1:
The patent implements partial action by allocating HARQ feedback bits dynamically based on actual transmission needs. Instead of always allocating N bits for N configurations, the system allocates only the necessary number of bits for configurations that are actively transmitting data. This allows the HARQ feedback mechanism to operate at partial capacity when needed, improving resource efficiency while maintaining reliable feedback coverage for active configurations.
3Measurement precision
If multiple HARQ codebooks are maintained for multiple SPS/CG configurations, then feedback accuracy for each configuration is preserved, but system complexity increases
Solution Approach 1:
The patent segments the unified HARQ codebook into distinct bit fields or regions, each corresponding to a specific SPS/CG configuration. This segmentation allows the system to maintain precise feedback accuracy for each configuration while managing complexity through a unified structure. Each configuration's feedback bits are clearly demarcated within the single codebook, enabling accurate individual feedback without requiring separate codebook management for each configuration.
Data Source
AI summary
Systems and methods are disclosed herein for transmission of Hybrid Automatic Repeat Request (HARQ) feedback for multiple Semi-Persistent Scheduling (SPS) or multiple Configured Grant (CG) transmission alignment. In one embodiment, a method performed by a wireless communication device comprises receiving N configurations, where N is an integer greater than one and the N configurations are N downlink semi-persistent scheduling. SPS, configurations or N uplink configured grant, CG, configurations. The method further comprises sending or receiving HARQ feedback for N physical uplink or downlink shared channels that are associated to the N configurations and belong to a same period, using a HARQ codebook that comprises a single HARQ acknowledgement or negative acknowledgement. ACK/NACK, for the N physical uplink or downlink shared channels. In this manner, construction of a smaller HARQ codebook is enabled, which helps in saving resources.