TDD HARQ Timing and UL Scheduling via DCI Index Fields
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Solution Overview
Problem
Current wireless communication technologies, such as 5G NR and LTE, face challenges in optimizing subframe scheduling and feedback signaling, particularly in time division duplex (TDD) configurations, which affect the efficiency of uplink and downlink data channel transmission and hybrid automatic repeat request (HARQ) processes.
Innovation Solution
The proposed solution involves configuring data channels and feedback signaling based on the uplink-to-downlink resource ratio in TDD subframe configurations, allowing for efficient scheduling of uplink data channels and HARQ signaling, with techniques such as using UL index and DAI fields in control information to manage resource allocation across multiple subframes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If TDD subframe configuration is used to support asymmetric uplink and downlink traffic, then spectral efficiency is improved, but scheduling complexity and resource allocation difficulty increase
Solution Approach 1:
The system segments the scheduling process by introducing separate uplink index (UL index) and downlink assignment index (DAI) fields in DCI messages. This segmentation allows independent tracking of uplink and downlink resource allocations, simplifying the management of asymmetric TDD configurations while maintaining high spectral efficiency.
Solution Approach 2:
The patent implements preliminary action by pre-configuring TDD subframe patterns and pre-calculating HARQ timing relationships. The UL index and DAI fields are prepared in advance in the DCI, enabling UEs to anticipate uplink transmission opportunities and downlink acknowledgment timing without real-time computation, thus reducing scheduling complexity.
2Reliability
If HARQ feedback timing is optimized for TDD configurations, then transmission reliability is improved, but control signaling overhead increases
Solution Approach 1:
The patent merges HARQ acknowledgment timing with uplink data channel scheduling by using the same DCI message to both schedule uplink transmissions and indicate HARQ feedback timing. The DAI field in the DCI simultaneously tracks downlink assignments and determines uplink acknowledgment timing, reducing separate control signaling while maintaining reliability.
Solution Approach 2:
The DCI message structure is designed with multi-functionality, where the UL index and DAI fields serve dual purposes: scheduling uplink resources and determining HARQ feedback timing. This universal approach reduces control signaling overhead by eliminating the need for separate HARQ timing indicators.
3Adaptability or versatility
If uplink and downlink resource allocation is dynamically adjusted based on traffic demand, then system adaptability is improved, but resource allocation computation time increases
Solution Approach 1:
The system implements dynamic resource allocation through pre-configured TDD subframe patterns that can be flexibly activated. The UL index and DAI fields enable real-time adjustment of uplink and downlink resource ratios without requiring complex real-time computation, as the adjustment logic is embedded in the pre-configured patterns and index fields.
Data Source
AI summary
Certain aspects provide a method for wireless communication by a user-equipment (UE). The method generally includes receiving first downlink (DL) control information (DCI) for scheduling resources in time in a system frame for transmission of one or more uplink (UL) data channels and hybrid automatic request (HARQ) signaling for acknowledging whether one or more downlink data channels have been successfully decoded, the one or more UL data channels and the HARQ signaling being configured based on a UL to DL resource ratio associated with a time-division duplex (TDD) subframe configuration. In certain aspects, the UE generates the one or more UL data channels and the HARQ signaling, and transmits the UL data channels and the HARQ signaling using the scheduled resources and in accordance with the TDD subframe configuration.