HARQ Feedback Segmentation for High Throughput Wireless Systems
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Solution Overview
Problem
Existing wireless communication systems face challenges in maintaining the benefits of Incremental Redundancy Hybrid Automatic Repeat Request (IR-HARQ) for high throughput use cases without increasing Double Data Rate (DDR) bandwidth, which is costly and requires significant memory resources.
Innovation Solution
The proposed solution involves configuring multiple Hybrid Automatic Repeat Request (HARQ)-ACK feedback occasions for a Physical Downlink Shared Channel (PDSCH) transmission, allowing the User Equipment (UE) to transmit HARQ feedback in initial and delayed occasions, thereby reducing the need for increased DDR bandwidth and supporting high throughput use cases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If DDR bandwidth is increased to maintain IR-HARQ benefits for high throughput use cases, then throughput and robustness are improved, but device cost and memory resource requirements increase
Solution Approach 1:
The feedback mechanism is segmented into multiple HARQ-ACK feedback occasions (initial and delayed) instead of requiring single-occasion feedback. This segmentation allows the UE to spread feedback transmissions over time, reducing the instantaneous memory bandwidth requirements while maintaining IR-HARQ functionality for high throughput scenarios
Solution Approach 2:
The system dynamically selects between initial and delayed HARQ-ACK feedback occasions based on channel conditions and throughput requirements. This dynamic adaptation allows the system to maintain high throughput when needed while using delayed feedback to reduce memory bandwidth demands during less critical transmission periods
2Productivity
If DDR bandwidth is increased to support high throughput use cases, then spectral efficiency is improved, but device complexity and cost increase
Solution Approach 1:
The feedback process is divided into multiple occasions, allowing the UE to manage HARQ acknowledgments in a more manageable manner. This reduces the complexity of memory access patterns and control logic required to support high throughput, while still achieving improved spectral efficiency through proper utilization of the segmented feedback opportunities
3Device complexity
If single HARQ-ACK feedback occasion is used, then device complexity is reduced, but throughput and robustness deteriorate
Solution Approach 1:
The multiple HARQ-ACK feedback occasions serve multiple functions: the initial occasion provides timely feedback for low-latency applications, while the delayed occasion supports high throughput scenarios requiring more processing time. This multi-functionality allows a single feedback mechanism to serve both simple and complex throughput requirements without increasing overall system complexity
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive, from a network node, a downlink grant scheduling a physical downlink shared channel (PDSCH) transmission that includes a transport block (TB) associated with a first hybrid automatic repeat request (HARQ) acknowledgment (HARQ-ACK) feedback occasion and a second HARQ-ACK feedback occasion, wherein the downlink grant schedules at least the first HARQ-ACK feedback occasion associated with the TB. The UE may transmit, to the network node, HARQ feedback for the TB in one or more of the first HARQ-ACK feedback occasion or the second HARQ-ACK feedback occasion associated with the TB. Numerous other aspects are described.