HARQ LLR Buffer Management via Quantization and Joint Reordering

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Solution Overview

Problem

Current wireless communication systems face high buffer overhead due to scaling conventional HARQ buffer management, particularly in systems supporting higher throughput like 5G, which increases latency and resource utilization inefficiencies.

Innovation Solution

The implementation of low-bitwidth LLR quantization and a joint HARQ and ARQ reordering buffer management system, which compresses and buffers log-likelihood ratios (LLRs) to reduce storage requirements and optimize buffer usage across multiple component carriers and interlaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional HARQ buffer management is scaled to support higher throughput, then system capacity and throughput are improved, but buffer overhead and resource utilization inefficiency worsen

Engineering Contradiction:

ImprovethroughputVSAvoidbuffer overhead

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The patent combines HARQ LLR buffer and ARQ reordering buffer into a single shared buffer structure. This merging eliminates redundant buffer allocations and reduces overall buffer overhead while maintaining the ability to support high throughput through efficient joint management of both buffer types

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The shared buffer is designed to serve multiple functions: storing HARQ LLR values for soft combining, buffering ARQ packets for reordering, and supporting both initial transmissions and retransmissions. This multi-functionality reduces the total buffer resources needed compared to separate dedicated buffers

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Productivity

If conventional HARQ buffer management is scaled to support higher throughput, then system capacity is improved, but latency increases

Engineering Contradiction:

ImprovethroughputVSAvoidlatency

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent implements dynamic buffer allocation and management mechanisms that adapt to varying traffic conditions and channel states. This allows the system to optimize buffer usage in real-time, reducing latency for time-sensitive data while maintaining high throughput for bulk data transmissions

Inventive Principle:

Principle #15Dynamics

3Quantity of substance

If low-bitwidth LLR quantization is applied, then buffer overhead is reduced, but measurement precision of LLR values deteriorates

Engineering Contradiction:

Improvebuffer overheadVSAvoidLLR quantization precision

Core Design Contradiction:

Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent employs variable bitwidth quantization where the precision of LLR values is dynamically adjusted based on channel conditions and decoding requirements. This allows the system to use lower precision (fewer bits) when channel conditions are good, reducing buffer overhead, while maintaining higher precision when needed for reliable decoding

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP3406039B1HARQ LLR buffer and reordering buffer management

Publication Date: 2023.12.13 QUALCOMM INC

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AI summary

Certain aspects of the present disclosure relate to methods and apparatus for management of hybrid automatic repeat request (HARQ) log likelihood ratio (LLR) and reordering buffers in wireless communication systems. According to certain aspects, a method for reducing buffer overhead that may be performed by a wireless node is provided. The method generally includes receiving one or more packets of at least one of an initial transmission or a retransmission; forming one or more log likelihood ratios (LLRs) based on the one or more packets; compressing the one or more LLRs by quantizing the one or more LLRs; and buffering the one or more compressed LLRs.