Cross-layer Scheduling via Unified Feedback Mechanisms

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Solution Overview

Problem

Current retransmission techniques in wireless communications systems, such as ARQ and HARQ, incur significant overhead and time delays due to separate feedback mechanisms and layered approaches, which hinder efficient data packet transmission between transmitters and receivers.

Innovation Solution

The proposed solution combines functions across the RLC, MAC, and PHY layers to reduce overhead by merging feedback mechanisms, allowing the transmitter to infer RLC layer ACK/NACK messages from HARQ messages, and dynamically adjust packet size, modulation, and coding schemes based on feedback, thereby eliminating the need for RLC polling and status reports.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate feedback mechanisms are used for ARQ and HARQ processes, then reliability of data transmission is improved, but overhead and time delay increase

Engineering Contradiction:

Improvedata transmission reliabilityVSAvoidfeedback time delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent merges the separate ARQ and HARQ feedback mechanisms into a unified feedback process. The transmitter determines whether received HARQ feedback messages represent ARQ ACK/NACK or HARQ ACK/NACK messages, allowing both protocols to share the same feedback channel and reduce overall feedback overhead and time delay while maintaining transmission reliability.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If separate feedback mechanisms are used for ARQ and HARQ processes, then reliability of data transmission is improved, but overhead increases

Engineering Contradiction:

Improvedata transmission reliabilityVSAvoidfeedback overhead

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent combines ARQ and HARQ feedback into a single unified feedback mechanism. By allowing the same feedback channel to carry both ARQ and HARQ acknowledgment messages and by implementing a unified feedback interpretation process at the transmitter, the system reduces the quantity of feedback overhead while preserving the reliability benefits of both protocols.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If RLC polling and status reports are used, then data transmission reliability is improved, but control overhead increases

Engineering Contradiction:

Improvedata transmission reliabilityVSAvoidcontrol overhead

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the separate RLC polling and status report mechanisms by relying on the unified ARQ/HARQ feedback system. The transmitter can determine packet transmission status through the unified feedback messages, removing the need for additional RLC-layer polling and status reporting procedures and thereby reducing control overhead.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentEP2817911B1Cross-layer scheduling based on lower layer feedback

Publication Date: 2020.08.12 MARVELL ASIA PTE LTD

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AI summary

Systems, methods, apparatus, and techniques are provided for retransmitting packets of data. A Radio Link Control (RLC) layer data packet is generated, and the RLC layer data packet is converted to one or more physical (PHY) layer data packets. The one or more PHY layer data packets are transmitted. At least one of a hybrid automatic transmission request (HARQ) acknowledgement (ACK) message and a HARQ negative acknowledgment (NACK) message is received from a receiver in response to transmission of the one or more PHY layer data packets. It is determined whether the at least one of the HARQ ACK message and the HARQ NACK message represents a automatic transmission request (ARQ) ACK message or a ARQ NACK message.