Simultaneous Tx/Rx Header Acknowledgment for Low-Latency Retransmission

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Solution Overview

Problem

The latency of feedback mechanisms in wireless communication leads to delayed adaptations in communication settings, such as modulation and coding scheme selection and retransmission decisions, due to the reliance on acknowledgment signals and channel quality information.

Innovation Solution

Implementing alternative feedback mechanisms that exploit the capability of simultaneous transmission and reception, allowing for early acknowledgement of packet headers and payloads, including separate acknowledgement signals for the header (H-ACK) and payload (P-ACK), enabling faster adaptations by reducing latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional feedback mechanisms are used for wireless communication, then communication reliability is maintained through acknowledgment signals, but feedback latency increases causing delayed adaptations in communication settings

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidfeedback latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the acknowledgment process into two separate signals: H-ACK for header acknowledgment and P-ACK for payload acknowledgment. This segmentation allows the receiver to provide feedback for the header immediately upon successful decoding, before the entire packet is fully received and processed, thereby reducing feedback latency while maintaining reliability through the subsequent payload acknowledgment

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The receiver performs preliminary decoding of the packet header and provides H-ACK feedback before the complete packet reception is finalized. This preliminary action enables the transmitter to adapt communication settings (such as MCS selection) based on header acknowledgment status, reducing the overall feedback loop time while ensuring reliable communication through the two-stage acknowledgment mechanism

Inventive Principle:
Principle #10Preliminary action

2Productivity

If early feedback mechanisms are implemented to reduce latency, then adaptation speed improves, but the complexity of the communication protocol increases

Engineering Contradiction:
Improveadaptation speedVSAvoidprotocol complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The protocol complexity is managed through structured segmentation of the acknowledgment into H-ACK and P-ACK components. Each segment has a clearly defined function and timing, which simplifies the implementation logic despite the enhanced functionality. The segmentation allows for systematic handling of different acknowledgment scenarios without requiring complex overall protocol restructuring

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a structured feedback mechanism where H-ACK and P-ACK signals provide explicit feedback at different stages of packet reception. This feedback approach enables adaptive communication settings changes based on reception status, improving productivity through faster adaptations while managing complexity through the systematic feedback structure that builds upon existing acknowledgment protocols

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3884604B1Acknowlegment for simultaneous transmission and reception
Publication Date: 2025.11.05 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3884604B1 patent drawingFigure 1~2(f)
  • EP3884604B1 patent drawingFigure 3
  • EP3884604B1 patent drawingFigure 4~6

AI summary

Methods are disclosed for communication devices capable of simultaneous transmission and reception, wherein a first method is for reception of a packet comprising a header and a payload and a second method is for transmission of a packet comprising a header and a payload. The second method comprises transmitting at least a part of the header. The first method comprises receiving at least a part of the header, attempting to decode the part of the header, and (when the part of the header is successfully decoded) transmitting a header acknowledgement signal. The second method comprises monitoring receipt of a header acknowledgement signal, and (when absence of the header acknowledgement signal is detected) interrupting the transmission of the packet and scheduling the packet for retransmission. Corresponding apparatuses, transceivers, communication devices and computer program products are also disclosed.