Nested Grant Error Detection in Wireless Control Channels

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Solution Overview

Problem

Wireless communication networks face significant performance loss due to error propagation in daisy-chain schemes, where a failure to detect the first grant leads to subsequent transmission failures, causing delays in error detection and recovery.

Innovation Solution

Implementing a method where a wireless communication device quickly determines if the second downlink control information is obtainable and transmits an indication to the radio network node, allowing for early detection and recovery from errors by using inband-control reception indicators, which can be sent on physical data channels or control channels, enabling faster error compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a daisy-chain scheme is used to transmit nested grants, then resource allocation efficiency is improved, but error propagation causes significant performance loss

Engineering Contradiction:
Improveresource allocation efficiencyVSAvoidperformance loss due to error propagation
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by having the UE send an indication of successful DCI reception before the network node sends subsequent grants. This early confirmation allows the system to detect errors promptly and switch to alternative grant transmission methods, preventing error propagation while maintaining the efficiency benefits of daisy-chain schemes during normal operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by introducing a mechanism where the UE provides confirmation (indication) to the network node about whether it successfully received and decoded the DCI. This feedback loop enables the network node to detect transmission errors early and take corrective actions, such as retransmitting grants through different channels, thereby resolving the reliability issue while preserving productivity.

Inventive Principle:
Principle #23Feedback

2Reliability

If early error detection is implemented by transmitting indications, then performance loss is reduced, but device complexity increases

Engineering Contradiction:
Improveerror detection capabilityVSAvoidcomplexity of error detection mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies the taking out principle by extracting the error detection function into a separate, simple indication transmission mechanism. Instead of making the entire communication system complex, only the UE needs to send a simple acknowledgment indication, while the network node handles the complexity of error detection and recovery. This separation keeps individual device complexity low while achieving high overall reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses an intermediary approach by introducing a simple indication message as a mediator between the DCI transmission and the grant execution. This intermediary element provides error detection capability without requiring complex mechanisms in either the UE or network node, as the indication serves as a lightweight bridge that enables reliable communication while maintaining simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Quantity of substance

If nested grants are transmitted on physical data channels, then control channel capacity is improved, but error propagation delays detection

Engineering Contradiction:
Improvecontrol channel capacityVSAvoiderror detection delay
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the UE send an indication of DCI reception status before the network node transmits subsequent nested grants on the physical data channel. This early indication allows the network node to detect errors promptly and switch to alternative transmission methods, preventing error propagation delays while maintaining the capacity benefits of using physical data channels for control information.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3228040B1Method and devices for mitigating error propagation in transmission assignments
Publication Date: 2020.05.13 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3228040B1 patent drawingFigure 1~2
  • EP3228040B1 patent drawingFigure 3~4
  • EP3228040B1 patent drawingFigure 5~6

AI summary

A method in a wireless communication device for communication with a radio network node comprises receiving (210) of a first downlink control information on a first assignment. The first downlink control information comprises a reference to a second assignment, on which a second downlink control information is assigned to be received. It is determined (220) if the second downlink control information is obtainable. An indication indicating whether or not the second downlink control information was obtainable is transmitted (230) to the radio network node. A method in the radio network node for communication with the wireless communication device comprises transmitting of the first and second downlink control information. It is determined whether or not the second downlink control information was obtainable by the wireless communication device and based in this, a third downlink control information is transmitted on a third assignment. Corresponding devices and computer programs are also described.