Variable HARQ Feedback Time for MTC Power Efficiency

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Solution Overview

Problem

In mobile networks, particularly in 3GPP LTE systems, low-performance MTC terminal devices face challenges in complying with synchronous HARQ feedback timing requirements, leading to inefficiencies and increased power consumption, especially when coexisting with conventional UEs and during low-power modes.

Innovation Solution

Implementing a retransmission protocol with a variable feedback time that allows the transmitter and receiver to determine and adjust the feedback time interval based on processing capabilities and radio channel conditions, enabling flexible timing compliance and power management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If synchronous HARQ feedback timing is used in 3GPP LTE systems, then timing requirements are met and transmission reliability is improved, but low-performance MTC terminal devices cannot comply with the timing requirements and power consumption increases

Engineering Contradiction:

ImproveHARQ feedback timing complianceVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by making the feedback time variable rather than fixed. The system dynamically adjusts the feedback time parameter based on the capabilities of the terminal device and current operating conditions. This allows low-performance MTC devices to use extended feedback times that match their processing capabilities, reducing power consumption while still maintaining reliable communication through the retransmission protocol.

Inventive Principle:

Principle #15Dynamics

2Device complexity

If fixed HARQ feedback timing is used, then transmission protocol compliance is simplified, but adaptability to different terminal device performance levels is reduced

Engineering Contradiction:

Improveprotocol implementation complexityVSAvoidadaptability to terminal device performance

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by modifying the feedback time parameter from a fixed value to a variable parameter that can be adjusted based on terminal device capabilities. The system maintains protocol compliance while introducing flexibility through parameter variation, allowing the same protocol to adapt to both high-performance conventional UEs and low-performance MTC devices without increasing overall implementation complexity.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If low-performance UE categories are introduced to reduce device complexity, then manufacturing cost and power consumption are reduced, but compliance with existing timing constraints becomes difficult

Engineering Contradiction:

Improveterminal device complexityVSAvoidtiming constraint compliance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent resolves this contradiction by making the feedback timing dynamic rather than static. Low-performance UE categories can now operate with extended feedback times that match their reduced processing capabilities, while the system maintains reliability through the retransmission protocol. This dynamic adjustment allows device complexity reduction without sacrificing timing compliance.

Inventive Principle:

Principle #15Dynamics

4Adaptability or versatility

If variable feedback time is implemented, then adaptability to different device capabilities is improved, but protocol complexity increases

Engineering Contradiction:

Improvefeedback time flexibilityVSAvoidretransmission protocol complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent introduces variable feedback time through parameter changes while maintaining relatively simple protocol implementation. The feedback time parameter can be adjusted based on device capabilities, and the retransmission protocol handles the timing variations through standard mechanisms. This approach achieves adaptability without proportionally increasing protocol complexity.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10432349B2Data block transmission with variable retransmission feedback time

Publication Date: 2019.10.01 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

Data Block Transmission with Variable Retransmission Feedback Time For communicating data between a transmitter (10) and a receiver (14), wireless transmission of data blocks is implemented on the basis a retransmission protocol with variable value of a feedback time. The feedback time defines a time interval between transmission of one of the data blocks (22) and transmission of a feedback message (23) indicating whether the data block (22) was successfully received. The transmitter (10) or the receiver (14) determines the value of the feedback time. Depending on the determined value of the feedback time, the transmitter (10) controls transmission of the data block (22) to the receiver and/or the receiver (14) controls reception of the data block (22) at the receiver (14). The transmitter (10) may for example be a base station of a mobile network, and the receiver (14) may be a terminal device connected to the mobile network.