Random Access Message 3 Channel Feedback for NB-IoT Retransmission

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Solution Overview

Problem

In NB-IoT systems, UEs face challenges in determining uplink and downlink channel quality, leading to inefficient resource allocation and potential resource waste due to incorrect selection of retransmission times and lack of feedback, especially in scenarios with multiple coverage enhancement levels and contention-based random access.

Innovation Solution

Incorporating channel quality information in the message 3 of the random access procedure, including mechanisms for reporting and configuring channel quality information through physical downlink control channels, and adjusting transport block sizes based on channel quality to optimize resource usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the UE determines retransmission times based only on downlink channel quality information, then the UE can simplify the measurement process, but the selection of retransmission times becomes inaccurate leading to resource waste or transmission failure

Engineering Contradiction:

Improvemeasurement process complexityVSAvoidretransmission times selection accuracy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent implements feedback by having the UE report uplink channel quality information to the base station through Message 3, and the base station uses this feedback to determine the appropriate number of retransmission times for downlink messages. This closed-loop feedback mechanism resolves the contradiction by providing accurate channel quality data without requiring complex UE-side measurements for both uplink and downlink.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent introduces the base station as an intermediary that receives uplink channel quality information from the UE and uses this information to determine downlink retransmission parameters. This intermediary approach allows the system to make accurate resource allocation decisions without requiring the UE to perform complex bidirectional channel measurements.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the base station sends downlink messages with a large number of retransmission times, then the reliability of message delivery improves, but resource waste increases due to unnecessary retransmissions

Engineering Contradiction:

Improvemessage delivery reliabilityVSAvoidresource waste

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent makes the downlink retransmission parameters dynamic by adjusting the number of retransmission times based on real-time uplink channel quality information reported by the UE. Instead of using fixed or overly conservative retransmission settings, the system adapts the retransmission count to the actual channel conditions, thereby improving reliability when needed and reducing resource waste when channel conditions are good.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of retransmission times from a static or predetermined value to a dynamic value that varies according to uplink channel quality conditions. The base station adjusts this parameter based on the UE's reported channel quality, optimizing the balance between message delivery reliability and resource efficiency.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the UE uses more retransmission times for uplink messages, then the success rate of message transmission improves, but the resource occupation increases causing resource waste

Engineering Contradiction:

Improvemessage transmission success rateVSAvoidresource occupation

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies preliminary action by having the UE report uplink channel quality information before the actual data transmission. This advance information allows the base station to pre-determine the optimal number of retransmission times, ensuring that the UE uses the minimum necessary retransmissions to achieve reliable delivery, thereby avoiding both transmission failures and excessive resource occupation.

Inventive Principle:

Principle #10Preliminary action

4Device complexity

If the base station cannot receive feedback on downlink channel quality, then the system complexity is reduced, but the base station cannot flexibly adjust downlink retransmission times leading to resource inefficiency

Engineering Contradiction:

Improvesystem complexityVSAvoiddownlink retransmission adjustment flexibility

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements feedback by having the UE report uplink channel quality information to the base station. Although this is uplink channel quality rather than direct downlink channel quality feedback, it provides the base station with the necessary information to infer downlink conditions and adjust downlink retransmission parameters accordingly, achieving flexibility without requiring complex bidirectional feedback mechanisms.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12568531B2Sending and configuring messaging in a random access procedure

Publication Date: 2026.03.03 ZTE CORP

AI summary

Disclosed are a message sending method and device, a message configuration method and device, and a storage medium. The message sending method includes: a terminal sends first information in a message 3 in a random access procedure, where the first information includes channel quality information; and the terminal determines second information according to a type of the message 3.