HARQ Process Management in TTI Bundling Transitions

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Solution Overview

Problem

The existing LTE system does not effectively manage hybrid automatic repeat request (HARQ) procedures during transitions between transmission time interval (TTI) bundling and non-bundling, leading to uncertainty for unfinished HARQ processes and inefficient uplink transmission.

Innovation Solution

A method and device that activate or deactivate TTI bundling by using unused HARQ processes in the first round trip time to continue unfinished HARQ processes, ensuring smooth transitions and synchronization with the network, and flushing or suspending processes as needed to maintain efficient uplink transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If TTI bundling is activated to improve uplink coverage, then uplink coverage is improved, but the HARQ procedure becomes uncertain during transition and transmission efficiency deteriorates

Engineering Contradiction:
Improveuplink coverageVSAvoidtransmission efficiency
Core Design Contradiction:
Volume of moving objectVSProductivity

Solution Approach 1:

The patent applies preliminary action by determining and executing specific HARQ process handling actions (suspending or flushing) before the TTI bundling transition is complete. The UE determines whether to suspend or flush unfinished HARQ processes based on the transition state, ensuring proper resource management and preventing protocol uncertainty before the transition fully occurs.

Inventive Principle:
Principle #10Preliminary action

2Stability of the object's composition

If unused HARQ processes are reused to continue unfinished processes, then transmission continuity is improved, but protocol complexity increases

Engineering Contradiction:
Improvetransmission continuityVSAvoidprotocol complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the HARQ process management adaptive to the TTI bundling transition state. The system dynamically determines whether to suspend or flush unfinished HARQ processes based on real-time transition conditions, and dynamically allocates unused HARQ processes to continue unfinished transmissions when appropriate, rather than following a fixed protocol.

Inventive Principle:
Principle #15Dynamics

3Reliability

If HARQ processes are suspended or flushed during transition, then protocol synchronization is improved, but transmission time increases

Engineering Contradiction:
Improveprotocol synchronizationVSAvoidtransmission time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies local quality by applying different handling strategies to different HARQ processes based on their individual states and the transition context. Some HARQ processes are suspended while others are flushed, and unused processes are selectively allocated to continue unfinished transmissions, rather than applying a uniform handling approach to all processes.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS8824423B2Method and apparatus for improving a hybrid automatic repeat request procedure in the transition of transmission time interval bundling in a wireless communication system
Publication Date: 2014.09.02 HTC CORP
  • US8824423B2 patent drawing
  • US8824423B2 patent drawing
  • US8824423B2 patent drawing

AI summary

A method of improving a hybrid automatic repeat request (HARQ) procedure in the transition of transmission time interval (TTI) bundling for a MAC layer of a user equipment in a wireless communication system, the method including activating TTI bundling upon receiving a bundling activation command, and using a first number of unused HARQ processes in the first round trip time after TTI bundling is activated to continue the first number of unfinished HARQ processes before TTI bundling is activated.