Timer Control Unit for Heterogeneous TTI Consistency

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Solution Overview

Problem

In LTE mobile communication systems, the determination of a unified TTI (Transmission Time Interval) for timer control operations across cells with different TTIs is unclear, leading to inconsistent timer expiration times and performance variability among user apparatuses.

Innovation Solution

A user apparatus is equipped with a timer control unit that determines the appropriate TTI based on the type of control operation, using either the LTE TTI for coarse control and 5G TTI for fine control, or vice versa, to ensure consistent timer operations across cells with different TTIs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separate timers based on individual TTI units are used for LTE and 5G cells, then each cell can operate with its native timing granularity, but timer control operations become inconsistent across cells leading to performance variability

Engineering Contradiction:
Improvetimer control consistencyVSAvoidperformance consistency
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies universality by introducing a unified timer control mechanism that serves multiple cells with different TTI configurations. The timer control unit is designed to handle both LTE-based timers and 5G-based timers through a single standardized interface, enabling consistent timer operations across heterogeneous cell types while maintaining compatibility with their respective TTI units.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The timer control unit acts as an intermediary between the scheduling unit and the communication unit. It receives scheduling decisions from the scheduling unit and translates them into standardized timer operations that can be executed consistently across cells with different TTI configurations, thereby mediating between the diverse timing requirements and the unified timer control objective.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a unified TTI unit is imposed across all cells, then timer control becomes consistent, but cells with shorter TTI (5G) cannot achieve fine-grained control for low-latency operations

Engineering Contradiction:
Improvetimer control consistencyVSAvoidlatency performance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies segmentation by dividing the timer control function into two distinct timer types: LTE-based timers with longer granularity for macro cell operations, and 5G-based timers with shorter granularity for small cell operations. This segmentation allows each cell type to use the appropriate timing resolution for its specific requirements while maintaining overall system consistency through the standardized timer control interface.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements local quality by allowing different timer granularities to be applied to different cells based on their specific requirements. LTE macro cells use longer TTI-based timers suitable for their broader coverage area, while 5G small cells use shorter TTI-based timers to achieve low-latency performance. Each cell's timer characteristics are locally optimized for its operational context.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If implementation-specific TTI selection is allowed, then flexibility is increased, but interoperability and standardized performance cannot be guaranteed

Engineering Contradiction:
Improveimplementation flexibilityVSAvoidinteroperability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies parameter changes by standardizing the timer control parameters (such as timer values, expiration conditions, and renewal mechanisms) across different cell types. While the underlying TTI units may differ between LTE and 5G cells, the timer control parameters are defined in a standardized manner, ensuring that timer operations exhibit consistent behavior regardless of the specific cell configuration, thereby guaranteeing interoperability.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3461205B1User apparatus and timer control method
Publication Date: 2021.03.24 NTT DOCOMO INC
  • EP3461205B1 patent drawingFigure 1
  • EP3461205B1 patent drawingFigure 2
  • EP3461205B1 patent drawingFigure 3

AI summary

A user apparatus is provided. The user apparatus communicates with a base station in a mobile communication system. The mobile communication system supports carrier aggregation which includes multiple cells including a first cell and a second cell which uses a TTI different from a TTI of the first cell. The user apparatus includes a communication unit configured to transmit and receive a signal to and from the base station; and a timer control unit configured to, according to a type of a control operation performed by the communication unit, determine a TTI as a unit time for operating a timer used for the control operation. The communication unit performs the control operation by operating the timer by using as a unit time the TTI determined by the timer control unit.