LTE Inactivity Timer Adjustment for RRC State Management

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Solution Overview

Problem

Current inactivity timer configurations in LTE networks are inflexible, leading to inefficient battery life for UEs in services with long connection times and excessive RRC state transitions in services with short connection times, affecting network traffic management and energy consumption.

Innovation Solution

A method and apparatus for evaluating and configuring inactivity timers based on specific service types, using a histogram analysis of RRC connection setups and releases to optimize the long inactivity timer settings on a per-UE basis, allowing for dynamic adjustment to minimize RRC connection setups and prolong UE stays in the RRC connected state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a common inactivity timer is set for all services, then the configuration is simple, but it leads to inefficient battery life for services with long connection times and excessive RRC state transitions for services with short connection times

Engineering Contradiction:
Improveinactivity timer configurationVSAvoidUE battery life
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The patent segments services into different groups (first group with long connection times like VoLTE, second group with short connection times like web browsing) and assigns different inactivity timer values to each group. This segmentation allows the system to optimize battery life for each service type independently, rather than using a single common timer for all services.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic adjustment of inactivity timers based on service type and historical connection patterns. The network entity determines appropriate timer values dynamically for different UEs and services, allowing the system to adapt to varying connection characteristics and optimize energy consumption accordingly.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If a common inactivity timer is set for all services, then the configuration is simple, but it causes significant increase in UE movements from RRC idle state to RRC connected state for services with short connection times

Engineering Contradiction:
Improveinactivity timer configurationVSAvoidnumber of RRC connection setups
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

By segmenting services into groups with different connection time characteristics, the patent enables differentiated timer configurations. For services with short connection times (second group), shorter inactivity timers prevent unnecessary RRC connection setups, thereby improving productivity by reducing the number of state transitions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the inactivity timer parameter values based on service type and historical connection data. By adjusting the timer parameter dynamically, the system optimizes the balance between maintaining connection readiness and reducing unnecessary connection setups, thereby improving overall network productivity.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If long inactivity timer is used for services with long connection times, then connection stability is improved, but UE spends longer time in RRC connected state leading to increased energy consumption

Engineering Contradiction:
ImproveRRC connection stabilityVSAvoidUE energy consumption
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The patent applies local quality by assigning different inactivity timer values to different service groups based on their specific characteristics. For services with long connection times (first group), longer timers maintain connection stability, while for services with short connection times (second group), shorter timers reduce energy consumption. This localized optimization resolves the contradiction between stability and energy loss.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

By changing the inactivity timer parameter based on service type and historical connection patterns, the patent optimizes the balance between connection stability and energy consumption. The parameter adjustment ensures that UEs maintain stable connections when needed while transitioning to idle state promptly when not needed, thereby minimizing energy loss.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3883334B1Adjustment of an inactivity timer
Publication Date: 2023.08.30 NOKIA SOLUTIONS & NETWORKS OY
  • EP3883334B1 patent drawingFigure 1
  • EP3883334B1 patent drawingFigure 2
  • EP3883334B1 patent drawingFigure 3

AI summary

There are provided measures for inactivity timer evaluation. Such measures exemplarily comprise monitoring an RRC connection state of a UE, determining, upon first changes of the RRC connection state indicative of successful RRC connection setups, a plurality of duration amounts of periods between said first changes of the RRC connection state and preceding second changes of the RRC connection state indicative of RRC connection releases, and adjusting, based on a distribution of the plurality of determined duration amounts, a long inactivity timer for triggering an RRC idle state of the UE.