RRC Idle Mobility State Reporting for Power Optimization
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Solution Overview
Problem
In LTE Advanced communication systems, mobile devices face challenges in optimizing power consumption and mobility due to inadequate mechanisms for reporting current mobility and power consumption states, leading to inefficient power management and potential delays in cell reselection processes.
Innovation Solution
Mobile devices are equipped with mechanisms to establish and report their current mobility and power consumption states to base stations using RRC protocol messages, allowing for dynamic configuration of inactivity timers and DRX cycles based on these reports, thereby optimizing power usage and mobility handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If mobile telephones frequently transition between RRC connected mode and RRC idle mode to optimize power consumption, then battery life is improved, but system resource overhead increases due to repeated signalling message exchange
Solution Approach 1:
The base station predicts the mobile telephone's future mobility state based on historical data and current conditions, and proactively configures inactivity timer values before the mobility state actually changes. This preliminary configuration prevents the need for frequent RRC mode transitions and associated signalling overhead, while still optimizing power consumption by having the correct timer values ready when needed.
2Use of energy by moving object
If inactivity timer values are set to enable early transition to idle mode, then power consumption is reduced, but mobility handling accuracy deteriorates due to insufficient time for proper cell reselection
Solution Approach 1:
The base station dynamically adjusts inactivity timer values based on the mobile telephone's predicted mobility state. For stationary or low-mobility devices, shorter timer values enable faster transition to idle mode and lower power consumption. For high-mobility devices, longer timer values ensure adequate time for proper cell reselection and maintain mobility handling accuracy. The timer configuration adapts in real-time to match the device's actual mobility characteristics.
3Use of energy by moving object
If base stations configure different inactivity timer values for different mobile telephones, then power consumption optimization is improved, but base station processing complexity increases
Solution Approach 1:
Mobile telephones autonomously measure their own mobility state based on cell reselection events and other mobility indicators. They then self-report this measured mobility state to the base station. The base station uses this self-reported information to configure appropriate inactivity timer values, reducing the need for complex base station-side mobility analysis and processing while still achieving personalized power optimization.
4Measurement precision
If mobile telephones report mobility state information frequently, then network optimization accuracy is improved, but signalling overhead increases
Solution Approach 1:
The reporting mechanism changes the parameter of reporting frequency based on the mobile telephone's actual mobility state. When the device is stationary or exhibits low mobility, reporting frequency is reduced or suspended entirely. When high mobility is detected, reporting frequency increases to provide the network with more accurate and timely mobility state information. This adaptive reporting parameter optimization balances measurement precision with signalling overhead reduction.
Data Source
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AI summary
A system is disclosed in which a mobile telephone provides information to a communication system comprising a plurality of base stations. The mobile telephone establishes its current mobility state, determines whether the current mobility state should be sent to the communication system, generates information identifying its current mobility state if it is determined that the current mobility state should be sent to the communication system, and sends the information identifying its current mobility state to at least one of the plurality of base stations.