Extended DRX Cycle Mode for Wireless UE Battery and Link Management

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Solution Overview

Problem

Current implementations of Discontinuous Reception (DRX) long cycles for Machine-Type-Communication (MTC) traffic are incompatible with measurement times, leading to Radio Link Failures and increased signaling, resulting in high battery usage and inefficient mobility management in wireless communication networks.

Innovation Solution

The introduction of an extended DRX cycle mode, where a User Equipment (UE) enters a new DRX cycle mode based on specific criteria such as not being scheduled by the network for a certain duration or completing a predefined number of long DRX cycles, allowing for reduced signaling and battery usage by adjusting measurement and reporting frequencies, and potentially adopting a terminal-controlled mobility scheme.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If current DRX long cycle implementations are used for MTC traffic, then battery consumption is reduced through longer sleep periods, but measurement timing becomes incompatible leading to Radio Link Failures and increased signaling overhead

Engineering Contradiction:

Improvebattery consumptionVSAvoidRadio Link Failure rate

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent introduces dynamic adjustment of measurement timing offsets based on the DRX cycle length. The measurement timing offset is configured to be proportional to the DRX cycle length, allowing the measurement schedule to adapt dynamically to different DRX configurations. This resolves the incompatibility between long DRX cycles and fixed measurement timing, preventing Radio Link Failures while maintaining energy efficiency.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of measurement timing offset to scale with DRX cycle length. By configuring the measurement timing offset as a function of the DRX cycle (e.g., offset = k × DRX_cycle_length), the system adjusts measurement timing parameters to match the extended sleep periods, ensuring measurements occur at appropriate intervals without requiring frequent wake-ups that would increase power consumption.

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If current DRX long cycle implementations are used for MTC traffic, then battery consumption is reduced through longer sleep periods, but signaling overhead increases due to mobility management requirements

Engineering Contradiction:

Improvebattery consumptionVSAvoidsignaling overhead

Core Design Contradiction:

Use of energy by moving objectVSLoss of information

Solution Approach 1:

The patent dynamically adjusts measurement reporting frequencies based on the DRX cycle configuration and UE mobility state. When long DRX cycles are configured, the system reduces measurement reporting frequency proportionally, avoiding unnecessary signaling during extended sleep periods. This dynamic adaptation reduces signaling overhead while maintaining network awareness of UE position and status.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent modifies multiple parameters including measurement timing offsets, measurement frequencies, and reporting thresholds to align with extended DRX cycles. By scaling these parameters with the DRX cycle length, the system reduces the number of measurements required and minimizes uplink signaling traffic, thereby reducing battery consumption without compromising mobility management effectiveness.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If measurement frequency is increased to prevent Radio Link Failures, then reliability improves, but battery consumption increases due to more frequent wake-ups

Engineering Contradiction:

ImproveRadio Link Failure rateVSAvoidbattery consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent optimizes the measurement timing offset parameter to achieve the minimum necessary measurement frequency for preventing Radio Link Failures. By calculating the appropriate offset based on DRX cycle length and UE mobility characteristics, the system schedules measurements at the least frequent interval that still ensures link reliability, thereby minimizing wake-up events and battery consumption while maintaining acceptable failure rates.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9900928B2User equipment, network node, and methods for managing an extended discontinuous reception cycle mode

Publication Date: 2018.02.20 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A method in a User Equipment, UE, for managing an extended Discontinuous Reception, DRX, cycle mode. The UE is operating in a network and is in a Radio Resource Control, RRC, connected state. The UE enters (401) the extended DRX cycle mode when a first criterion is satisfied. The first criterion relates to anyone or more out of that the UE has not been scheduled by the network during a specific time duration, that the UE has completed a predefined or configured number of long DRX cycles when being in a long DRX cycle mode, that the UE has received an order from the network to enter to the extended DRX cycle mode.