Multi-State DRX State Transitions for 5G NR Power and Latency

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Solution Overview

Problem

Current wireless communication systems, particularly 5G NR, face challenges in achieving higher data rates, lower latency, and improved energy efficiency due to limited granularity in discontinuous reception (DRX) states, leading to suboptimal power saving and increased latency.

Innovation Solution

Implementing a multi-state DRX scheme with finer granularity, including states like PDCCH monitoring, WUS monitoring, and data ready states, allowing dynamic transitions and adaptive bandwidth usage to optimize power consumption and latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional two-state DRX is used, then device complexity is reduced, but power saving performance deteriorates

Engineering Contradiction:
Improvepower savingVSAvoidDRX state management complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent segments the conventional two-state DRX into multiple intermediate states (RRC_INACTIVE, RRC_IDLE, and connected mode DRX states), creating a hierarchical state structure. This segmentation allows the UE to transition through different power consumption levels based on traffic patterns, achieving better power saving while managing complexity through standardized state transition rules.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic state transitions where the UE can move between different DRX states based on real-time conditions such as traffic activity, timer expirations, and network signaling. This dynamic approach allows the system to adapt power consumption levels continuously rather than being stuck in fixed states, improving power saving performance.

Inventive Principle:
Principle #15Dynamics

2Productivity

If DRX on duration is extended, then data transmission opportunities increase, but latency increases

Engineering Contradiction:
Improvedata transmission opportunitiesVSAvoidlatency
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent implements periodic DRX cycles with configurable on-duration and off-duration parameters. By optimizing the periodicity and duration of active monitoring periods, the system increases data transmission opportunities during on-duration while keeping off-duration sufficiently short to maintain low latency. The periodic structure allows predictable scheduling and reduced waiting times.

Inventive Principle:
Principle #19Periodic action

3Loss of time

If DRX inactivity timer is shortened, then latency is reduced, but power saving performance deteriorates

Engineering Contradiction:
ImprovelatencyVSAvoidpower saving
Core Design Contradiction:
Loss of timeVSLoss of energy

Solution Approach 1:

The patent introduces multiple timer parameters (drx-InactivityTimer, drx-RetransmissionTimer, drx-HARQ-RTT-Timer) with different functions and durations. By adjusting these parameters independently based on traffic patterns and QoS requirements, the system can reduce latency for time-sensitive applications while maintaining power saving for background traffic, resolving the contradiction between latency and power consumption.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If UE monitors PDCCH continuously, then data reception reliability improves, but power consumption increases

Engineering Contradiction:
Improvedata reception reliabilityVSAvoidUE power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements preliminary actions before full PDCCH monitoring by first checking for wake-up signals or pre-emption indicators during brief active periods. This preliminary check allows the UE to determine whether full monitoring is necessary, maintaining data reception reliability for important transmissions while reducing power consumption by avoiding continuous full-scale monitoring during periods when no data is expected.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3622779B1Techniques for multi-state DRX in new radio
Publication Date: 2021.08.11 QUALCOMM INC
  • EP3622779B1 patent drawingFigure 1
  • EP3622779B1 patent drawingFigure 2A
  • EP3622779B1 patent drawingFigure 2B

AI summary

The present disclosure describes various examples of a method, an apparatus, and a computer readable medium for multi-state discontinuous reception (DRX) in wireless communications. For example, one of the methods described may include identifying, by a user equipment (UE), at least two states in connected mode, determining, by the UE, one or more triggers for transitioning between the at least two states, and transitioning, by the UE, from a first state of the at least two states to a second state of the at least two states in response to a determination of the one or more triggers. In an aspect, the transitioning comprises transitioning between cross-slot scheduling and same-slot scheduling, or between a narrow bandwidth and a wide bandwidth, or between a larger periodicity and a smaller periodicity for monitoring.