HARQ DRX Timer Coordination for Unicast and Multicast Reception

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Solution Overview

Problem

Existing wireless communication systems face challenges in efficiently handling Discontinuous Reception (DRX) timers for data reception of unicast and multicast services, particularly in evolving networks like E-UTRAN and NR, which are transitioning from voice communication to IP data packet transmission, impacting the delivery of services such as voice over IP and multimedia.

Innovation Solution

The proposed solution involves optimizing DRX timers for unicast and multicast services by implementing specific DRX configurations and timers, such as onDurationTimerSCPTM, drx-InactivityTimerSCPTM, and SCPTM-SchedulingCycle, to manage PDCCH monitoring activity efficiently, allowing for dynamic switching between PTP and PTM transmission methods in multicast and broadcast services.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If DRX timers are used for multicast data reception, then power consumption is reduced, but data reception reliability deteriorates

Engineering Contradiction:
Improvepower consumptionVSAvoiddata reception reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent segments the DRX timer handling into separate configurations for unicast and multicast services. Specifically, it introduces dedicated DRX parameters for multicast (e.g., drx-HARQ-RTT-TimerDLMBS, drx-RetransmissionTimerDLMBS) distinct from unicast DRX timers, allowing independent optimization of power saving for multicast while maintaining reliable reception through service-specific timer control

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic switching between PTP (Point-to-Point) and PTM (Point-to-Multipoint) transmission methods based on service requirements. The network can dynamically select the appropriate transmission mode and corresponding DRX configuration, enabling adaptive power management that maintains reliability across different service scenarios

Inventive Principle:
Principle #15Dynamics

2Reliability

If separate DRX configurations are implemented for unicast and multicast, then service quality is improved, but system complexity increases

Engineering Contradiction:
Improveservice qualityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates a universal DRX framework that handles both unicast and multicast services through a common MAC entity configuration structure. The system uses unified parameter naming conventions and similar timer management logic, allowing the same DRX mechanism to serve multiple service types without requiring entirely separate implementation paths

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

Solution Approach 2:

The patent applies local quality by introducing service-specific DRX parameter suffixes (e.g., SCPTM for SC-PTM, MBS for Multicast-Broadcast Service) that allow customized timer values and configurations for different service types while maintaining the overall DRX operational framework. This enables tailored optimization for each service without affecting the global system architecture

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If dynamic switching between PTP and PTM is enabled, then service adaptability is improved, but control complexity increases

Engineering Contradiction:
Improveservice adaptabilityVSAvoidcontrol complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements feedback mechanisms where the network monitors service conditions and dynamically adjusts the PTP/PTM transmission mode and corresponding DRX configurations. The system receives feedback on service quality, traffic patterns, and UE capabilities, then adapts the transmission method and timer settings accordingly, enabling intelligent service adaptation without manual reconfiguration

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4149034B1Method and apparatus for handling discontinuous reception (DRX) timer for data reception of unicast and multicast in a wireless communication system
Publication Date: 2025.08.06 ASUSTEK COMPUTER INC
  • EP4149034B1 patent drawingFigure 1
  • EP4149034B1 patent drawingFigure 2
  • EP4149034B1 patent drawingFigure 3

AI summary

In an example, a User Equipment, UE, receives and/or detects a transmission of data from a network. The transmission of the data is addressed to a Group Radio Network Temporary Identifier, G-RNTI, for a Hybrid Automatic Repeat Request, HARQ, process (905). In response to receiving and/or detecting the transmission of the data, the UE (i) starts a first HARQ Round Trip Time, RTT, timer associated with the G-RNTI for the HARQ process, and (ii) starts a second HARQ RTT timer associated with a Cell Radio Network Temporary Identifier, C-RNTI, for the HARQ process (910). The UE starts a multicast retransmission timer for the HARQ process in response to expiry of the first HARQ RTT timer (915). The UE starts a unicast retransmission timer for the HARQ process in response to expiry of the second HARQ RTT timer (920). The UE receives and/or detects a first retransmission of the DL data addressed to the G-RNTI for the HARQ process (925). In response to receiving and/or detecting the first retransmission of the data, the UE (i) stops the multicast retransmission timer, and (ii) stops the unicast retransmission timer (930).