RLC Retransmission Timing with DRX On-Duration Alignment
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Solution Overview
Problem
RLC retransmissions in wireless communications networks using Discontinuous Reception (DRX) often miss onDuration opportunities, leading to increased delays and potential call drops due to the RLC ARQ functionality's unawareness of DRX transmission restrictions, particularly impacting time-critical procedures like handovers.
Innovation Solution
A method where a network node determines the time until the next DRX on-duration period to allow for Hybrid Automatic Repeat Request (HARQ) operations to complete retransmissions of Medium Access Control (MAC) PDUs associated with RLC PDUs, ensuring retransmissions do not miss transmission opportunities and thus improving network performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If RLC ARQ retransmissions are performed without considering DRX on-duration periods, then retransmission operations can be initiated immediately, but transmission opportunities are missed and delays increase
Solution Approach 1:
The network node determines the timing of DRX on-duration periods in advance and schedules RLC retransmissions to coincide with these predetermined windows, ensuring transmission opportunities are not missed while maintaining efficient retransmission operations
Solution Approach 2:
The system dynamically adjusts retransmission timing based on the UE's DRX cycle configuration, adapting the RLC retransmission schedule to match the varying on-duration periods while maintaining optimal transmission speed within available windows
2Reliability
If RLC retransmissions are aligned with DRX on-duration periods, then transmission opportunities are maximized, but system complexity increases due to coordination requirements
Solution Approach 1:
The network node utilizes feedback information from the UE regarding DRX cycle configuration and on-duration timing to automatically adjust RLC retransmission schedules, achieving reliable transmission coordination without complex manual configuration
Solution Approach 2:
The system achieves self-coordination by having the network node autonomously determine retransmission timing based on received DRX parameters, eliminating the need for complex external scheduling coordination while maximizing transmission reliability
3Productivity
If RLC retransmissions ignore HARQ operation completion time, then retransmission can start immediately, but HARQ operations are interrupted and data integrity is compromised
Solution Approach 1:
The network node calculates and reserves sufficient time for HARQ operation completion before initiating RLC retransmissions, ensuring data integrity is maintained while efficiently utilizing available time windows for retransmission operations
Data Source
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AI summary
A method performed by a network node for retransmitting a Radio Link Control, Protocol Data Unit (RLC PDU), to a UE is provided. The UE and the network node operate in a wireless communications network. The UE is configured to use Discontinuous Reception (DRX). When an RLC PDU transmitted to the UE is indicated to not being received by the UE, the network node determines (601 ) a time until a first DRX on-duration time period that is possible to allow time for Hybrid Automatic Repeat Request (HARQ) operations to complete a retransmission of a Medium Access Control (MAC) PDU. The MAC PDU is associated to the RLC PDU. The network node then initiates a retransmission (603) of the RLC PDU to the UE according to the determined time.