DRX Active Time Alignment Across Uu and Sidelink Interfaces
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Solution Overview
Problem
In 5G NR communication systems, there is a need to align discontinuous reception (DRX) active times across Uu and sidelink (SL) interfaces to ensure that sidelink grants scheduled during Uu DRX active times of transmitting user equipment (UEs) coincide with the DRX active times of receiving UEs, thereby optimizing power management and communication efficiency.
Innovation Solution
The method involves determining a Uu active time and offset time for transmitting UEs, accounting for processing times of sidelink resource grants and data transmission, and synchronizing these with the DRX active times of receiving UEs, ensuring that sidelink active times start no earlier than the Uu active time plus the offset and end no later than the Uu active time, while considering factors like path loss, traffic patterns, and quality of service.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DRX active times are not aligned across Uu and sidelink interfaces, then transmitting UEs can operate independently on each interface, but sidelink grants scheduled during Uu DRX active times will not coincide with receiving UE DRX active times, causing communication inefficiency and increased power consumption
Solution Approach 1:
The system performs preliminary determination of offset times for transmitting UEs and preliminary determination of active times for receiving UEs before actual sidelink communication occurs. This advance planning ensures that sidelink grants scheduled during Uu DRX active times will coincide with receiving UE DRX active times, preventing communication failures while allowing UEs to enter sleep modes efficiently.
Solution Approach 2:
The system dynamically adjusts the offset time parameter for transmitting UEs and the active time parameters for receiving UEs based on their respective DRX configurations. By changing these time parameters, the system aligns sidelink communication windows with both transmitting and receiving UEs' active periods, ensuring reliable communication while optimizing power consumption.
2Manufacturing precision
If offset time is not accounted for in transmitting UE DRX configuration, then Uu DRX active time determination is simpler, but sidelink grant processing and data transmission timing will be misaligned
Solution Approach 1:
The system performs preliminary determination of the offset time for the transmitting UE, accounting for processing of sidelink resource grants and data for sidelink transmission before actual communication occurs. This advance calculation of the offset time ensures precise timing alignment without adding complex real-time adjustments.
Solution Approach 2:
The system segments the timing configuration by treating the offset time as a separate, predetermined parameter distinct from the main DRX active time. This segmentation allows the offset to be calculated and configured independently, simplifying the overall configuration process while maintaining precise timing control for sidelink communications.
3Reliability
If RxUE SL active times are not constrained within TxUE Uu DRX active time windows, then receiving UEs can operate with more flexible scheduling, but sidelink communication reliability will deteriorate when TxUEs are in DRX sleep modes
Solution Approach 1:
The system applies different timing constraints to different UEs based on their roles. Transmitting UEs have their Uu DRX active times with specific offset requirements, while receiving UEs have their SL active times constrained within those same windows. This localized quality approach ensures that each UE operates with appropriate timing characteristics for its function, maintaining reliability while preserving necessary flexibility.
Solution Approach 2:
The system performs preliminary determination of both the transmitting UE's Uu DRX active time and the receiving UE's SL active time before sidelink communication occurs. This advance coordination ensures that receiving UEs are awake and ready to receive during the exact windows when transmitting UEs will send data, guaranteeing communication reliability while allowing flexible DRX configuration.
Data Source
AI summary
For each UE (TxUE) in discontinuous reception (DRX) in sidelink (SL) with each second UE(RxUE), and in communication over an air interface (Uu) with a gNB, determining a TxUE Uu active time. Further determining a TxUE Uu offset time accounting for TxUE processing of both a TxUE SL grant from the gNB and data for SL transmission to each RxUE. The TxUE Uu offset time is greater than or equal to a minimum TxUE Uu offset time. Further determining, for each RxUE, one or more RxUE SL active times, each RxUE SL active time: starting no earlier than a start of the TxUE Uu active time plus the TxUE Uu offset time for a TxUE from which the each RxUE is to receive data, and ending no later than the end of the TxUE Uu active time for a TxUE from which the each RxUE is to receive data.