Sidelink BWP Deactivation and DRX Timer Coordination
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Solution Overview
Problem
Current wireless communication systems face challenges in optimizing the timing of sidelink transmission and resource allocation for devices operating in sidelink resource allocation mode 1, particularly during discontinuous reception (DRX) active times, especially when sidelink HARQ feedback is disabled, leading to inefficiencies in sidelink communication.
Innovation Solution
Implementing a method where a DRX HARQ round trip time (RTT) timer starts after a specific repetition of sidelink transmission, and a DRX retransmission timer is initiated upon expiry of the HARQ RTT timer and a maximum number of transmissions not being reached, allowing for optimized PDCCH monitoring during the active time for sidelink retransmission grants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a UE simultaneously performs UL transmission and SL transmission, then communication efficiency is improved, but it becomes difficult to properly handle BWP deactivation and timing coordination
Solution Approach 1:
The patent implements dynamic BWP switching and deactivation mechanisms that adapt to the UE's transmission state. When UL and SL transmissions overlap, the system dynamically deactivates SL BWP and adjusts timing coordinates based on real-time transmission requirements, allowing the UE to efficiently handle simultaneous transmissions without manual configuration complexity
Solution Approach 2:
The patent changes key timing parameters including the start point of active time for PDCCH monitoring and the timing of BWP deactivation. By adjusting these parameters dynamically based on transmission type and HARQ feedback status, the system resolves conflicts between UL and SL transmissions while maintaining high communication efficiency
2Reliability
If PDCCH monitoring is continuously performed for SL retransmission grants, then retransmission reliability is improved, but power consumption increases during DRX operation
Solution Approach 1:
The patent implements periodic PDCCH monitoring during DRX operation by defining specific active time intervals. The UE monitors PDCCH for SL retransmission grants only during these periodic active periods rather than continuously, reducing power consumption while ensuring reliable retransmission detection when needed
Solution Approach 2:
The system autonomously determines the start and end points of active time based on HARQ RTT timer expiry and timing coordinate information, without requiring continuous network control. This self-managed monitoring approach optimizes the balance between reliability and power consumption by activating monitoring only when retransmission grants are expected
3Speed
If the start point of active time for PDCCH monitoring is set early, then SL retransmission timing is improved, but system resource allocation efficiency deteriorates
Solution Approach 1:
The patent sets the start point of active time for PDCCH monitoring based on preliminary timing calculations using the timing coordinate provided by the network and the HARQ RTT timer expiry. This preliminary positioning ensures the UE is ready to receive retransmission grants at the optimal moment without unnecessarily extending the active time period, thus improving timing while maintaining resource efficiency
Solution Approach 2:
The patent optimizes the active time start parameter by calculating it as a function of the timing coordinate and HARQ RTT timer expiry rather than using fixed offsets. This dynamic parameter adjustment achieves early enough monitoring start for timely retransmissions while avoiding excessive resource allocation
Data Source
AI summary
A method and apparatus for bandwidth parts (BWPs) deactivation and discontinuous reception (DRX) for communication between wireless devices is provided. A first wireless device operating in a wireless communication system performs transmission of a media access control (MAC) protocol data unit (PDU) to a second wireless device, and starts a discontinuous (DRX) hybrid automatic repeat request (HARQ) round trip time (RTT) timer for a HARQ process ID after end of a specific repetition of the transmission of the MAC PDU. The first wireless device starts a DRX retransmission timer based on 1) the DRX HARQ RTT timer being expired, and 2) a number of transmissions of the MAC PDU not reaching a maximum number of transmissions, and monitors a physical downlink control channel (PDCCH) carrying a sidelink retransmission grant during an active time including a time interval for which the DRX retransmission timer is running.