DRX Timer Configuration for Multicast HARQ Retransmission
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Solution Overview
Problem
Current wireless communication systems face inefficiencies in managing Discontinuous Reception (DRX) timers for multicast data reception, particularly in scenarios where UE does not support PTM retransmission via C-RNTI, leading to unnecessary power consumption and resource wastage.
Innovation Solution
The proposed solution involves clarifying that a UE does not need to start the drx-HARQ-RTT-TimerDL for the corresponding HARQ process after receiving a PTM transmission if it does not support PTM retransmission via C-RNTI, optimizing DRX configurations to avoid unnecessary monitoring of the PDCCH for unicast retransmissions when no unicast retransmission is scheduled.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a UE starts the drx-HARQ-RTT-TimerDL for the corresponding HARQ process after receiving a PTM transmission, then the UE can monitor for potential retransmissions, but the UE experiences unnecessary power consumption and resource wastage when it does not support PTM retransmission via C-RNTI
Solution Approach 1:
The patent changes the operational parameters of the DRX timer based on the UE's capability to support PTM retransmission. When the UE does not support PTM retransmission via C-RNTI, the timer configuration is modified to prevent unnecessary activation, thereby changing the energy consumption parameter from high to low while maintaining appropriate retransmission monitoring capability.
Solution Approach 2:
The patent applies partial action by selectively activating the drx-HARQ-RTT-TimerDL only when necessary (when PTM retransmission is supported). When PTM retransmission is not supported, the timer activation is partially suppressed, avoiding excessive monitoring actions that would consume unnecessary power while still maintaining basic reception functionality.
2Reliability
If a UE monitors the PDCCH for unicast retransmissions during DRX cycles, then the UE can receive retransmitted data, but the UE experiences resource utilization inefficiencies when unicast retransmissions are not scheduled
Solution Approach 1:
The patent modifies the monitoring behavior parameters by adjusting the DRX timer configuration based on UE capability. When PTM retransmission is not supported, the monitoring parameters are changed to reduce PDCCH checking frequency, improving resource utilization efficiency while maintaining data reception capability through alternative mechanisms.
Solution Approach 2:
The patent introduces dynamic adjustment of PDCCH monitoring behavior based on real-time conditions (whether unicast retransmission is scheduled and UE capability). The monitoring intensity and timing are dynamically adapted to match actual network conditions, preventing wasteful resource utilization during periods when unicast retransmissions are not scheduled.
Data Source
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AI summary
A method and apparatus are disclosed. In an example from the perspective of a User Equipment, UE, the UE receives and/or detects a multicast transmission of downlink data on a configured downlink multicast resource, wherein the multicast transmission is associated with a Hybrid Automatic Repeat Request, HARQ, process (1005). The UE starts a multicast HARQ Round Trip Time, RTT, timer associated with the HARQ process (1010). The UE determines whether to start a unicast HARQ RTT timer associated with the HARQ process based on whether the UE is configured with a Configured Scheduling Radio Network Temporary Identifier, CS-RNTI, (1015).