DRX Retransmission Timer Power Optimization in LTE
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Solution Overview
Problem
In the LTE wireless communications system, the DRX Retransmission Timer causes unnecessary power consumption as the UE continues to monitor the PDCCH even when no retransmission packets are received during the HARQ process, leading to increased power usage.
Innovation Solution
The method involves starting and stopping the DRX Retransmission Timer based on the indication of downlink transmissions by the PDCCH, regardless of successful decoding, to prevent unnecessary monitoring and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the DRX Retransmission Timer is kept running to monitor for retransmission packets, then the UE can detect retransmissions, but power consumption increases unnecessarily during HARQ round trip time
Solution Approach 1:
The patent applies dynamics by making the DRX Retransmission Timer adjustable and conditional rather than static and continuous. The timer's running state is dynamically changed based on whether the UE is in active monitoring mode or sleep mode, allowing the system to adapt its behavior to current operational needs and optimize power consumption while maintaining retransmission detection capability when necessary
Solution Approach 2:
The patent implements periodic action by introducing specific time windows (DRX active periods) during which the UE monitors for retransmissions, separated by sleep periods. The DRX Retransmission Timer is configured to operate periodically within these active windows rather than continuously, enabling the UE to wake up at scheduled intervals to check for retransmissions and then return to sleep mode, thus reducing overall power consumption while maintaining reliable detection
2Reliability
If the UE monitors PDCCH continuously during DRX Retransmission Timer operation, then no retransmission packets are missed, but standby time is reduced
Solution Approach 1:
The patent applies periodic action by configuring the DRX Retransmission Timer to operate in periodic cycles with defined active monitoring periods and sleep periods. During active periods, the UE monitors PDCCH for retransmissions; during sleep periods, the UE stops monitoring to extend standby time. This periodic operation pattern ensures that retransmissions are detected when they occur during active windows while maximizing battery life through extended sleep intervals
Solution Approach 2:
The patent makes the monitoring duration dynamic by adjusting the DRX Retransmission Timer's operation based on system state and traffic conditions. The timer can be configured to run for different durations or be suspended entirely depending on whether data transmission is active, allowing the system to extend standby time during idle periods while maintaining reliable packet reception during active transmission periods
Data Source
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AI summary
A method for improving discontinuous reception (DRX) functionality for a user equipment (UE) of a wireless communication system is disclosed. The method includes steps of starting a DRX Retransmission Timer to monitor a Physical Downlink Control Channel (PDCCH) (502); and stopping the DRX Retransmission Timer when a downlink transmission for a Hybrid Automatic Repeat Request (HARQ) process is indicated by the monitored PDCCH no matter whether the downlink transmission is successfully decoded (504).