DRX Uplink Wakeup Using Threshold-Based Transmission Updates
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Solution Overview
Problem
In wireless communications systems, UEs in DRX mode experience power inefficiencies and latency due to unscheduled wake-ups for uplink data transmission, and outdated uplink transmission parameters that require updating before transmission, which can prolong latency and power consumption.
Innovation Solution
A UE determines the elapsed time since the last update of transmission parameters and initiates an uplink transmission (e.g., SR or RACH) before a scheduled DRX cycle if the elapsed time is less than a threshold, skipping the parameter update if the time is below the threshold, or waits for reference signals if the time exceeds the threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the UE waits to receive reference signals before transmitting uplink data, then transmission parameter accuracy is improved, but transmission latency increases
Solution Approach 1:
The UE performs uplink transmission before receiving reference signals by using previously stored transmission parameters. This preliminary action allows the UE to transmit data immediately upon waking from DRX sleep mode without waiting for reference signals, thereby reducing transmission latency while maintaining acceptable parameter accuracy through prior parameter validation
Solution Approach 2:
The system dynamically adjusts the reference signal reception timing based on the validity status of stored transmission parameters. If parameters are valid (elapsed time below threshold), the UE transmits immediately without waiting for reference signals. If parameters are invalid (elapsed time at or above threshold), the UE waits for reference signals to update parameters before transmitting. This dynamic adjustment optimizes the balance between latency and parameter accuracy
2Reliability
If the UE updates transmission parameters frequently, then transmission reliability is improved, but power consumption increases
Solution Approach 1:
The UE changes the operational state of transmission parameter updates from frequent/periodic to conditional/threshold-based. By comparing the elapsed time since the last reference signal against a threshold value, the system determines whether parameter updates are necessary. This parameter change approach maintains transmission reliability by updating parameters when needed (at or above threshold) while avoiding unnecessary updates that would consume additional power
Solution Approach 2:
Instead of performing full parameter updates every DRX cycle, the UE performs partial action by only updating transmission parameters when the elapsed time threshold is met. This partial update approach maintains sufficient transmission reliability by updating parameters when they become outdated, while significantly reducing power consumption by avoiding excessive unnecessary updates during short intervals
3Loss of time
If the UE transmits uplink data immediately upon waking, then transmission latency is reduced, but transmission reliability may deteriorate due to outdated parameters
Solution Approach 1:
The UE performs preliminary validation of stored transmission parameters before immediate uplink transmission by checking whether the elapsed time since the last reference signal is below a threshold. This preliminary check ensures that if parameters are still valid, the UE can transmit immediately with high reliability. If parameters are outdated, the UE performs the preliminary action of waiting for reference signals to update parameters, thus maintaining reliability while minimizing latency
4Use of energy by moving object
If the UE remains in DRX sleep mode, then power consumption is reduced, but responsiveness to uplink data transmission deteriorates
Solution Approach 1:
The system performs preliminary action by validating transmission parameters before the UE wakes from DRX sleep mode. By determining whether stored parameters are still valid (elapsed time below threshold), the system prepares the UE for immediate transmission upon waking. This preliminary validation ensures that when the UE does wake for uplink data, it can transmit immediately with reliable parameters, thus maintaining high responsiveness while minimizing the time spent in active state and reducing overall power consumption
Data Source
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Figure 3A~3B
AI summary
Methods, systems, and devices for wireless communications are described in which a user equipment (UE) may wake up from a sleep mode of a discontinuous reception (DRX) cycle based on receipt of uplink data. The UE may determine if an elapsed time between a prior receipt of one or more reference signals and an uplink transmission to the base station after waking up from the sleep mode is less than a threshold time value. If the elapsed time is less than the threshold time value, the UE may transmit an uplink transmission associated with the received uplink data prior to receiving one or more reference signals that may be used to update transmission parameters for uplink transmissions. If the elapsed time is at or above the threshold value, the UE may wait to receive the one or more reference signals and update the transmission parameters prior to the uplink transmission.