User Equipment Sleep DRX Mode for Wireless Latency and Energy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional DRX solutions in LTE wireless networks are inefficient for bursty data and short packet transmissions, leading to high energy consumption and long wake-up latency, especially in ultra-dense networks.
Innovation Solution
A user equipment with a novel 'sleep DRX' mode that switches the receiver on and off synchronously with downlink control signals, maintaining an RRC connection and using explicit wake-up signals to optimize power consumption and reduce latency, allowing for shorter subframes and improved mobility handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional DRX schemes are used in LTE, then energy saving is achieved during idle mode, but wake-up latency becomes very long due to random access procedure and RRC connection establishment
Solution Approach 1:
The UE performs cell search, synchronization, and system information acquisition in advance during idle mode before entering connected mode. This preliminary action prepares the UE so that when data arrives, it only needs to perform random access and RRC connection establishment rather than starting from scratch, significantly reducing wake-up latency while maintaining energy efficiency
Solution Approach 2:
The patent implements dynamic switching between idle mode and connected mode DRX based on data arrival patterns. When data arrives, the UE transitions to connected mode with optimized DRX parameters. This dynamic adaptation allows the system to balance energy saving during idle periods with low latency when data transmission is needed
2Use of energy by moving object
If DRX is optimized for long packets, then energy consumption is reduced, but performance deteriorates for bursty data and short packet transmissions
Solution Approach 1:
The patent dynamically adjusts DRX parameters including cycle length, on-duration, and offset based on the characteristics of incoming data. For short packets and bursty traffic, the system uses shorter DRX cycles and optimized on-duration timings to ensure the UE is awake when data arrives, maintaining high productivity while adapting energy consumption to actual traffic patterns
Solution Approach 2:
The patent segments the DRX operation into different phases: idle mode DRX for maximum energy saving, connected mode DRX for active data transmission, and transition phases. This segmentation allows optimization for different traffic types - long packets use extended DRX cycles while short bursts use aggressive wake-up schedules, resolving the contradiction between energy efficiency and transmission efficiency
3Reliability
If receiver is kept on continuously, then data reception reliability is improved, but energy consumption increases significantly
Solution Approach 1:
The patent implements periodic DRX cycles where the receiver alternates between active and sleep states. During connected mode, the UE wakes up at scheduled intervals to monitor PDCCH for downlink assignments. This periodic operation maintains data reception reliability by ensuring the receiver is active when data is scheduled while dramatically reducing energy consumption during sleep periods
Solution Approach 2:
The system uses feedback mechanisms where the network scheduler monitors UE availability and adjusts downlink scheduling accordingly. When the UE is in DRX sleep mode, the network can buffer data and schedule transmission during UE wake-up periods, ensuring reliable delivery without requiring continuous receiver operation
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Implementations described herein relate generally to a user equipment, to an access node, and to methods for a user equipment and for an access node. The user equipment includes a receiver configured to receive a downlink control signal (CTRLS) over a downlink control channel (PDCCH) from an access node. The user device also includes a processor configured to, when the user equipment is in a Radio Resource Control (RRC) connected mode, switch on the receiver at a time point (tstart_symbol) when a symbol comprising the downlink control signal (CTRLS) starts in time domain. The processor is further configured to switch off the receiver at a time point (tend_symbol) when the symbol comprising the downlink control channel (CTRLS) ends in time domain.