Two-Layer DRX Control for Power Saving and Low-Latency Scheduling
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Solution Overview
Problem
Existing LTE wireless systems face challenges in optimizing discontinuous reception (DRX) for power savings while maintaining flexibility in data transmission and handling varying data traffic patterns, particularly in RRC_CONNECTED state, where current DRX methods struggle to balance power consumption and scheduling efficiency.
Innovation Solution
Implementing a two-layer DRX operation with RRC-controlled regular DRX and MAC-controlled interim DRX, utilizing RRC signaling for reliable DRX settings and configuration information, and MAC signaling for quick DRX activation commands, along with dynamic DRX cycle adjustments based on data availability and WTRU capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If DRX is activated to save power, then energy consumption is reduced, but data transmission flexibility and scheduling efficiency deteriorate
Solution Approach 1:
The patent segments DRX operation into two distinct layers: RRC-controlled regular DRX for power saving and MAC-controlled interim DRX for flexible data transmission. This segmentation allows each layer to independently manage different aspects of DRX, resolving the contradiction by enabling simultaneous power saving and transmission flexibility through coordinated operation of the two layers
Solution Approach 2:
The patent implements dynamic DRX cycle adjustments where the MAC layer can modify DRX parameters based on real-time data availability and WTRU activity. The interim DRX mechanism allows dynamic switching between different DRX configurations, enabling the system to adapt to varying traffic patterns while maintaining power efficiency
2Use of energy by moving object
If DRX cycle length is increased to save more power, then energy consumption is reduced, but latency and responsiveness to data arrivals increase
Solution Approach 1:
The patent implements periodic DRX cycles at the RRC layer for power saving while superimposing periodic monitoring opportunities at the MAC layer. The interim DRX mechanism creates additional periodic wake-up instances within the longer RRC DRX cycle, allowing the WTRU to check for data arrivals more frequently without fully abandoning the power-saving benefits of the longer cycle
Solution Approach 2:
The MAC layer performs preliminary actions by monitoring for data arrivals during the active periods of the RRC DRX cycle. When data is detected, the MAC layer can trigger interim DRX adjustments to ensure timely data transmission, preventing latency issues before they occur
3Reliability
If RRC signaling is used for DRX configuration, then reliability of DRX settings is improved, but signaling overhead and complexity increase
Solution Approach 1:
The patent segments the DRX signaling function into two parts: RRC signaling for reliable configuration of regular DRX parameters, and MAC signaling for efficient control of interim DRX operations. This segmentation reduces overall signaling complexity by assigning different signaling tasks to the most appropriate layer, while maintaining reliability for critical configurations
Solution Approach 2:
The MAC layer acts as an intermediary between the RRC layer and the physical layer for DRX control. It receives reliable configuration from RRC and translates it into actionable interim DRX commands, reducing the direct signaling burden on RRC while maintaining configuration reliability through the intermediary's coordination
Data Source
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AI summary
A method of discontinuous reception (DRX) in a wireless transmit receive unit (WTRU). The method includes the WTRU receiving DRX setting information over a radio resource control (RRC) signal, and the WTRU receiving DRX activation information over medium access control (MAC) signal.