Discontinuous Reception Listening Indication for Idle State Power Saving
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Solution Overview
Problem
In LTE systems, User Equipment (UE) in an idle state experiences high power consumption and shortened battery life due to periodic wake-ups to listen for control information on the Physical Downlink Control Channel, leading to inefficient energy usage.
Innovation Solution
Implementing discontinuous reception (DRX) by receiving listening indication information from the base station to determine whether to continue listening for control information, allowing the UE to switch between DRX on and off stages based on the presence of downlink transmission units or control signaling, thereby reducing unnecessary listening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE periodically wakes up to listen for control information on the Physical Downlink Control Channel in the on-duration stage, then the UE can detect scheduling information and switch to active state when needed, but the power consumption of the UE increases and battery life is shortened
Solution Approach 1:
The patent implements discontinuous reception by dividing the reception cycle into periodic on-duration stages and off-duration stages. During off-duration stages, the UE stops listening to save power, while during on-duration stages, the UE wakes up to check for scheduling information. This periodic action pattern resolves the contradiction by making the listening behavior periodic rather than continuous, thereby reducing overall power consumption while maintaining the ability to detect scheduling information when needed.
Solution Approach 2:
The patent uses a wake-up signal mechanism where the base station sends a preliminary indication before the actual scheduling information. The UE first checks for the wake-up signal during the on-duration stage, and only if the signal indicates activity is present does the UE proceed to fully wake up and decode the control information. This preliminary action allows the UE to avoid unnecessary full wake-ups, thereby reducing power consumption while ensuring reliable detection when scheduling information is actually present.
2Reliability
If the UE continues to listen for control information throughout the entire DRX on stage, then no scheduling information is missed, but invalid detection occurs when no downlink transmission is scheduled, wasting energy
Solution Approach 1:
The patent extracts the essential function of detecting scheduling information from the continuous listening process. By using wake-up signals and transmission direction indication information, the UE can determine in advance whether downlink transmission is scheduled before performing full control information detection. This extraction of the critical detection function from the continuous listening process eliminates invalid detections and associated energy waste while maintaining reliable detection when scheduling information is actually present.
Solution Approach 2:
The patent introduces preliminary indication mechanisms (wake-up signals and transmission direction indication information) that are sent before the actual control information. The UE first checks these preliminary indicators during the on-duration stage, and only proceeds to fully decode control information when the indicators suggest activity is present. This preliminary action prevents invalid detections and energy waste while ensuring that valid scheduling information is reliably detected.
Data Source
AI summary
A method for implementing discontinuous reception includes: when UE is switched from a DRX off stage in an idle state to a DRX on stage, listening indication information sent by a base station is received; and when it is determined based on the listening indication information that it is not needed to continue listening control information in the DRX on stage, the UE is controlled to switch from the DRX on stage to the DRX off stage.