LTE DRX Cycle Adjustment During Handover
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Solution Overview
Problem
In LTE networks, handover latency is increased due to the DRX sleep period, leading to delayed handover commands during extended discontinuous reception cycles, which affects battery life and network responsiveness.
Innovation Solution
The user equipment (UE) can transition to continuous channel monitoring or a shorter DRX sleep period after sending a measurement report, and the source eNB can signal the UE to adjust its DRX cycle based on handover initiation decisions and estimated latency, ensuring timely handover processing and minimizing battery consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the UE uses extended DRX sleep period to save battery, then battery life is improved, but handover latency increases
Solution Approach 1:
The patent applies dynamics by making the DRX cycle length adjustable rather than fixed. The UE transitions between different DRX cycle configurations based on handover status: using extended DRX cycles during normal operation to save battery, and switching to shorter DRX cycles or continuous monitoring when handover is detected or expected, thereby dynamically optimizing both battery life and handover responsiveness
Solution Approach 2:
The patent applies preliminary action by having the UE send measurement reports that trigger handover preparation in advance. The source eNB initiates handover procedures before the UE would naturally wake from an extended DRX sleep period, and the UE transitions to a shorter DRX cycle or continuous monitoring in anticipation of the upcoming handover command, ensuring it will be responsive when the command arrives
2Loss of time
If the UE monitors channel continuously to reduce handover latency, then handover latency is reduced, but battery consumption increases
Solution Approach 1:
The patent applies periodic action by using DRX (Discontinuous Reception) cycles where the UE periodically wakes to monitor channels and then returns to sleep mode. During normal operation, extended periodic cycles are used to minimize battery consumption. When handover is triggered or anticipated, the periodic action frequency increases (shorter cycles or continuous monitoring), reducing handover latency while maintaining battery efficiency during non-critical periods
Solution Approach 2:
The patent makes the channel monitoring behavior dynamic by transitioning between extended DRX cycles and shorter DRX cycles or continuous monitoring based on handover status. This dynamic adjustment allows the system to optimize battery consumption during stable conditions while ensuring low latency responsiveness when handover events occur
Data Source
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AI summary
A method and system for efficient DRX operation during handover in LTE_ACTIVE in which a user equipment expects handover to occur, the method having the steps of: checking (114,314) whether a no handover initiation decision is received within a predetermined time period; if no, performing the steps of: ensuring (118,320) the user equipment is not in a DRX sleep period during reception of a handover grant; checking (120,322) whether a handover grant is received, and if yes, performing (122,330) a handover procedure; and if no, resuming (125,340) a DRX sleep interval; and if yes, ending (116,316) the process.