Scheduling Request Triggering for LTE Handover Flow Continuity
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Solution Overview
Problem
In LTE mode, during handovers with high cell interference and poor signal quality, user equipment experiences reduced FTP flow rates, suspended data transmission, and potential loss of uplink authorization, leading to prolonged FTP window blockage and connection disconnection.
Innovation Solution
A method and apparatus that set an advance time interval for triggering a scheduling request when user equipment hands over to a new cell, determining a trigger time based on the subframe for sending uplink data, and triggering the request accordingly to ensure timely uplink FTP data transmission and prevent flow interruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conventional BSR trigger condition is used for scheduling request, then the scheduling request is triggered only when buffer status changes, but the uplink FTP data transmission is blocked for a long time during handover due to loss of uplink authorization
Solution Approach 1:
The patent applies preliminary action by triggering a scheduling request in advance during handover before the conventional BSR trigger condition would activate. Specifically, when the MAC entity detects handover execution, it triggers a scheduling request proactively with a priority level higher than conventional BSR triggers, ensuring uplink authorization is obtained before data transmission is blocked, thus preventing FTP window blockage and maintaining transmission reliability
2Device complexity
If the scheduling request is triggered only when conventional BSR trigger condition is satisfied, then the device complexity is reduced, but the FTP connection is disconnected finally due to prolonged uplink authorization loss
Solution Approach 1:
The patent applies dynamics by implementing a dynamic scheduling request trigger mechanism that adapts to handover scenarios. The MAC entity dynamically determines whether to trigger a scheduling request based on detecting handover execution, and if triggered, it dynamically sets a priority level higher than conventional BSR triggers. This dynamic adaptation ensures FTP connection reliability during handover without significantly increasing overall system complexity
Solution Approach 2:
The patent applies parameter changes by modifying the priority level parameter of the scheduling request trigger. When handover is detected, the trigger priority is changed to a higher level than conventional BSR triggers, ensuring the scheduling request is processed with higher urgency. This parameter change enables the system to differentiate between normal buffer status changes and handover-induced authorization loss, maintaining FTP connection reliability
Data Source
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AI summary
A method and apparatus for processing a scheduling request in a handover scenario are provided. The method comprises: when user equipment has just handed over to a new cell, setting an advance time interval for triggering a scheduling request in advance according to a number of a subframe for sending a handover completion message of the user equipment; in the advance time interval, determining a trigger time for triggering the scheduling request in advance according to the number of the subframe for sending uplink data of the user equipment; and triggering the scheduling request in advance according to the trigger time. The technical solution is applied to guarantee that uplink FTP data are sent in time through sending a triggered scheduling request in advance, and avoid the occurrence of the FTP flow interruption phenomenon.