Dynamic Playback Buffer Adjustment for Handover Reliability
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Solution Overview
Problem
During handovers in mobile networks, especially in LTE, users experience playback interruptions and low video quality due to buffer underrun and insufficient pre-configured playback buffer sizes, which can lead to data waste if the buffer is overfilled before streaming completion.
Innovation Solution
A method to dynamically adjust the playback buffer levels in User Equipment (UE) by increasing the upper and lower buffer settings based on measurements indicating an upcoming handover, allowing for a larger data download before the handover occurs, thereby maintaining higher video quality during the transition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the playback buffer size is increased to prevent buffer underrun during handover, then playback reliability is improved, but data resource waste increases due to user abandonment of streaming before completion
Solution Approach 1:
The buffer size is made dynamic rather than static. The system adjusts the buffer size in real-time based on handover detection: when handover is detected, the buffer size is increased to prevent underrun; when normal operation continues, the buffer size returns to its original value. This dynamic adjustment resolves the contradiction by only increasing buffer size when necessary for reliability, avoiding continuous resource waste.
Solution Approach 2:
The buffer size parameter is changed based on system state. Upon detecting handover conditions, the buffer size parameter is modified to a larger value to ensure playback continuity. When handover completes or is not detected, the parameter reverts to its original value. This parameter change strategy allows the system to optimize reliability during critical handover periods while minimizing resource waste during normal operation.
2Stability of the object's composition
If the buffer size is pre-configured to be large enough to cover handover interruption, then playback continuity is improved, but the complexity of buffer management increases
Solution Approach 1:
The system performs self-service by automatically detecting handover conditions and adjusting buffer size without requiring complex external buffer management mechanisms. The playback client monitors its own buffer state and network conditions, detecting handover interruptions and autonomously adjusting the buffer size to maintain continuity, thereby avoiding the need for complex centralized buffer management.
Solution Approach 2:
The system uses feedback from buffer state monitoring and handover detection to automatically adjust buffer size. When the system detects that the buffer is approaching dangerous levels or that handover is occurring, it receives feedback about this state and responds by adjusting the buffer size accordingly, maintaining playback continuity through a simple feedback loop rather than complex management procedures.
3Reliability
If rate adaptation is used to step down to lower rate during handover, then buffer underrun is reduced, but video quality deteriorates and the adaptation may not be fast enough to compensate for throughput degradation
Solution Approach 1:
Instead of reactively reducing rate during handover, the system takes preliminary action by increasing the buffer size before and during handover to store enough media data to cover the interruption period. This preliminary buffer filling allows the system to maintain the original playback rate and video quality while simply having sufficient data in the buffer to survive the handover interruption, avoiding the quality deterioration associated with rate adaptation.
Data Source
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AI summary
There is provided methods that enables a User Equipment to adjust a playback buffer in the case of a potential handover to thereby mitigate problems with buffer underrun and freezing of playback of media content. There is also provided a User Equipment and a Network Controller configured to perform the steps of the methods as well as a computer program.