Adaptive De-Jitter Buffer for Voice Playback
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Solution Overview
Problem
VoIP systems over the Internet lack adaptive de-jitter buffer management, leading to sub-optimal user experience due to unnecessary delay and distortion caused by unanticipated packet delay variations, as current de-jitter buffers are reactive and often configured with conservatively large sizes.
Innovation Solution
A method for adapting de-jitter buffers by detecting air link characteristics, estimating packet delay, and dynamically adjusting the buffer size to anticipate and manage jitter, including initialization and handoff events, using a processor to calculate and configure the de-jitter buffer size based on measured air link characteristics and scheduled handoffs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If de-jitter buffer size is configured conservatively large, then packet delay variations can be handled, but unnecessary delay is added to message playback
Solution Approach 1:
The de-jitter buffer size is made dynamic rather than static, allowing it to adapt its size based on current network conditions. The buffer automatically adjusts between minimum and maximum sizes in response to detected air interface characteristics, enabling it to handle packet delay variations when needed while minimizing delay when conditions are good.
Solution Approach 2:
The buffer size parameter is changed dynamically based on air interface conditions. The system monitors air interface characteristics and adjusts the de-jitter buffer size parameter accordingly, transitioning between different buffer size states to optimize the trade-off between handling delay variations and minimizing playback delay.
2Reliability
If de-jitter buffer is configured with large size, then packet delay variations are accommodated, but user experience deteriorates due to unnecessary delay
Solution Approach 1:
The buffer transitions from a static large-size configuration to a dynamic configuration that adapts to actual network conditions. This dynamic behavior ensures the buffer only uses large sizes when necessary, improving user experience by eliminating unnecessary delay while maintaining reliability when packet delay variations occur.
Solution Approach 2:
The de-jitter buffer system monitors air interface conditions itself and automatically adjusts its own buffer size without external intervention. This self-service capability allows the buffer to optimize performance based on real-time conditions, accommodating packet delays when needed while minimizing delay for good conditions, thereby improving overall user experience.
3Adaptability or versatility
If de-jitter buffer is reactive and adjusts only after packet delay changes, then adaptation to current conditions is achieved, but anticipation of changes is lost
Solution Approach 1:
The system performs preliminary actions by detecting air interface characteristics and anticipating packet delay changes before they fully manifest. By monitoring air interface conditions, the de-jitter buffer can proactively adjust its size in advance of actual packet delay variations, rather than waiting reactively for delays to occur.
Solution Approach 2:
The system implements feedback by continuously monitoring air interface characteristics and using this information to adjust buffer size. This feedback mechanism enables the buffer to respond to changing network conditions in real-time, improving both the timeliness of adaptation and the accuracy of anticipating packet delay variations.
4Loss of time
If de-jitter buffer size is dynamically adjusted based on air interface characteristics, then unnecessary delay is reduced, but system complexity increases
Solution Approach 1:
The de-jitter buffer system performs self-service by autonomously monitoring air interface characteristics and adjusting its own buffer size without requiring complex external control mechanisms. This self-managing approach reduces the need for additional system complexity while achieving dynamic buffer optimization to minimize playback delay.
Solution Approach 2:
The system manages complexity by focusing parameter changes primarily on the buffer size based on air interface conditions. Rather than complex multi-parameter adjustments, the invention simplifies the control mechanism to primarily adjust the buffer size parameter in response to air interface characteristics, reducing overall system complexity while achieving the goal of minimizing unnecessary delay.
Data Source
AI summary
Systems and methods for adapting a de-jitter buffer to conform to air link conditions. An air link characteristic may be detected before that characteristic begins to affect packet delivery, such as by slowing or speeding delivery delay at a subscriber station. A receiver-side de-jitter buffer, which adds delay to received packets, may adaptively adjust its size based upon the detected air link characteristic, such that the de-jitter buffer is appropriately sized for anticipated data packets before they are received at the subscriber station.