Adaptive Jitter Buffer Level Control via Probability Mass Function
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Solution Overview
Problem
Existing jitter buffer systems face a trade-off between buffer delay and packet losses, with prior methods struggling to accurately estimate and control end-to-end delay due to sample clock drift and requiring synchronized clocks, leading to suboptimal performance in maintaining continuous audio playback.
Innovation Solution
An adaptive jitter buffer system that continuously updates a probability mass function for inter-arrival times to determine a suitable buffer level, minimizing a cost function that balances delay and expected duration of an empty buffer, using a weighting factor to account for different data traffic types and adjusting the buffer level based on statistical measures of network conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the buffer level is increased to reduce packet losses, then the reliability of continuous playback is improved, but the buffer delay increases which is detrimental to two-way human communication
Solution Approach 1:
The jitter buffer level is made dynamic and adaptive rather than fixed. The buffer level is continuously adjusted based on real-time statistical measures of network conditions, specifically using a probability mass function that is updated with observed inter-arrival times between packets. This allows the system to optimize the trade-off between buffer delay and packet losses adaptively.
Solution Approach 2:
The system changes the buffer level parameter based on network conditions. By using a probability mass function to model inter-arrival times and calculating the expected duration of an empty buffer, the system determines an optimal buffer level that minimizes a cost function balancing delay and packet loss risk, rather than using a static buffer level.
2Loss of time
If the buffer level is decreased to reduce delay, then the responsiveness to two-way communication is improved, but the probability of packet losses due to late arrivals increases
Solution Approach 1:
The system implements feedback by continuously monitoring network conditions through observed inter-arrival times between packets. This feedback is used to update the probability mass function, which in turn is used to calculate the expected duration of an empty buffer and adjust the buffer level accordingly. This closed-loop control allows the system to respond to changing network conditions and maintain optimal performance.
Solution Approach 2:
The jitter buffer level is made dynamic and adaptive rather than fixed. The buffer level is continuously adjusted based on real-time statistical measures of network conditions, specifically using a probability mass function that is updated with observed inter-arrival times between packets. This allows the system to optimize the trade-off between buffer delay and packet losses adaptively.
3Measurement precision
If synchronized clocks are used to estimate end-to-end delay, then the delay estimation accuracy is improved, but the system complexity increases due to clock synchronization requirements
Solution Approach 1:
The invention extracts and eliminates the complex clock synchronization requirement from the system. Instead of using synchronized clocks at both ends to estimate end-to-end delay, the solution uses only the receiver's local clock to measure inter-arrival times between packets. This local measurement approach achieves sufficient accuracy without the complexity of maintaining synchronized clocks across distributed systems.
Solution Approach 2:
The probability mass function serves as an intermediary that bridges the gap between simple local measurements and accurate delay characterization. By modeling the statistical distribution of inter-arrival times, the system can derive meaningful insights about network conditions and buffer underflow risk without directly measuring end-to-end delay using complex synchronized timing mechanisms.
Data Source
AI summary
The invention relates to a method and a receiver having control logic means for determining a target packet level of a jitter buffer adapted to receive packets with digitized signal samples, which packets are subject to delay jitter, from a packet data network. According to the invention, the jitter buffer is made adaptive to current network conditions, i.e., the nature and magnitude of the jitter observed by the receiver, by collecting statistical measures that describe these conditions. The target buffer level is determined with regard to the effect of packet losses in terms of duration of the discontinued playback of the true signal. This effect is derived from statistical measures of the network conditions as perceived by the receiving side and as reflected by a probability mass function which is continuously updated with packet inter-arrival times. The target buffer level is the result of minimization of a cost function which weights the internal buffer delay and an expected length of buffer underflow.