Secondary Jitter Buffer for Telecommunications Network
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Solution Overview
Problem
High jitter levels in packet-switched networks cause gaps in media streams, leading to undesirable effects like stuttering in audio calls, and existing jitter buffers become ineffective when gaps exceed their capacity, increasing transmission delay or being restricted by hardware/software constraints.
Innovation Solution
Implementing a secondary jitter buffer upstream of the primary jitter buffer in a telecommunications network, which monitors packet departure times and dynamically controls its operation based on the primary buffer's state to maintain a consistent play-out rate, extending the primary buffer's capacity and mitigating jitter-induced gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the jitter buffer size is increased to absorb larger gaps in the input stream, then the ability to mitigate jitter-induced gaps is improved, but the transmission delay increases
Solution Approach 1:
The jitter buffer functionality is segmented into two separate buffers: a primary jitter buffer at the user device and a secondary jitter buffer at the network node. This segmentation allows the system to distribute the gap-absorbing capacity across multiple locations, mitigating jitter without requiring a single large buffer that would increase delay. The secondary buffer handles large gaps upstream while the primary buffer maintains constant play-out rate downstream.
Solution Approach 2:
The secondary jitter buffer acts as an intermediary between the network and the primary jitter buffer. It monitors packet departure times and dynamically controls its operation based on the primary buffer's state, effectively mediating the jitter problem by absorbing large gaps before packets reach the primary buffer, thus preventing buffer depletion without requiring the primary buffer to be oversized.
2Reliability
If the jitter buffer size is increased to handle high jitter conditions, then the reliability of media stream continuity is improved, but the buffer may exceed hardware or software constraints
Solution Approach 1:
The jitter buffer functionality is segmented into two separate buffers: a primary jitter buffer at the user device and a secondary jitter buffer at the network node. This segmentation allows the system to distribute the gap-absorbing capacity across multiple locations, mitigating jitter without requiring a single large buffer that would exceed hardware or software constraints.
Solution Approach 2:
The solution moves the jitter buffer functionality from a single-dimension approach (one large buffer at the endpoint) to a multi-dimensional approach (distributed buffers across network and endpoint). The secondary buffer at the network node provides additional buffering capacity in a different location, effectively increasing total buffering capability without exceeding local hardware constraints at any single point.
3Device complexity
If a single jitter buffer is used at the user device, then the device complexity is kept simple, but the buffer becomes ineffective when gaps exceed its capacity
Solution Approach 1:
The jitter buffer functionality is segmented into two separate buffers: a primary jitter buffer at the user device and a secondary jitter buffer at the network node. This segmentation allows the system to distribute the gap-absorbing capacity across multiple locations, mitigating jitter without requiring a single large buffer that would exceed hardware or software constraints.
Data Source
AI summary
In a telecommunications network including at least a user device and a network node separated by at least a packet-switched part of the telecommunications network, the user device including a primary jitter buffer having a constant packet play-out rate, the network node including a secondary jitter buffer, incoming packets destined for the user device are received and passed through the secondary jitter buffer of the network node downstream towards the primary jitter buffer of the user device. The departure times of packets passing through the secondary jitter buffer of the network node downstream towards the primary jitter buffer of the user device are monitored. On the basis of the monitoring and one or more known characteristics of the primary jitter buffer, an estimate of a current state of the primary jitter buffer is maintained. Operation of the secondary jitter buffer is dynamically controlled according to the maintained estimate.