Multicast Video Delivery Jitter Management in Wireless Networks
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Solution Overview
Problem
Current multicast video delivery over wireless networks faces challenges in efficiently managing packet loss and jitter, especially in home environments with multiple clients, due to the one-to-many relationship between the access point and receiving clients, which can lead to degraded video quality and increased bandwidth demands, particularly with ultra-high definition (UHD) streaming.
Innovation Solution
The method involves transmitting test sequences at varying transmission rates to determine critical and safe jitter levels, adjusting the transmission rate of media sequences to prevent packet loss from exceeding safe limits, and implementing policies to manage network loading, ensuring reliable video delivery by monitoring and adjusting bitrates based on client-specific radio reception characteristics and traffic levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the access point degrades the stream to a rate based on the weakest client, then all clients can receive the stream, but all clients are down-graded to weakest client quality
Solution Approach 1:
The patent segments clients into different multicast groups based on their reception capabilities and channel conditions. Each group receives streams at appropriate quality levels, allowing weak clients to receive lower quality streams while strong clients receive higher quality streams, resolving the contradiction between client compatibility and video quality.
Solution Approach 2:
The system dynamically adjusts stream rates and quality levels based on real-time channel conditions and client capabilities. The access point monitors packet loss rates and jitter for each client and adapts the multicast stream rate accordingly, enabling clients to receive optimal quality without degrading to the weakest client's capability.
2Manufacturing precision
If the access point serialises (unicast) to each client, then each client receives optimal quality, but greater bandwidth demands are introduced
Solution Approach 1:
The patent merges multiple unicast streams into a single multicast stream by identifying clients with similar reception capabilities and channel conditions. These clients are grouped together and served by a single multicast stream at an appropriate rate, reducing bandwidth consumption compared to individual unicast streams while maintaining optimal quality for each client group.
Solution Approach 2:
The multicast stream serves multiple functions simultaneously by delivering content to multiple clients in a single transmission. The system makes the multicast mechanism universal by adapting it to serve clients with different capabilities through group-based segmentation, achieving efficient bandwidth utilization while maintaining quality.
3Productivity
If multicast transmission is used, then network efficiency is improved, but packet loss and jitter affect video quality
Solution Approach 1:
The system performs preliminary channel assessment and client capability evaluation before establishing multicast streams. By pre-determining appropriate stream rates based on historical packet loss and jitter data, the system configures multicast transmissions to avoid problematic rate ranges, thereby maintaining both network efficiency and video delivery reliability.
Solution Approach 2:
The patent implements feedback mechanisms where clients report packet loss rates and jitter measurements back to the access point. The access point uses this feedback to dynamically adjust multicast stream rates and reconfigure client groupings, continuously optimizing the balance between network efficiency and video delivery reliability based on actual channel conditions.
Data Source
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AI summary
The invention sets out a method where a critical loading related to jitter associated with a link between the access point and a client device is determined. This critical load is the load beyond which retransmissions are insufficient for the client device to repair the video stream. The critical load is determined by sending data at varying transmission rates during a calibration mode, and measuring the jitter and packet loss rate. A safe load is then set as a fraction of this critical load. The loading associated with a multicast stream is then monitored with reference to this safe load, and if the safe load is met or exceeded, then action is taken to avoid packet loss increasing to a critical level. One action may be to adjust the transmission rate of the multicast stream for example, such that the load is reduced to below the safe load level.