Media Stream Synchronization in QoS Wireless Networks
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Solution Overview
Problem
Wireless networks, such as IEEE 802.11, face challenges in synchronizing multiple data streams like voice and video, leading to decreased throughput and increased delay, particularly in applications like video conferencing where lip-sync is critical, due to the higher priority given to voice traffic.
Innovation Solution
Implementing a method and system for negotiating and enforcing media stream synchronization at the link layer in QoS-enabled wireless networks, allowing mobile stations to signal for on-the-fly throttling and specifying synchronization constraints, such as the XY constraints, to ensure timely delivery of audio and video packets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If voice traffic is given higher priority in QoS-enabled wireless networks, then voice call delivery timeliness is improved, but data traffic throughput decreases and delay increases
Solution Approach 1:
The patent implements dynamic QoS parameter adjustment where EDCA parameters (CWmin, CWmax, AIFS, TXOP) are not fixed but can be modified in real-time based on application requirements. The system allows on-the-fly renegotiation of parameters to adapt to changing traffic conditions and application needs, enabling the network to dynamically balance voice and video traffic priorities rather than using static priority assignments
Solution Approach 2:
The patent changes the QoS parameters themselves (EDCA parameters) from fixed values to adjustable variables. By modifying parameters like contention window size, arbitration interframe space, and transmission opportunity limits, the system can tune the network behavior to accommodate different application requirements, allowing video traffic to receive adequate resources when needed while maintaining voice quality
2Reliability
If EDCA parameters are adjusted to balance voice capacity and video performance, then both voice and video traffic can coexist, but statistical underutilization of resources occurs
Solution Approach 1:
The patent performs preliminary setup of QoS parameters and synchronization requirements during session establishment. By pre-configuring EDCA parameters and synchronization constraints (such as XY constraints for lip-sync) before actual media transmission begins, the system ensures that both voice and video streams are properly synchronized from the start, preventing synchronization issues without requiring excessive resource reservations that would lead to underutilization
Solution Approach 2:
The patent implements feedback mechanisms where the system monitors the actual performance and synchronization status of media streams, then uses this information to adjust QoS parameters dynamically. This closed-loop approach allows the network to maintain optimal resource utilization by adjusting parameters based on actual needs rather than over-provisioning, ensuring efficient use of wireless resources while maintaining synchronization
3Manufacturing precision
If strict QoS parameters are enforced for video conferencing, then synchronization is maintained, but network flexibility and adaptability decrease
Solution Approach 1:
The patent makes QoS parameters dynamic rather than static, allowing them to be adjusted during the session based on changing conditions. The system can renegotiate EDCA parameters and synchronization constraints in real-time, providing both the precision needed for synchronization and the flexibility to adapt to varying network conditions and application requirements
Solution Approach 2:
The patent establishes synchronization requirements and QoS parameters in advance through preliminary negotiation during session setup. This preliminary action defines the synchronization constraints (such as XY constraints) that will be enforced, providing precision for media stream synchronization while allowing flexibility in how these constraints are implemented and adjusted during actual operation
Data Source
AI summary
A method and system directed to negotiating and triggering media stream synchronization at the link layer in a QoS-enabled 802.11 WLAN, or other wireless, network. In one implementation, the present invention allows for improved performance of streaming network applications, such as video conferencing, over wireless links. In one implementation, the present invention also provides an optional mechanism whereby a mobile station can signal a need for on-the-fly throttling, if an application on the mobile detects that there is a need for better synchronization of two streams, such as a lower priority stream to a higher priority stream.