Synchronous Channel Access Control for XR Latency
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Solution Overview
Problem
Wireless communication systems, particularly those supporting extended reality (XR) experiences, face challenges in meeting strict latency and packet loss requirements due to the lack of effective control over the wireless medium, leading to issues like synchronization problems and lag.
Innovation Solution
Implementing a method for synchronous channel access control using target wake time (TWT) sessions and differentiated priority settings for physical layer protocol data units (PPDUs) to ensure controlled transmission of data units over the wireless medium, allowing for prioritization and efficient management of XR data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If synchronous channel access control with TWT sessions and differentiated priority settings is implemented, then latency requirements are met and synchronization is improved, but device complexity and protocol overhead increase
Solution Approach 1:
The patent implements dynamic priority assignment where PPDUs are assigned different priorities based on their position in the application file (first PPDU gets highest priority, subsequent PPDUs get lower priorities). This dynamic differentiation allows the system to optimize latency for critical initial data while managing overall traffic flow, directly addressing the latency requirement without requiring complete protocol redesign
Solution Approach 2:
The patent employs Target Wake Time (TWT) sessions that operate in periodic intervals, allowing devices to wake at scheduled times for data transmission and then enter sleep mode. This periodic structure provides predictable latency bounds for XR traffic while reducing overall power consumption and medium contention, resolving the contradiction between latency requirements and system complexity
2Productivity
If differentiated priority settings are used for first and subsequent PPDUs, then transmission efficiency and synchronization are improved, but control mechanism complexity increases
Solution Approach 1:
The patent applies local quality by assigning different priority levels to different portions of the data transmission. Specifically, the first PPDU carrying application file headers or critical initialization data receives highest priority, while subsequent PPDUs receive progressively lower priorities. This localized differentiation optimizes transmission efficiency for critical data without requiring complex global control mechanisms
Solution Approach 2:
The patent changes the priority parameter of PPDUs based on their sequence number and content type. By modifying this single parameter dynamically during transmission, the system achieves efficient resource allocation and synchronization without introducing complex control logic, resolving the contradiction between transmission efficiency and control complexity
3Reliability
If strict priority control is enforced for XR traffic, then packet loss and lag are reduced, but wireless medium sharing efficiency decreases
Solution Approach 1:
The patent implements partial priority control rather than strict control across all traffic. Highest priority is given only to the first PPDU and critical data, while subsequent PPDUs use progressively lower priorities that allow other devices to share the medium. This partial application of priority control reduces packet loss for critical XR traffic while maintaining reasonable medium sharing efficiency for non-critical traffic
Data Source
AI summary
This disclosure provides systems, methods and apparatus for synchronous channel access control of a wireless system. In some aspects, a device may use a TWT session to communicate with a second device during one or more TWT service periods. Uplink and downlink communications may be coordinated to both be in a TWT service period to allow a device to enter a low power mode outside of the TWT service period. The TWT session, including the service periods, may be configured and managed by the device or the second device to ensure the communications associated with an XR experience between the devices (such as pose data frames or tracking frames provided as uplink data and video data frames provided as downlink data) meet latency requirements or other requirements for the XR experience. Use of TWT service periods allows other devices to use the wireless medium outside of the TWT service periods.