Multi-Link Device Latency Reduction via RF Sensing Segmentation
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Solution Overview
Problem
Virtual Reality (VR) systems face significant latency issues due to competing over-the-air bandwidth demands in multi-user environments, which degrade the user experience by increasing latency in data exchanges between head-mounted devices (HMDs) and network stations.
Innovation Solution
A multi-link device (MLD) HMD is configured to operate on multiple wireless communication links, utilizing a first link for latency-sensitive downlink data and a second link for radio frequency (RF) sensing with variable bandwidths and pulse frequencies, enabling simultaneous data exchanges and object detection, with inertial measurement sensors providing motion information to reduce latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple stations compete for over-the-air bandwidth in a VR environment, then data exchange capacity is improved, but latency increases
Solution Approach 1:
The wireless communication system is segmented into multiple independent radio links (e.g., 2.4 GHz and 5 GHz bands), allowing different stations to transmit data simultaneously on different links without interfering with each other. This segmentation resolves the latency issue by eliminating the need for stations to wait for turn-taking bandwidth access while maintaining high data exchange capacity through parallel transmissions.
Solution Approach 2:
The patent introduces a frequency dimension to bandwidth allocation by utilizing multiple radio links at different frequency bands. Instead of stations competing for a single shared bandwidth resource, the system expands into multiple frequency dimensions, allowing concurrent data exchanges without increasing latency. This dimensional expansion enables both high productivity and low latency simultaneously.
2Device complexity
If a single radio link is used for both data transmission and RF sensing, then device complexity is reduced, but measurement precision and latency performance deteriorate
Solution Approach 1:
The system segments RF sensing and data transmission functions onto separate radio links. The first radio link is dedicated to data transmission while the second radio link is dedicated to RF sensing operations. This functional segmentation eliminates the precision degradation caused by resource sharing, as each function can now operate with optimal parameters without interference from the other function's transmission activity.
Solution Approach 2:
The patent implements multi-functionality at the system level where multiple radio links work together to provide both data transmission and RF sensing capabilities. While individual links are specialized, the combined system achieves universal functionality without sacrificing precision, as each link can be optimized for its specific purpose while contributing to the overall system objectives.
3Difficulty of detecting and measuring
If RF sensing operations are performed continuously to detect motion and objects, then object detection capability is improved, but bandwidth consumption and latency increase
Solution Approach 1:
The system segments sensing operations into discrete time intervals and frequency bands. By performing RF sensing on a dedicated second radio link during specific time windows rather than continuously, the system maintains motion detection capability while reducing the time resources consumed. This segmented approach allows the primary data transmission link to operate with minimal interruption, thereby reducing overall system latency.
Solution Approach 2:
The patent implements periodic RF sensing operations rather than continuous sensing. The second radio link performs sensing at scheduled intervals, which is sufficient for detecting motion and objects in most VR applications. This periodic action reduces the cumulative time and bandwidth consumed by sensing operations, thereby reducing latency without significantly compromising detection capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces signaling latency in VR systems, enhancing the user experience by efficiently managing bandwidth and providing real-time object detection and motion control information, even in multi-user environments.
Implementation Method 1
performing radio frequency sensing with a second radio link
Data Source
AI summary
Techniques are provided for reducing signaling latency in multi-link devices (MLDs). An example method of providing latency sensitive information with a MLD includes receiving downlink data packets from a station via a first radio link, performing radio frequency sensing with a second radio link, detecting a latency sensitive event, and transmitting an indication of the latency sensitive event.