AP-Scheduled WLAN Radar Measurement Across Multiple STAs
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Solution Overview
Problem
The FTM technology in WLAN is limited to active objects and does not support radar measurement for passive objects, leading to interference and collision issues when multiple nodes perform radar measurements without coordination.
Innovation Solution
An access point (AP) generates a first frame with radar measurement information to coordinate multiple stations (STAs) for synchronized radar measurements, using polling, scheduling, or contention-based methods to reduce interference and collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple STAs perform radar measurements without coordination, then each STA can independently conduct measurements, but interference and collision between radar signals increase
Solution Approach 1:
The AP acts as an intermediary that coordinates radar measurements among multiple STAs. The AP sends trigger frames to schedule measurement opportunities, manages resource allocation, and controls the timing of radar signal transmission, thereby preventing collisions while maintaining independent measurement capabilities at each STA.
Solution Approach 2:
The system implements periodic radar measurement opportunities scheduled by the AP through trigger frames. STAs perform measurements at designated periodic intervals rather than continuously, which reduces signal collision while ensuring each STA maintains its measurement capability at scheduled times.
2Measurement precision
If the AP coordinates multiple STAs to perform radar measurements simultaneously, then measurement accuracy improves through orthogonal signals, but system complexity increases
Solution Approach 1:
The coordination system segments the radar measurement process into distinct phases: AP sends trigger frames with resource allocation information, STAs perform measurements in scheduled time slots using orthogonal signals, and results are reported back. This segmentation manages complexity by breaking down the coordination task into manageable, standardized steps.
Solution Approach 2:
The system uses parameter changes in the form of orthogonal signaling parameters (different time slots, frequencies, or codes) assigned by the AP to each STA. This allows multiple STAs to transmit simultaneously without interference while the AP manages coordination through parameter assignment rather than complex real-time control.
3Measurement precision
If the AP sends trigger frames to all STAs for radar measurement, then measurement synchronization is achieved, but communication overhead increases
Solution Approach 1:
The trigger frame structure is designed as a universal multi-functional message that simultaneously provides synchronization timing, resource allocation information, and measurement parameters to all STAs. This multi-functionality reduces the need for multiple separate control messages, thereby achieving synchronization while minimizing communication overhead.
Data Source
AI summary
A radar measurement method and an apparatus are disclosed, which relate to the field of communications technologies, and are used to support radar measurement in a wireless local area network (WLAN). The method includes: An access point (AP) generates a first frame, where the first frame includes radar measurement information. Then the AP sends the first frame to M stations (STAs), to configure the way the M STAs perform radar measurement. This application is applicable to a radar measurement procedure.