Multi-User Ranging Using Preliminary IDs for Unassociated Stations
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Solution Overview
Problem
In wireless communication systems, particularly in WLANs, determining the position of a communication device using WLAN technology is challenging when unassociated client stations lack assigned association identifiers, as existing methods struggle to efficiently manage multi-user ranging exchanges, leading to inefficiencies in allocating frequency resources and spatial streams for accurate distance measurement.
Innovation Solution
The method involves selecting or receiving preliminary IDs for unassociated client stations, generating a trigger frame that indicates frequency resource and spatial stream allocations, and transmitting this frame to initiate an uplink multi-user transmission, allowing for simultaneous ranging exchanges even among unassociated devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If unassociated client stations are excluded from ranging exchanges, then association management is simplified, but positioning accuracy and network performance deteriorate
Solution Approach 1:
The patent introduces an intermediary identifier (temporary ID or preliminary ID) as a mediator between unassociated client stations and the ranging system. This intermediary serves as a placeholder that allows unassociated stations to participate in ranging exchanges without requiring full association status, thus resolving the contradiction by enabling positioning accuracy while maintaining simplified association management.
Solution Approach 2:
The patent segments the identifier system into two parts: association identifiers for associated stations and preliminary identifiers for unassociated stations. This segmentation allows the system to handle different station types differently, enabling unassociated stations to participate in ranging using preliminary IDs without complicating the association management for associated stations.
2Device complexity
If traditional single-user ranging methods are used, then protocol implementation is simpler, but ranging duration and network inefficiency increase
Solution Approach 1:
The patent merges multiple single-user ranging operations into a single multi-user ranging exchange by introducing trigger frames that coordinate simultaneous transmissions from multiple stations. This combining approach maintains relatively simple protocol implementation while dramatically improving ranging efficiency by serving multiple stations in parallel rather than sequentially.
Solution Approach 2:
The patent employs preliminary actions by having the access point send trigger frames that pre-coordinate resource allocations (frequency resources, spatial streams) before the actual ranging transmissions occur. This preliminary coordination enables efficient multi-user ranging without requiring complex real-time negotiation, thus maintaining protocol simplicity while improving productivity.
3Adaptability or versatility
If frequency resources and spatial streams are not pre-allocated, then resource management is more flexible, but ranging accuracy and simultaneous exchange capability deteriorate
Solution Approach 1:
The patent implements dynamic resource allocation where the access point assigns frequency resources and spatial streams based on the specific needs of each ranging exchange. The trigger frames carry dynamic allocation information that adapts to the current set of participating stations, maintaining flexibility while ensuring accurate measurements through proper resource assignment for each user.
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 enables efficient multi-user ranging by allowing unassociated client stations to participate in ranging exchanges, improving the accuracy of distance measurement and reducing the duration of ranging processes, thereby enhancing the overall performance of wireless communication networks.
Implementation Method 1
a distance between a first communication and a second communication device is determined by measuring a time of flight of WLAN transmissions between the first communication device and the second communication device
Data Source
AI summary
A first communication i) selects one or more respective preliminary identifiers (IDs) for one or more second communication devices, or ii) receives one or more respective preliminary IDs from one or more second communication devices, the one or more respective preliminary IDs having been respectively selected by the one or more second communication devices. The first communication device generates a trigger frame, the trigger frame indicating one or more first frequency resource and/or spatial stream allocations to one or more second communication devices using the one or more respective preliminary IDs. The first communication device transmits the trigger frame to initiate at least an uplink (UL) MU transmission by multiple second communication devices for a ranging procedure.