Round Trip Time Determination via MIMO Frame Synchronization
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Solution Overview
Problem
Traditional methods for determining round trip time (RTT) in wireless communication systems, such as those using Multiple-Input Multiple-Output (MIMO) technology, require separate transactions that consume time and bandwidth, making location determination of access points (APs) and other applications less efficient.
Innovation Solution
The method involves acquiring RTT measurements by sending a downlink trigger frame and receiving an uplink MIMO frame, using synchronization sequences within the frame to determine the RTT, which can be stored and provided on demand, thereby reducing the need for separate RTT transactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate RTT measurement transactions are used, then RTT measurements can be obtained, but time and bandwidth are consumed
Solution Approach 1:
The patent merges the RTT measurement function with existing MIMO frame transactions. The AP determines RTT by measuring the time difference between sending a DL trigger frame and receiving the corresponding UL MIMO frame, combining location determination with regular data communication operations rather than using separate measurement transactions.
Solution Approach 2:
The UL MIMO frame serves multiple functions: it carries data communication payload and simultaneously provides the timing reference for RTT measurement. The synchronization sequence within the UL MIMO frame enables both frame alignment and RTT calculation, making the communication infrastructure multi-functional.
2Measurement precision
If separate RTT measurement transactions are used, then RTT measurements can be obtained, but bandwidth is consumed
Solution Approach 1:
The patent combines RTT measurement with existing MIMO data communication transactions. The same DL trigger frame and UL MIMO frame exchange used for data transfer are also used for RTT measurement, eliminating the need for dedicated measurement transactions and thus conserving bandwidth.
Solution Approach 2:
The existing MIMO frame structure and timing mechanisms serve dual purposes: data communication and RTT measurement. The synchronization sequences and frame timing already present in the communication protocol are leveraged to provide measurement functionality without requiring additional dedicated resources.
3Device complexity
If location determination is made less accessible, then system complexity is reduced, but application accessibility is worsened
Solution Approach 1:
The AP automatically determines RTT measurements as part of its normal operation of receiving and processing UL MIMO frames. The measurement function is self-activating and requires no additional configuration or separate measurement procedures, making location determination readily accessible without increasing operational complexity.
Solution Approach 2:
The existing MIMO communication infrastructure is enhanced to provide both data transfer and location determination functions. By making the system multi-functional, location determination becomes accessible through the same communication channels and protocols already in use, without requiring separate dedicated systems.
Data Source
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AI summary
Round trip time (RTT) measurements may be obtained from downlink (DL) trigger frame and uplink (UL) Multiple-Input Multiple-Output (MIMO) frame transactions, which can replace and/or complement separate RTT measurements. By implementing such techniques, wireless systems can make access to RTT measurements, and consequently, location determination of access points (APs) within the system, more easily accessible to navigation and/or other applications benefitting from such measurements and determinations.