CSI Measurement Without WiFi Network Association
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Solution Overview
Problem
Existing CSI measurement methods require receivers to join WiFi networks, leading to increased bandwidth overheads and time delays, especially when multiple transmitters are involved in indoor positioning applications.
Innovation Solution
A CSI measurement method that allows receivers to obtain CSI without joining a WiFi network by negotiating session parameters using CREQ and CRSP frames, enabling CSI measurement through null data packets and preamble sequences without the need for network association.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a receiver joins a WiFi network to measure CSI, then CSI measurement can be performed, but bandwidth overheads and time delay increase
Solution Approach 1:
The patent extracts the essential CSI measurement function from the complete WiFi network joining process. The receiver can measure CSI by receiving null data packets and preamble sequences directly from the transmitter without completing the full network association process (scanning, authentication, association), thereby removing unnecessary steps that consume time and bandwidth
Solution Approach 2:
The transmitter sends null data packets containing preamble sequences in advance, before any formal network connection is established. These pre-prepared measurement signals allow the receiver to perform CSI measurement immediately upon receipt, eliminating the need to wait for network joining procedures to complete
2Measurement precision
If a receiver joins multiple WiFi networks to measure CSI for positioning, then positioning accuracy improves, but bandwidth overheads and time delay increase significantly
Solution Approach 1:
The patent extracts only the necessary CSI measurement capability from each WiFi network interaction. The receiver can measure CSI from multiple transmitters by receiving null data packets directly, without repeatedly performing full network joining procedures for each transmitter, thus maintaining positioning accuracy while improving efficiency
Solution Approach 2:
The null data packet mechanism serves multiple functions simultaneously: it enables CSI measurement for positioning, provides channel sounding information, and works across multiple WiFi networks without requiring separate network joining processes for each transmitter
3Reliability
If a receiver joins a WiFi network before CSI measurement, then network protocols ensure reliable communication, but device complexity and operation difficulty increase
Solution Approach 1:
The patent extracts the essential reliability mechanism (preamble sequence transmission in null data packets) from the complete WiFi network protocol stack. The receiver can obtain reliable channel information through the structured preamble sequences without needing to implement or complete the complex network joining and authentication protocols
Data Source
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AI summary
This application relates to the field of communications technologies, and provides a channel state information measurement method and apparatus, so that a receiver can measure CSI without joining a network of a WiFi transmitter. The method includes: sending, by a CSI request apparatus, a first CREQ frame, where the first CREQ frame is used to request a CSI response apparatus that receives the first CREQ frame to determine, in at least one group of session parameters, a group of session parameters used to transmit a CS frame, and the CS frame is used by the CSI request apparatus to perform channel state measurement; receiving, by the CSI request apparatus, a CRSP frame sent by a first CSI response apparatus, where the CRSP frame includes a first session parameter, and the first session parameter is a group of session parameters of the at least one group of session parameters; receiving, by the CSI request apparatus, the CS frame by using the first session parameter; and measuring, by the CSI request apparatus, the CS frame to obtain CSI. The method is applied to a scenario of positioning or a scenario in which CSI measurement needs to be customized.