Wireless Keystroke Tracking via Channel State Information
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current virtual keyboard systems face challenges in portability and accuracy, particularly due to the need for wearable sensors and sensitivity to lighting conditions, as well as issues with false alarms from ambient interference in acoustic-based approaches.
Innovation Solution
A wireless tracking system that uses a transmitter and receiver to process wireless channel information, such as channel state information, channel impulse response, and received signal strength index, to detect and locate keystrokes on a surface without the need for wearable sensors, thereby providing a non-contact and interference-resistant solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If vision-based approaches are used for virtual keyboard detection, then portability is improved, but measurement precision deteriorates due to sensitivity to lighting conditions
Solution Approach 1:
The patent replaces vision-based optical detection with electromagnetic radiation detection (radio frequency signals). The system uses RF signals reflected from the keyboard surface and processed through channel state information to detect keystrokes, eliminating dependence on visible light and camera-based optical systems that are sensitive to lighting conditions.
Solution Approach 2:
The patent changes the detection parameter from optical (light-based) to electromagnetic (radio frequency). By using RF signals and analyzing changes in channel state information, phase, and amplitude, the system achieves detection capability that is independent of lighting conditions while maintaining portability.
2Ease of operation
If acoustic-based approaches are used for virtual keyboard detection, then portability is improved, but measurement precision deteriorates due to false alarms from ambient interference
Solution Approach 1:
The patent replaces acoustic detection with electromagnetic radiation detection. Instead of using microphones to detect sound waves generated by keystrokes, the system uses RF signals that are reflected from the keyboard surface and analyzes changes in the wireless channel state information to detect keystrokes, thereby eliminating false alarms from ambient acoustic interference.
Solution Approach 2:
The patent introduces an intermediary approach by using reflected RF signals as a mediator between the transmitter and receiver. The channel state information acts as an intermediary carrier that encodes keystroke information, allowing the system to detect keystrokes without direct contact with the user or sensitivity to ambient acoustic noise.
3Measurement precision
If wearable sensors are used for virtual keyboard detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts the detection function from wearable sensors and relocates it to a wireless communication system. Instead of requiring sensors attached to the user's body, the system uses existing wireless channel state information and signal processing techniques to detect keystrokes, thereby eliminating the need for wearable sensor hardware and reducing overall system complexity.
Solution Approach 2:
The patent makes the wireless communication system serve multiple functions: both data transmission and keystroke detection. By utilizing channel state information from the wireless channel for detection purposes, the system eliminates the need for separate detection hardware, thereby reducing device complexity while maintaining or improving measurement precision.
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
Enables accurate and portable virtual keyboard functionality by detecting keystrokes and determining key locations through wireless channel information processing, enhancing user experience and reducing the need for bulky physical keyboards.
Implementation Method 1
a transmitter configured for transmitting, using a transmit antenna, a first wireless signal through a wireless channel of a venue including the surface; a receiver configured for receiving, using a plurality of receive antennas, a second wireless signal through the wireless channel, wherein the second wireless signal comprises a reflection of the first wireless signal by at least one moving object in the venue
Data Source
AI summary
Methods, apparatus and systems for wirelessly tracking keystrokes on a surface are described. In one example, a described system comprises: a transmitter configured for transmitting, using a transmit antenna, a first wireless signal through a wireless channel of a venue including the surface; a receiver configured for receiving, using a plurality of receive antennas, a second wireless signal through the wireless channel, wherein the second wireless signal comprises a reflection of the first wireless signal by at least one moving object in the venue; and a processor. The processor is configured for: obtaining, regarding each receive antenna, a time series of channel information (CI) of the wireless channel based on the second wireless signal, detecting at least one keystroke on the surface based on the time series of CI (TSCI) obtained regarding each receive antenna, determining at least one location of the at least one keystroke on the surface, and determining at least one key associated with the at least one keystroke based on the at least one location.