Acoustic BPSK Data Modulation for RF-Limited Mobile Payments
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In jurisdictions where radio frequency (RF) communication features are not ubiquitous, such as in many mobile phones, especially in rural areas, existing mobile payment technologies like NFC and Bluetooth are not available, limiting the ability to conduct digital transactions.
Innovation Solution
The method involves packetizing data, modulating it using Binary Phase Shift Keying (BPSK), upsampling, filtering to a frequency band within the range of speakers and microphones, and transmitting it as sound between computing devices, enabling digital data communication without the need for RF-based technologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RF-based technologies (NFC, Bluetooth) are used for mobile payment, then communication reliability is improved, but device compatibility and accessibility are worsened in jurisdictions without RF infrastructure
Solution Approach 1:
The patent replaces RF-based electromagnetic communication systems with acoustic communication using speakers and microphones. This substitution enables mobile payment functionality on devices without RF infrastructure by using sound wave transmission through the air medium, thereby improving device compatibility while maintaining communication capability
Solution Approach 2:
The patent changes the communication parameter from RF frequency to audible frequency range (20Hz-20kHz). By modulating data onto sound waves within the speaker-microphone frequency response range, the system achieves compatibility with basic mobile devices that lack RF capabilities but possess acoustic transducers
2Speed
If acoustic frequency is increased for faster data transmission, then transmission speed is improved, but compatibility with speaker-microphone response ranges is worsened
Solution Approach 1:
The patent employs dynamic frequency selection within the audible range, adjusting the modulated signal frequency based on the specific speaker-microphone characteristics of the communicating devices. This dynamic adaptation optimizes transmission speed while ensuring compatibility with the acoustic response ranges of the devices involved
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 solution extends mobile payment capabilities to devices without RF-based technologies, allowing for peer-to-peer digital data communication through sound, enhancing transaction capabilities in areas with limited RF infrastructure.
Implementation Method 1
transmitting, by the first computing device, the filtered signal as sound using the speaker of the first computing device
Implementation Method 2
in the response range of a microphone of a second computing device
Implementation Method 3
modulating, by the first computing device, a stream of the packetized data using binary phase shift keying, BPSK, modulation
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Communicate data between devices using sound by dividing the data into blocks, encoding each block, and adding a header and footer to each encoded block. The header is a pseudorandom sequence and the footer is a bit-flipped version of the header. Modulating a stream of the packetized data using binary phase shift keying (BPSK) modulation. Upsampling and filtering the stream to one signal in a frequency band in the response range of speakers and microphones of the devices. Transmitting the filtered signal as sound using a speaker. At the receiving device, acquiring the transmitted signal as modified by the intervening channel by cross-correlating the received signal with an upsampled/bandpassed version of the pseudorandom sequence. Locating peaks of the cross-correlation corresponding to the header/footer. Estimating the channel impulse response as a function of the correlation. Equalizing the signal based on the impulse response, and downsampling, demodulating, and depacketizing.