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Consulting Domain Expertise:
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| EMAIL: mar42@cornell.edu | |
| PHONE (mobile): +1 (732) 832-9723 | |
| PERSONAL URL: https://www.ramalho.us | |
| CISCO TEAMS: Invite: "mar41@cornell.edu" as a person |
I am Dr. Michael A. Ramalho founder of AcousticComms Consulting. I am the first person to exploit Discrete Sequence Spread Spectrum (DSSS) technology using sound at or near the upper audible limit of human hearing and apply it to the multi-path environment of reverberant rooms.
A particular variant of DSSS technology is in use today in virtually all of Cisco Systems Telepresence product
where it is used for Proximity Pairing
of user endpoints (such as PCs and mobile phones) to cloud-connected Telepresence systems.
This pairing uses only audio signal processing and acoustic signal capture capabilities normally present on the user endpoints.
The base patent for this work can be found in US Patent 10,003,377.
This acoustic DSSS variant is literally in thousands of endpoints and robustly supports hundreds of thousands
of associations/paring events
each and every day.
The key part of that last sentence is the tiny word robustly
– as simple designs using tones or
short chirps can be designed to work >90% of the time, but few can work robustly virtually 100% of the time.
AcousticComms was formed to provide unique spread spectrum consultation and designs for other low-bit communications needs such as audio watermarking, acoustic transfer of WiFi SSID/passwords, reply/relay attack proof identity solutions and more. There are a multitude of applications that can exploit this technology natively on virtually all user endpoints as no special wireless (e.g., BLE) or other special hardware capabilities are required. Systems can exploit this technology for proximity (discovery of nearby devices), provisioning (information transfer of provisioning keys/codes), or other secure information transfer between devices without a network connection between devices.
Of particular newfound interest is the use of acoustic transmission as an out-of-band factor in a multi-factor authentication framework. AcousticComms has filed a non-profisional on this use (see patents at my Personal URL). Using this method one can obtain seamless preiodic re-authentication (i.e., without user intervention) as long as the user's other device (aka the roaming authenticator) is acoustically nearby. Additionally if ultrasound (non-human hearable) sound is used, the reauthentication can occur without the user's knowledge - thereby allowing re-authentication without interrupting the user from his/her present task. Lastly, if an implementation using a keyed form of the acoustic spread spectrum is used, this re-authentication is immune to reply or relay attacks (a major weakness of SMS or OTP techniques). A deck describing this use case can be found here.
AcousticComms can design a system to your particular needs and use requirements (e.g., audible/inaudible, existing hardware or system constraints) for robust information transfer in the most challenging of acoustic environments. Reverberant rooms create a high-multipath transmission environment creating acoustic nulls and a form of self-interference that thwarts most non-spread spectrum-based communications systems.
Room-based communications via acoustics might appear to be straightforward and easy.
After all, humans communicate in such rooms every day.
The whitepaper Why is Room-Based Information Transfer Difficult
reveals
why robust room-based communications are, in fact, very challenging.
If you find the whitepaper convincing and would like to discuss your particular needs and requirements, please feel free to contact me. If you would like to learn more of my background, please visit my Personal URL.
Michael A. Ramalho, Ph.D.
Founder of AccousticComms Consulting
http://www.ramalho.us
Michael A. Ramalho
Last Modified on :
May 16, 2025
Page Owner :
Michael A. Ramalho, Ph.D.