A Fully Free Cell Phone Experience, No Baseband Required
Who am I?
- Denver Gingerich - https://ossguy.com/
- copyleft compliance work at Software Freedom Conservancy
- but most of my time is spent on Soprani.ca
- ossguy on all the things
my actual title slide should maybe be...
Ossguy's Grand Vision for Replacing the Phone Network
A "cell phone experience"?
the features one expects when one has "service":
- calling/texting: everyone has a number - can receive? 2FA?
- emergency services: calling or, now, texting (112, 911, etc.)
- Internet access: through a web browser and/or apps
what is "service" and where can we get it?
- when near a population centre in your home country (or $$$)
- (with some carriers/phones) when close to wifi as well
the device/hardware that you use; some inessential features:
- an identifier (phone number) tied to your phone/SIM
- using non-free baseband firmware
do we even need a baseband?
The easy part: calling on wifi
SIP
most smartphones have a decent SIP client
- Replicant/Android's built-in SIP client (since 2.3)
- any of the 5 SIP clients in F-Droid
- even more options for Debian-based smartphones
VoIP carriers are happy to give you US$0.01/minute CA/US calls
a number (if you want) for ~$0.90/month, and 911 service
probably a communication service - could make own carrier
The in-progress part: [SM]MS
- a small percentage of VoIP providers offer SMS
- much smaller % of providers support MMS and/or short codes
- SMS often requires a special app, or for you to code to an API
- fortunately, the work of coding to an API has been done...
SMS/MMS over data with JMP
- I wrote an XMPP gateway to one of those SMS/MMS APIs
- JMP is my gateway + Cheogram for nice JIDs and flexibility
- both are part of the Soprani.ca family of projects, AGPLv3+
- here's how JMP works...
DEMO
How far does that get us?
- turned calling and SMS/MMS into "data" using SIP and XMPP
- now all we need is a decent Internet connection: wifi or ...
- cellular data?
BUT!
- we wanted to do this without a baseband at all
The hard part: long-range data
- wifi mesh - covers wider area (seamless roaming?)
- satellite - has its own firmware, possibly no free options
- unlicensed bands: MURS (150 MHz), FRS (460 MHz), 900 MHz
- Personal Locator Beacon/EPIRB (121.5, 243, and 406 MHz)
what can we do with these?
- maybe ok for realtime data, but text/picture messages better
- text and picture messages can be sent >35km in my tests
- more options are coming: white spaces (54 Mhz to 698 MHz)
why don't we have any of these in our existing phones?
The other part: your phone/SIM
build our own hardware that includes more (P2P/mesh) radios
modify OS to use SIP/XMPP in default apps, report number via API
to avoid, make a SIM card that delivers calls/SMS via Internet
important note:
- carrier SIM cards have non-free firmware, too
but we don't need a SIM card for emergency calls
- with free baseband, can still have fully free emergency calls
What can we do right now?
features we can use right now with fully free software
- phone calls using a variety of SIP clients
- SMS, MMS, and short codes using JMP and any XMPP client
- emergency calls using FreeCalypso and Neo FreeRunner
what we can start building (know how? let's chat!)
- free SIM card firmware that uses VoIP/XMPP, not cellular
- phone-like devices that support more unlicensed bands
- apps and mobile OS code that bridge these together
Questions?
JMP - https://jmp.chat/ (AGPLv3+)
Denver Gingerich - https://ossguy.com/
the slides:
- https://ossguy.com/talks/20170326_libreplanet/
- the source code for this talk is available here
- these slides are licensed under CC BY-SA 4.0
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