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