1xBTS

1xBTS is an experimental CDMA2000 1x base station and core-network stack implemented primarily in Rust. It includes BTS, BSC, MSC, HLR, SMSC, packet data, voice, SDR radio backends, and a web dashboard for development and operation.

This project is intended for research, interoperability testing, and lab use. Operate RF hardware only where you are authorized to transmit. You have been warned.

Why 1xBTS

While CDMA2000 was a major technology in the US and some other places around the world, it was never as ubiquitious as other standards like GSM. Up until now there has never been a way to revive old CDMA2000 devices. I started this project to change that.

Status

1xBTS is under active development. The current stack can run as a network-in-a-box process for local integration, or split BTS/BSC operation over the included Abis transport. Support varies by handset, radio backend, channel configuration, and service option.

Currently many things are working (SMS, Voice, Packet Data) and while they work there is still much work to be done for production hardening. It still is a lot of fun though.

Architecture

The Rust workspace keeps first-party crates flat under crates/ and external integration wrappers under external/:

• crates/ - CDMA protocol, RAN, core-network, packet, voice, and tooling crates.
• external/ - SDR, SIP/native, and other outside-library wrapper crates.
• 1xbts-web - Next.js dashboard backed by the management gRPC APIs.
• proto - protobuf service definitions.

Full documentation lives at 1xbts.org/docs.

Network Nodes

The stack implements the full 3GPP2 1x reference architecture, with each node running as its own process and communicating over standard reference points:

• BTS (cdma-bts) - air-interface PHY/MAC, SDR-driven radio.
• BSC (cdma-bsc) - radio resource management; speaks Abis to the BTS.
• MSC (cdma-msc) - circuit-switched core; speaks A1 to the BSC.
• HLR (cdma-hlr) - subscriber database (PostgreSQL-backed).
• SMSC (cdma-smsc) - short message service center.
• PCF (cdma-pcf) - packet control function; A8/A9 to BSC, A10/A11 to PDSN.
• PDSN (cdma-pdsn) - packet data serving node, FoU/TUN packet path.
• voice-gw (cdma-voice-gw) - SIP gateway for voice calls.
• NIB (cdma-nib) - network-in-a-box launcher that runs the full stack in one process.

Prerequisites

At minimum:

• Rust toolchain with Cargo.
• PostgreSQL for HLR/SMSC state (docker compose up -d postgres starts a local 1xbts database on port 45432).
• protoc for protobuf code generation.
• pkg-config and a C compiler for native bindings.

Optional radio and voice dependencies depend on enabled features and hardware: UHD/USRP, LimeSuite, SoapySDR, bladeRF, and Baresip libre/re.

Tested SDR Hardware

• bladeRF Micro 2.0
• Ettus USRP B210 (UHD)
• LimeSDR Mini v2

Other SoapySDR-compatible devices may work but are not regularly exercised.

Tested Handsets

• Apple iPhone (CDMA)
• Motorola V60s
• Qualcomm QCP-860
• Nokia Lumia 735
• Samsung SCH-U340
• BlackBerry 8830

Quick Start

Clone, bring up the support services, and run the network-in-a-box:

git clone https://github.com/chrismoos/1xbts.git
cd 1xbts
docker compose up -d
# postgres :45432 · dashboard :3000 · fou-nat :17012
cargo run --release -p cdma-nib --no-default-features --features bladerf-backend -- \
    --config-dir config \
    --radio-config config/radio_bladerf_micro2.json

For headless development without RF hardware, swap the cargo invocation for cargo run -p cdma-nib -- --config-dir config --null-radio to run the full stack against a stubbed radio.

Default service ports are listed in docs/PORTS.md. If port 3000 is already in use, set ONEXBTS_WEB_PORT, for example ONEXBTS_WEB_PORT=3001 docker compose up 1xbts-web.

SDR Backend Features

Enable exactly one SDR backend at build time:

Tests

Run focused tests while developing:

cargo test -p cdma-bts
cargo test -p cdma-bsc

Web Dashboard

The dashboard ships in 1xbts-web (Next.js) and is started by docker compose up above. To run it directly:

cd 1xbts-web
npm install
npm run dev

License

The main 1xBTS workspace is licensed under Apache-2.0. The SDR wrapper crates under external/ (bladerf, bladerf-sys, limesuite, limesuite-sys, uhd, uhd-sys) are dual-licensed MIT OR Apache-2.0; see the individual Cargo.toml files for package-level license metadata.

The optional native Baresip libre/re dependency used by the SIP voice gateway is provided by the system and is distributed upstream under BSD-3-Clause terms.