Description
The Raspberry Pi 3B+ (BCM43455c0) and Raspberry Pi 4 (BCM43455c0 / CM4 with BCM43436) are the most common edge hosts for CSI capture in the historical literature, almost always paired with nexmon-csi firmware patches. They function as cheap, network-attached CSI sniffers that can be deployed in dozens around an indoor area for the kind of distributed sensing the thesis envisions. The Pi 4 also has enough CPU to do online CSI preprocessing (PCA, denoising, neural inference) before forwarding to a central server, which is practical for the BLE-calibration architecture.
Specs / capabilities
- Pi 3B+ / Pi 4: BCM43455c0 chip (802.11ac 1x1 MIMO, 80 MHz, 2.4 + 5 GHz)
- 802.11ac CSI (256 subcarriers @ 80 MHz) via Nexmon
- USB 2.0 / 3.0, Gigabit Ethernet, plenty of GPIO for paired sensors
- ARM Cortex-A53 (Pi 3B+) / Cortex-A72 (Pi 4), 1-8 GB RAM
- ~$35-75 per board
Tooling
- Raspberry Pi OS (Debian-based)
- Nexmon CSI Pi-specific build instructions in nexmon-csi
- Paired CSI loggers in Python (
csikit) or C
Quirks / known issues
- BCM43436 on the CM4 is not supported by Nexmon CSI; check chip variant before deploying
- Pi 5 uses an entirely different Wi-Fi chip (Cypress CYW43455 successor) and is currently not supported by mainline Nexmon
- Sustained 80 MHz capture at high packet rates can saturate the SD card; use USB SSDs
Used by (papers)
- Many post-2019 deployments use the Raspberry Pi as the Nexmon host