Description
The Atheros CSI Tool, released by Yaxiong Xie et al. (2015, NTU Singapore), patches the open-source ath9k Linux driver for Atheros AR9xxx 802.11n chipsets to expose per-subcarrier CSI. Compared to the Intel 5300 it reports the full 56-subcarrier OFDM grid (no decimation) at higher resolution (10-bit I / 10-bit Q), which made it preferable for research that needs fine-grained subcarrier information (phase calibration, ranging, super-resolution AoA). Atheros chipsets are also widely used in OpenWrt routers, so the same tool runs on cheap commodity APs.
Specs / capabilities
- 802.11n, 2.4 GHz / 5 GHz, up to 3x3 MIMO depending on chip (AR9580, AR9590, AR9344)
- 56 subcarriers per 20 MHz channel (full OFDM grid), 114 per 40 MHz HT channel
- 10-bit signed I / 10-bit signed Q per subcarrier per (Tx, Rx) antenna pair
- AP, monitor, and injection modes all supported
- Runs on x86 hosts AND on OpenWrt-capable Atheros routers (TP-Link WDR4300, etc.)
Tooling
- Atheros CSI Tool (Xie, Li, Li — NTU Singapore, 2015): https://wands.sg/research/wifi/AtherosCSI/
- Patched
ath9kdriver + user-spacerecvCSI/sendDatautilities - Python parser ports in
csikitand community repos - Often paired with OpenWrt to deploy CSI loggers on commodity routers
Used by (papers)
- xie2015 — original Atheros CSI Tool paper
- Used by ranging / AoA / phase-calibration papers that need full-resolution subcarriers