Hi All,

I am very new to OpenWrt. But I have a dream. Recently a Ph.D. student from MIT published a paper in an international conference, using WiFi channel state information (CSI) tool to construct a time-of-flight
measurement for indoor position with great result. The CSI tool they used support only Intel wifi 3500. I
did a quick search and found that some of the Atheros WiFi ICs (AR9k such as AR 9590, AR9580 etc) are
supported by an open source CSI tool

http://pdcc.ntu.edu.sg/wands/Atheros/

Because there are many wifi APs are based on AR9K, I am wondering if there is a possibility to combine
the open source CSI tool into OpenWRT and make my TP-Link WDR4310 a device for indoor positioning?

Best regards,

Everett

Take a look to this thread https://forum.openwrt.org/viewtopic.php?id=63452

Hi iasimov，

Thanks for the reply. I took a look at the threads. They were trying to read RSSI (received signal strength indicator) for positioning. They probably do not need to work in phy layer. The CSI tool (channel state information) gains the
access to the PHY layer through WIFI IC's firmware. CSI tools for Intel 5300 WIFI and Ath9k work under self-built Linux kernel under Intel PC. Since the CSI tools are open sourced, they should work in OpenWrt in princple. But how to do that is challenging.

This is MIT's Chronos system based on WIFI CSI tool. It is so much better then RSSI positioning:
 
http://news.mit.edu/2016/wireless-tech- … -wifi-0331

Hi,

I would also find this useful, there are a number of projects which uses CSI to locate a client device to within a meter;
"We present Chronos, a system that enables asingleWiFiaccesspointtolocalizeclientstowithintens of centimeters. Such a system can bring indoor positioning to homes and small businesses which typically have a single access point. The key enabler underlying Chronos is a novel algorithm that can compute sub-nanosecond time-of-flight using commodity WiFi cards. By multiplying the time-offlight with the speed of light, a MIMO access point computes the distance between each of its antennas and the client, hence localizing it."

APSense - phpathak.com/files/apsense.pdf
Chronos  - usenix.org/system/files/conference/nsdi16/nsdi16-paper-vasisht.pdf
DeepFi  - arxiv.org/pdf/1603.07080.pdf
SpotFi - conferences.sigcomm.org/sigcomm/2015/pdf/papers/p269.pdf