1*a4eb2001SXianjun Jiao<!-- 2*a4eb2001SXianjun JiaoAuthor: Xianjun jiao 3*a4eb2001SXianjun JiaoSPDX-FileCopyrightText: 2019 UGent 4*a4eb2001SXianjun JiaoSPDX-License-Identifier: AGPL-3.0-or-later 5*a4eb2001SXianjun Jiao--> 6*a4eb2001SXianjun Jiao 7*a4eb2001SXianjun JiaoOne super power of the openwifi platform is "Full Duplex" which means that openwifi baseband can receive its own TX signal. Just like a radar! This brings a unique capability of "joint radar and communication" to openwifi. For instance, put two directional antennas to openwifi TX and RX, and the CSI (Channel State Information) of the self-TX signal will refect the change of the target. 8*a4eb2001SXianjun Jiao  9*a4eb2001SXianjun Jiao 10*a4eb2001SXianjun Jiao## Quick start 11*a4eb2001SXianjun Jiao- Power on the SDR board. 12*a4eb2001SXianjun Jiao- Connect a computer to the SDR board via Ethernet cable. The computer should have static IP 192.168.10.1. Open a terminal on the computer, and then in the terminal: 13*a4eb2001SXianjun Jiao ``` 14*a4eb2001SXianjun Jiao ssh [email protected] 15*a4eb2001SXianjun Jiao (password: openwifi) 16*a4eb2001SXianjun Jiao cd openwifi 17*a4eb2001SXianjun Jiao ./fosdem.sh 18*a4eb2001SXianjun Jiao (After the AP started by above command, you can connect a WiFi client to this openwifi AP) 19*a4eb2001SXianjun Jiao (Or setup other scenario according to your requirement) 20*a4eb2001SXianjun Jiao ./ifconfig 21*a4eb2001SXianjun Jiao (Write down the openwifi AP MAC address. For example 66:55:44:33:22:5a) 22*a4eb2001SXianjun Jiao insmod side_ch.ko num_eq_init=0 23*a4eb2001SXianjun Jiao ./side_ch_ctl wh1h4001 24*a4eb2001SXianjun Jiao ./side_ch_ctl wh7h4433225a 25*a4eb2001SXianjun Jiao (Above two commands ensure receiving CSI only from XX:XX:44:33:22:5a. In this case, it is the openwifi self-TX) 26*a4eb2001SXianjun Jiao ./sdrctl dev sdr0 set reg xpu 1 1 27*a4eb2001SXianjun Jiao (Above unmute the baseband self-receiving to receive openwifi own TX signal/packet) 28*a4eb2001SXianjun Jiao ./side_ch_ctl g0 29*a4eb2001SXianjun Jiao ``` 30*a4eb2001SXianjun Jiao You should see on board outputs like: 31*a4eb2001SXianjun Jiao ``` 32*a4eb2001SXianjun Jiao loop 64 side info count 4 33*a4eb2001SXianjun Jiao loop 128 side info count 5 34*a4eb2001SXianjun Jiao ... 35*a4eb2001SXianjun Jiao ``` 36*a4eb2001SXianjun Jiao If the second number (4, 5, ...) keeps increasing, that means the CSI is going to the computer smoothly. 37*a4eb2001SXianjun Jiao 38*a4eb2001SXianjun Jiao- On your computer (NOT ssh onboard!), run: 39*a4eb2001SXianjun Jiao ``` 40*a4eb2001SXianjun Jiao cd openwifi/user_space/side_ch_ctl_src 41*a4eb2001SXianjun Jiao python3 side_info_display.py 0 42*a4eb2001SXianjun Jiao ``` 43*a4eb2001SXianjun Jiao The python script needs "matplotlib.pyplot" and "numpy" packages installed. Now you should see figures showing run-time **CSI** and **frequency offset**. Meanwhile the python script prints the **timestamp**. 44*a4eb2001SXianjun Jiao  45*a4eb2001SXianjun Jiao 46*a4eb2001SXianjun Jiao While running, all CSI data is also stored into a file **side_info.txt**. A matlab script **test_side_info_file_display.m** is offered to help you do CSI analysis offline. In this case, run test_side_info_file_display(0) in Matlab. 47*a4eb2001SXianjun Jiao  48*a4eb2001SXianjun Jiao 49*a4eb2001SXianjun JiaoPlease learn the python and Matlab script for CSI data structure per packet according to your requirement. 50*a4eb2001SXianjun Jiao 51*a4eb2001SXianjun JiaoDo read the [normal CSI app note](csi.md) to understand the basic implementation architecture. 52
