1<!-- 2Author: Xianjun jiao 3SPDX-FileCopyrightText: 2019 UGent 4SPDX-License-Identifier: AGPL-3.0-or-later 5--> 6 7One 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 object. 8  9  10 11(See this https://github.com/open-sdr/openwifi/discussions/344 to understand how to map the collected data to the packet via the TSF timestamp) 12 13## Quick start 14- Power on the SDR board. 15- 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: 16 ``` 17 ssh [email protected] 18 (password: openwifi) 19 ``` 20- On computer, build the latest driver and FPGA package after clone/update openwifi and openwifi-hw-img repository: 21 ``` 22 export XILINX_DIR=your_Xilinx_install_directory 23 (Example: export XILINX_DIR=/opt/Xilinx. The Xilinx directory should include sth like: Downloads, Vitis, etc.) 24 export OPENWIFI_HW_IMG_DIR=your_openwifi-hw-img_directory 25 (The directory where you get the open-sdr/openwifi-hw-img repo via git clone) 26 export BOARD_NAME=your_board_name 27 (Check the BOARD_NAME definitions in README) 28 29 cd openwifi/user_space 30 ./drv_and_fpga_package_gen.sh $OPENWIFI_HW_IMG_DIR $XILINX_DIR $BOARD_NAME 31 scp drv_and_fpga.tar.gz [email protected]:openwifi/ 32 scp ./side_ch_ctl_src/side_ch_ctl.c [email protected]:openwifi/ 33 scp ./inject_80211/* [email protected]:openwifi/inject_80211/ 34 ``` 35- On SDR board (/root/openwifi directory): 36 ``` 37 cd /root/openwifi/ 38 ./wgd.sh drv_and_fpga.tar.gz 39 ./monitor_ch.sh sdr0 1 40 insmod ./drv_and_fpga/side_ch.ko 41 gcc -o side_ch_ctl side_ch_ctl.c 42 ./side_ch_ctl wh1h4001 43 ./side_ch_ctl wh7h4433225a 44 (Above two commands ensure receiving CSI only from XX:XX:44:33:22:5a, which will be set by our own packet injector later) 45 ./sdrctl dev sdr0 set reg xpu 1 1 46 (Above unmute the baseband self-receiving to receive openwifi own TX signal/packet) 47 ./side_ch_ctl g0 48 ``` 49- Open another ssh session on SDR board: 50 ``` 51 cd /root/openwifi/inject_80211 52 make 53 ./inject_80211 -m g -r 4 -t d -e 0 -b 5a -n 99999999 -s 20 -d 1000 sdr0 54 55 (Above command injects the 802.11a/g packet, for 802.11n packet please use: 56 ./inject_80211 -m n -r 4 -t d -e 8 -b 5a -n 99999999 -s 20 -d 1000 sdr0) 57 ``` 58- Now you should see the increasing numbers in the previous ssh terminal of the SDR board. 59- On your computer (NOT ssh session!), run: 60 ``` 61 cd openwifi/user_space/side_ch_ctl_src 62 python3 side_info_display.py 8 waterfall 63 ``` 64 The python script needs "matplotlib.pyplot" and "numpy" packages installed. Now you should see figures showing run-time **CSI**, **CSI waterfall**, **Equalizer out** and **frequency offset**. The following photo shows the CSI change in the waterfall plot when I left my seat in front of two directional antennas (Tx/Rx antenna). 65  66 67 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** in Matlab. 68  69 70Please learn the python and Matlab script for CSI data structure per packet according to your requirement. 71 72Do read the [normal CSI app note](csi.md) to understand the basic implementation architecture. 73
