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56 lines
2.6 KiB
Markdown
56 lines
2.6 KiB
Markdown
<!--
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Author: Xianjun jiao
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SPDX-FileCopyrightText: 2019 UGent
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SPDX-License-Identifier: AGPL-3.0-or-later
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-->
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One 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.
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## Quick start
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- Power on the SDR board.
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- 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:
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```
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ssh root@192.168.10.122
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(password: openwifi)
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cd openwifi
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./wgd.sh
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./fosdem.sh
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(After the AP started by above command, you can connect a WiFi client to this openwifi AP)
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(Or setup other scenario according to your requirement)
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ifconfig
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(Write down the openwifi AP MAC address. For example 66:55:44:33:22:5a)
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insmod side_ch.ko num_eq_init=0
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./side_ch_ctl wh1h4001
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./side_ch_ctl wh7h4433225a
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(Above two commands ensure receiving CSI only from XX:XX:44:33:22:5a. In this case, it is the openwifi self-TX)
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./sdrctl dev sdr0 set reg xpu 1 1
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(Above unmute the baseband self-receiving to receive openwifi own TX signal/packet)
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./side_ch_ctl g0
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```
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You should see on board outputs like:
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```
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loop 64 side info count 4
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loop 128 side info count 5
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...
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```
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If the second number (4, 5, ...) keeps increasing, that means the CSI is going to the computer smoothly.
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- On your computer (NOT ssh onboard!), run:
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```
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cd openwifi/user_space/side_ch_ctl_src
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python3 side_info_display.py 0
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```
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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**.
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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.
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The following picture is generated by data processing on the captured openwifi CSI while people move in front of two directional antennas (Tx/Rx antenna).
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Please learn the python and Matlab script for CSI data structure per packet according to your requirement.
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Do read the [normal CSI app note](csi.md) to understand the basic implementation architecture.
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