[[Include(WikiToC)]]

=== mmWave OFDM based ISAC Tutorial

==== Description
This tutorial demonstrates how to perform an mmWave OFDM based ISAC (Integrated Sensing and Communications) experiment using the COSMOS testbed.

[[PageOutline(3-6,,inline,unnumbered)]]

==== Prerequisites
* COSMOS account and reservation established
* Access to the radar SDR nodes and PAAM mobile node
* Chrome Remote Desktop for graphical access

==== Related COSMOS Documentation
* [wiki:Tutorials#SDRandWireless SDR and Wireless]
* [wiki:Hardware/SubSystems/IBM#IBM28-GHzPhasedArrayBoardForCOSMOS IBM 28-GHz Phased Array Board For COSMOS]
* [wiki:UserGuide/RemoteAccess/ChromeRemoteDesktop#ChromeRemoteDesktopSetupPage Chrome Remote Desktop Setup Page]

==== Resource Requirements
* SDRs: `sdr1-radar`, `sdr2-radar`
* PAAMs: `rfdev-sdr1-radar`, `rfdev-sdr2-radar`
* Mobile PAAM: `mob4-1`
* Server: `srv1-lg1`
* OMF Image: `ubuntu2004-uhd4.3-gr3.8-paam-radar-new.ndz`

==== Setup

Load the required images onto the server and mobile PAAM:

{{{#!shell
omf load -i ubuntu2004-uhd4.3-gr3.8-paam-radar-new.ndz -t srv1-lg1
omf load -i ubuntu2004-uhd4.3-gr3.8-paam-radar-new.ndz -t mob4-1
}}}

Power on the experiment hardware:

{{{#!shell
omf tell -a on -t sdr1-radar,rfdev-sdr1-radar,sdr2-radar,rfdev-sdr2-radar,mob4-1,srv1-lg1
}}}

Connect to the server:

{{{#!shell
ssh root@srv1-lg1
}}}

Run the PAAM setup script:

{{{#!shell
cd IBM_PAAM_Software_vFINAL/examples/
python3 paam_radar_setup.py
}}}

Connect via Chrome Remote Desktop and choose the first **GNOME on Xorg**.

===== PAAM Antennas Configuration
[[Image(radar setup.png, 600px)]]

==== Execution

===== Radar Side (srv1-lg1)

Terminal 1: Network and packet generator configuration:

{{{#!shell
sudo ip link set dev eno1 mtu 9000
sudo sysctl -w net.core.wmem_max=25000000
O-JRC/examples/build-mimo-ofdm-packet-generator-Desktop-Debug/mimo-ofdm-packet-generator
}}}

Configure signal parameters:

* Sample Rate: 100 MHz
* Packet size: 50 bytes
* TX Antennas: 2

Press Start once configured.

===== Packet Generator Configuration
[[Image(packet generator.png, 600px)]]

Terminal 2: GNU Radio Execution

Execute the following command to open GNU Radio
{{{#!shell
gnuradio-companion
}}}

==== Calibration

Open the calibration flowgraph:

* `O-JRC/examples/usrp/V0_JRC_calibration.grc`

Verify calibration parameters:

* Variables
  * `usrp_freq: 3e9`
  * `samp_rate: 100e6`
* usrp_mimo_trx
  * Number of MBoards: 2
  * Number of TX: 2
  * Number of RX: 2
  * USRP Arguments: `"addr0=10.38.24.1, addr1=10.38.24.2, master_clock_rate=200e6"`
  * Clock Sources: `"internal,external"`
  * Time Sources: `"internal,external"`

Execute the flowgraph and adjust the following parameters until waveforms are aligned:

* RX2 Gain
* RX2 Phase

Record these calibration values and terminate flowgraph.


[[Image(calibration.png, 1200px)]]


==== Radar Transmission

Open TRX flowgraph:

* `O-JRC/examples/usrp/V1_JRC_TRX.grc`

Verify calibration parameters:

* Variables
  * `usrp_freq: 3e9`
  * `samp_rate: 100e6`
  * `rf_freq: 28e9`

Update defaults for:

* `amp_rx2` = calibrated gain
* `phase_rx2` = calibrated phase

Run radar transmission.

==== Mobile PAAM Receiver (mob4-1)

Terminal setup:

{{{#!shell
sudo ip link set dev eno1 mtu 9000
sudo sysctl -w net.core.wmem_max=25000000
curl "http://am1.orbit-lab.org:5054/array_mgmt/configure?dev_name=rfev-mob4-1.sb1.cosmos-lab.org&ics=all&num_elements=16&txrx=rx&pol=h&theta=0&phi=0"
}}}

Launch GRC:

{{{#!shell
gnuradio-companion
}}}

Open RX Flowgraph:

* `O-JRC/examples/usrp/V1_JRC_RX.grc`

Check parameters:

* Variables
  * `usrp_freq: 3e9`
  * `samp_rate: 100e6`
  * `rf_frequency: 28e9`
* UHD Source
  * Device Address: `"serial=31557B9,master_clock_rate=200e6"`
  * Device Arguments: `"resource:RIO0"`
  * Mb0: Subdev Spec: `"A:0"`

Execute to receive the OFDM data.