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= Massive MIMO Channel Sounding =

=== Description ===
In this tutorial, we demonstrate the TDD 16x1 Massive MIMO channel sounding procedure using 1 Massive MIMO rack (8 USRP-X310s) and 1 USRP-B210 in the [https://www.orbit-lab.org/wiki/Hardware/bDomains/aGrid ORBIT grid] and the [https://github.com/renew-wireless/RENEWLab/ RENEW Sounder software]

* The instructions of the RENEW Platform Sounder software can be found [https://docs.renew-wireless.org/dev-suite/design-flows/cpp/sounder/ here] under [https://docs.renew-wireless.org/license/ RENEW license].
* The COSMOS team contributes to adding the UHD support for the Sounder software under the [https://github.com/EttusResearch/uhd/blob/master/LICENSE.md UHD license].

Author: Zhenzhou (Tom) Qi, Duke University (zhenzhou.qi [at] duke [dot] edu)

Last updated: Jul. 07, 2022

=== Prerequisites ===

In order to access grid, create a reservation in grid and have it approved by the reservation service. Access to the resources is granted after the reservation is confirmed. Please follow the process shown on the COSMOS getting [https://wiki.cosmos-lab.org/wiki/GettingStarted started page] to get started.


=== Resources Required ===

* 1 Massive MIMO Rack ({{{node23-1}}} to {{{node23-8}}})
* 1 USRP-B210 ({{{node8-7}}})
* 1 Server ({{{node21-1}}})

=== Tutorial Setup ===

Follow the steps below to gain access to the grid console and set up nodes with appropriate images.
 1. If you don't have one already, sign up for a [https://www.orbit-lab.org/userManagement/register ORBIT account]
 1. [wiki:/GettingStarted#MakeaReservation Create a resource reservation] on ORBIT grid
 1. [Documentation/Short/Login Login] into grid console ({{{grid.orbit-lab.org}}}) with two SSH sessions. 
 1. Make sure all the nodes and devices used in the experiment are turned off
{{{#!shell
omf tell -a offh -t node21-1,node8-7
}}}
{{{#!shell
omf tell -a offh -t [23,1..8]
}}}
 1. Use the {{{ubuntu2004-uhd4.1-gr3.9.ndz}}} node image with Ubuntu 20.04, UHD 4.10, and gnuradio 3.9. Load {{{ubuntu2004-uhd4.1-gr3.9.ndz}}} on both the server and ({{{node8-7}}}).  
{{{#!shell
omf load -i ubuntu2004-uhd4.1-gr3.9.ndz -t node21-1
}}}
{{{#!shell
omf load -i ubuntu2004-uhd4.1-gr3.9.ndz -t node8-7
}}}
 1. Turn all the required resources on and check the status
{{{#!shell
omf tell -a on -t node21-1,node8-7
}}}
{{{#!shell
omf tell -a on -t [23,1..8]
}}}
{{{#!shell
omf stat -t all
}}}
 1. {{{ssh}}} to the server and ({{{node8-7}}}) from two terminals, use option -Y for using GUI.
{{{#!shell
[Terminal 1] ssh -Y root@node21-1,
[Terminal 2] ssh -Y root@node8-7
}}}

=== Experiment Execution ===
==== Find and prepare USRPs and the Sounder software ====

* The IP addresses for Ethernet Port 1(10G) on {{{sdr2-s1-lg1}}} and {{{sdr2-md1}}} were hard-coded to {{{10.118.2.2}}} and {{{10.118.3.2}}} respectively. To access them from {{{srv2-lg1}}}, configure the network interface {{{eno2}}} as follows:
{{{#!shell
root@srv2-lg1:~# ifconfig eno2 10.118.1.2 netmask 255.255.0.0 mtu 9000 up
root@srv2-lg1:~# sudo sysctl -w net.core.wmem_max=24862979
net.core.wmem_max = 24862979
root@srv2-lg1:~# sudo sysctl -w net.core.rmem_max=24862979
net.core.rmem_max = 24862979
root@srv2-lg1:~# ifconfig 
eno2: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 9000
        inet 10.118.1.2  netmask 255.255.0.0  broadcast 10.118.255.255
        inet6 fe80::9a03:9bff:fe61:9609  prefixlen 64  scopeid 0x20<link>
        ether 98:03:9b:61:96:09  txqueuelen 1000  (Ethernet)
        RX packets 4053772  bytes 17770502341 (17.7 GB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 1727950  bytes 2972166223 (2.9 GB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

}}}

* Run {{{uhd_find_device}}} to make sure that the USRP-2974s can be reached:
{{{#!shell
root@srv2-lg1:~# uhd_find_devices --args="addr=10.118.2.2"
[INFO] [UHD] linux; GNU C++ version 7.5.0; Boost_106501; UHD_3.15.0.HEAD-0-gaea0e2de
--------------------------------------------------
-- UHD Device 0
--------------------------------------------------
Device Address:
    serial: 318F20F
    addr: 10.118.2.2
    fpga: XG
    name: 
    product: NI-2974
    type: x300

root@srv2-lg1:~# uhd_find_devices --args="addr=10.118.3.2"
[INFO] [UHD] linux; GNU C++ version 7.5.0; Boost_106501; UHD_3.15.0.HEAD-0-gaea0e2de
--------------------------------------------------
-- UHD Device 0
--------------------------------------------------
Device Address:
    serial: 3165747
    addr: 10.118.3.2
    fpga: XG
    name: 
    product: X310
    type: x300
}}}

* Download and build the RENEW Sounder software **on the {{{develop}}} branch** at [https://github.com/renew-wireless/RENEWLab/ here] and follow the [https://docs.renew-wireless.org/dev-suite/design-flows/cpp/sounder/ instructions] to build it. Note that the {{{master}}} branch does not have UHD support.

* Include in {{{files/usrp-bs-serials.txt}}} the IP address {{{10.118.2.2}}}, i.e., use {{{sdr2-s1-lg1}}} as the base station (BS). In {{{files/usrp-bs-only.json}}}, set {{{"channel" : "AB",}}} to enable dual-channel on {{{sdr2-s1-lg1}}}.

* Similarly, in {{{files/usrp-client-only.json}}}, set {{{"sdr_id" : [ "10.118.3.2" ]}}} (i.e., use {{{sdr2-md1}}} as the user) and {{{"channel" : "AB",}}} to enable dual-channel on {{{sdr2-md1}}}.