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 ​ORBIT grid and the ​RENEW Sounder software

• The instructions of the RENEW Platform Sounder software can be found ​here under ​RENEW license.
• The COSMOS team contributes to adding the UHD support for the Sounder software under the ​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 ​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 ​ORBIT account
2. Create a resource reservation on ORBIT grid
3. Login into grid console (grid.orbit-lab.org) with two SSH sessions.
4. Make sure all the nodes and devices used in the experiment are turned off

   omf tell -a offh -t node21-1,node8-7
   

   omf tell -a offh -t [23,1..8]
   

5. 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).

   omf load -i ubuntu2004-uhd4.1-gr3.9.ndz -t node21-1
   

   omf load -i ubuntu2004-uhd4.1-gr3.9.ndz -t node8-7
   

6. Turn all the required resources on and check the status

   omf tell -a on -t node21-1,node8-7
   

   omf tell -a on -t [23,1..8]
   

   omf stat -t all
   

7. ssh to the server and (node8-7) from two terminals, use option -Y for using GUI.

   [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 node23-1 to node23-8 were hard-coded to 10.10.23.1 to 10.10.23.8 respectively. To access them from the server node21-1, no configure of the network interface is needed, however, for better performance, we suggest the following operations:

  root@node21-1:~# ifconfig CTRL mtu 9000 up
  root@node21-1:~# sudo sysctl -w net.core.wmem_max=24862979
  net.core.wmem_max = 24862979
  root@node21-1:~# sudo sysctl -w net.core.rmem_max=24862979
  net.core.rmem_max = 24862979
  root@srv2-lg1:~# ifconfig 
  root@node21-1:~# ifconfig CTRL
  CTRL: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 9000
          inet 10.10.21.1  netmask 255.255.0.0  broadcast 10.10.255.255
          inet6 fe80::9a03:9bff:fe3b:81e3  prefixlen 64  scopeid 0x20<link>
          ether 98:03:9b:3b:81:e3  txqueuelen 1000  (Ethernet)
          RX packets 28985875  bytes 107820952173 (107.8 GB)
          RX errors 121  dropped 0  overruns 0  frame 121
          TX packets 12711747  bytes 14132140459 (14.1 GB)
          TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
  

• Similarly in node23-8, no further configuration of the network interface is needed.

• Run uhd_find_device to make sure that the USRP-2974s can be reached:

  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 ​here and follow the ​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.