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IBM 28GHz PAAM Basics

Description

In this tutorial, we demonstrate the basic use of the ​IBM 28 GHz phased array antenna modules (PAAMs) with USRP N310 software-defined radios (SDRs) in the ​COSMOS Sandboxes (sb1, sb2).

The following paper describes the integration of the IBM 28 GHz PAAMs (beta-version) with USRP SDRs in the COSMOS testbed. We would appreciate it if you cite this paper when publishing results obtained using the PAAMs deployed in COSMOS.

• X. Gu, A. Paidimarri, B. Sadhu, C. Baks, S. Lukashov, M. Yeck, Y. Kwark, T. Chen, G. Zussman, I. Seskar, and A. Valdes-Garcia, "Development of a compact 28-GHz software-defined phased array for a city-scale wireless research testbed," in Proc. IEEE International Microwave Symposium (IMS’21) (to appear), 2021.

Author: Tingjun Chen, Duke University / Columbia University (tingjun.chen [at] duke [dot] edu)

Last updated: Apr. 11, 2021

Acknowledgements

This work is collaboration with IBM. We thank Xiaoxiong Gu, Arun Paidimarri, Bodhisatwa Sadhu, and Alberto Valdes-Garcia for their contributions and support. More detailed information about the IBM 28 GHz PAAM can be found in the following references:

• B. Sadhu, Y. Tousi, J. Hallin, S. Sahl, S. K. Reynolds, O. Renstrom, K. Sjogren, O. Haapalahti, N. Mazor, B. Bokinge, G. Weibull, H. Bengtsson, A. Carlinger, E. Westesson, J. Thillberg, L. Rexberg, M. Yeck, X. Gu, M. Ferriss, D. Liu, D. Friedman, A. Valdes-Garcia, "A 28-GHz 32-element TRX phased-array IC with concurrent dual-polarized operation and orthogonal phase and gain control for 5G communications," IEEE Journal of Solid-State Circuits, vol. 52, no. 12, pp. 3373-3391, 2017.

Prerequisites

In order to access a COSMOS sandbox, create a reservation 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

In this tutorial we will use the following hardware resources in sb2, which are also shown in the figure below.

• 2 USRP N310 SDRs (sdr1-in1 and sdr1-in2 in SB1, sdr1-s1-lg1 and sdr1-md1 in SB2)
• 2 IBM 28GHz PAAMs (rfdev4-in1 and rfdev4-in2 in SB1, rfdev2-1 and rfdev2-2 in SB2 )
• 1 Server (srv1-lg1)

The current hardware connection in SB1 as shown in this ​diagram

• sdr1-in1 RF2 TX/RX — rfdev4-in1 IC0/TX/H, sdr1-in1 RF2 RX2 — rfdev4-in1 IC0/RX/H
• sdr1-in1 RF3 TX/RX — rfdev4-in1 IC0/TX/V, sdr1-in1 RF3 RX2 — rfdev4-in1 IC0/RX/V
• sdr1-in2 RF2 TX/RX — rfdev4-in2 all ICs/TX/H, sdr1-in2 RF2 RX2 — rfdev4-in2 all ICs/RX/H
• sdr1-in2 RF3 TX/RX — rfdev4-in2 all ICs/TX/V, sdr1-in2 RF2 RX2 — rfdev4-in2 all ICs/RX/V

The current hardware connection in SB2:

• sdr1-s1-lg1 RF2 TX/RX — rfdev2-1 IC1/TX/H, sdr1-s1-lg1 RF2 RX2 — rfdev2-1 IC2/RX/H
• sdr1-md1 RF2 TX/RX — rfdev2-2 IC1/TX/H, sdr1-md1 RF2 RX2 — rfdev2-2 IC2/RX/H

Tutorial Setup

Follow the steps below to gain access to the sandbox console and set up nodes with appropriate images.

1. If you don't have one already, sign up for a ​COSMOS account
2. Create a resource reservation on COSMOS SB1 or SB2
3. Login into sandbox console (console.sb1.cosmos-lab.org or console.sb2.cosmos-lab.org) with two SSH sessions.
4. Make sure all the nodes and devices used in the experiment are turned off. Use the first command for SB1 and the second command for SB2 (note the difference in the device names)

   omf tell -a offh -t sdr1-in1,sdr1-in2,rfdev4-in1,rfdev4-in2,srv1-lg1
   

   omf tell -a offh -t sdr1-s1-lg1,sdr1-md1,rfdev2-1,rfdev2-2,srv1-lg1
   

5. Use the paam28GHz-tutorial-cosmos.ndz node image with Ubuntu 18.04, UHD 3.15, gnuradio 3.8, and a grc example used in this tutorial. Load paam28GHz-tutorial-cosmos.ndz on the server.

   omf load -i paam28GHz-tutorial-cosmos.ndz -t srv1-lg1
   

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

   omf tell -a on -t sdr1-in1,sdr1-in2,rfdev4-in1,rfdev4-in2,srv1-lg1
   

   omf tell -a on -t sdr1-s1-lg1,sdr1-md1,rfdev2-1,rfdev2-2,srv1-lg1
   

   omf stat -t all
   

7. ssh to the server with option -Y for using GUI with gnuradio.

   ssh -Y root@srv1-lg1,
   

Experiment Execution

Find and prepare USRPs

• Upon logging into the server, run eth_config.sh script. This sets up the 10G data interfaces eno1, eno2. After running the script, you should see that the data interfaces have the appropriate IP addresses assigned, as per the tables for ​SB1 and ​SB2.

SB1 root@srv1-lg1:~# ./eth_config.sh root@srv1-lg1:~# ifconfig DATA1 DATA1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 9000 inet 10.38.1.1 netmask 255.255.0.0 broadcast 10.38.255.255 inet6 fe80::1e34:daff:fe42:c3c prefixlen 64 scopeid 0x20<link> ether 1c:34:da:42:0c:3c txqueuelen 1000 (Ethernet) RX packets 61195963 bytes 199994153268 (199.9 GB) RX errors 0 dropped 6680 overruns 0 frame 0 TX packets 58734853 bytes 190912589303 (190.9 GB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 root@srv1-lg1:~# ifconfig DATA2 DATA2: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 9000 inet 10.39.1.1 netmask 255.255.0.0 broadcast 10.39.255.255 inet6 fe80::1e34:daff:fe42:c3d prefixlen 64 scopeid 0x20<link> ether 1c:34:da:42:0c:3d txqueuelen 1000 (Ethernet) RX packets 7378 bytes 651944 (651.9 KB) RX errors 0 dropped 6682 overruns 0 frame 0 TX packets 282 bytes 82239 (82.2 KB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

• Run und_find_devices to make sure that both USRP N310s can be reached:

SB1 root@srv1-lg1:~# uhd_find_devices [INFO] [UHD] linux; GNU C++ version 7.5.0; Boost_106501; UHD_3.15.0.0-release -------------------------------------------------- -- UHD Device 0 -------------------------------------------------- Device Address: serial: 3176DF5 addr: 10.38.2.1 claimed: False mgmt_addr: 10.37.2.1 mgmt_addr: 10.38.2.1 mgmt_addr: 10.39.2.1 product: n310 type: n3xx -------------------------------------------------- -- UHD Device 1 -------------------------------------------------- Device Address: serial: 3196937 addr: 10.38.3.1 claimed: False mgmt_addr: 10.37.3.1 mgmt_addr: 10.38.3.1 mgmt_addr: 10.39.3.1 product: n310 type: n3xx

Configure IBM 28GHz PAAM

COSMOS uses a RESTful ​service for IBM PAAM management The service can be used for

• Dynamic array management - where the user connects to the antenna using connect command, dynamically steers the antenna during the experiment using steer command, and disconnects once the experiment is done.
• Static array management - where the user can connect, steer and disconnect using a single command, configure

Details and examples for the above are provided at the ​array management page. For this experiment we use static array management commands as shown below. First, start PAAM #1 (rfdev2-1) in TX mode with H-polarization using 4 antenna elements on IC 1, and configure the TX beamforming direction to be in the broadside (0,0). Check the current consumption on 2v7_1 and make sure IC1 has been successfully initialized (e.g., 2v7_1 has a current consumption of 1.026A in the example below).

root@console:~# curl "http://am1.orbit-lab.org:5054/array_mgmt/configure?dev_name=rfdev4-in1.sb1.cosmos-lab.org&ics=0&num_elements=4&txrx=rx&pol=v&theta=0&phi=0"

<?xml version="1.0" encoding="UTF-8"?>
<response status="OK">
  <action service="array_mgmt" name="configure" ipaddr="10.37.7.1">
    <step name="open" duration="3.552750"/>
    <step name="initializaition" duration="0.070964"/>
    <step name="enabling" duration="0.008952"/>
    <step name="steering" duration="0.002530"/>
    <state PAAM_ID="0x36" LO_switch="PLL" if_sw1="0x0" if_sw2="0x0" if_sw3="0x0" if_sw4="0x0"/>
    <adc>
      <conv index="0" name="1v2" tADC="114" tVolt="0.279" tCurr="0.139"/>
      <conv index="1" name="1v5" tADC="176" tVolt="0.430" tCurr="0.860"/>
      <conv index="2" name="1v8" tADC="12" tVolt="0.029" tCurr="0.015"/>
      <conv index="3" name="2v7_0" tADC="138" tVolt="0.337" tCurr="0.674"/>
      <conv index="4" name="2v7_1" tADC="27" tVolt="0.066" tCurr="0.132"/>
      <conv index="5" name="2v7_2" tADC="51" tVolt="0.125" tCurr="0.249"/>
      <conv index="6" name="2v7_3" tADC="19" tVolt="0.046" tCurr="0.093"/>
      <conv index="7" name="3v3_pll" tADC="114" tVolt="0.279" tCurr="0.139"/>
      <conv index="8" name="5v_uzed" tADC="310" tVolt="0.758" tCurr="0.758"/>
      <conv index="9" name="12v" tADC="132" tVolt="0.323" tCurr="1.075"/>
      <conv index="10" name="0V" tADC="0" tVolt="0.000"/>
      <conv index="11" name="1V8" tADC="737" tVolt="1.801"/>
    </adc>
    <step name="status" duration="0.020860"/>
    <step name="close" duration="0.101753"/>
  </action>
</response>

• [Terminal 2] Similarly, start PAAM #2 (rfdev2-2) in RX mode with H-polarization using 4 antenna elements on IC 2, and configure the RX beamforming direction to be in the broadside (0,0). Check the current consumption on 2v7_2 and make sure IC2 has been successfully initialized (e.g., 2v7_2 has a current consumption of 0.821A in the example below).

  root@console:~# curl "http://am1.orbit-lab.org:5054/array_mgmt/configure?dev_name=rfdev4-in2.sb1.cosmos-lab.org&ics=all&num_elements=16&txrx=rx&pol=v&theta=0&phi=0"
  

  <?xml version="1.0" encoding="UTF-8"?>
  <response status="OK">
    <action service="array_mgmt" name="configure" ipaddr="10.37.7.2">
      <step name="open" duration="3.608602"/>
      <step name="initializaition" duration="0.071819"/>
      <step name="enabling" duration="0.016513"/>
      <step name="steering" duration="0.007925"/>
      <state PAAM_ID="0x30" LO_switch="PLL" if_sw1="0x0" if_sw2="0x0" if_sw3="0x0" if_sw4="0x0"/>
      <adc>
        <conv index="0" name="1v2" tADC="114" tVolt="0.279" tCurr="0.139"/>
        <conv index="1" name="1v5" tADC="366" tVolt="0.894" tCurr="1.789"/>
        <conv index="2" name="1v8" tADC="3" tVolt="0.007" tCurr="0.004"/>
        <conv index="3" name="2v7_0" tADC="179" tVolt="0.437" tCurr="0.875"/>
        <conv index="4" name="2v7_1" tADC="212" tVolt="0.518" tCurr="1.036"/>
        <conv index="5" name="2v7_2" tADC="208" tVolt="0.508" tCurr="1.017"/>
        <conv index="6" name="2v7_3" tADC="187" tVolt="0.457" tCurr="0.914"/>
        <conv index="7" name="3v3_pll" tADC="128" tVolt="0.313" tCurr="0.156"/>
        <conv index="8" name="5v_uzed" tADC="262" tVolt="0.640" tCurr="0.640"/>
        <conv index="9" name="12v" tADC="243" tVolt="0.594" tCurr="1.979"/>
        <conv index="10" name="0V" tADC="0" tVolt="0.000"/>
        <conv index="11" name="1V8" tADC="733" tVolt="1.791"/>
      </adc>
      <step name="status" duration="0.020535"/>
      <step name="close" duration="0.101897"/>
    </action>
  </response>
  

Run the experiment

• In the first terminal, start gnuradio companion and open the example experiment that established a single tone transmission:

  root@srv1-lg1:~# gnuradio-companion example_paam_tone.grc 
  

• In gnuradio-companion, start gnuradio-companion, configure the USRP sink (TX) with sdr1-in2 ("mgmt_addr=10.37.6.2,addr=10.38.6.2") and the USRP source (RX) with sdr1-in1("mgmt_addr=10.37.6.1,addr=10.37.6.2"). Set the carrier frequency to 3GHz (3e9) and the subdev to be "B:1" (RF3) on both TX and RX. In this example flowgraph, the sampling rate and the tone frequency are set to be 2.5MHz (2.5e6) and 1MHz (1e6), respectively.

Observe the results

The left figure shows the frequency response of the received tone at 1MHz offset. Experiment can for example increase the link SNR by using more antenna elements (i.e., 8 for TX and 8 for RX) via the PAAM API, and the corresponding results are shown in the right figure.

root@srv1-lg1:~/paam_api/examples# python3 setup_betaboard_v1.2.py -c ethernet -a rfdev2-1 --ic 1 -n 8 --txrx tx --pol h --dir 0 0
root@srv1-lg1:~/paam_api/examples# python3 setup_betaboard_v1.2.py -c ethernet -a rfdev2-2 --ic 2 -n 8 --txrx rx --pol h --dir 0 0

Finish the experiments

When the experiments are completed, make sure to turn off both PAAMs and see that the IC current consumption drops to the minimal values:

root@srv1-lg1:~/paam_api/examples# python3 reset_betaboard_v1.2.py -c ethernet -a rfdev2-1
...
Index   Name    ADC Volt.   Curr.
0   1v2 30  0.073   0.037
1   1v5 45  0.110   0.220
2   1v8 1   0.002   0.001
3   2v7_0   38  0.093   0.186
4   2v7_1   45  0.110   0.220
5   2v7_2   47  0.115   0.230
6   2v7_3   37  0.090   0.181
7   3v3_pll 57  0.139   0.070
8   5v_uzed 264 0.645   0.645
9   12v 106 0.259   0.863
10  0V  0   0.000   x
11  1V8 735 1.796   x
Closed port to Zynq
PAAM board shutdown...!!!

root@srv1-lg1:~/paam_api/examples# python3 reset_betaboard_v1.2.py -c ethernet -a rfdev2-2
...
Index   Name    ADC Volt.   Curr.
0   1v2 109 0.266   0.133
1   1v5 140 0.342   0.684
2   1v8 23  0.056   0.028
3   2v7_0   9   0.022   0.044
4   2v7_1   11  0.027   0.054
5   2v7_2   51  0.125   0.249
6   2v7_3   10  0.024   0.049
7   3v3_pll 115 0.281   0.141
8   5v_uzed 223 0.545   0.545
9   12v 99  0.242   0.806
10  0V  0   0.000   x
11  1V8 735 1.796   x
Closed port to Zynq
PAAM board shutdown...!!!