IBM 28GHz PAAM: Link Rate vs. SNR


In this tutorial, we demonstrate the example use case of MAMBAS, a novel system that maneuvers analog MUBF using an ASA to support simultaneous communication with multiple users located in close proximity using the 28 GHz IBM PAAM board.

  • The instructions for the MAMBAS can be found here

The following papers describe the integration of the IBM 28 GHz PAAMs with MAMBAS in the COSMOS testbed. We would appreciate it if you cite this paper when publishing results obtained using the PAAMs deployed in COSMOS.

  • Z. Gao, Z. Qi, and T. Chen, "Mambas: Maneuvering Analog Multi-User Beamforming using an Array of Subarrays in mmWave Networks". in Proc. ACM Mobi Com'24, 2023
  • Z. Qi, Z. Gao, C. Tung, and T. Chen, "Programmable Millimeter-Wave MIMO Radios with Real-Time Baseband Processing". in Proc. ACM Mobi Com'23 Workshop on Wireless Network Testbeds, Experimental evaluation & Characterization (WiNTECH '23), 2023

Zhihui Gao, Duke University <zhihui.gao[at]duke[dot]edu>
Zhenzhou (Tom) Qi, Duke University <zhenzhou.qi[at]duke[dot]edu>
Tingjun Chen, Duke University <tingjun.chen[at]duke[dot]edu>

Last updated: Mar. 21, 2024


In order to access COSMOS-SB2, create a reservation in COSMOS testbed 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

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

The current hardware connection in SB2 as shown below

  • sdr1-s1-lg1 RF2 TX/RX — rfdev2-1 IC0/TX/H, sdr1-s1-lg1 RF2 RX2 — rfdev2-1 IC1/RX/H
  • sdr1-s1-lg1 RF3 TX/RX — rfdev2-1 IC0/TX/V, sdr1-s1-lg1 RF3 RX2 — rfdev2-1 IC1/RX/V
  • sdr1-md1 RF2 TX/RX — rfdev2-2 IC0/TX/H, sdr1-md1 RF2 RX2 — rfdev2-2 IC1/RX/H
  • sdr1-md1 RF3 TX/RX — rfdev2-2 IC0/TX/V, sdr1-md1 RF2 RX2 — rfdev2-2 IC1/RX/V

The required software components used in this demo are already loaded to the MobiCom24-MAMBAS.ndz node image, the node image includes:

  • Ubuntu 20.04, UHD 4.1.0
  • PAAM Control to initialize the PAAM boards to integrate with USRPs.
  • MAMBAS.Please refer to main branch at here for more information.

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 SB2
  3. Login into sandbox console with four SSH sessions.
  4. In terminal 1, make sure all the nodes and devices used in the experiment are turned off. Use the following command for SB2
    omf tell -a offh -t sdr1-s1-lg1,sdr1-md1,rfdev2-1,rfdev2-2,srv1-lg1
  5. Load MobiCom24-MAMBAS.ndz on the server.
    omf load -i MobiCom24-MAMBAS.ndz -t srv1-lg1 -r 0
  6. Turn all the required resources on and check the status of all the resources. Use the following commands for SB2.
    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 -X for using GUI for our live demo.
    ssh -X root@srv1-lg1

Find and prepare USRPs

  • Upon logging into the server, set up the 10G data interfaces DATA1, DATA2 in terminal 1.
    ifconfig DATA1 netmask mtu 9000 up
    ifconfig DATA2 netmask mtu 9000 up
    sudo sysctl -w net.core.rmem_max=536870912
    sudo sysctl -w net.core.wmem_max=536870912

After running the above commands, you should see that the data interfaces have the appropriate IP addresses assigned.

root@srv1-lg1:~# ifconfig DATA1
        inet6 fe80::1e34:daff:fe42:d4c  prefixlen 64  scopeid 0x20<link>
        ether 1c:34:da:42:0d:4c  txqueuelen 1000  (Ethernet)
        RX packets 21092  bytes 1881634 (1.8 MB)
        RX errors 0  dropped 19183  overruns 0  frame 0
        TX packets 686  bytes 204975 (204.9 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
root@srv1-lg1:~# ifconfig DATA2
        inet6 fe80::1e34:daff:fe42:d4d  prefixlen 64  scopeid 0x20<link>
        ether 1c:34:da:42:0d:4d  txqueuelen 1000  (Ethernet)
        RX packets 21091  bytes 1881530 (1.8 MB)
        RX errors 0  dropped 19184  overruns 0  frame 0
        TX packets 690  bytes 226549 (226.5 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
  • Run uhd_find_devices to make sure that both USRP N310s can be reached:
    [INFO] [UHD] linux; GNU C++ version 9.4.0; Boost_107100; UHD_4.1.0.HEAD-0-g25d617ca
    -- UHD Device 3
    Device Address:
        serial: 315A35A
        claimed: False
        fpga: XG
        product: n310
        type: n3xx
    -- UHD Device 4
    Device Address:
        serial: 3176DF7
        claimed: False
        fpga: XG
        product: n310
        type: n3xx

Configure IBM 28GHz PAAM

COSMOS uses the IBM 28GHz PAAM API to configure and initialize the PAAM boards. Under the console in terminal 2, please run the following 4 commands:

<user_name>@console:~$ curl ""
<user_name>@console:~$ curl ""
<user_name>@console:~$ curl ""
<user_name>@console:~$ curl ""

An example message will print out to after each command to indicate that the PAAM board is being successfully configured:

<?xml version="1.0" encoding="UTF-8"?>
<response status="OK">
  <action service="array_mgmt" name="configure" ipaddr="">
    <step name="open" duration="3.780022"/>
    <step name="initializaition" duration="0.125465"/>
    <step name="enabling" duration="0.022732"/>
    <step name="steering" duration="0.006349" theta="0" phi = "0" ipaddr = "" />
    <state PAAM_ID="0x23" LO_switch="PLL" if_sw1="0xF" if_sw2="0xF" if_sw3="0xF" if_sw4="0xF" txrx="rx" polarization="v" />
      <conv index="0" name="1v2" tADC="114" tVolt="0.279" tCurr="0.139"/>
      <conv index="1" name="1v5" tADC="214" tVolt="0.523" tCurr="1.046"/>
      <conv index="2" name="1v8" tADC="4" tVolt="0.010" tCurr="0.005"/>
      <conv index="3" name="2v7_0" tADC="13" tVolt="0.032" tCurr="0.064"/>
      <conv index="4" name="2v7_1" tADC="183" tVolt="0.447" tCurr="0.894"/>
      <conv index="5" name="2v7_2" tADC="18" tVolt="0.044" tCurr="0.088"/>
      <conv index="6" name="2v7_3" tADC="40" tVolt="0.098" tCurr="0.196"/>
      <conv index="7" name="3v3_pll" tADC="303" tVolt="0.740" tCurr="0.370"/>
      <conv index="8" name="5v_uzed" tADC="276" tVolt="0.674" tCurr="0.674"/>
      <conv index="9" name="12v" tADC="140" tVolt="0.342" tCurr="1.140"/>
      <conv index="10" name="0V" tADC="0" tVolt="0.000"/>
      <conv index="11" name="1V8" tADC="735" tVolt="1.796"/>
    <step name="status" duration="0.069065"/>
    <step name="close" duration="0.100179"/>

Experiment Execution

Activate MATLAB

MATLAB are preinstalled to the image, users are expected to activate MATLAB with their own MATLAB license as the following in terminal 1:

root@srv1-lg1:# cd /usr/local/MATLAB/R2022b/bin
root@srv1-lg1:/usr/local/MATLAB/R2022b/bin# ./
root@srv1-lg1:/usr/local/MATLAB/R2022b/bin# ./

The codebase is preloaded to the image, in terminal 1, please direct to the ~/MAMBAS_new/MAMBAS-MobiCom2024 folder

Open MATLAB interface as background as

root@srv1-lg1:# cd ~/MAMBAS_new/MAMBAS-MobiCom2024
root@srv1-lg1:~/MAMBAS_new/MAMBAS-MobiCom2024# matlab &

Configure USRP parameters

In MATLAB, open ~/MAMBAS_new/MAMBAS-MobiCom2024/5g-phy-implementation/GetParam.m, and make sure the parameters are configured as below:

% USRP Setting
param.carrier = 3.0e9;

param.subdevTx = "B:1";
param.deviceTx = "";
param.gainTx = 30;
param.deviceRx = "";
param.subdevRx = "B:1";
param.gainRx = 40;

param.carrier: the carrier frequency of the TX and RX. Please set it as 3.0e9 for 3 GHz carrier frequency to the IBM 28 GHz PAAM.

param.deviceTx and param.deviceRx: the IP address of the TX/RX USRP, which is and

param.subdevTx and param.subdevRX: the subdevice settings of the TX/RX USRP. The connection on the sb2 requires to set both parameters as B:1 to use the port RF3.

param.gainTx and param.gainRx: the TX/RX gain of the USRPs, whose range varies over different USRP types, which can be found by running uhd_usrp_probe command in the terminal. In sb2, the recommended value for param.gainTx is 30, for param.gainRx is 40.

Conduct the transmission

In MATLAB, open main.m, and directly run this script.

The displayed information includes:

CFO: carrier frequency offset

SNR: signal-to-noise ratio

EVM: error vector magnitude

BLER: block error rate (only one block is transmitted and it can be either 0 for success and 1 for failure);

BER: bit error rate

Constel.png: the saved constellation plot.

Change the SNR/MCS

To change SNR, you may either

Change the amplitude (by default, 0.5) of the generated waveform in line 13 of main.m, or

Change the TX gain param.gainTx in GetParam.m.

To change MCS, open GetParam.m and customize param.modu for modulation and param.code for code rate.

For the 28 levels of MCSs in 5G, you may refer to the table Table MCS index table 2 for PDSCH in the link below:

Finish the experiments

When the experiments are completed, make sure to clean up and turn off the PAAMs as the following in terminal 2

    <user_name>@console:~$ curl ""
    <user_name>@console:~$ omf tell -a offh -t
    <user_name>@console:~$ curl ""
    <user_name>@console:~$ omf tell -a offh -t
Last modified 2 months ago Last modified on Mar 26, 2024, 3:08:38 AM

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