# Overview This tutorial contains instructions for running the openairinterface eNB and UE on various platforms. It adapts the Eurecom tutorial at : ​https://gitlab.eurecom.fr/oai/openairinterface5g/wikis/HowToConnectOAIENBWithOAIUEWithoutS1Interface for the ORBIT and COSMOS testbeds.

# Prerequisites

1. Two nodes, with appropriate hardware, within RF range
2. Currently supported: USRP x310, USRP 2974, USRP b210
3. Load the image tutorial-oai.ndz onto both nodes
4. Turn the nodes on
5. If graphical display is desired, enable x11 tunneling to console and then to nodes
6. ssh to the nodes

## On node 1

1. run /opt/oaiscripts/build_oai.sh to build for the current hardware and kernel
2. edit the file /opt/oaiscripts/run_enb.sh for the SDR in use, for example, set SDR IP addr and max gain
3. run /opt/oaiscripts/run_enb.sh

Example script, change parameters as needed: run_enb.sh: ` #! /bin/bash #sdr_addrs takes standard uhd arguments, such as: #"type=x300,addr=192.168.40.2" #x310 over direct network #"type=x300,resource=rio0" #x310 over pcie #"type=b210" #b210 over usb #values for RUs.[0] override config file, must be set per usrp type #-d enables xforms charts

cd /opt/openairinterface5g source oaienv cd ./cmake_targets ./lte_build_oai/build/lte-softmodem \ -O $OPENAIR_HOME/ci-scripts/conf_files/enb.band7.tm1.25PRB.usrpb210.conf \ —nokrnmod 1 —noS1 —eNBs.[0].rrc_inactivity_threshold 0 \ —RUs.[0].att_tx 40 —RUs.[0].att_rx 0 \ —usrp-args "type=b200" \ -d `

## On Node 2

1. run /opt/oaiscripts/build_oai.sh to build for the current hardware and kernel
2. edit the file /opt/oaiscripts/run_ue.sh for the SDR in use, for example, set SDR IP addr and max gain
3. run /opt/oaiscripts/run_ue.sh

Example script, change parameters as needed: run_ue.sh ` #! /bin/bash #sdr_addrs takes standard uhd arguments, such as: #"type=x300,addr=192.168.40.2" #x310 over direct network #"type=x300,resource=rio0" #x310 over pcie #"type=b210" #b210 over usb #values for RUs.[0] override config file, must be set per usrp type #-d enables xforms charts

cd /opt/openairinterface5g source oaienv cd ./cmake_targets/lte_build_oai/build ./lte-uesoftmodem \ -C 2680000000 -r 25 \ —ue-scan-carrier —nokrnmod 1 —noS1 \ —ue-rxgain 120 —ue-txgain 30 —ue-max-power 0 \ —ue-nb-ant-tx 1 —ue-nb-ant-rx 1 \ —usrp-args "type=b200" \ -d `

# Results

## Once Both nodes are running

• if all is successfull, you shouuld see new interfaces on the two nodes, with addresses:
  • 10.0.1.1
  • 10.0.1.2
• you should be able to run ping, iperf, and so on

# Understanding xforms terms and plots

• Explanations from:
  • [Mathworks LTE](​https://www.mathworks.com/help/lte/physical-channels.html)

• PBCH: physical broadcast channel
  • The PBCH carries part of the system information required for terminals to access the network
• PUSCH: physical uplink control channel
• PDCCH: physical downlink control channel
  • The PDCCH conveys control information, scheduling decisions for PDSCH reception, and for scheduling grants enabling transmission on the PUSCH.
• PUSCH: physical uplink shared channel
• PDSCH: physical downlink shared channel
  • The PDSCH carries user data and paging information to the terminal.

# Details and Troubleshooting ## Calibration

• physical attenuation
• received signal at UE
• received signal at eNB
• pdsch constellation at UE
• pdsch constellation at eNB

## Expected Performance This depends on a number of factors, including:

• the total bandwidth (number of resource blocks)
  • 5mhz:25prb
  • 10mhz:50prb
  • 20mhz:100prb
• p(d/u)sch modulation:
  • qpsk
  • 16qam
  • 64qam
  • 256qam
• FDD vs TDD
• number of MIMO channels
• control vs data channel split

For the default config file in this tutorial, it's:

• 1/1 non-mimo
• FDD band 7
• 5mhz/25PRB
• up to 256qam, depending on signal
• control / data split of (0.25/0.75?)
• so you can expect up to 19mbps downlink at 64qam, and 25mbps downlink at 256qam

## Specifics per domain ### sb2.cosmos-lab.org

1. set usrp address to "type=x3xx,resource=rio0"
2. on eNB, set att_tx=70, att_rx=10
3. use RFSWITCH service to set all switches to port 1 for antenna

### sb2.orbit-lab.org

1. set usrp address to "type=x3xx,addr=192.168.40.2"
2. bring up usrp ethernet interface, set ip to 192.168.40.1/16

### sb1.orbit-lab.org

1. set usrp address to "type=b210"
2. UE_rxgain: 120
3. UE_txgain: 30
4. UE_maxpower: 0
5. eNB_att_tx: 40
6. eNB_att_rx: 0

### sb4.orbit-lab.org ===

1. set usrp address to "type=b210"
2. configure RF matrix for 60db of attenuation between eNB and UE node chosen