This repository contains the Multi-UE Proxy to allow UEs to communicate with a single eNB (LTE mode), or both an eNB and gNB (NSA mode), or a single gNB (SA/NR mode) using the customized OpenAirInterface (OAI) software. The OAI code is located at https://gitlab.eurecom.fr/oai/openairinterface5g. The UEs communicate to the eNB via the bypass PHY layer. Various multi-UE scenarios can be tested without the overhead of a PHY layer.

The LTE mode functional description of this multi-UE proxy is shown in the following image:

The NSA mode functional description of this multi-UE proxy is shown in the following image:

The SA mode functional description of this multi-UE proxy is shown in the following image:

The multi-UE proxy includes the following:

• Socket communciation from/to UE(s)
• Socket communication from/to eNB
• Socket communciation from/to nrUE(s)
• Socket communication from/to gNB
• LTE Proxy mode and NSA Proxy mode
• Uplink/downlink packet queueing
• nFAPI compatibility
• Logging mechanism
• Test scripts

Build and install the EpiSys version of the OAI repository.

1. Open a terminal and clone openairinterface5g repo.
2. git checkout develop
3. Open a terminal and clone oai-lte-multi-ue-proxy repo.
4. git checkout master
5. If you run the proxy in loopback mode, add the following loopback interface for the VNF in the gNB.

sudo ifconfig lo: 127.0.0.2 netmask 255.0.0.0 up

6. Verify that SCTP support is enabled.

checksctp

If SCTP is not supported, then do the following.

sudo insmod /lib/modules/$(uname -r)/kernel/net/sctp/sctp.ko

7. If you plan to use the EPC or 5GCN, be sure to follow the instructions listed in Eurecom's respective repository.

• The EPC is used for both LTE and NSA mode. The 5GCN is used for SA mode.
• The EPC installation and deployment instructions are found here: https://github.com/OPENAIRINTERFACE/openair-epc-fed/blob/master/docs/DEPLOY_HOME_MAGMA_MME.md
• The 5GCN installation and deployment instructions are found here: https://gitlab.eurecom.fr/oai/cn5g/oai-cn5g-fed/-/blob/master/docs/DEPLOY_HOME.md
• It is critical to update the configuration files in the eNB/gNB/UE/NRUE if running with the 5GCN/EPC.
  Instructions to update the configuration files are oulined in the EPC/5GCN documentation
• Each softmodem command will not have the --noS1 when running with the EPC or 5GCN.
• The UE and NRUE launch commands will have a --ue-idx-standalone $node_id flag added when running with the ECP/5GCN to distinguish USIM information for multiple UEs.

cd .../openairinterface5g
source oaienv
cd cmake_targets
sudo ./build_oai --UE --eNB --nrUE --gNB

cd .../oai-lte-multi-ue-proxy
make

./proxy_testscript.py --num-ues 1 --mode=lte

./proxy_testscript.py --num-ues 1 --mode=nsa

./proxy_testscript.py --num-ues 1 --mode=nr

See ./proxy_testscript.py --help for more information.

The launch order is important, as follows. Note, there are three different proxy modes: LTE, NSA and SA. Please refer to the table below to determine which executables to launch and the necessary flags for each command. Steps 1-5 below show how to launch NSA mode. For example, in SA mode, replace the --nsa flag with --sa and only launch NRUE(s), a gNB and the proxy.

cd .../openairinterface5g
source oaienv
cd cmake_targets
sudo -E ./ran_build/build/lte-softmodem -O ../ci-scripts/conf_files/episci/proxy_rcc.band7.tm1.nfapi.conf \
--noS1 --emulate-l1 --nsa --log_config.global_log_options level,nocolor,time,thread_id | tee eNB.log 2>&1

cd .../openairinterface5g
source oaienv
cd cmake_targets
cd ran_build/build
../../../targets/bin/conf2uedata -c ../../../ci-scripts/conf_files/episci/episci_ue_test_sfr.conf -o .
../../../targets/bin/usim -g -c ../../../ci-scripts/conf_files/episci/episci_ue_test_sfr.conf -o .
../../../targets/bin/nvram -g -c ../../../ci-scripts/conf_files/episci/episci_ue_test_sfr.conf -o .
cp .u* ../../../cmake_targets
cd ../..
sudo -E ./ran_build/build/lte-softmodem -O ../ci-scripts/conf_files/episci/proxy_rcc.band7.tm1.nfapi.conf \
--emulate-l1 --nsa --log_config.global_log_options level,nocolor,time,thread_id | tee eNB.log 2>&1

cd .../openairinterface5g
source oaienv
cd cmake_targets
sudo -E ./ran_build/build/nr-softmodem -O ../ci-scripts/conf_files/episci/proxy_rcc.band78.tm1.106PRB.nfapi.conf \
--nfapi 2 --noS1 --nsa --emulate-l1 --log_config.global_log_options level,nocolor,time,thread_id | tee gNB.log 2>&1

cd .../openairinterface5g
source oaienv
cd cmake_targets
sudo -E ./ran_build/build/nr-softmodem -O ../ci-scripts/conf_files/episci/proxy_rcc.band78.tm1.106PRB.nfapi.conf \
--nfapi 2 --nsa --emulate-l1 --log_config.global_log_options level,nocolor,time,thread_id | tee gNB.log 2>&1

NUMBER_OF_UES is the total number of UEs.

cd .../oai-lte-multi-ue-proxy
number_of_ues=1
sudo -E ./build/proxy $number_of_ues --nsa enb_ipaddr gnb_ipaddr proxy_ipaddr ue_ipaddr

If you do not specify the parameters ending with ipaddr, the default IP addresses are as follows:

• enb_ipaddr = 127.0.0.1
• gnb_ipaddr = 127.0.0.2
• proxy_ipaddr = 127.0.0.1
• ue_ipaddr = 127.0.0.1

• nrUE NODE_ID starts from 2 from the first nrUE. If you run one more nrUE, the
• next NODE_ID = 3 in additional terminal.

cd .../openairinterface5g
source oaienv
cd cmake_targets
node_id=2
sudo -E ./ran_build/build/nr-uesoftmodem -O ../ci-scripts/conf_files/episci/proxy_nr-ue.nfapi.conf --nokrnmod 1 \
--noS1 --nfapi 5 --node-number $node_id --emulate-l1 --nsa \
--log_config.global_log_options level,nocolor,time,thread_id | tee nrue_$node_id.log 2>&1

• nrUE NODE_ID starts from 2 from the first nrUE. If you run one more nrUE, the
• next NODE_ID = 3 in additional terminal.
• IMSI config should match 5GCN configuration ($imsi)

cd .../openairinterface5g
source oaienv
cd cmake_targets
node_id=2
sudo -E ./ran_build/build/nr-uesoftmodem -O ../ci-scripts/conf_files/episci/proxy_nr-ue.nfapi.conf --nokrnmod 1 \
--ue-idx-standalone $node_id --nfapi 5 --node-number $node_id --emulate-l1 --nsa \
--log_config.global_log_options level,nocolor,time,thread_id | tee nrue_$node_id.log 2>&1 \
--uicc0.imsi $imsi

• The UE node_id starts at 2.

cd .../openairinterface5g
source oaienv
cd cmake_targets
node_id=2
sudo -E ./ran_build/build/lte-uesoftmodem -O ../ci-scripts/conf_files/episci/proxy_ue.nfapi.conf --L2-emul 5 \
--nokrnmod 1 --noS1 --num-ues 1 --node-number $node_id --nsa \
--log_config.global_log_options level,nocolor,time,thread_id | tee ue_$node_id.log 2>&1

• The UE node_id starts at 2.

cd .../openairinterface5g
source oaienv
cd cmake_targets
node_id=2
sudo -E ./ran_build/build/lte-uesoftmodem -O ../ci-scripts/conf_files/episci/proxy_ue.nfapi.conf --L2-emul 5 \
--nokrnmod 1 --ue-idx-standalone $node_id --num-ues 1 --node-number $node_id --nsa \
--log_config.global_log_options level,nocolor,time,thread_id | tee ue_$node_id.log 2>&1

After running the programs for 30 seconds or more, stop the processes using Ctrl-C. Open the log files and check the following logs to verify the run results.

• gNB.log : search for "CFRA procedure succeeded" log message for each UE.
• eNB.log : search for "Sent rrcReconfigurationComplete to gNB".
• nrue_1.log : search for "Found RAR with the intended RAPID".
• ue_1.log : search for "Sent RRC_CONFIG_COMPLETE_REQ to the NR UE".

The following is an example of how to search for a particular log in the generated log file.

cat gNB.log | grep -n 'CFRA procedure succeeded'

For more information, refer to the analyze_log section of the proxy_testscript.py script.