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How to use device-to-device communication (D2D, 4G)

⚠️ ATTENTION ⚠️

D2D is currently unfinished, the following documentation steps are likely not enough to make it work.

SynchREF UE (UE1)

graph LR
    UE1[UE1
eth0: 10.10.10.1] --- UE2[UE2
eno1: 10.10.10.2]

Example of /etc/network/interfaces configuration for UE1

auto eth0 
   iface eth0 inet static 
   address 10.10.10.1 
   netmask 255.255.255.0 
   gateway 10.10.10.1

Prepare the environment:

git clone https://gitlab.eurecom.fr/matzakos/LTE-D2D.git
cd LTE-D2D
git checkout master

This branch contains all the current development for DDPS, including: - UE MAC <-> UE MAC for Scenario 1 (off-network communication) - eNB MAC <-> UE MAC using NFAPI Transport (on-network communication) - RRC Extensions to support on-network cases

NFAPI configuration (required even for Scenario 1 target)

git clone https://github.com/cisco/open-nFAPI.git
cd open-nfapi
patch -p1 --dry-run < $OPENAIR_HOME/open-nfapi.oai.patch
Validate that there are no errors:

patch -p1 < $OPENAIR_HOME/open-nfapi.oai.patch

OAI build/execute

export NFAPI_DIR=XXX (place where NFAPI was installed)
cd cmake_targets
./build_oai --UE --ninja #If necessary, use ./build_oai -I --UE to install required packages
cd ran_build/build/

UE1

sudo ifconfig oip0 10.0.0.1
sudo iptables -A POSTROUTING  -t mangle -o oip0 -d 224.0.0.3 -j MARK --set-mark 3

NOTE

If necessary, add a default gateway:

sudo route add default gw 10.10.10.1 eth0

UE2

sudo ifconfig oip0 10.0.0.2
sudo iptables -A POSTROUTING  -t mangle -o oip0 -d 224.0.0.3 -j MARK --set-mark 3

NOTE

If necessary, add a default gateway:

sudo route add default gw 10.10.10.1 eno1

UE1 and UE2: Get and build vencore_app from d2d-l3-stub (branch: l3_stub)

gcc -I . vencore_app.c -o vencore_app -lpthread

TEST ONE-TO-MANY

Run UE1 then UE2, for example:

  • UE1: 
    sudo ./lte-softmodem-stub -U --emul-iface eth0
  • UE2: 
    sudo ./lte-softmodem-stub -U --emul-iface eno1

Test with Ping

  • Sender - UE1: 
    ping -I oip0 224.0.0.3
  • Receiver - UE2: using wireshark

Test with Iperf

  • Sender - UE1: 

    iperf -c 224.0.0.3 -u -b 0.1M --bind 10.0.0.1 -t 100

  • Receiver - UE2: 

    sudo ./mcreceive 224.0.0.3 5001

Filter the incoming packets according to GroupL2Id: receiver (one-to-many) can discard the packets if it doesn’t belong to this group. For the moment, both sender and receiver use the same set of Ids (hardcoded)

  • UE1 (sender): 

    sudo ./lte-softmodem-stub -U --emul-iface eth0
./vencore_app  #send the sourceL2Id, groupL2Id to OAI
ping -I oip0 224.0.0.3

  • UE2(receiver) 

    sudo ./lte-softmodem-stub -U --emul-iface eno1 
#we can see the incomming packets from OAI log, however, cannot see from Wireshark -> they are discarded at MAC layer
./vencore_app  #we can see the packets appearing in Wireshark

TEST PC5-S (UE1 -sender, UE2 - receiver) and PC5-U for ONE-TO-ONE scenario

Configure UE1/UE2

Configure ports and routing table for UE1 and UE2

UE1: 

sudo ifconfig oip0 10.0.0.1
sudo iptables -A POSTROUTING  -t mangle -o oip0 -d 10.0.0.2 -j MARK --set-mark 3
sudo route add default gw 10.10.10.1 eth0
UE2: 
sudo ifconfig oip0 10.0.0.2
sudo iptables -A POSTROUTING  -t mangle -o oip0 -d 10.0.0.1 -j MARK --set-mark 3
sudo route add default gw 10.10.10.1 eno1

Step 1:

Run the traffic emulated over Ethernet on UE1 using lte-softmodem-stub to test the behaviour without RF board.

UE1: 

sudo ./lte-softmodem-stub -U --emul-iface eth0

Step 2:

Run the traffic emulated over Ethernet on UE2 and set it as listening to incoming messages from PC5-S

UE2: 

sudo ./lte-softmodem-stub -U --emul-iface eno1
./vencore_app -r #listen to incomming message from PC5-S

Step 3:

Send a message from UE1 to UE2

UE1: 

./vencore_app -s #send a message via PC5-S (e.g., DirectCommunicationRequest)

Generate unicast traffic

UE1: 

ping -I oip0 10.0.0.2

TEST PC5-D

Step 1:

Run the traffic emulated over Ethernet on UE1 and send a discovery message via PC5-D

UE1: 

sudo ./lte-softmodem-stub -U --emul-iface eth0
./vencore_app -d #send a PC5-Discovery-Announcement via PC5D

Step 2:

Run the traffic emulated over Ethernet on UE2 and send a discovery message via PC5-D

UE2: 

sudo ./lte-softmodem-stub -U --emul-iface eno1
./vencore_app -d #send a PC5-Discovery-Announcement via PC5D