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1 General introduction

The C-RAN project has the goal of providing a complete high level use-case definition for future 5G mobile Radio Access Network (RAN) and providing a Virtual Network Function (VNF) for the deployment and testing of open source platform functions. It will also define test cases and platform interfaces of the use-case, and optimize the performance both of the platform and the VNF.

The C-RAN project has one task that would simulate the whole process of RAN function, and provide an open source VNF of wireless protocol stack.

In 4G network, RAN base station is referred as eNodeB. The eNodeB has two parts, Base Band Unit (BBU) and the Radio Remote Unit (RRU). BBU is responsible for base band processing, which including RRC, PDCP, RLC, MAC and PHY protocol function. RRU is responsible for signal amplifying. And all the code comes from the develop-nos1-fixes version of OAI.

The eNodeB code link :

https://drive.google.com/open?id=1_BiK2vgfxdHg3hsBxvwCObcal3bVP0SD


The UE code link:

https://drive.google.com/open?id=1pwepCkk2FU6hClRL_lLnsTVYkKkGcUci


This document would introduce what the test case is and how to use it.

2 Architecture design

 

Figure2. The test case of RAN

This test case provides two VMs that run the RAN protocol stack. VM1 simulates the BBU function, including MAC, RLC, PDCP stack function. VM2 simulates the end user protocol stack, including PHY, MAC, RLC, PDCP function. Note that, the system does not have radio frequency unit which simulate the radio channel. Therefore, the original PHY function of BBU and the PHY function of UE had been merged, that would be favorable for channel simulation. These two VMs constitute the full function of RAN.

In addition, as this system does not have the core network, existing functional modules could not realize the creation of user data bearer, the RB_tools has been involved which can be used to create and configure the Data Radio Bearer (DRB), allocate IP address for UE and BBU, finish the creation of data plane connection channel. In conclusion, the network connection of the whole system has been realized.


3 Installation manual

Based on the OAI community, CMCC contributes different version of BBU function realization. CMCC will update code when the internal legal process finished. 

3.1 Initial environment construction

1. Operating System : ubuntu14.04 version, linux kernel 3.19

2. In VM1, decompress the eNB.tar. In VM2, decompress the UE.tar.

eNB.tar and UE.tar can be stored anywhere you like, take /home/ as an example.

cd /home/

tar –xzvf eNB.tar

tar –xzvf UE.tar

3. Run the following command in two VMs respectively:

Open directory: cd openairinterface5g-develop-nos1/cmake_targets

Executive command (under root mode): ./build_oai -I --oaisim -x --install-system-files

Intall the lib and related tools.

3.2 VM1 configuration:

一. Configure the VM external communication IP

Open file: openairinterface5g-develop-nos1/targets/PROJECTS/GENERIC-LTE-EPC/CONF/ rrc.band7.tm1.if4p5.50PRB.conf

1. Modify the local network address, including the UE IP and local network port IP.

 RUs=(

{

local_if_name = "";//Local network port name, e.g.eth0

remote_address = ""; //UE IP

 local_address = "";// IP of local network port

……

})

二. Code compiling:

1. Open directory: openairinterface5g-develop-nos1/cmake_targets

2. Run the script: sh build_rcc.sh

3. Run the script: sh run_rcc.sh

3.3 VM1 configuration

一. Configure the VM external communication IP

1. Open: openairinterface5g-develop-nos1/targets/PROJECTS/GENERIC-LTE-EPC/CONF/ rru.oaisim.conf

2. Modify the local network address, including the UE IP and local network port IP.

 RUs=(

{

local_if_name = "";//Local network port name, e.g.eth0

remote_address = ""; //UE IP

 local_address = "";// IP of local network port

……

})

二. Code compiling:

1. Open directory: openairinterface5g-develop-nos1/cmake_targets

2. Run the script: sh build_rcc.sh

3. Run the script: sh run_rcc.sh

4. access success: In VM1, get the following log  RRCConnectionReconfigurationComplete

4 Test case description

Figure 3. The test architecture

 

Test objection: Test the NFVI platform supporting for radio access network

Test index: Observe the downlink bandwidth of radio access network

Test scheme: Launch the Iperf function respectively in VM1 and VM2. The UE VM launches the iperf server, eNB launches the iperf client.

Test procedure:  

  1. IP: eNB ip is 10.0.1.1, UE ip is 10.0.1.2  (If you want to modify the ip, check the openairinterface5g-develop-nos1/targets/tools/init_nas_nos1)
  2. The destination IP is: 10.0.1.2, , the source IP is: 10.0.1.1

Under UDP mode, Iperf client sends the packets to iperf server, the test time continues 120s, the number of connection is one, the packet loss limit to 0.6%, recording the network bandwidth.

5  Test sample:

In CMCC lab, the test case had been verified.

Hardware environment:

HP DL380 PGen8, memory 64G, frequency 3.0, network card 100Mbps, hard disk 600GB

 Software environment:

Host OS: centos  x86_64-linux-3.10.0-51.el7.x86_64

Guest os: ubuntu 14.04.3 linux kernel>=3.19

VM model: Memory: 4GB, hard disk: 15GB, vCPU: 2

 

The result of execution:

(1)   Executive command with 5Mbps bandwidth generated from eNodeB:

Iperf client side:

 

Iperf server side:

(2) Executive command with 10Mbps bandwidth generated from eNodeB:

 Iperf client side:

Iperf server side:

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