OpenAirInterface (OAI) is an open-source platform for wireless communication systems, developed at Eurecom’s Mobile Communications Department. It allows one to prototype and experiment with LTE and LTE-Advanced (Rel-10)systems, so as to perform evaluation, validation and pre-deployment tests of protocol and algorithmic solutions. OAI allows one to experiment with link-level simulation, system emulation and real-time radio frequency experimentation. As such, it is widely used to setup Cloud-RAN and Virtual-RAN prototypes. It includes a 3GPP-compliant LTE protocol
stack, namely the entire access stratum for both eNB and UE and a subset of the 3GPP LTE Evolved Packet Core protocols.
OAI can be used in two modes: the first one is a real-time mode, where it provides an open implementation of a 4G system interoperable with commercial terminals, so as to allow experimentation. This requires using a software-defined radio frontend (e.g. USRP210 external boards) for airtime transmission.The second mode is an emulation mode, where software modules emulating eNBs and UEs communicate through an emulated physical channel. In the emulation mode, scenarios are completely repeatable since channel emulation is based on pseudo-random number generation. In emulation mode, OAI can emulate a complete LTE network, using the oaisim package. Several eNBs and UEs can be virtualized on the same machine or in different machines communicating over an Ethernet-based LAN. The PHY and the radio channels are either fully emulated (which is time-consuming) or approximated in a PHY abstraction mode, which is considerably faster. In both cases, emulation mode runs the entire protocol stack, using the same MAC code as the real-time mode. This way, the oaisim package can be used to alpha-test and validate new implementations or sample scenarios, dispensing with all the problems that airtime transmission on a SDR frontend may bring about. Since the same code is used in the emulation and the real-time mode, a developer can then switch seamlessly to the real-time environment.
When we are setting the Core Network, usually we are configuring it at a Virtual Machine. The core components of the EPC(Core Network) is the HSS,the MME and the SPGW and they are the one's that must be configured as we said so the simulation can be executed with S1 interface support.
But this way of setting up the CN is not as flexible and ideal i would say.
It requires a lot of steps and network configurations into the configs of the HSS/MME/SPGW directories.
The main idea is inspired by splitting the 3 components into 3 different VMs,so right now we are trying to split each one of those at a different containers and make the configurations configure themselves based on the host system which will host the eNB (ANTENNA) and the UE (User Equipment). That way the whole execution of the EPC(Core network) will be faster,easier and the user will not have to get involved into the networking process.