# A Survey on Open Radio Access Networks: Challenges, Research Directions, and Open Source Approaches
## 3 Open RAN Movement and the Related Technologies
### Technologies Related to Open RAN
The virtualization concept introduced by vRAN caused a significant change in the way network systems were designed. This change has significantly increased the use of server-based platforms and virtualized network functions in vRAN, and also in Open RAN, thus opening new chances for companies and network vendors to rebuild their RAN hardware and software to server-based platforms based on open-source software. Simply, open-source software has become a major solution to overcome challenges for RAN's software infrastructures. Its big contribution to RAN's software caused O-RAN Alliance and other communities and groups to develop open source solutions and adopted them to Open RAN's significant functions. Although these open source solutions are still in the early deployments stage, the telecommunication industry is mostly expecting companies to use open source-based software infrastructure solutions to run RAN applications. Another related RAN technology is the smart network interface card (NIC). A smart NIC is a programmable accelerator that can increase the efficiency and flexibility of the  
Figure 4: Three types of RIC. data center network, data security, and data storage. Smart NIC can offload computation from its host processor [34]. Smart NIC can transparently unpack virtual switching data path processing for networking functions, such as network overlays, network security, load balancing, and telemetry. Through the use of Smart NIC or accelerator cards, a regular server performance and latency can be enhanced to meet the requirements needed to function as vBBU. Xilinx T1, T2, and T3 Telco Accelerator Card are some example of accelerators. The other technology related to Open RAN is MEC. MEC is a cloud service that runs at the edge of a network. It performs several specific tasks that would be processed in centralized core or cloud infrastructures. MEC moves the computing process closer to the users for enabling applications and services requiring some specific network characteristics that differ from other applications or services. MEC is capable to move content and functionalities to the edge; providing any private cellular network services by using its localized data process; deploying computational offloading to IoT devices; leveraging the proximity of edge devices to end users; and enhancing the privacy and security of mobile applications [4; 35]. Until today, there are several researches remaining for MEC, some of them are binary and partial offloading for MEC; MEC resource management system; MEC-open RAN-network slicing integration and their combined orchestrators; and MEC-embedded-RIC or called inter-near-RT RIC [32; 35]. Until this part, we already knew that Open RAN is related to many technologies. These technologies related to Open RAN can improve costs in the future 5G network [36]. The term used to measure the total cost spent for deploying a network is called total cost of ownership (TCO). TCO is the sum of CapEx and OpEx needed when deploying a network. The reports also mentioned that the average TCO reduced from implementing these related technologies is 20% if we compare it to 4G's TCO. The potential savings can surpass 20%, as a 5G network integrating these advanced technologies can generate significant business benefits essential for any enterprise. 1. SDN and NFV: The deployment of SDN and NFV concept in 5G network can save for about 25% 5G's TCO. This 25% savings are covered both from RAN and core virtualization. In the future 5G era, NFV will be a potential-generating tool, and maybe people will heavily rely on NFV when using 5G network. 2. Automation and intelligence: Automation and intelligence are heavily related to AI. AI in 5G will be expected to save about 25% 5G's TCO. We already know that AI in 5G has made Open RAN able to do many things, including automation and deploying ML. However, AI applications in cellular telecoms for now, are relatively rare. While this is expected to evolve over time, operators should acknowledge this situation when strategizing for the near future. 3.