# Open RAN--Radio Access Network Evolution, Benefits and Market Trends
## 3 Open RAN Landscape
### Software Development for Open RAN  
O-RAN Software Community (O-RAN SC)--which is placed close to the O-RAN Alliance--was established in 2019 under Linux Foundation and its goal is to deliver open-source RAN software. The software developed within the project is distributed via Standard Apache 2 license of open source software contributions. The main tasks of O-RAN SC encompass development, maintaining documentations, testing, integration and specification alignment. The software is released in versions (see Table 2) and includes the outcomes of projects related to the reference architecture. The software is compliant with the O-RAN specification or xApps. Currently, release E of the software is under development, and its new functionalities include xAPP RAN Control, RAN Slicing, and new use cases, among others.  
Regarding software development, in 2020, the Open Networking Foundation (ONF) formed the Software Defined Radio Access Network (SD-RAN) project, aimed at developing open source SW platforms for multi-vendor 4G/5G RAN solutions. The initial focus of the project was on O-RAN nRT-RIC functionality, referred to as uONOS-RIC [35]. In October 2021, ONF tougher with Deutsche Telekom launched an SD-RAN field trial based on disaggregated Open RAN and ONF-based RIC [36]. Before the O-RAN Alliance was established, at least two other groups were active in the area of network openness and disaggregation, namely, Telecom Infra Project (TIP) and Small Cell Forum. TIP was founded in 2016 and currently has hundreds of members (service providers, system integrators, and others). Its goal is to test, develop, and deploy standards-based solutions related to open and disaggregated RAN [31]. TIP does not develop its own specifications; however, it takes part in both lab and field interfaces interoperability and end-to-end testing. Within TIP, an OpenRAN project group was established to support productization of solutions from 2G to 5G RAT [32]. The second organization--Cell Forum--releases specifications of Functional Application Platform Interface (FAPI/nFAPI) related to Open RAN in small cells multi-vendor deployments, which enable network densification. nFAPI defines its own open functional split between DU and RU (called S-DU and S-CU).  
Next to the standardization oriented organizations and the others related to technical issues, there is an Open RAN Policy Coalition established in USA that focuses on policy moving towards adoption of Open RAN and interoperable solutions [37]. Conversely, in January 2021, Deutsche Telekom, Orange, Telefonica, Vodafone Group signed a memo  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Release Name** & **Current Phase** & **Next Phase** & **Release Date** \\ \hline E Release & Development & Test and Deploy & Planned for 12.2021 \\ D Release & Current Release & End of Life & 30 June 2021 \\ Cherry & End of Life & End of Life & 12 December 2020 \\ Bronze & End of Life & End of Life & 21 June 2020 \\ Amber & End of Life & End of Life & 30 November 2019 \\ \hline \hline \end{tabular}
\end{table}
Table 2: O-RAN SC releases (according to-O-RAN SC Wiki [30]).  
random of understanding (MoU) on the implementation of open RAN-based networks in Europe [45]. Following this initiative, in June 2021, the MoU published a document defining technical priorities for Open RAN [46].