# Open RAN--Radio Access Network Evolution, Benefits and Market Trends
## 3 Open RAN Landscape  
The transformation of radio access networks towards Open RAN is driven by operators, vendors and other R&D organizations. Within this section, the selected main players who are involved in RAN transformation towards its openness are presented. In addition, some crucial public activities and events are grouped and listed together on a timeline shown in Figure 4. The commercial and proof-of-concepts field deployments are not presented here, as some of up-to-date operators activities may not be communicated to wider public, which finally may lead to inaccuracies in the review. The Open RAN race engages greenfield vendors which see the business potential to develop and further deploy their solutions. Overall, the Open RAN activities should be also assessed from a (geo)political perspective [26]. In Table 1, only selected main organizations related to Open RAN and its open-source software development are presented.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Organization** & & **Main Tasks in Brief** & **Source** \\ \hline O-RAN Alliance & \(\bullet\) & O-RAN specification; & \\ \multirow{4}{*}{O-RAN Alliance} & \(\bullet\) & The open-source software development for the RAN & \\  & \(\bullet\) & (together with Linux Foundation); & [27] \\  & \(\bullet\) & Support of members in testing and integration of & \\  & & their implementations. & \\ \hline O-RAN Software & \(\bullet\) & Collaboration between the O-RAN Alliance and & \\ \multirow{4}{*}{O-RAN Software Community (under Linux foundation)} & \(\bullet\) & Linux Foundation; & [28; 29; 30] \\  & \(\bullet\) & RAN Software implementation; & \\  & \(\bullet\) & SW testing, integration and O-RAN specification & \\  & & alignment. & \\ \hline \hline \multirow{4}{*}{Telecom Infra Project (Project group) OpenRAN} & \(\bullet\) & Focus on the RAN implementation on General & \\  & & Purpose Processing (GPP) HW deployment; & \\ \multirow{4}{*}{Small Cell Forum} & \(\bullet\) & Demonstration of performance (via GPP HW); & \\  & \(\bullet\) & Identification of requirements for virtualized & [31; 32; 33] \\ \cline{1-1}  & \(\bullet\) & Environments; & \\ \cline{1-1}  & \(\bullet\) & Interoperability testing. & \\ \hline \hline \end{tabular}
\begin{tabular}{c c} \hline \hline \multirow{4}{*}{ONF (SD-RAN Project)} & \(\bullet\) & Specification of FAPI/nFAPI; \\  & \(\bullet\) & Open LLS Interface. & [34] \\ \hline \hline \multirow{4}{*}{ONF (SD-RAN Project)} & \(\bullet\) & Open source SW platform for multi-vendor 4G/5G & \\  & & RAN solutions; & \\ \cline{1-1}  & \(\bullet\) & Project is initially focus on O-RAN nRT-RIC; & [35; 36] \\ \cline{1-1}  & \(\bullet\) & Cooperation with TIP, O-RAN Alliance, O-RAN SC. \\ \hline \hline \multirow{4}{*}{Open RAN Policy Coalition} & \(\bullet\) & Promotion of policies moving on the adoption of & \\ \cline{1-1}  & & Open RAN and interoperable solution; & \\ \cline{1-1}  & \(\bullet\) & Promotion solution to enable expanding the wireless & \\ \cline{1-1}  & & technologies supply chain. & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Main organizations related to Open RAN development.  
The evaluated Open RAN solutions are generally related to 3 GPP standardization activity, i.e., the future open networks are perceived as enhanced 4G/LTE and 5G/NR RATs (Radio Access Technology) with new functions, logical blocks and platforms. One of the most important in this field is a reference architecture--called O-RAN--was developed by O-RAN Alliance founded by AT&T, China Mobile, Deutsche Telekom, NTT DOCOMO and Orange in August 2018 [27]. O-RAN Alliance was established as a fusion of two former organizations, C-RAN Alliance and xRAN Forum [38,39]. Those two organizations had different origins, i.e., Chinese from one side and United States, European, Japanese and Korean from the other. Since that time, O-RAN Alliance has signed some liaisons and collaboration agreements as well as published a set of specifications (see Figure 4).