# On Analyzing Beamforming Implementation in O-RAN 5G
## 4 O-RAN Beamforming
### Open Research Issues
#### 4.2.1 Fronthaul Model Concept
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Section Type** & **Target Scenario** & **Function** & **Parameters** & **Bits** \\ \hline \multirow{8}{*}{0} & \multirow{4}{*}{\begin{tabular}{c} Must DL/UL radio \\ channels \\ \end{tabular} } & \multirow{4}{*}{\begin{tabular}{c} Here, “most” refers to \\ channels not requiring \\ time or frequency offsets \\ such as those needed for \\ mixed-numerology \\ channels \\ \end{tabular} } & \begin{tabular}{c} Used for indicating idle \\ or guard periods from \\ O-DU to O-RU \\ \end{tabular} & \begin{tabular}{c} dataDirection, payloadVersion, \\ filterIndex, frameld, subframework, slotID, \\ startSymbol, numberOfscions, \\ scriptType, timeOfist, frameStructure, \\ cpLength, reserved, sectionID,rb, \\ symMicro, starttype, numPrbc, reMask, \\ numSymbol, e.f, reserved \\ \end{tabular} } & \multirow{4}{*}{\begin{tabular}{c} 128 \\ 128 \\ 128 \\ \end{tabular} } \\  & & & & \\ \cline{3-4}  & & & & \\ \hline \hline \multirow{8}{*}{1} & \multirow{4}{*}{\begin{tabular}{c} Most DL/UL radio \\ channels \\ \end{tabular} } & \multirow{4}{*}{\begin{tabular}{c} Here, “most” refers to \\ channels not requiring \\ time or frequency offsets \\ such as those needed for \\ mixed-numerology \\ channels \\ \end{tabular} } & \begin{tabular}{c} dataDirection, payloadVersion, \\ filterIndex, frameld, subframework, slotID, \\ startSymbol, numberOfscions, \\ exceptionType, timeOfist, frameStructure, \\ cpLength, CompHdr, sectionID, rb, \\ symMicro, startPrbc, numPrbc, reMask, numSymbol, ef, \\ numSymbol, ef, beamld \\ \end{tabular} & \begin{tabular}{c} var \\ 192 \\ 192 \\ \end{tabular} \\ \hline \hline \multirow{8}{*}{4} & \multirow{4}{*}{\begin{tabular}{c} Reserved for future \\ use \\ \end{tabular} } & \multirow{4}{*}{\begin{tabular}{c} dataDirection, payloadVersion, \\ filterIndex, frameld, subframework, slotID, \\ startSymbol, numberOfscions, \\ sectionType, timeOfist, frameStructure, \\ cpLength, CompHdr, sectionID, rb, \\ symMicro, startPrbc, reMask, numSymbol, ef, \\ netID, freqOffset, reserved \\ \end{tabular} } & \multirow{4}{*}{\begin{tabular}{c} var \\ 192 \\ var \\ \end{tabular} } \\  & & & \\ \cline{3-4}  & & & \\ \cline{3-4}  & & & \\ \cline{3-4}  & & & \\ \cline{3-4}  & & & \\ \cline{3-4}  & & & \\ \cline{3-4}  & & & \\ \hline \hline \multirow{8}{*}{6} & \multirow{8}{*}{Channel information} & \multirow{8}{*}{\begin{tabular}{c} Sends UE-specific \\ channel information \\ from the O-DU to the \\ O-RU \\ \end{tabular} } & \multirow{8}{*}{\
\begin{tabular}{c} dataDirection, payloadVersion, \\ filterIndex, frameld, subframework, slotID, \\ startSymbol, numberOfscions, \\ set, numOf, numPrbc, reMask, numSymbol, ef, \\ netID, freqOffset, reserved \\ \end{tabular} } & \multirow{8}{*}{
\begin{tabular}{c} per \\ MCOT/DRS \\ cISample, cISample \\ \end{tabular} } \\ \cline{3-4}  & & & & \\ \cline{3-4}  & & & \\ \cline{3-4}  & & & \\ \cline{3-4}  & & & \\ \cline{3-4}  & & & \\ \cline{3-4}  & & & \\ \cline{3-4}  & & & \\ \cline{3-4}  & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Number of bits of the application and the section layer for each section type [11]. As shown in Table 2, each section has multibit parameters with different numbers of bits. Some of these parameters specify the beamforming method; for example, the weight-based dynamic beamforming method implements the beamforming in O-RU based on parameters carried by the C-plane and transferred from O-DU through the front-haul, such as precoding beam weights (carried by the BeamID parameter, Sections 1 and 3) and channel state information (carried by cilsample and ciQsample parameters, Section 6).