hat over time antenna interfaces will evolve beyond mere multi-point coordination to full multi-point cooperation. For example, future antenna interfaces may support distributed 4.1 Introduction coherent beamforming, which demands that fronthaul and its antenna interface messages be delivered with higher precision time and phase sync capabilities provided by that fron- thaul transport. Open, distributed, low-latency antenna control is already contemplated in, for instance, O-RAN's split-PHY fronthaul specification, and the performance enabled by this type of split is essential to go-forward antenna interfaces for many emerging advanced multi-point TxRx capabilities. An additional emerging need is near real-time support. Between the high-latency OSS 3GPP beamforming antenna interfaces at the top of the 3GPP and O-RAN stack and the extremely low-latency antenna interfaces at the bottom, there is an emerging need to enable value-added intermediate-latency near real-time control/monitoring interfaces in support of various O-RAN Alliance and 3GPP value-added AI-enhanced controllers and distributed-self-organizing network (SON) and centralized SON efforts. Finally, it is also worth noting that those emerging beamforming antenna subsystem interface improvements and capabilities, which are both feasible and make business sense for LTE, will likely be backported for certain market segments. 4.1.4 gNB Functional Split(s) As we have already seen in the previous subsection, the monolithic base station architec- ture proved to be too limiting and there has always been a desire to standardize a more flexible split base station architecture. Such split architectures are more flexible in adapt- ing to various deployment scenarios, in which it may not be possible to deploy baseband processing hardware close to an antenna or there may be a need to control multiple cells from a centralized remote location. Even in cases when RF and baseband processing units are installed in close proximity to each other, oftentimes these are develo