ds, business districts busy- hours are in weekdays). CMRI projected cost savings through lower maintenance and (feature) development through unified development environment and use of off-the-shelf hardware and software components. In addition, capacity increase can be achieved through advanced algorithm support, such as PHY layer interference cancellation through network multiple-input, multiple-output (MIMO) and MAC layer interference avoidance and joint scheduling (cooperativeRRM, CoMP). The C-RAN concept imposed many early engineering challenges: Bandwidth and timing requirements for antenna sample transport are high/strict. The concept of a C-RAN virtualized environment assumes a virtualized SDR environment which leads to high-performance requirements. Choice of a single processing environment (such as a general-purpose processor) means a likely choice for suboptimal environments for portions of the processing chain: general-purpose processors are simply not as efficient at signal processing as an optimized digital signal processing (DSP). Limited or no use of fixed-function acceleration. These engineering challenges triggered the alternative interpretation of the "C" in C-RAN: Centralized. The Centralized RAN architecture does use the resource pooling concept and provides many of the C-RAN advantages (capacity sharing, advanced algorithms) without imposing the engineering challenge of implementing DSP algorithms on (inefficient) general-purpose processors. Keep in mind that O-RAN does not dictate the hardware 8 Open Radio Access Network (O-RAN) Systems Architecture and Design implementation of the system either but rather defines the interfaces between hardware components, thus allowing for proprietary implementations of those components. Having said that, there is an implied assumption that O-RAN solutions indeed will be software- centric and using general-purpose processors. The xRAN Forum was established in 2016, releasing its first specification in 2018 for fronthaul communication between (what is now c