# Oceania's 5G Multi-Tier Fixed Wireless Access Link's Long-Term Resilience and Feasibility Analysis
## 2 Materials and Methods
### Functional Split in 5G Networks  
The earlier RAN architectures of 2G, 3G, and 4G were based on monolithic building blocks with little interaction between logical nodes. Since the beginning of research on new radio stations (NR), it has been argued that dividing the gNB (NR logical node) into CU and DU provides flexibility [40]. Scalable and affordable network implementation can be achieved through flexible hardware and software implementations, but only if hardware and software components from different vendors are combined, adapted, and interoperable. A split architecture between centralized and decentralized entities is needed to accommodate the different use cases and QoS that games, voice, and video must support [41]. These QoS aspects have variable delay tolerances depending on transport, different deployment scenarios (e.g., rural or urban), and different transmission schemes (fiber, etc.). It also tunes performance characteristics, load management, and performance optimization in real time [42]. The fronthaul refers to the connection from the cell site antenna to the central office where the baseband unit is housed, with the option for distributed units (DUs) with added intelligence processing closer to the antenna is shown in Figure 3.  
The dynamic architecture of Parallel Wireless enables mobile operators to use various 3 GPP-compatible splits depending on the architecture and infrastructure availability. While higher splits are preferred for rural deployment, lower splits will be the best option for  
Figure 3: Application of optical transceivers from Intel Silicon Photonics in various 5G networks [42]. crowded metropolitan areas. Lower-level splits must use almost perfect fronthauls (FHs), but higher-level splits can use less-than-ideal FHs [43]. By utilizing various software implementations, Parallel Wireless' dynamic approach will allow mobile operators to select any RAN splits based on the same hardware and network components. If network conditions change, these splits will also be upgradeable via software. Depending on FH availability and system architecture, different protocol layers will sit in various components. For mobile operators, this strategy will significantly lower their entire total cost of ownership (TCO). The decision about how to divide NR functions in the architecture is influenced by several radio network deployment scenarios, constraints, and desired supported use case variables. A variety of transport networks range from perfect to suboptimal in terms of performance [44]. Mobile operators want the freedom to select various splits based on identical hardware, which is a standard product that currently exists and is readily available from commercial sources, as well as network components by employing various software implementations. Depending on fronthaul availability and deployment scenarios, different protocol layers will reside in different components. For mobile operators, this strategy will result in lower TCO and operational costs. In densely populated metropolitan regions, higher functional splits are preferable for capacity use cases, whereas lower functional divides will be the best choices for coverage use cases. Therefore, while less-than-ideal fronthaul is used for smaller functional splits, fronthaul performance is more crucial for higher functional splits. Due to the increasing scale of 5G, a more effective interface is needed between the BBU and the RRH. This is a critical factor when industry groups are considering new network architectures [38]. The fundamental question is how much processing power should be allocated to the BBU versus RRH. The use case determines the answer. To provide the required speed, latency, and throughput, a network design can be customized to specific use cases and needs using configurable splits. Option 7 (xRAN 7-2x) also reduces the impact of changes to 3 GPP specifications on the RRH, which is another advantage.