With the advent of the 5G era, the network is evolving in the direction of openness. Mobile network operators (Mnos) and communications service providers (CSPS) are looking for solutions that will reduce costs and speed up deployment to meet demanding network coverage and capacity targets in the coming years. This makes it a challenge for cellular providers to balance cost and performance in providing 4G, 5G, dual-mode, acer stations, and small indoor and outdoor base stations. As a result, equipment vendors are turning to chip vendors for chip solutions that offer implementation flexibility, low cost, low power consumption, and support such as Open Access Network (RAN) and industry standard interfaces.
5G RAN and distributed networks
Over the past 3-4 years, open wireless access networks have become a hot topic of widespread discussion among industry groups and government departments, as they provide diverse solutions to the cellular supply chain and allow new players to compete with the increasingly concentrated incumbent players. The cost pressures of operators, the need for network security, and the expectation of diversified equipment suppliers are driving equipment vendors to seek solutions that meet both stringent requirements and best practices.
In addition to the interface between the core network and RAN devices defined by 3GPP, and the FAPI interface between the MAC and PHY defined by the Small Cell Forum (SCF), Carrier-led organizations such as the O-RAN Alliance have also been working on the development and integration of an open prepass interface standard for distributed networks. This split architecture of RAN, consisting of central units (CU), distributed units (DU), and wireless units (RU), enables RAN devices from multiple vendors to interconnect, reducing costs by introducing industry competition. This architecture also provides additional network expansion capabilities to meet operators' needs for increased capacity and coverage.
Disaggregated networks isa concept that was developed in the LTE (4G) era, and it uses cloud aggregated RAN as a way to break down networks, and it's becoming more prevalent, Some of this RAN processing can be offloaded onto off-the-shelf Commercial off-the-shelf (COTS) servers or x86-processor-based servers and then connected to low-cost wireless units via standardized interfaces. CPRI interfaces are used between ultra-low cost wireless units and baseband units (Bbus); However, there is a lot of proprietary content in the CPRI interface, which needs to be standardized to achieve the diversification of equipment suppliers.
Another factor in the adoption of a forward or backpass infrastructure architecture is that enterprise private network development and new deployment networks can benefit from fiber investments between the core network, baseband and wireless devices. This enables high transmission bandwidth and low latency forward connections between DU and RU, allows more RAN processing in DU, and makes RU simpler. For copper cable situations where the prepass infrastructure is "not ideal", a better deployment would be to use a fully integrated RAN or a split 2 or split 6 architecture that gives more processing power to the wireless unit.
In different application scenarios, the RAN architecture and specifications play a role in a variety of deployment use cases, including:
● Large outdoor base stations providing wide-area network coverage: large-scale multiinput multioutput (mMIMO) mode with up to 64 antennas is often used to provide highly energy efficient directional beam.
● Low-band outdoor microcell base stations: Solutions that provide coverage up to 4T4R or 8T8R with high energy efficiency requirements.
● Wireless units for indoor enterprise-class applications: Transmission power is severely limited by the need for Power over Ethernet (PoE) and the use of radiators only when mounted on walls or ceilings.
● Wireless units of neutral network service providers: with multi-carrier solutions, the bandwidth needs to be 2-3 times wider than 100MHz FR1.
● Solutions that serve diverse spectrum: As the global spectrum diversity of 5G NR is more significant than LTE, there are many challenges to channel band, bandwidth and carrier aggregation. This has led to many customer-specific RF front-end designs and flexible baseband solutions, and customers are looking to chip manufacturers for chip designs that support such solutions.
● Low time and late application: Edge servers, such as video on demand, are needed for maximum performance and efficiency.
● Dual-mode 5G/LTE wireless units, Non-Standalone Access (NSA), and applications that support spectrum refarming: require both 5G and LTE support within the same wireless unit, or the ability to switch flexibly through software upgrades to minimize the carrier's Bill of Materials (BOM) costs.
5G brings challenges, open RAN offers solutions
The new 5G network poses numerous challenges for equipment vendors.
First, due to environmental protection policy restrictions and economic considerations of electricity costs, operators must ensure that the 5G infrastructure deployed is a low-power solution that can meet sustainability goals, which is crucial for the implementation and successful deployment of 5G. In addition, the wireless unit needs to operate without active heat dissipation, and in many cases needs to operate within PoE power limits.
Second, the next generation of open interfaces defined by 3GPP, the O-RAN Consortium, and SCF, such as the Open prequel of the O-RAN Consortium, are in the process of further optimizing and developing the standard.Existing mature and optimized system-on-a-chip (SoC) systems, even if they include interfaces such as eCPRI, need to be scalable to support standards for further evolution.
Third, the needs of different types of customers, such as carriers, private ISPs and neutral third party network providers, require flexible RAN to meet diverse spectrum requirements and carrier bandwidth, but existing first-generation solutions are not ideal, The root cause is that such solutions are often based on expensive and power-hungry implementations of servers, accelerator cards, and field programmable logic gate arrays (FPGas).
While 5G standards such as Open RAN are not a panacea, they can (and do) address some of these challenges and provide 5G equipment vendors and operators with a faster, more cost-effective path to market for their devices/services. Operators are aiming for lower material (BOM) costs and looking to optimize chip solutions to enable batch deployment. In ecosystems such as Open RAN, the diversity of device vendors will increase competition and thus reduce costs. Chip vendors such as Bikocki have developed high performance baseband SoC products and product roadmaps to reduce system power consumption. The Digital Pre-Distortion (DPD) algorithm in hardened baseband /RFIC helps to improve RF power efficiency. Equipment vendors, carriers, and organizations such as the O-RAN Consortium and the Telecommunications Infrastructure Project (TIP) have set up open RAN LABS that are constantly testing interoperability of open RAN interfaces.
Conclusion
The network of the future must be based on open, flexible, optimized, and interoperable chips, with a diverse ecosystem of industry leaders. In order to compete, challenger Open RAN equipment vendors need access to chips that support 5G standards such as Open RAN and that they can buy on the open market to compete with traditional vendors. The PC802 is the industry's first PHY SoC designed specifically for a distributed and integrated RAN architecture for small 5G NR/LTE base stations; With the PC802 SoC, Bikocki is able to compete in the Open RAN equipment market through new entrants and challengers among enabling equipment manufacturers and contribute to the development of new 5G standards such as Open RAN.
