The Emergence of Private 5G Networks
Private 5G networks are emerging to address critical requirements in public safety, industrial automation, and infrastructure. These non-public wireless networks will give enterprise, private venue, and government users the infrastructure to optimize and redefine processes that are not possible with the limitations of today's Ethernet, 4G LTE, and Wi-Fi networks. This article details the advantages and complexities of setting up private 5G networks.
5G Primer
5G is the next generation of cellular telecommunications. In many ways, it has already extended the use cases and viability of cellular telecommunications far beyond that of the earlier generations. Where earlier cellular systems were predominantly seen as a way for one cell phone user to communicate with another via text or voice, 5G has been designed with the understanding that this is only one of the few, and possibly not even the most significant, forms of telecommunication to support.
Three Main 5G Use Cases/Modes
With 4G LTE, image and video messaging/streaming and general internet communications quickly became the highest data rate uses of the service. With 5G, the data traffic of these forms is predicted to be many magnitudes greater. Moreover, there is a general demand for faster, more reliable, and more responsive data services for mobile user devices. These parameters are the main attributes of one of the three prominent 5G use cases (Figure 1), enhanced mobile broadband (eMMB). The backbone of eMMB is generally to offer high data rates, more responsive access to high-speed data, and the ability to simultaneously service hundreds of users, even in areas outside of heavily trafficked metropolitan centers.
Ultra-reliable and low-latency communication (URLLC) is another key use case for 5G. This 5G mode is designed to offer extremely low-latency response to better facilitate uses where latency is undesirable or simply dangerous, such as with autonomous machines, vehicle-to-vehicle (V2V), and vehicle-to-infrastructure (V2I) communications. Another aspect of URLLC 5G is the expectation for reliability, not simply from a human user perspective but also from a machine perspective. The goal here is cable-like reliability and determinism from a wireless communication service.
Lastly, one of the most significant potential uses for 5G in private installations is massive machine-type communication (mMTC). With mMTC 5G, the idea is that machines will be intercommunicating a variety of data payloads with various requirements, and that 5G should support this myriad of communication styles. This use case of 5G is designed to enable machines to effectively communicate without relying on a centralized infrastructure, which may require peer-to-peer (P2P) and even mesh networking capabilities.
Figure 1: A variety of example 5G use cases. (Source: leremy/stock.adobe.com)
Homogenous vs. Heterogeneous 5G Deployments
A homogeneous "cell" typology was chosen for previous generations of cellular communications. With 4G LTE this changed to accommodate high use areas, and heterogeneous networks in urban environments began to emerge. With 5G, the mix of heterogeneous network styles is only increasing, with macro, micro, nano, pico, and even femto cells, all potentially with their own variety of services. The rise of this diversity of wireless access has spawned from the diverse needs of a greater mix of spaces, such as offices, stadiums, private venues, transportation hubs, and college/business campuses.
The typical homogeneous cell approach isn't viable for the needs of these emerging spaces, and telecommunication service providers (telcos) aren't necessarily able to install cellular service in these areas as many of them are privately owned and operated. Hence, public cellular telecommunication systems do not serve many of these private spaces, such as shopping centers, office complexes, manufacturing/warehouse facilities, and industrial environments (agriculture, oil/gas, construction, and mining).
Limitations of Wi-Fi, Ethernet, and 4G LTE
Many existing communication solutions may not fulfill all the legacy and emerging requirements of private spaces. For instance, ethernet services are only able to serve physically connected systems. While Wi-Fi is certainly more mobile, and the most recent generation of Wi-Fi devices (Wi-Fi 6e) has enhanced mobility and range features, Wi-Fi still suffers from mobility, latency, and reliability issues.
Moreover, Wi-Fi communications use the ISM bands, which are not licensed and must accept interference from other services, making reliability in critical scenarios possibly untenable. 4G LTE, like previous cellular communications generations, is mainly a device-to-infrastructure communication style and doesn't facilitate peer-to-peer communications. What’s more, the 4G LTE standard isn't built with modes that minimize latency or ensure reliability.
Advantages of Private 5G Networks
Private 5G networks hold all the advantages of public 5G but additional features and benefits that can be implemented depending on the space needs. Though 5G standards, in general, have enhanced security, latency, reliability, bandwidth/spectrum, and mobility features compared to other wireless standards, private networks can be deployed that optimize certain feature aspects coinciding with the goals of the service.
Security
While public 5G networks respond over the public telecommunication network and the internet through a telco and/or ISP, private 5G networks can be configured with additional options or feature prioritization. A private 5G network can be built only to handle encrypted traffic that travels through intranets or internal networks. With additional options to change the modulation type and encryption of 5G wireless signals, a private 5G network can be designed to only operate with approved/provisioned 5G devices. This enables complete internal security by eliminating exposure to public interfaces for operations that may have critical use cases, such as government, industrial, or specific corporate environments. Otherwise, a private 5G network can be carefully monitored to ensure any suspicious activity is quickly identified and prevented. Some private 5G network offerings claim that a network can be real-time cryptographically certified to be 100 percent trusted.
Latency
Where typical 5G networks need to communicate from a user device to the infrastructure, a private 5G network can be configured to communicate to a central server/database that is in the same facility as the private 5G network infrastructure hardware. This can dramatically reduce the latency to the server, and 5G infrastructure hardware placement can be optimized to minimize latency to meet the needs of the applications that require this type of performance. It is possible to achieve sub-millisecond latency in privately managed 5G networks, while 4G LTE and Wi-Fi latencies are typically in the tens of milliseconds, even when privately managed.
Furthermore, if minimizing latency is the goal, there are features within the 5G standards that can be used to reduce communications overhead. These features may not generally be desirable for all 5G use cases, where private 5G customizations can be attractive for certain use cases.
Availability/Reliability
Availability for many private wireless communication installations is a primary goal. With public cellular service or even private Wi-Fi, availability cannot be guaranteed, which is often unacceptable. Many critical applications aren't viable without highly assured availability, as safety and responsiveness to shut-down or new directives can't be guaranteed. This is where 5G URLLC features with the standardized goal of six nines reliability (99.9999%) can provide reliability and uptime assurance previously only achievable with wired communication solutions.
Bandwidth Allocation and Quality of Service (QoS)
Spectrum use and bandwidth allocation often has a high impact on the utility of wireless service. For instance, Wi-Fi relies solely on unlicensed ISM bands in the 2.4 GHz, 5GHz, and 6GHz parts of the spectrum. These bands are intrinsically limited in bandwidth and must share that spectrum with every other service operating within those frequencies. 4G LTE is also limited to sub-6 GHz frequencies, where there is a substantial amount of spectrum congestion and potential for interference.
With 5G New Radio (NR), licensed and unlicensed spectrum is available in the sub-1 GHz, sub-6 GHz, 24 GHz to 29 GHz, and 37 GHz to 43 GHz. Specifically, there can be hundreds of megahertz of available bandwidth in the millimeter-wave (mmWave) or "high" band spectrum. Due to the high directivity and atmospheric losses in the mmWave range, there is also far less interference from common sources and even services that share the same spectrum. Hence, 5G can facilitate more reliable service with other enhanced QoS metrics than private LTE installations.
Mobility & Communication Type Diversity
The wide range of spectrum available for 5G services enables a potential mix of services without the typical trade-offs of wireless services with less spectrum options. For instance, for extremely long-range but relatively low data rates, sub-1 GHz 5G can be used to cover vast areas with limited infrastructure. Also, mmWave 5G can be used to cover shorter ranges but offer much lower latency and much higher throughput services.
The various types of communication supported by 5G, including massive multi-user multi-input multi-output (mMu-MIMO) for both human and machine users, offer the ability to service a high number of users that can also be highly mobile or stationary. Moreover, the latest 5G standards also support machine-type communications (low data rate and low duty cycle) through high data rate and responsive services needed to support cloud-based services, such as augmented reality and virtual reality (AR/VR) training or troubleshooting.
Setting Up a Non-public 5G Network
There are no one-size-fits-all private 5G network solutions. The type of 5G hardware and configurations will ultimately depend on the planned uses and requirements of the 5G network. Fortunately, as private 5G installations continue to grow, 5G hardware solution providers and private network installers continue to expand their offerings and capabilities. A few general guidelines can aid with a private 5G installation, namely network architecture considerations, how to host control-plane functions, and how to host user-plane functions.
When setting up a private 5G network, installing the network as part of a private IP network will likely be most desirable. In this way, a private 5G network can be part of a private VPN supported by the typical routers and switches that would typically be used. This is much the same as incorporating a typical IoT network, though a 5G network may need a greater emphasis on lower latency and high-available hardware.
For most installations, it is likely best to host 5G RAN and O-RAN control-plane elements as close to the 5G cells as possible, ideally concentrated to where the highest demand 5G features will be required. This requires host servers, middleware, and software to support these functions and would ideally be conformal for ease of monitoring, maintenance, and future retrofitting. Similarly, 5G core user-plane functions can also be hosted on servers at least co-located with the 5G RAN control-plane features. In some cases, both user-/control-plane features can share the save servers. If other traffic types also need to be serviced, white boxes can be used to host the user-plane functions. For 5G core user-plane functions, these should be hosted on white boxes if these functions will support a high volume of traffic, as the additional capacity may be beneficial and allow for higher availability and lower latency for these services.
In the end, 5G radio transceivers will be needed to wirelessly connect the 5G infrastructure to 5G users or IoT devices (Figure 2). Designing 5G RF hardware from scratch is an expensive and time-consuming endeavor and requires a broad mix of engineering talent and facilities. For designing and deploying private 5G systems, some software customization may be required, but fortunately, there are 5G transceiver hardware platforms, with common high-speed digital interfaces that can readily be integrated with O-RAN wireless solutions (Figure 3). An example of such a 5G prototype platform is the ADI ADRV9026 evaluation board with either the ADRV9026-HB/PCBZ or ADRV9026-MB/PCBZ radio cards. This radio cards for this board provide a 4x4 transceiver platform for rapid device evaluation and development.
(Figure 2) Complete5G transceiver signal chain. (Image Source: Analog Devices)
(Figure 3) 5G prototype platform with re-bandable RF front-end. (Image Source: Analog Devices)
Conclusion
This is the dawn of 5G private networks for enterprise, government, and industrial applications. Beyond what previous wireless communication technologies can provide, private 5G can enable the most secure, lowest latency, highest availability, and most diverse wireless service.