What you’ll learn:
- The trend toward open RANs will broadly increase interoperability between equipment from disparate suppliers.
- Open RAN development is spearheaded by the O-RAN Alliance.
- U.S. DoD and NIST are looking into leveraging open RAN for military and government networks.
Radio technologies continue to evolve and add diverse radio formats to an ever-crowded operating environment. Although many frequencies and radio configurations may be incompatible, the open radio-access network (O-RAN) is an attempt to enable the U.S. Department of Defense (DoD) and other users to mix and match components and radio systems from different suppliers to enable a wide range of radio hardware and software to be interoperable.
By establishing an O-RAN ecosystem, the use of emerging technologies such as artificial intelligence (AI) and machine learning (ML) can provide increased efficiency and flexibility to modern radio systems. It will also support communications across commercial and military systems, including 5G cellular wireless radios.
As cellular wireless technology has evolved, starting with early work by Motorola and the development of the Advanced Mobile Phone System (AMPS) by Bell Laboratories, it has extended from 3G and 4G to the current 5G. Maintaining compatibility among hardware and software in any one generation is a chore, let alone among multiple generations in use at the same time.
Early RANs have developed into a central RAN (C-RAN) architecture capable of taking more equipment and software into service. There's dedicated support for in-building wireless communications and high-speed, low-loss, fiber-optic links.
O-RAN Cuts Cost Without Performance Degradation
O-RAN extends the range of usable hardware and software further, promoting lower latency, lower equipment costs, and higher system performance. O-RANs enable carriers to use cost-effectively disparate components with minimal tradeoffs in performance.
Development of O-RAN specifications for compatibility of hardware and software includes secure access and control of data to minimize network cybersecurity concerns. Aided by O-RAN methods, integration of indoor and outdoor cellular networks will be simplified and less expensive for installers and network operators.
5G incorporates equipment from many earlier wireless cellular generations and many cell configurations, such as small and large cells and indoor and outdoor cells at different frequencies. Thus, requirements for 5G O-RAN can define neutral hosting of multiple wireless cellular access types, including distributed-antenna-system (DAS) cells, small cells, and macro cells.
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The O-RAN architecture is being developed by the O-RAN Alliance, a worldwide association of mobile network operators, manufacturers, designers, and researchers working to redefine RAN methodologies for O-RAN and 5G.
One goal for the group is to support the development of hardware and software that will operate seamlessly and securely in a 5G wireless cellular network and beyond, to 6G wireless cellular networks. Some commonality exists for 5G network components: antennas and radio-unit (RU) software are usually from the same manufacturer, while the distribution unit (DU) and centralized unit (CU) may be from another company.
Communication and Synchronization Among Network Functions
By breaking the O-RAN into multiple network functions, such as a RU, DU, and CU, those functions can be clearly defined for development by multiple vendors. Communication among the network segments is essential for reliable operation and requires well-defined communications interfaces, with requirements and specifications available to multiple vendors for development on an open computing platform or open cloud.
To maintain timing and synchronization among the multiple network segments, the O-RAN Alliance sets exacting time and frequency synchronization standards for O-RAN 5G equipment vendors. To better understand the special test requirements for O-RAN equipment and systems, Keysight Technologies offers a comprehensive eBook on its website.
Building upon a $14 billion, five-year O-RAN agreement with AT&T in 2023, Ericsson recently signed a 5G upgrade contract with MasOrange, Spain’s largest telecommunications operator, to upgrade its network with O-RAN technologies. MasOrange was formed by the merger of the Spanish part of France’s Orange company and the telecommunications company MasMovil. It's one example of the wireless telecommunications industry embracing O-RAN technology as it hopes to improve performance and value as the number of wireless cellular customers ramps up.
Cisco, one of the pioneers in O-RAN technology for wireless cellular networks as part of the O-RAN Alliance, has developed computing and switching equipment to assist with multivendor equipment interoperability in cellular networks. The company's Nexus 9000 Series switches provide the hardware and software support capabilities aided by AI and ML technologies to enable O-RAN operation with minimal latency and congestion.
These compact switches provide high performance with excellent power efficiency and can be adapted for high cybersecurity visibility in the most critical security situations. For example, the Cisco Nexus 93180YC-FX3 fits into a single rack-mount unit (see figure) that supports 3.6-Tb/s bandwidth. It provides 48 downlink ports at switching speeds to 25 Gb/s, and uplink ports can be configured as 40- or 100-Gb/s Ethernet channels.
Optical telecommunication equipment developers such as Corning Optical Communications are also contributing to the progress of 5G O-RAN technology by providing the high-speed, wide-bandwidth links for transferring data, video, and voice within buildings and wireless base stations.
The firm’s success in achieving optimal 5G O-RAN solutions involves a balanced approach to employing 5G O-RAN gear with existing systems, such as centralized RAN (CRAN) equipment. Its expectation is that O-RAN will provide the basis for 6G cellular wireless networks and beyond.
U.S. DoD Evaluating O-RAN for Command and Control
While O-RAN makes the interaction of many different components and systems possible for 5G and beyond, it's not just for civilians. The U.S. Department of Defense (DoD) recently contracted Hughes Network Systems LLC, a subsidiary of 5G innovator EchoStar, for $6,514,697.51 to develop an O-RAN prototype at Fort Bliss, Texas.
The prototype equipment will be used in a temporary network for evaluation and then serve as part of Hughes’ commercial wireless network supporting the DoD and commercial customers around Fort Bliss. The project will offer the U.S. Army and DoD the opportunity to explore the real-time command and control capabilities of an O-RAN system, and for the Army to size up O-RAN as a component for the Army Unified Network.
To keep pace, the U.S. Navy recently contacted BAE Systems concerning the use of O-RAN technology in its Network Technical Common Data Link (NTCDL) systems. These systems enable simultaneous transmission and reception of real-time intelligence, surveillance, and reconnaissance (ISR) data.
Within the U.S. government, NIST is conducting research on O-RAN with the intent on developing effective networking strategies for optimizing multi-vendor devices. The strategies must ensure the highest security while promoting interoperability in collaboration with the O-RAN community.
NIST researchers are applying ML algorithms to simulate a wide range of operating conditions that must be handled by O-RAN systems. The experimentation is meant to aid both commercial and government stakeholders, using NIST's O-RAN testbeds to evaluate different setups.
In mid-2024, in collaboration with NIST’s National Cybersecurity Center of Excellence, the organization’s Wireless Networks Division hosted an interim meeting of the O-RAN Alliance’s Security Working Group. These attendees brought concerns about the cybersecurity of O-RAN systems. While focused on 5G, consideration was given to emerging 6G designs and how AI and ML could be applied for heightened O-RAN security.
