China Unicom and Nokia have partnered on a cooperative 4G and 5G network running on a cloud-based radio access network (cRAN) in the newly created “mega city” of Xiongan, China. The network, which the vendors have dubbed the “world’s largest field trial,” will target use cases for 5G and demonstrate how networks can separate software and hardware to more rapidly deploy 5G.
The companies claim this is the first network with 4G and 5G running on the same cloud infrastructure. It’s using 10 4G base stations and 50 5G base stations, and architecture split between central units and distributed units. They plan on verifying 4G/5G cRAN technologies and to share results with industry groups to advance the foundation for 5G deployments.
“There are multiple technology shifts taking place in the RAN,” noted Stefan Pongratz, senior director of mobile RAN research at Dell’Oro Group, in response to questions. Network operators are moving from dedicated baseband equipment to compute resources that exist in different locations with the aid of cRAN architectures, he explained.
“Distributed RAN architecture remains dominant for LTE deployments, however with 5G the compute resources are expected to gradually start to show up in various places and future RAN deployments will gradually move away from the concept of using regular baseband equipment,” Pongratz added.
Operators Seek Co-Located RAN Functions
Centralized and cloud-based RAN are both expected to play a greater role in 5G because the technology improves efficiencies, scale, and coordination capabilities by placing computing resources in a central location or in the cloud, Pongratz explained. “We anticipate operators will approach the shift toward [both technologies] methodically, which will mean that the migration from LTE to the new 5G architecture will take time and likely evolve gradually.”
As network operators transition to 5G, most will opt to colocate core functions on distributed units and central units. “As operators embark on their journey toward virtualization, the next most logical step will be to place some of the non-critical function at the central unit,” Pongratz wrote. “Operators ultimately want to reach a point where they can deploy software from a wide ecosystem on standard GPP-based hardware, not just for the [central unit] but also for the [distributed unit].”
Dell’Oro Group predicts distributed units will continue to outnumber central units in 5G New Radio baseband architecture by at least double through 2023.
In Xiongan, China Unicom and Nokia want to build a foundation for data analysis, artificial intelligence (AI), and management of 5G air interface resources, including basic network functions. The companies said the test network will also enable further exploration by combining RAN, core network, and multi-access edge computing for 5G.
The test network, which includes two LTE sites running on distributed units, eight LTE sites integrated with 5G sites in non-standalone (NSA) mode, and 40 5G sites running on cRAN distributed units, is based on Nokia’s AirScale cRAN technology. By 2035, China expects Xiongan to house new headquarters for businesses in IT, biotechnology, materials, and agriculture.