AT&T is adding three markets to its ongoing 5G technology trials, with plans to cover portions of Waco, Texas; Kalamazoo, Michigan; and South Bend, Indiana, with the latest in wireless technology by the end of the year.
As part of the trials, AT&T plans to test fixed and mobile wireless services using virtualization technologies and millimeter wave (mmWave) spectrum. Participants may include universities, hospitals, churches, restaurants, and small businesses. Among other services, AT&T will test streaming of video content from its DirecTV Now platform using a 5G connection.
Ericsson is providing radios designed to work with mmWave spectrum, a virtualized radio access network (vRAN), and a 5G virtualized core. Samsung is delivering a 5G router, virtualized core, and vRAN for its part in the trial in South Bend.
The carrier is also working on the role of software-defined networking (SDN) in controlling network assets, previously noting it plans to “experiment with new virtualized-RAN core network capabilities later this year.”
Virtualizing the RAN is the process of separating functions from a traditional remote radio unit or base station to run them as virtualized network functions (VNFs) on commodity hardware. The move is designed to reduce operating costs and increase performance and scalability as operators move toward 5G.
“The beauty of SDN capability is I can have a common hardware in different locations and can spin up capacity in different locations,” Mansfield explained. “Today you have dedicated hardware and changing gears is not something you can do overnight.”
A report earlier this year from Mobile Experts found that full virtualization of the RAN is working, “but there are some technical limitations in energy consumption and other factors that limit its adoption to major equipment manufacturers and operators.”
The expanded trial builds on AT&T’s work in Austin, Texas, where in June it launched a test of streaming video content over mmWave spectrum. The trial used Ericsson’s 5G RAN and Intel’s 5G Mobile Trial Platform.
Network performance showed speeds up to 1 Gb/s and latency under 10 milliseconds.
The Austin trial provided insight into the coverage characteristics of mmWave spectrum. This included performance impacted by foliage, building materials, device placement, surrounding environment, and weather impact on the signal and system in a real-world environment.
Millimeter wave spectrum is typically viewed as those airwaves operating above 6 GHz. Higher spectrum bands don’t travel as far and are impacted more by obstacles than lower spectrum bands. This is often referred to as poorer propagation characteristics.
To accommodate propagation weaknesses, AT&T has built multiple sites so that when one site is impacted, the traffic will be redirected to another site. This type of redundancy is important in real-world scenarios using mmWave spectrum.
“Nothing has really surprised us,” Mansfield said of the current trials. “The whole point of friendly user trials is to learn. And we are learning things as we progress.”
AT&T remains on track to deploy standards-based 5G services by late next year.
LTE networks already deployed by carriers use spectrum bands lower than 3 GHz, thus operators are using mmWave trials to gain insight into the different performance characteristics of the higher bands in commercial settings.
Current plans for 5G networks include a growing use of mmWave spectrum bands, highlighted by recent bidding wars between carriers over companies that control those assets.
Research firm SNS estimates that 5G-based fixed wireless access deployments will generate $1 billion in revenue in 2019, and account for more than $40 billion in revenue between 2019 and 2025. The analyst firm singled out the 5G fixed wireless deployments by U.S. operators AT&T and Verizon as being a boon for both service providers and equipment makers.
According to SNS, the 28 GHz band of spectrum is preferred for these early 5G-based fixed wireless deployments and many vendors are already developing 28 GHz equipment.