U.K.-based telecommunications operator BT partnered with mobile operators EE and Three to trial a cloud radio access network (C-RAN) 5G service in Leeds, England.

The trial is currently limited to three units covering part of the town’s city center, with plans to add three more units “in the coming months.” BT’s Wholesale unit deployed the equipment and is using the trial to track the infrastructure’s performance characteristics.

U.K. operators EE, which is owned by BT, and Three, which is owned by CK Hutchison Holdings, are running mobile 5G services on the C-RAN network equipment.

A cloud RAN architecture uses a centralized baseband unit (BBU) pool, remote radio units (RRUs), and a transport network between the two. The BBU is the brains of the outfit where all of the processing is accomplished. The RRUs are the actual radio transmitting units that send out the signal as told to it by the BBU. The transport part is the connection between the two and is analogous to a fronthaul connection in a more traditional network deployment.

This deployment architecture can lead to lower the total cost of ownership as BBU resources can be shared; can improve low-latency network performance by allowing for more easily deployed radio units closer to an end-user application; and allow for centralized management of RAN resources.

However C-RAN deployments can use proprietary equipment that makes it different from the open RAN architecture that allows for interchangeable equipment and software pieces.

BT earlier this year worked with Nokia on a series of 5G standalone (SA) network trials that aggregated four separate spectrum channels into a single transmission channel. The initial four-carrier channel aggregation (4CCA) trial was conducted at BT’s Radio Lab in Bristol. The companies then conducted a similar trial using a BT-owned cell tower in a park in Suffolk.

BT also tapped Ericsson to provide 5G network equipment and to replace previous vendor Huawei. That equipment included Ericsson’s dual-mode 5G core platform, which includes its evolved packet core (EPC) and 5G core products.