Telefónica and Huawei trial “cell-less” 5G RAN concept

Features

Telefónica and Huawei have developed a new proof-of-concept for a 5G radio access network (RAN) that transfers the logistics of cellular handover from the mobile device to the network.

The technology, called UCNC (user centric and no cell), will minimise potential disruption to 5G services, compared with current mobility management techniques, and enable operators to more reliable and efficient 5G services, according to Telefónica.

In lab trials, the pair claimed to have been able to increase the number of connections per cell by 233 percent, reduce “signalling overheads” by 78 percent and decrease latency by 95 percent, compared with latest versions of LTE.

To connect to the network, devices currently take a positional reading, and issue it to the network. The network then provides a temporary identifier, which is pegged to the nearest cell site, and the device opens a broadcast channel.

As the device roams about, it is required to continually prompt the network for a new identifier, and a new cell site, by issuing positional data. This way, the network can handoff the call or data session.

With UCNC, Huawei and Telefónica propose that each device gets a permanent identifier, which the network is required to constantly monitor. This way, the network does the work to define the position and movement of the device, and make the best broadcast channels available to it.

“In terms of the radio infrastructure, it is very similar; it just means we don’t need the concept of cells, as they exist right now,” said Ignacio Berberana, RAN Innovation Manager at Telefónica.

“But UCNC provides a better way to handle mobility, which is more suited to 5G – better energy consumption, better coverage, a higher number per cell, all of which might reduce the number of radio ports that have to be deployed and therefore the cost of infrastructure.”

The introduction of beam-forming techniques with 5G technologies, and the hyper density of 5G networks, will make the concept of “cell borders” more difficult, said Berberana. 

“We believe a UCNC model is better for 5G. If we continue to handle mobility in the conventional way, we will have a lot of handover because the cells are so close together,” he said, suggesting potential disruption to services as devices prompt networks to switch cell sites continually.

Telefónica has a job to get the technology on the industry radar, admitted Berberana. “Very few people are designing 5G infrastructure in this way. It is a fundamental change to the way we manage mobility, where certain very important functionalities in the network would be handled in a completely different way,” he said.

Even so, Telefónica and Huawei reckon there are significant advantages for infrastructure roll out. Berberana explained: “It may require more complex processing, but, if anything, infrastructure costs should come down because of the coverage and capacity advantages the technology affords, which require us to deploy fewer cell sites.”

He also suggested manufacturers stand to benefit as UCNC would offload some complexity from devices onto the network. “That’s definitely one of the potential upsides,” he said.

Telefónica and Huawei are looking to establish the technology on the 3GPP’s agenda for 5G. But Berberana warned the industry must resolve whether to take the easy road, and work with what it knows, or use the advent of 5G to bring about more efficient network practices.

“On the one hand, we want to be able to use all of the LTE infrastructure we are deploying right now, and which we have a long way to go with still, to be compatible with 5G. On the other, we don’t want to preclude making significant improvements to previous technologies – because we were too conservative in the standardisation process. We need to keep all our options open.”