Ericsson and SK Telekom recently completed a trial of something called Elastic Cell technology, which allows for a device to connect to a number of cell sites at once, as opposed to just one. While 5G remains an undefined technology, it’s solutions like Elastic Cell and various others that will ultimately lead to the next evolution of the network.
Joakim Sorelius, head of services and infrastructure within LTE at Ericsson, explained that as it stands, a smartphone only connects to one base station and then hands over to another when the signal gets weak, which can lead to peaks and valleys in connectivity.
“What elastic means, from a UE [User Equipment] perspective, what it perceives is a cell that adapts its shape depending on where it’s located, because it’s connected to several base stations,” Sorelius said in an interview with Wireless Week.
So what are the benefits of this kind of solution? Put plainly, Elastic Cell, also called Flexible Cell, could mean more seamless data transmission by mitigating degradation that can occur when the handset moves across cell boundaries, something that could become more important as we move to networks composed of thousands of small cells.
Sorelius said that it’s technology that has been around for some time, and in places like Korea they could get the same effect by assigning the same cell ID to a number of neighboring base stations and then have all those cells transmit the same information at once. But there are problems with that method.
“Unfortunately, the drawback of that is that you lose capacity,” Sorelius explained, noting that the result is a division of your capacity by the number of cell sites with the same cell ID.
That said, Sorelius points to new techniques from 3GPP that help mitigate that effect, including User Specific Reference Symbols which allow the UE to measure several sites simultaneously and tell the network which ones it should transmit on in order to reduce interference.
SK Telecom and Ericsson claim that their trial proves that Elastic Cell technology can improve data transfer rates by up to 50 percent at the cell boundary areas compared to existing LTE networks. SK Telecom said it aims to commercialize the technology by 2016.
Sorelius says that perhaps the biggest obstacle in driving Elastic Cell is to get the other parts of the ecosystem on board.
“Everything that the carriers need in terms of hardware in the networks is already there,” he said. “What’s needed now is the chipsets and devices and for those to become available. So the infrastructure is there and carriers like Verizon and Sprint and AT&T are prepared for these types of features already.”