When Sprint launches its 5G New Radio network — as it is expected to do this week — it will be unique in a number of ways. The mobile network operator has laid out plans for an ambitious footprint at launch in four cities: Atlanta, Georgia; Chicago, Illinois; Dallas, Texas; and Kansas City. Five additional markets will go live shortly afterward. In several markets, the carrier expects to have a more than 100 square miles of coverage right away, as it leverages its vast spectrum holdings at 2.5 GHz and split-mode capabilities of massive MIMO (multiple-input multiple-output) equipment to support both LTE and 5G NR simultaneously.
Another characteristic that will make Sprint’s 5G NR network a world-first will be the use of 5G/LTE dual-connectivity, according to Ryan Sullivan, Sprint’s VP of product engineering and development, who is responsible for launching all of the company’s connected devices, including 5G.
What is ENDC?
So what is ENDC? ENDC stands for E-UTRAN New Radio – Dual Connectivity, in standards parlance. According to 3GPP standards documents, ENDC allows user equipment to connect to an LTE enodeB that acts as a master node and a 5G gnodeB that acts as a secondary node. For Sprint, ENDC will allow devices to access both LTE and 5G simultaneously on the same spectrum band: Band 41/2.5 GHz.
“We are the only ones who in the world at initial launch that are going to launch LTE and 5G simultaneously on the same band and have the dual-connectivity path,” said Sullivan. Other operators, he noted, will have an anchor LTE band in one band of spectrum, with 5G NR operating in a different band to boost speed when available. As Sprint’s 5G deployment (like most planned 5G deployments at this point) is the Nonstandalone 5G NR implementation, the control plane traffic will still be carried via LTE and the LTE core.
What are some advantages of ENDC for Sprint?
With ENDC, Sullivan said, “there is less ping-ponging for the device” because it is connected via both LTE and 5G in the same spectrum.
“The handovers are much smoother. … You’re able to hold a connection much more elegantly,” Sullivan said. This is particularly important for Sprint’s plans for a large 5G footprint that allows mobility. Its 5G launch will not just be about the achievable peak speeds, Sullivan said, but being able to get in a vehicle or move around a geographic cluster with a 5G-enabled device and maintain a 5G connection.
Sullivan also described the use of both LTE and 5G as “cumulative for performance,” because it’s not just relying on one or the other technologies, but both added together and operating in the same wide swath of up to 120 megahertz of spectrum (60 megahertz dedicated to LTE and another 60 for 5G NR). Combined with capacity enhancements from the deployment of massive MIMO, Sullivan said, Sprint is aiming to lay claim to its 5G network launch as the first “real” mobile 5G network.