Sprint has sued AT&T, alleging the wireless carrier falsely and deceptively brands its 4G network as 5G technology. What is 5G? 5G is a wireless network technology that promises super-fast speeds and other benefits. The “G” stands for “generation,” so “5G” is the fifth generation of wireless technology. Most wireless connections today still use fourth-generation tech, or “4G.” Does 5G exist yet? Yes. AT&T\n \n (T), which owns CNN parent company WarnerMedia, launched the United States’ first 5G network in December. Access is extremely limited. AT&T’s network is up and running in parts of 12 cities. Customers can only access the network with a particular hotspot, which went on sale in December on an invitation-only basis. AT&T’s competitors have not yet launched their 5G networks for customers. Although Verizon sells a home broadband product that it brands “5G Home,” that product does not use the accepted 5G standards. If AT&T has 5G, why did it upset Sprint? Building out a 5G network takes years. To complement 5G, AT&T has upgraded its 4G network with a fourth-generation technology called LTE-Advanced. Verizon\n \n (VZ), Sprint and T-Mobile have already deployed LTE-Advanced across much of their networks. It offers theoretical speeds of up to twice as fast as older 4G network technologies. Rival carriers label LTE-Advanced networks as “4G.” But AT&T calls its LTE-Advanced network “5G evolution.” It updated its phones’ software last month to display a “5GE” indicator when its phones access LTE-Advanced. “We introduced 5G Evolution more than two years ago, clearly defining it as an evolutionary step to standards-based 5G,” AT&T said in a statement. “5G Evolution and the 5GE indicator simply let customers know when their device is in an area where speeds up to twice as fast as standard LTE are available.” What is Sprint claiming? In its lawsuit, filed Thursday in a federal court in the Southern District of New York, Sprint\n \n (S) said AT&T is cheating. “AT&T … has sought to gain an unfair advantage in the race to 5G by embarking on a nationwide advertising campaign to deceive consumers into believing that its existing 4G LTE Advanced network is now a 5G network,” Sprint said in its lawsuit. “This technology is indisputably not 5G. Adding an ‘E’ or the word ‘Evolution’ to 5G does not mitigate the deception.” Sprint claims AT&T’s branding violates federal and state laws governing false advertising. It wants a judge to prevent AT&T from branding its LTE-Advanced network as “5GE.” “The reality is that this network isn’t ‘new’ and ‘5G E’ is a false and misleading term,” a Sprint spokeswoman said in a statement. Who determines what 5G is? Telecommunications companies around the world send representatives to meetings held by wireless network technology standards-setting bodies. They agree on a universal standard so people’s phones can make calls and access the internet no matter where they travel. The first standards-setting body is called the Third Generation Partnership Project, which defines how the network technology works. The second standards-setting body, the United Nations’ International Telecommunication Union, sets objectives for the network, including how fast it must be. Has this branding dispute happened before? Yes. The industry goes through the same motions every time a new network technology launches. For example, in 2010, T-Mobile\n \n (TMUS) and AT&T updated their 3G networks and branded them “4G.” Verizon launched the country’s first standards-based 4G network later that year.